[GitHub] [nifi] exceptionfactory commented on a change in pull request #4785: NIFI-8175: Add WindowsEventLogReader controller service

[GitBox <gi...@apache.org>]

exceptionfactory commented on a change in pull request #4785:
URL: https://github.com/apache/nifi/pull/4785#discussion_r565347021



##########
File path: nifi-nar-bundles/nifi-standard-services/nifi-record-serialization-services-bundle/nifi-record-serialization-services/src/main/java/org/apache/nifi/windowsevent/WindowsEventLogReader.java
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@@ -0,0 +1,49 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.nifi.windowsevent;
+
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.controller.AbstractControllerService;
+import org.apache.nifi.logging.ComponentLog;
+import org.apache.nifi.schema.access.SchemaNotFoundException;
+import org.apache.nifi.serialization.MalformedRecordException;
+import org.apache.nifi.serialization.RecordReader;
+import org.apache.nifi.serialization.RecordReaderFactory;
+import org.apache.nifi.serialization.record.RecordFieldType;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Map;
+
+
+@Tags({"xml", "windows", "event", "log", "record", "reader", "parser"})
+@CapabilityDescription("Reads Windows Event Log data as XML content having been generated by ConsumeWindowsEventLog, ParseEvtx, etc. (see Additional Details) and creates Record object(s). If the "
+        + "root tag of the input XML is 'Events', the child content is expected to be a series of 'Event' tags, each of which will constitute a single record. If the root tag is 'Event', the "
+        + "content is expected to be a single 'Event' and thus a single record. No other root tags are valid. Only events of type 'System' are currently supported.")
+public class WindowsEventLogReader extends AbstractControllerService implements RecordReaderFactory {
+
+    private static final String dateFormat = RecordFieldType.DATE.getDefaultFormat();
+    private static final String timeFormat = RecordFieldType.TIME.getDefaultFormat();
+    private static final String timestampFormat = "yyyy-MM-dd'T'18:07:51.SSS"; // The timestamps have nanoseconds but need a SimpleDateFormat string here

Review comment:
       Is there a reason for the specific value of `18:07:51` or should that be changed to `HH:mm:ss`?  Should the variable name be changed to TIMESTAMP_FORMAT to reflect common conventions for static final values?

##########
File path: nifi-nar-bundles/nifi-standard-services/nifi-record-serialization-services-bundle/nifi-record-serialization-services/src/main/java/org/apache/nifi/windowsevent/WindowsEventLogRecordReader.java
##########
@@ -0,0 +1,626 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.nifi.windowsevent;
+
+import org.apache.nifi.logging.ComponentLog;
+import org.apache.nifi.schema.inference.TimeValueInference;
+import org.apache.nifi.serialization.MalformedRecordException;
+import org.apache.nifi.serialization.RecordReader;
+import org.apache.nifi.serialization.SimpleRecordSchema;
+import org.apache.nifi.serialization.record.DataType;
+import org.apache.nifi.serialization.record.MapRecord;
+import org.apache.nifi.serialization.record.Record;
+import org.apache.nifi.serialization.record.RecordField;
+import org.apache.nifi.serialization.record.RecordFieldType;
+import org.apache.nifi.serialization.record.RecordSchema;
+import org.apache.nifi.serialization.record.type.ArrayDataType;
+import org.apache.nifi.serialization.record.type.MapDataType;
+import org.apache.nifi.serialization.record.type.RecordDataType;
+import org.apache.nifi.serialization.record.util.DataTypeUtils;
+import org.apache.nifi.stream.io.NonCloseableInputStream;
+import org.apache.nifi.util.StringUtils;
+import org.apache.nifi.xml.inference.XmlSchemaInference;
+
+import javax.xml.stream.XMLEventReader;
+import javax.xml.stream.XMLInputFactory;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.events.Attribute;
+import javax.xml.stream.events.Characters;
+import javax.xml.stream.events.StartElement;
+import javax.xml.stream.events.XMLEvent;
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.text.DateFormat;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.Supplier;
+
+public class WindowsEventLogRecordReader implements RecordReader {
+
+    private final ComponentLog logger;
+    private final RecordSchema schema;
+    private boolean isArray = false;
+    private XMLEventReader xmlEventReader;
+
+    private StartElement currentRecordStartTag;
+    // Utility used to infer <Data> tag data types
+    private final XmlSchemaInference xmlSchemaInference;
+
+    private final Supplier<DateFormat> LAZY_DATE_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIME_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIMESTAMP_FORMAT;
+
+
+    public WindowsEventLogRecordReader(InputStream in, final String dateFormat, final String timeFormat, final String timestampFormat, ComponentLog logger)
+            throws IOException, MalformedRecordException {
+
+        this.logger = logger;
+
+        final DateFormat df = dateFormat == null ? null : DataTypeUtils.getDateFormat(dateFormat);
+        final DateFormat tf = timeFormat == null ? null : DataTypeUtils.getDateFormat(timeFormat);
+        final DateFormat tsf = timestampFormat == null ? null : DataTypeUtils.getDateFormat(timestampFormat);
+
+        LAZY_DATE_FORMAT = () -> df;
+        LAZY_TIME_FORMAT = () -> tf;
+        LAZY_TIMESTAMP_FORMAT = () -> tsf;
+
+        FilterInputStream inputStream;
+        try {
+            final XMLInputFactory xmlInputFactory = XMLInputFactory.newInstance();
+            // Avoid XXE Vulnerabilities
+            xmlInputFactory.setProperty(XMLInputFactory.SUPPORT_DTD, false);
+            xmlInputFactory.setProperty("javax.xml.stream.isSupportingExternalEntities", false);
+
+            inputStream = new NonCloseableInputStream(in);
+            inputStream.mark(Integer.MAX_VALUE);
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            xmlSchemaInference = new XmlSchemaInference(new TimeValueInference(dateFormat, timeFormat, timestampFormat));
+
+            // Do a streaming pass through the input looking for <Data> tags, then reset the input
+            schema = determineSchema();
+
+            // Restart the XML event stream and advance to the first Event tag
+            inputStream.reset();
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            if (isArray) {
+                skipToNextStartTag();
+            }
+            setNextRecordStartTag();
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);

Review comment:
       Since this error is rather general, would it make sense to break up this try-catch block into smaller chunks?  For example, separating the XML Input Factory and Event Reader creation from the schema determination would allow for a little more specific error reporting.

##########
File path: nifi-nar-bundles/nifi-standard-services/nifi-record-serialization-services-bundle/nifi-record-serialization-services/src/main/java/org/apache/nifi/windowsevent/WindowsEventLogRecordReader.java
##########
@@ -0,0 +1,626 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.nifi.windowsevent;
+
+import org.apache.nifi.logging.ComponentLog;
+import org.apache.nifi.schema.inference.TimeValueInference;
+import org.apache.nifi.serialization.MalformedRecordException;
+import org.apache.nifi.serialization.RecordReader;
+import org.apache.nifi.serialization.SimpleRecordSchema;
+import org.apache.nifi.serialization.record.DataType;
+import org.apache.nifi.serialization.record.MapRecord;
+import org.apache.nifi.serialization.record.Record;
+import org.apache.nifi.serialization.record.RecordField;
+import org.apache.nifi.serialization.record.RecordFieldType;
+import org.apache.nifi.serialization.record.RecordSchema;
+import org.apache.nifi.serialization.record.type.ArrayDataType;
+import org.apache.nifi.serialization.record.type.MapDataType;
+import org.apache.nifi.serialization.record.type.RecordDataType;
+import org.apache.nifi.serialization.record.util.DataTypeUtils;
+import org.apache.nifi.stream.io.NonCloseableInputStream;
+import org.apache.nifi.util.StringUtils;
+import org.apache.nifi.xml.inference.XmlSchemaInference;
+
+import javax.xml.stream.XMLEventReader;
+import javax.xml.stream.XMLInputFactory;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.events.Attribute;
+import javax.xml.stream.events.Characters;
+import javax.xml.stream.events.StartElement;
+import javax.xml.stream.events.XMLEvent;
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.text.DateFormat;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.Supplier;
+
+public class WindowsEventLogRecordReader implements RecordReader {
+
+    private final ComponentLog logger;
+    private final RecordSchema schema;
+    private boolean isArray = false;
+    private XMLEventReader xmlEventReader;
+
+    private StartElement currentRecordStartTag;
+    // Utility used to infer <Data> tag data types
+    private final XmlSchemaInference xmlSchemaInference;
+
+    private final Supplier<DateFormat> LAZY_DATE_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIME_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIMESTAMP_FORMAT;
+
+
+    public WindowsEventLogRecordReader(InputStream in, final String dateFormat, final String timeFormat, final String timestampFormat, ComponentLog logger)
+            throws IOException, MalformedRecordException {
+
+        this.logger = logger;
+
+        final DateFormat df = dateFormat == null ? null : DataTypeUtils.getDateFormat(dateFormat);
+        final DateFormat tf = timeFormat == null ? null : DataTypeUtils.getDateFormat(timeFormat);
+        final DateFormat tsf = timestampFormat == null ? null : DataTypeUtils.getDateFormat(timestampFormat);
+
+        LAZY_DATE_FORMAT = () -> df;
+        LAZY_TIME_FORMAT = () -> tf;
+        LAZY_TIMESTAMP_FORMAT = () -> tsf;
+
+        FilterInputStream inputStream;
+        try {
+            final XMLInputFactory xmlInputFactory = XMLInputFactory.newInstance();
+            // Avoid XXE Vulnerabilities
+            xmlInputFactory.setProperty(XMLInputFactory.SUPPORT_DTD, false);
+            xmlInputFactory.setProperty("javax.xml.stream.isSupportingExternalEntities", false);
+
+            inputStream = new NonCloseableInputStream(in);
+            inputStream.mark(Integer.MAX_VALUE);
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            xmlSchemaInference = new XmlSchemaInference(new TimeValueInference(dateFormat, timeFormat, timestampFormat));
+
+            // Do a streaming pass through the input looking for <Data> tags, then reset the input
+            schema = determineSchema();
+
+            // Restart the XML event stream and advance to the first Event tag
+            inputStream.reset();
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            if (isArray) {
+                skipToNextStartTag();
+            }
+            setNextRecordStartTag();
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);
+        }
+    }
+
+    @Override
+    public Record nextRecord(final boolean coerceTypes, final boolean dropUnknownFields) throws IOException, MalformedRecordException {
+        if (currentRecordStartTag == null) {
+            return null;
+        }
+        try {
+            final Record record = parseRecord(currentRecordStartTag, this.schema, coerceTypes, dropUnknownFields);
+            setNextRecordStartTag();
+            if (record != null) {
+                return record;
+            } else {
+                return new MapRecord(this.schema, Collections.emptyMap());
+            }
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);
+        }
+    }
+
+    @Override
+    public RecordSchema getSchema() throws MalformedRecordException {
+        return schema;
+    }
+
+    @Override
+    public void close() throws IOException {
+        try {
+            xmlEventReader.close();
+        } catch (XMLStreamException e) {
+            logger.error("Unable to close XMLEventReader");
+        }
+    }
+
+    private RecordSchema determineSchema() throws XMLStreamException {
+
+        setNextRecordStartTag();
+        if (currentRecordStartTag == null) {
+            throw new XMLStreamException("No root tag found, must be one of <Events> or <Event>");
+        }
+
+        if (currentRecordStartTag.getName().getLocalPart().equals("Events")) {
+            isArray = true;
+            setNextRecordStartTag();
+        }
+
+        // If there was an <Events></Events> tag pair with no Events in it, use the default schema
+        if (currentRecordStartTag == null) {
+            return generateFullSchema(new SimpleRecordSchema(Collections.emptyList()));
+        }
+
+        List<RecordField> dataFields = new ArrayList<>();
+        List<String> dataFieldNames = new ArrayList<>();
+        while (currentRecordStartTag != null) {
+            if (!currentRecordStartTag.getName().getLocalPart().equals("Event")) {
+                // Unknown and invalid tag
+                throw new XMLStreamException("Expecting <Event> tag but found unknown/invalid tag " + currentRecordStartTag.getName().getLocalPart());
+            }
+
+            setNextRecordStartTag();
+            // At an Event tag, skip the event log type tag (System, e.g.), go into EventData tag then add all the Data tags to the partial schema
+            while (currentRecordStartTag != null && !currentRecordStartTag.getName().getLocalPart().equals("EventData")) {
+                skipElement();
+                setNextRecordStartTag();
+            }
+
+            if (currentRecordStartTag == null) {
+                throw new XMLStreamException("Expecting <EventData> tag but found none");
+            }
+
+            setNextRecordStartTag();
+            if (currentRecordStartTag == null) {
+                // There was an <EventData></EventData> tag but no Data/Binary tags, so this record has been fully processed
+                continue;
+            }
+
+            String eventDataElementName = currentRecordStartTag.getName().getLocalPart();
+            while ("Data" .equals(eventDataElementName)) {
+                // Save reference to Data start element so we can continue to get the value/content
+                StartElement dataElement = currentRecordStartTag;
+                String content = getContent();
+
+                // Create field for the data point using attribute "Name"
+                String dataFieldName;
+                final Iterator<?> iterator = dataElement.getAttributes();
+                if (!iterator.hasNext()) {
+                    // If no Name attribute is provided, the Name is the content of the Data tag and there should be a following Binary tag
+                    dataFieldName = content;
+                    setNextRecordStartTag();
+                    eventDataElementName = currentRecordStartTag.getName().getLocalPart();
+                    if (!"Binary" .equals(eventDataElementName)) {
+                        throw new XMLStreamException("Expecting <Binary> tag containing data for element: " + dataFieldName);
+                    }
+                    content = getContent();
+
+                } else {
+                    final Attribute attribute = (Attribute) iterator.next();
+                    final String attributeName = attribute.getName().getLocalPart();
+                    if (!"Name" .equals(attributeName)) {
+                        throw new XMLStreamException("Expecting 'Name' attribute, actual: " + attributeName);
+                    }
+                    dataFieldName = attribute.getValue();
+                }
+                // Skip this if it has been processed in a previous record
+                if (!dataFieldNames.contains(dataFieldName)) {
+                    final DataType dataElementDataType = xmlSchemaInference.inferTextualDataType(content);
+                    RecordField newRecordField = new RecordField(dataFieldName, dataElementDataType, true);
+                    dataFields.add(newRecordField);
+                    dataFieldNames.add(dataFieldName);
+                }
+
+                // Advance to next data point (or end of EventData)
+                setNextRecordStartTag();
+                eventDataElementName = currentRecordStartTag == null ? null : currentRecordStartTag.getName().getLocalPart();
+            }
+        }
+
+        return generateFullSchema(new SimpleRecordSchema(dataFields));
+    }
+
+    private void skipElement() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+
+            if (xmlEvent.isStartElement()) {
+                skipElement();
+            }
+            if (xmlEvent.isEndElement()) {
+                return;
+            }
+        }
+    }
+
+    private void skipToNextStartTag() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isStartElement()) {
+                return;
+            }
+        }
+    }
+
+    private void setNextRecordStartTag() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isStartElement()) {
+                currentRecordStartTag = xmlEvent.asStartElement();
+                return;
+            }
+        }
+        currentRecordStartTag = null;
+    }
+
+    private RecordSchema generateFullSchema(final RecordSchema dataElementsSchema) {
+        final SimpleRecordSchema rootSchema;
+
+        // Generate the full (input) schema even if the output schema is flattened
+        List<RecordField> systemProviderFields = new ArrayList<>();
+        systemProviderFields.add(new RecordField("Guid", RecordFieldType.STRING.getDataType(), false));
+        systemProviderFields.add(new RecordField("Name", RecordFieldType.STRING.getDataType(), false));
+        SimpleRecordSchema systemProviderSchema = new SimpleRecordSchema(systemProviderFields);
+        systemProviderSchema.setSchemaName("Provider");
+
+        List<RecordField> systemTimeCreatedFields = new ArrayList<>(1);
+        systemTimeCreatedFields.add(new RecordField("SystemTime", RecordFieldType.STRING.getDataType(), false));
+        SimpleRecordSchema systemTimeCreatedSchema = new SimpleRecordSchema(systemTimeCreatedFields);
+        systemTimeCreatedSchema.setSchemaName("TimeCreated");
+
+        List<RecordField> systemExecutionFields = new ArrayList<>(2);
+        systemExecutionFields.add(new RecordField("ThreadID", RecordFieldType.INT.getDataType(), true));
+        systemExecutionFields.add(new RecordField("ProcessID", RecordFieldType.INT.getDataType(), true));
+        SimpleRecordSchema systemExecutionSchema = new SimpleRecordSchema(systemExecutionFields);
+        systemExecutionSchema.setSchemaName("Execution");
+
+        List<RecordField> systemFields = new ArrayList<>(14);
+        systemFields.add(new RecordField("Provider", RecordFieldType.RECORD.getRecordDataType(systemProviderSchema)));
+        systemFields.add(new RecordField("EventID", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Version", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Level", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Task", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Opcode", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Keywords", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("TimeCreated", RecordFieldType.RECORD.getRecordDataType(systemTimeCreatedSchema)));
+        systemFields.add(new RecordField("EventRecordID", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Correlation", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("Execution", RecordFieldType.RECORD.getRecordDataType(systemExecutionSchema)));
+        systemFields.add(new RecordField("Channel", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("Computer", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("Security", RecordFieldType.STRING.getDataType(), true));
+
+        SimpleRecordSchema systemSchema = new SimpleRecordSchema(systemFields);
+        systemSchema.setSchemaName("System");
+
+        List<RecordField> fullSchemaFields = new ArrayList<>(2);
+        fullSchemaFields.add(new RecordField("System", RecordFieldType.RECORD.getRecordDataType(systemSchema)));
+        fullSchemaFields.add(new RecordField("EventData", RecordFieldType.RECORD.getRecordDataType(dataElementsSchema)));
+
+        SimpleRecordSchema fullSchema = new SimpleRecordSchema(fullSchemaFields);
+        fullSchema.setSchemaName("Event");
+
+        rootSchema = fullSchema;
+        return rootSchema;
+    }
+
+    private String getContent() throws XMLStreamException {
+        StringBuilder content = new StringBuilder();
+        while (xmlEventReader.hasNext()) {
+            XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isCharacters()) {
+                final Characters characters = xmlEvent.asCharacters();
+                if (!characters.isWhiteSpace()) {
+                    content.append(characters.getData());
+                }
+            } else if (xmlEvent.isEndElement()) {
+                break;
+            } else if (xmlEvent.isStartElement()) {
+                this.skipElement();
+            }
+        }
+        return content.toString();
+    }
+
+    private Record parseRecord(StartElement startElement, RecordSchema schema, boolean coerceTypes, boolean dropUnknown) throws XMLStreamException, MalformedRecordException {
+        final Map<String, Object> recordValues = new HashMap<>();
+
+        // parse attributes
+        final Iterator<?> iterator = startElement.getAttributes();
+        while (iterator.hasNext()) {
+            final Attribute attribute = (Attribute) iterator.next();
+            final String targetFieldName = attribute.getName().toString();
+
+            if (dropUnknown) {
+                final Optional<RecordField> field = schema.getField(targetFieldName);
+                if (field.isPresent()) {
+
+                    // dropUnknown == true && coerceTypes == true
+                    if (coerceTypes) {
+                        final Object value;
+                        final DataType dataType = field.get().getDataType();
+                        if ((value = parseStringForType(attribute.getValue(), targetFieldName, dataType)) != null) {
+                            recordValues.put(targetFieldName, value);
+                        }
+
+                        // dropUnknown == true && coerceTypes == false
+                    } else {
+                        recordValues.put(targetFieldName, attribute.getValue());
+                    }
+                }
+            } else {
+
+                // dropUnknown == false && coerceTypes == true
+                if (coerceTypes) {
+                    final Object value;
+                    final Optional<RecordField> field = schema.getField(targetFieldName);
+                    if (field.isPresent()) {
+                        if ((value = parseStringForType(attribute.getValue(), targetFieldName, field.get().getDataType())) != null) {
+                            recordValues.put(targetFieldName, value);
+                        }
+                    } else {
+                        recordValues.put(targetFieldName, attribute.getValue());
+                    }
+
+                    // dropUnknown == false && coerceTypes == false
+                } else {
+                    recordValues.put(targetFieldName, attribute.getValue());
+                }
+            }
+        }
+
+        // parse fields
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+
+            if (xmlEvent.isStartElement()) {
+                final StartElement subStartElement = xmlEvent.asStartElement();
+                String fieldName = subStartElement.getName().getLocalPart();
+
+                final Optional<RecordField> field = schema.getField(fieldName);
+
+                if (dropUnknown) {
+                    if (field.isPresent()) {
+                        // dropUnknown == true && coerceTypes == true
+                        if (coerceTypes) {
+                            final Object value = parseFieldForType(subStartElement, fieldName, field.get().getDataType(), recordValues, true);
+                            if (value != null) {
+                                recordValues.put(fieldName, value);
+                            }
+
+                            // dropUnknown == true && coerceTypes == false
+                            // subElements of subStartElement can only be known if there is a corresponding field in the schema defined as record
+                        }
+                    } else {
+                        if ("Data" .equals(fieldName)) {
+                            Map<String, Object> namedValue = parseDataField(subStartElement, schema, true);
+                            if(namedValue != null && !namedValue.isEmpty()) {
+                                final String name = namedValue.keySet().iterator().next();
+                                recordValues.put(name, namedValue.get(name));
+                            }
+                        } else {
+                            skipElement();
+                        }
+                    }
+                } else {
+                    // dropUnknown == false && coerceTypes == true
+                    if (coerceTypes) {
+                        if (field.isPresent()) {
+                            final Object value = parseFieldForType(subStartElement, fieldName, field.get().getDataType(), recordValues, false);
+                            if (value != null) {
+                                recordValues.put(fieldName, value);
+                            }
+                        } else {
+                            if ("Data" .equals(fieldName)) {
+                                Map<String, Object> namedValue = parseDataField(subStartElement, schema, dropUnknown);
+                                if(namedValue != null && !namedValue.isEmpty()) {

Review comment:
       ```suggestion
                                   if (namedValue != null && !namedValue.isEmpty()) {
   ```

##########
File path: nifi-nar-bundles/nifi-standard-services/nifi-record-serialization-services-bundle/nifi-record-serialization-services/src/main/java/org/apache/nifi/windowsevent/WindowsEventLogRecordReader.java
##########
@@ -0,0 +1,626 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.nifi.windowsevent;
+
+import org.apache.nifi.logging.ComponentLog;
+import org.apache.nifi.schema.inference.TimeValueInference;
+import org.apache.nifi.serialization.MalformedRecordException;
+import org.apache.nifi.serialization.RecordReader;
+import org.apache.nifi.serialization.SimpleRecordSchema;
+import org.apache.nifi.serialization.record.DataType;
+import org.apache.nifi.serialization.record.MapRecord;
+import org.apache.nifi.serialization.record.Record;
+import org.apache.nifi.serialization.record.RecordField;
+import org.apache.nifi.serialization.record.RecordFieldType;
+import org.apache.nifi.serialization.record.RecordSchema;
+import org.apache.nifi.serialization.record.type.ArrayDataType;
+import org.apache.nifi.serialization.record.type.MapDataType;
+import org.apache.nifi.serialization.record.type.RecordDataType;
+import org.apache.nifi.serialization.record.util.DataTypeUtils;
+import org.apache.nifi.stream.io.NonCloseableInputStream;
+import org.apache.nifi.util.StringUtils;
+import org.apache.nifi.xml.inference.XmlSchemaInference;
+
+import javax.xml.stream.XMLEventReader;
+import javax.xml.stream.XMLInputFactory;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.events.Attribute;
+import javax.xml.stream.events.Characters;
+import javax.xml.stream.events.StartElement;
+import javax.xml.stream.events.XMLEvent;
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.text.DateFormat;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.Supplier;
+
+public class WindowsEventLogRecordReader implements RecordReader {
+
+    private final ComponentLog logger;
+    private final RecordSchema schema;
+    private boolean isArray = false;
+    private XMLEventReader xmlEventReader;
+
+    private StartElement currentRecordStartTag;
+    // Utility used to infer <Data> tag data types
+    private final XmlSchemaInference xmlSchemaInference;
+
+    private final Supplier<DateFormat> LAZY_DATE_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIME_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIMESTAMP_FORMAT;
+
+
+    public WindowsEventLogRecordReader(InputStream in, final String dateFormat, final String timeFormat, final String timestampFormat, ComponentLog logger)
+            throws IOException, MalformedRecordException {
+
+        this.logger = logger;
+
+        final DateFormat df = dateFormat == null ? null : DataTypeUtils.getDateFormat(dateFormat);
+        final DateFormat tf = timeFormat == null ? null : DataTypeUtils.getDateFormat(timeFormat);
+        final DateFormat tsf = timestampFormat == null ? null : DataTypeUtils.getDateFormat(timestampFormat);
+
+        LAZY_DATE_FORMAT = () -> df;
+        LAZY_TIME_FORMAT = () -> tf;
+        LAZY_TIMESTAMP_FORMAT = () -> tsf;
+
+        FilterInputStream inputStream;
+        try {
+            final XMLInputFactory xmlInputFactory = XMLInputFactory.newInstance();
+            // Avoid XXE Vulnerabilities
+            xmlInputFactory.setProperty(XMLInputFactory.SUPPORT_DTD, false);
+            xmlInputFactory.setProperty("javax.xml.stream.isSupportingExternalEntities", false);
+
+            inputStream = new NonCloseableInputStream(in);
+            inputStream.mark(Integer.MAX_VALUE);
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            xmlSchemaInference = new XmlSchemaInference(new TimeValueInference(dateFormat, timeFormat, timestampFormat));
+
+            // Do a streaming pass through the input looking for <Data> tags, then reset the input
+            schema = determineSchema();
+
+            // Restart the XML event stream and advance to the first Event tag
+            inputStream.reset();
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            if (isArray) {
+                skipToNextStartTag();
+            }
+            setNextRecordStartTag();
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);
+        }
+    }
+
+    @Override
+    public Record nextRecord(final boolean coerceTypes, final boolean dropUnknownFields) throws IOException, MalformedRecordException {
+        if (currentRecordStartTag == null) {
+            return null;
+        }
+        try {
+            final Record record = parseRecord(currentRecordStartTag, this.schema, coerceTypes, dropUnknownFields);
+            setNextRecordStartTag();
+            if (record != null) {
+                return record;
+            } else {
+                return new MapRecord(this.schema, Collections.emptyMap());
+            }
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);
+        }
+    }
+
+    @Override
+    public RecordSchema getSchema() throws MalformedRecordException {
+        return schema;
+    }
+
+    @Override
+    public void close() throws IOException {
+        try {
+            xmlEventReader.close();
+        } catch (XMLStreamException e) {
+            logger.error("Unable to close XMLEventReader");
+        }
+    }
+
+    private RecordSchema determineSchema() throws XMLStreamException {
+
+        setNextRecordStartTag();
+        if (currentRecordStartTag == null) {
+            throw new XMLStreamException("No root tag found, must be one of <Events> or <Event>");
+        }
+
+        if (currentRecordStartTag.getName().getLocalPart().equals("Events")) {
+            isArray = true;
+            setNextRecordStartTag();
+        }
+
+        // If there was an <Events></Events> tag pair with no Events in it, use the default schema
+        if (currentRecordStartTag == null) {
+            return generateFullSchema(new SimpleRecordSchema(Collections.emptyList()));
+        }
+
+        List<RecordField> dataFields = new ArrayList<>();
+        List<String> dataFieldNames = new ArrayList<>();
+        while (currentRecordStartTag != null) {
+            if (!currentRecordStartTag.getName().getLocalPart().equals("Event")) {
+                // Unknown and invalid tag
+                throw new XMLStreamException("Expecting <Event> tag but found unknown/invalid tag " + currentRecordStartTag.getName().getLocalPart());
+            }
+
+            setNextRecordStartTag();
+            // At an Event tag, skip the event log type tag (System, e.g.), go into EventData tag then add all the Data tags to the partial schema
+            while (currentRecordStartTag != null && !currentRecordStartTag.getName().getLocalPart().equals("EventData")) {
+                skipElement();
+                setNextRecordStartTag();
+            }
+
+            if (currentRecordStartTag == null) {
+                throw new XMLStreamException("Expecting <EventData> tag but found none");
+            }
+
+            setNextRecordStartTag();
+            if (currentRecordStartTag == null) {
+                // There was an <EventData></EventData> tag but no Data/Binary tags, so this record has been fully processed
+                continue;
+            }
+
+            String eventDataElementName = currentRecordStartTag.getName().getLocalPart();
+            while ("Data" .equals(eventDataElementName)) {
+                // Save reference to Data start element so we can continue to get the value/content
+                StartElement dataElement = currentRecordStartTag;
+                String content = getContent();
+
+                // Create field for the data point using attribute "Name"
+                String dataFieldName;
+                final Iterator<?> iterator = dataElement.getAttributes();
+                if (!iterator.hasNext()) {
+                    // If no Name attribute is provided, the Name is the content of the Data tag and there should be a following Binary tag
+                    dataFieldName = content;
+                    setNextRecordStartTag();
+                    eventDataElementName = currentRecordStartTag.getName().getLocalPart();
+                    if (!"Binary" .equals(eventDataElementName)) {
+                        throw new XMLStreamException("Expecting <Binary> tag containing data for element: " + dataFieldName);
+                    }
+                    content = getContent();
+
+                } else {
+                    final Attribute attribute = (Attribute) iterator.next();
+                    final String attributeName = attribute.getName().getLocalPart();
+                    if (!"Name" .equals(attributeName)) {
+                        throw new XMLStreamException("Expecting 'Name' attribute, actual: " + attributeName);
+                    }
+                    dataFieldName = attribute.getValue();
+                }
+                // Skip this if it has been processed in a previous record
+                if (!dataFieldNames.contains(dataFieldName)) {
+                    final DataType dataElementDataType = xmlSchemaInference.inferTextualDataType(content);
+                    RecordField newRecordField = new RecordField(dataFieldName, dataElementDataType, true);
+                    dataFields.add(newRecordField);
+                    dataFieldNames.add(dataFieldName);
+                }
+
+                // Advance to next data point (or end of EventData)
+                setNextRecordStartTag();
+                eventDataElementName = currentRecordStartTag == null ? null : currentRecordStartTag.getName().getLocalPart();
+            }
+        }
+
+        return generateFullSchema(new SimpleRecordSchema(dataFields));
+    }
+
+    private void skipElement() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+
+            if (xmlEvent.isStartElement()) {
+                skipElement();
+            }
+            if (xmlEvent.isEndElement()) {
+                return;
+            }
+        }
+    }
+
+    private void skipToNextStartTag() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isStartElement()) {
+                return;
+            }
+        }
+    }
+
+    private void setNextRecordStartTag() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isStartElement()) {
+                currentRecordStartTag = xmlEvent.asStartElement();
+                return;
+            }
+        }
+        currentRecordStartTag = null;
+    }
+
+    private RecordSchema generateFullSchema(final RecordSchema dataElementsSchema) {
+        final SimpleRecordSchema rootSchema;
+
+        // Generate the full (input) schema even if the output schema is flattened
+        List<RecordField> systemProviderFields = new ArrayList<>();
+        systemProviderFields.add(new RecordField("Guid", RecordFieldType.STRING.getDataType(), false));
+        systemProviderFields.add(new RecordField("Name", RecordFieldType.STRING.getDataType(), false));
+        SimpleRecordSchema systemProviderSchema = new SimpleRecordSchema(systemProviderFields);
+        systemProviderSchema.setSchemaName("Provider");
+
+        List<RecordField> systemTimeCreatedFields = new ArrayList<>(1);
+        systemTimeCreatedFields.add(new RecordField("SystemTime", RecordFieldType.STRING.getDataType(), false));
+        SimpleRecordSchema systemTimeCreatedSchema = new SimpleRecordSchema(systemTimeCreatedFields);
+        systemTimeCreatedSchema.setSchemaName("TimeCreated");
+
+        List<RecordField> systemExecutionFields = new ArrayList<>(2);
+        systemExecutionFields.add(new RecordField("ThreadID", RecordFieldType.INT.getDataType(), true));
+        systemExecutionFields.add(new RecordField("ProcessID", RecordFieldType.INT.getDataType(), true));
+        SimpleRecordSchema systemExecutionSchema = new SimpleRecordSchema(systemExecutionFields);
+        systemExecutionSchema.setSchemaName("Execution");
+
+        List<RecordField> systemFields = new ArrayList<>(14);
+        systemFields.add(new RecordField("Provider", RecordFieldType.RECORD.getRecordDataType(systemProviderSchema)));
+        systemFields.add(new RecordField("EventID", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Version", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Level", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Task", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Opcode", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Keywords", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("TimeCreated", RecordFieldType.RECORD.getRecordDataType(systemTimeCreatedSchema)));
+        systemFields.add(new RecordField("EventRecordID", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Correlation", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("Execution", RecordFieldType.RECORD.getRecordDataType(systemExecutionSchema)));
+        systemFields.add(new RecordField("Channel", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("Computer", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("Security", RecordFieldType.STRING.getDataType(), true));
+
+        SimpleRecordSchema systemSchema = new SimpleRecordSchema(systemFields);
+        systemSchema.setSchemaName("System");
+
+        List<RecordField> fullSchemaFields = new ArrayList<>(2);
+        fullSchemaFields.add(new RecordField("System", RecordFieldType.RECORD.getRecordDataType(systemSchema)));
+        fullSchemaFields.add(new RecordField("EventData", RecordFieldType.RECORD.getRecordDataType(dataElementsSchema)));
+
+        SimpleRecordSchema fullSchema = new SimpleRecordSchema(fullSchemaFields);
+        fullSchema.setSchemaName("Event");
+
+        rootSchema = fullSchema;
+        return rootSchema;
+    }
+
+    private String getContent() throws XMLStreamException {
+        StringBuilder content = new StringBuilder();
+        while (xmlEventReader.hasNext()) {
+            XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isCharacters()) {
+                final Characters characters = xmlEvent.asCharacters();
+                if (!characters.isWhiteSpace()) {
+                    content.append(characters.getData());
+                }
+            } else if (xmlEvent.isEndElement()) {
+                break;
+            } else if (xmlEvent.isStartElement()) {
+                this.skipElement();
+            }
+        }
+        return content.toString();
+    }
+
+    private Record parseRecord(StartElement startElement, RecordSchema schema, boolean coerceTypes, boolean dropUnknown) throws XMLStreamException, MalformedRecordException {
+        final Map<String, Object> recordValues = new HashMap<>();
+
+        // parse attributes
+        final Iterator<?> iterator = startElement.getAttributes();
+        while (iterator.hasNext()) {
+            final Attribute attribute = (Attribute) iterator.next();
+            final String targetFieldName = attribute.getName().toString();
+
+            if (dropUnknown) {
+                final Optional<RecordField> field = schema.getField(targetFieldName);
+                if (field.isPresent()) {
+
+                    // dropUnknown == true && coerceTypes == true
+                    if (coerceTypes) {
+                        final Object value;
+                        final DataType dataType = field.get().getDataType();
+                        if ((value = parseStringForType(attribute.getValue(), targetFieldName, dataType)) != null) {
+                            recordValues.put(targetFieldName, value);
+                        }
+
+                        // dropUnknown == true && coerceTypes == false
+                    } else {
+                        recordValues.put(targetFieldName, attribute.getValue());
+                    }
+                }
+            } else {
+
+                // dropUnknown == false && coerceTypes == true
+                if (coerceTypes) {
+                    final Object value;
+                    final Optional<RecordField> field = schema.getField(targetFieldName);
+                    if (field.isPresent()) {
+                        if ((value = parseStringForType(attribute.getValue(), targetFieldName, field.get().getDataType())) != null) {
+                            recordValues.put(targetFieldName, value);
+                        }
+                    } else {
+                        recordValues.put(targetFieldName, attribute.getValue());
+                    }
+
+                    // dropUnknown == false && coerceTypes == false
+                } else {
+                    recordValues.put(targetFieldName, attribute.getValue());
+                }
+            }
+        }
+
+        // parse fields
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+
+            if (xmlEvent.isStartElement()) {
+                final StartElement subStartElement = xmlEvent.asStartElement();
+                String fieldName = subStartElement.getName().getLocalPart();
+
+                final Optional<RecordField> field = schema.getField(fieldName);
+
+                if (dropUnknown) {
+                    if (field.isPresent()) {
+                        // dropUnknown == true && coerceTypes == true
+                        if (coerceTypes) {
+                            final Object value = parseFieldForType(subStartElement, fieldName, field.get().getDataType(), recordValues, true);
+                            if (value != null) {
+                                recordValues.put(fieldName, value);
+                            }
+
+                            // dropUnknown == true && coerceTypes == false
+                            // subElements of subStartElement can only be known if there is a corresponding field in the schema defined as record
+                        }
+                    } else {
+                        if ("Data" .equals(fieldName)) {
+                            Map<String, Object> namedValue = parseDataField(subStartElement, schema, true);
+                            if(namedValue != null && !namedValue.isEmpty()) {
+                                final String name = namedValue.keySet().iterator().next();
+                                recordValues.put(name, namedValue.get(name));
+                            }
+                        } else {
+                            skipElement();
+                        }
+                    }
+                } else {
+                    // dropUnknown == false && coerceTypes == true
+                    if (coerceTypes) {
+                        if (field.isPresent()) {
+                            final Object value = parseFieldForType(subStartElement, fieldName, field.get().getDataType(), recordValues, false);
+                            if (value != null) {
+                                recordValues.put(fieldName, value);
+                            }
+                        } else {
+                            if ("Data" .equals(fieldName)) {
+                                Map<String, Object> namedValue = parseDataField(subStartElement, schema, dropUnknown);
+                                if(namedValue != null && !namedValue.isEmpty()) {
+                                    final String name = namedValue.keySet().iterator().next();
+                                    recordValues.put(name, namedValue.get(name));
+                                }
+                            }
+                        }
+
+                        // dropUnknown == false && coerceTypes == false
+                    } else {
+                        if ("Data" .equals(fieldName)) {
+                            Map<String, Object> namedValue = parseDataField(subStartElement, schema, dropUnknown);
+                            if(namedValue != null && !namedValue.isEmpty()) {

Review comment:
       ```suggestion
                               if (namedValue != null && !namedValue.isEmpty()) {
   ```

##########
File path: nifi-nar-bundles/nifi-standard-services/nifi-record-serialization-services-bundle/nifi-record-serialization-services/src/main/java/org/apache/nifi/windowsevent/WindowsEventLogRecordReader.java
##########
@@ -0,0 +1,626 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.nifi.windowsevent;
+
+import org.apache.nifi.logging.ComponentLog;
+import org.apache.nifi.schema.inference.TimeValueInference;
+import org.apache.nifi.serialization.MalformedRecordException;
+import org.apache.nifi.serialization.RecordReader;
+import org.apache.nifi.serialization.SimpleRecordSchema;
+import org.apache.nifi.serialization.record.DataType;
+import org.apache.nifi.serialization.record.MapRecord;
+import org.apache.nifi.serialization.record.Record;
+import org.apache.nifi.serialization.record.RecordField;
+import org.apache.nifi.serialization.record.RecordFieldType;
+import org.apache.nifi.serialization.record.RecordSchema;
+import org.apache.nifi.serialization.record.type.ArrayDataType;
+import org.apache.nifi.serialization.record.type.MapDataType;
+import org.apache.nifi.serialization.record.type.RecordDataType;
+import org.apache.nifi.serialization.record.util.DataTypeUtils;
+import org.apache.nifi.stream.io.NonCloseableInputStream;
+import org.apache.nifi.util.StringUtils;
+import org.apache.nifi.xml.inference.XmlSchemaInference;
+
+import javax.xml.stream.XMLEventReader;
+import javax.xml.stream.XMLInputFactory;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.events.Attribute;
+import javax.xml.stream.events.Characters;
+import javax.xml.stream.events.StartElement;
+import javax.xml.stream.events.XMLEvent;
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.text.DateFormat;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.Supplier;
+
+public class WindowsEventLogRecordReader implements RecordReader {
+
+    private final ComponentLog logger;
+    private final RecordSchema schema;
+    private boolean isArray = false;
+    private XMLEventReader xmlEventReader;
+
+    private StartElement currentRecordStartTag;
+    // Utility used to infer <Data> tag data types
+    private final XmlSchemaInference xmlSchemaInference;
+
+    private final Supplier<DateFormat> LAZY_DATE_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIME_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIMESTAMP_FORMAT;
+
+
+    public WindowsEventLogRecordReader(InputStream in, final String dateFormat, final String timeFormat, final String timestampFormat, ComponentLog logger)
+            throws IOException, MalformedRecordException {
+
+        this.logger = logger;
+
+        final DateFormat df = dateFormat == null ? null : DataTypeUtils.getDateFormat(dateFormat);
+        final DateFormat tf = timeFormat == null ? null : DataTypeUtils.getDateFormat(timeFormat);
+        final DateFormat tsf = timestampFormat == null ? null : DataTypeUtils.getDateFormat(timestampFormat);
+
+        LAZY_DATE_FORMAT = () -> df;
+        LAZY_TIME_FORMAT = () -> tf;
+        LAZY_TIMESTAMP_FORMAT = () -> tsf;
+
+        FilterInputStream inputStream;
+        try {
+            final XMLInputFactory xmlInputFactory = XMLInputFactory.newInstance();
+            // Avoid XXE Vulnerabilities
+            xmlInputFactory.setProperty(XMLInputFactory.SUPPORT_DTD, false);
+            xmlInputFactory.setProperty("javax.xml.stream.isSupportingExternalEntities", false);
+
+            inputStream = new NonCloseableInputStream(in);
+            inputStream.mark(Integer.MAX_VALUE);
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            xmlSchemaInference = new XmlSchemaInference(new TimeValueInference(dateFormat, timeFormat, timestampFormat));
+
+            // Do a streaming pass through the input looking for <Data> tags, then reset the input
+            schema = determineSchema();
+
+            // Restart the XML event stream and advance to the first Event tag
+            inputStream.reset();
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            if (isArray) {
+                skipToNextStartTag();
+            }
+            setNextRecordStartTag();
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);
+        }
+    }
+
+    @Override
+    public Record nextRecord(final boolean coerceTypes, final boolean dropUnknownFields) throws IOException, MalformedRecordException {
+        if (currentRecordStartTag == null) {
+            return null;
+        }
+        try {
+            final Record record = parseRecord(currentRecordStartTag, this.schema, coerceTypes, dropUnknownFields);
+            setNextRecordStartTag();
+            if (record != null) {
+                return record;
+            } else {
+                return new MapRecord(this.schema, Collections.emptyMap());
+            }
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);
+        }
+    }
+
+    @Override
+    public RecordSchema getSchema() throws MalformedRecordException {
+        return schema;
+    }
+
+    @Override
+    public void close() throws IOException {
+        try {
+            xmlEventReader.close();
+        } catch (XMLStreamException e) {
+            logger.error("Unable to close XMLEventReader");
+        }
+    }
+
+    private RecordSchema determineSchema() throws XMLStreamException {
+
+        setNextRecordStartTag();
+        if (currentRecordStartTag == null) {
+            throw new XMLStreamException("No root tag found, must be one of <Events> or <Event>");
+        }
+
+        if (currentRecordStartTag.getName().getLocalPart().equals("Events")) {
+            isArray = true;
+            setNextRecordStartTag();
+        }
+
+        // If there was an <Events></Events> tag pair with no Events in it, use the default schema
+        if (currentRecordStartTag == null) {
+            return generateFullSchema(new SimpleRecordSchema(Collections.emptyList()));
+        }
+
+        List<RecordField> dataFields = new ArrayList<>();
+        List<String> dataFieldNames = new ArrayList<>();
+        while (currentRecordStartTag != null) {
+            if (!currentRecordStartTag.getName().getLocalPart().equals("Event")) {
+                // Unknown and invalid tag
+                throw new XMLStreamException("Expecting <Event> tag but found unknown/invalid tag " + currentRecordStartTag.getName().getLocalPart());
+            }
+
+            setNextRecordStartTag();
+            // At an Event tag, skip the event log type tag (System, e.g.), go into EventData tag then add all the Data tags to the partial schema
+            while (currentRecordStartTag != null && !currentRecordStartTag.getName().getLocalPart().equals("EventData")) {
+                skipElement();
+                setNextRecordStartTag();
+            }
+
+            if (currentRecordStartTag == null) {
+                throw new XMLStreamException("Expecting <EventData> tag but found none");
+            }
+
+            setNextRecordStartTag();
+            if (currentRecordStartTag == null) {
+                // There was an <EventData></EventData> tag but no Data/Binary tags, so this record has been fully processed
+                continue;
+            }
+
+            String eventDataElementName = currentRecordStartTag.getName().getLocalPart();
+            while ("Data" .equals(eventDataElementName)) {
+                // Save reference to Data start element so we can continue to get the value/content
+                StartElement dataElement = currentRecordStartTag;
+                String content = getContent();
+
+                // Create field for the data point using attribute "Name"
+                String dataFieldName;
+                final Iterator<?> iterator = dataElement.getAttributes();
+                if (!iterator.hasNext()) {
+                    // If no Name attribute is provided, the Name is the content of the Data tag and there should be a following Binary tag
+                    dataFieldName = content;
+                    setNextRecordStartTag();
+                    eventDataElementName = currentRecordStartTag.getName().getLocalPart();
+                    if (!"Binary" .equals(eventDataElementName)) {
+                        throw new XMLStreamException("Expecting <Binary> tag containing data for element: " + dataFieldName);
+                    }
+                    content = getContent();
+
+                } else {
+                    final Attribute attribute = (Attribute) iterator.next();
+                    final String attributeName = attribute.getName().getLocalPart();
+                    if (!"Name" .equals(attributeName)) {
+                        throw new XMLStreamException("Expecting 'Name' attribute, actual: " + attributeName);
+                    }
+                    dataFieldName = attribute.getValue();
+                }
+                // Skip this if it has been processed in a previous record
+                if (!dataFieldNames.contains(dataFieldName)) {
+                    final DataType dataElementDataType = xmlSchemaInference.inferTextualDataType(content);
+                    RecordField newRecordField = new RecordField(dataFieldName, dataElementDataType, true);
+                    dataFields.add(newRecordField);
+                    dataFieldNames.add(dataFieldName);
+                }
+
+                // Advance to next data point (or end of EventData)
+                setNextRecordStartTag();
+                eventDataElementName = currentRecordStartTag == null ? null : currentRecordStartTag.getName().getLocalPart();
+            }
+        }
+
+        return generateFullSchema(new SimpleRecordSchema(dataFields));
+    }
+
+    private void skipElement() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+
+            if (xmlEvent.isStartElement()) {
+                skipElement();
+            }
+            if (xmlEvent.isEndElement()) {
+                return;
+            }
+        }
+    }
+
+    private void skipToNextStartTag() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isStartElement()) {
+                return;
+            }
+        }
+    }
+
+    private void setNextRecordStartTag() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isStartElement()) {
+                currentRecordStartTag = xmlEvent.asStartElement();
+                return;
+            }
+        }
+        currentRecordStartTag = null;
+    }
+
+    private RecordSchema generateFullSchema(final RecordSchema dataElementsSchema) {
+        final SimpleRecordSchema rootSchema;
+
+        // Generate the full (input) schema even if the output schema is flattened
+        List<RecordField> systemProviderFields = new ArrayList<>();
+        systemProviderFields.add(new RecordField("Guid", RecordFieldType.STRING.getDataType(), false));

Review comment:
       Is it possible to declare some of these `RecordField` definitions statically as opposed to creating new objects on every invocation?

##########
File path: nifi-nar-bundles/nifi-standard-services/nifi-record-serialization-services-bundle/nifi-record-serialization-services/src/main/java/org/apache/nifi/windowsevent/WindowsEventLogRecordReader.java
##########
@@ -0,0 +1,626 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.nifi.windowsevent;
+
+import org.apache.nifi.logging.ComponentLog;
+import org.apache.nifi.schema.inference.TimeValueInference;
+import org.apache.nifi.serialization.MalformedRecordException;
+import org.apache.nifi.serialization.RecordReader;
+import org.apache.nifi.serialization.SimpleRecordSchema;
+import org.apache.nifi.serialization.record.DataType;
+import org.apache.nifi.serialization.record.MapRecord;
+import org.apache.nifi.serialization.record.Record;
+import org.apache.nifi.serialization.record.RecordField;
+import org.apache.nifi.serialization.record.RecordFieldType;
+import org.apache.nifi.serialization.record.RecordSchema;
+import org.apache.nifi.serialization.record.type.ArrayDataType;
+import org.apache.nifi.serialization.record.type.MapDataType;
+import org.apache.nifi.serialization.record.type.RecordDataType;
+import org.apache.nifi.serialization.record.util.DataTypeUtils;
+import org.apache.nifi.stream.io.NonCloseableInputStream;
+import org.apache.nifi.util.StringUtils;
+import org.apache.nifi.xml.inference.XmlSchemaInference;
+
+import javax.xml.stream.XMLEventReader;
+import javax.xml.stream.XMLInputFactory;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.events.Attribute;
+import javax.xml.stream.events.Characters;
+import javax.xml.stream.events.StartElement;
+import javax.xml.stream.events.XMLEvent;
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.text.DateFormat;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.Supplier;
+
+public class WindowsEventLogRecordReader implements RecordReader {
+
+    private final ComponentLog logger;
+    private final RecordSchema schema;
+    private boolean isArray = false;
+    private XMLEventReader xmlEventReader;
+
+    private StartElement currentRecordStartTag;
+    // Utility used to infer <Data> tag data types
+    private final XmlSchemaInference xmlSchemaInference;
+
+    private final Supplier<DateFormat> LAZY_DATE_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIME_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIMESTAMP_FORMAT;
+
+
+    public WindowsEventLogRecordReader(InputStream in, final String dateFormat, final String timeFormat, final String timestampFormat, ComponentLog logger)
+            throws IOException, MalformedRecordException {
+
+        this.logger = logger;
+
+        final DateFormat df = dateFormat == null ? null : DataTypeUtils.getDateFormat(dateFormat);
+        final DateFormat tf = timeFormat == null ? null : DataTypeUtils.getDateFormat(timeFormat);
+        final DateFormat tsf = timestampFormat == null ? null : DataTypeUtils.getDateFormat(timestampFormat);
+
+        LAZY_DATE_FORMAT = () -> df;
+        LAZY_TIME_FORMAT = () -> tf;
+        LAZY_TIMESTAMP_FORMAT = () -> tsf;
+
+        FilterInputStream inputStream;
+        try {
+            final XMLInputFactory xmlInputFactory = XMLInputFactory.newInstance();
+            // Avoid XXE Vulnerabilities
+            xmlInputFactory.setProperty(XMLInputFactory.SUPPORT_DTD, false);
+            xmlInputFactory.setProperty("javax.xml.stream.isSupportingExternalEntities", false);
+
+            inputStream = new NonCloseableInputStream(in);
+            inputStream.mark(Integer.MAX_VALUE);
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            xmlSchemaInference = new XmlSchemaInference(new TimeValueInference(dateFormat, timeFormat, timestampFormat));
+
+            // Do a streaming pass through the input looking for <Data> tags, then reset the input
+            schema = determineSchema();
+
+            // Restart the XML event stream and advance to the first Event tag
+            inputStream.reset();
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            if (isArray) {
+                skipToNextStartTag();
+            }
+            setNextRecordStartTag();
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);
+        }
+    }
+
+    @Override
+    public Record nextRecord(final boolean coerceTypes, final boolean dropUnknownFields) throws IOException, MalformedRecordException {
+        if (currentRecordStartTag == null) {
+            return null;
+        }
+        try {
+            final Record record = parseRecord(currentRecordStartTag, this.schema, coerceTypes, dropUnknownFields);
+            setNextRecordStartTag();
+            if (record != null) {
+                return record;
+            } else {
+                return new MapRecord(this.schema, Collections.emptyMap());
+            }
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);
+        }
+    }
+
+    @Override
+    public RecordSchema getSchema() throws MalformedRecordException {
+        return schema;
+    }
+
+    @Override
+    public void close() throws IOException {
+        try {
+            xmlEventReader.close();
+        } catch (XMLStreamException e) {
+            logger.error("Unable to close XMLEventReader");
+        }
+    }
+
+    private RecordSchema determineSchema() throws XMLStreamException {
+
+        setNextRecordStartTag();
+        if (currentRecordStartTag == null) {
+            throw new XMLStreamException("No root tag found, must be one of <Events> or <Event>");
+        }
+
+        if (currentRecordStartTag.getName().getLocalPart().equals("Events")) {
+            isArray = true;
+            setNextRecordStartTag();
+        }
+
+        // If there was an <Events></Events> tag pair with no Events in it, use the default schema
+        if (currentRecordStartTag == null) {
+            return generateFullSchema(new SimpleRecordSchema(Collections.emptyList()));
+        }
+
+        List<RecordField> dataFields = new ArrayList<>();
+        List<String> dataFieldNames = new ArrayList<>();
+        while (currentRecordStartTag != null) {
+            if (!currentRecordStartTag.getName().getLocalPart().equals("Event")) {
+                // Unknown and invalid tag
+                throw new XMLStreamException("Expecting <Event> tag but found unknown/invalid tag " + currentRecordStartTag.getName().getLocalPart());
+            }
+
+            setNextRecordStartTag();
+            // At an Event tag, skip the event log type tag (System, e.g.), go into EventData tag then add all the Data tags to the partial schema
+            while (currentRecordStartTag != null && !currentRecordStartTag.getName().getLocalPart().equals("EventData")) {
+                skipElement();
+                setNextRecordStartTag();
+            }
+
+            if (currentRecordStartTag == null) {
+                throw new XMLStreamException("Expecting <EventData> tag but found none");
+            }
+
+            setNextRecordStartTag();
+            if (currentRecordStartTag == null) {
+                // There was an <EventData></EventData> tag but no Data/Binary tags, so this record has been fully processed
+                continue;
+            }
+
+            String eventDataElementName = currentRecordStartTag.getName().getLocalPart();
+            while ("Data" .equals(eventDataElementName)) {

Review comment:
       There appears to be an extra space after the `"Data"` string.  Would it be possible to move this loop into a separate method that returns the list of parsed data `RecordField` objects?

##########
File path: nifi-nar-bundles/nifi-standard-services/nifi-record-serialization-services-bundle/nifi-record-serialization-services/src/main/java/org/apache/nifi/windowsevent/WindowsEventLogRecordReader.java
##########
@@ -0,0 +1,626 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.nifi.windowsevent;
+
+import org.apache.nifi.logging.ComponentLog;
+import org.apache.nifi.schema.inference.TimeValueInference;
+import org.apache.nifi.serialization.MalformedRecordException;
+import org.apache.nifi.serialization.RecordReader;
+import org.apache.nifi.serialization.SimpleRecordSchema;
+import org.apache.nifi.serialization.record.DataType;
+import org.apache.nifi.serialization.record.MapRecord;
+import org.apache.nifi.serialization.record.Record;
+import org.apache.nifi.serialization.record.RecordField;
+import org.apache.nifi.serialization.record.RecordFieldType;
+import org.apache.nifi.serialization.record.RecordSchema;
+import org.apache.nifi.serialization.record.type.ArrayDataType;
+import org.apache.nifi.serialization.record.type.MapDataType;
+import org.apache.nifi.serialization.record.type.RecordDataType;
+import org.apache.nifi.serialization.record.util.DataTypeUtils;
+import org.apache.nifi.stream.io.NonCloseableInputStream;
+import org.apache.nifi.util.StringUtils;
+import org.apache.nifi.xml.inference.XmlSchemaInference;
+
+import javax.xml.stream.XMLEventReader;
+import javax.xml.stream.XMLInputFactory;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.events.Attribute;
+import javax.xml.stream.events.Characters;
+import javax.xml.stream.events.StartElement;
+import javax.xml.stream.events.XMLEvent;
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.text.DateFormat;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.Supplier;
+
+public class WindowsEventLogRecordReader implements RecordReader {
+
+    private final ComponentLog logger;
+    private final RecordSchema schema;
+    private boolean isArray = false;
+    private XMLEventReader xmlEventReader;
+
+    private StartElement currentRecordStartTag;
+    // Utility used to infer <Data> tag data types
+    private final XmlSchemaInference xmlSchemaInference;
+
+    private final Supplier<DateFormat> LAZY_DATE_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIME_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIMESTAMP_FORMAT;
+
+
+    public WindowsEventLogRecordReader(InputStream in, final String dateFormat, final String timeFormat, final String timestampFormat, ComponentLog logger)
+            throws IOException, MalformedRecordException {
+
+        this.logger = logger;
+
+        final DateFormat df = dateFormat == null ? null : DataTypeUtils.getDateFormat(dateFormat);
+        final DateFormat tf = timeFormat == null ? null : DataTypeUtils.getDateFormat(timeFormat);
+        final DateFormat tsf = timestampFormat == null ? null : DataTypeUtils.getDateFormat(timestampFormat);
+
+        LAZY_DATE_FORMAT = () -> df;
+        LAZY_TIME_FORMAT = () -> tf;
+        LAZY_TIMESTAMP_FORMAT = () -> tsf;
+
+        FilterInputStream inputStream;
+        try {
+            final XMLInputFactory xmlInputFactory = XMLInputFactory.newInstance();
+            // Avoid XXE Vulnerabilities
+            xmlInputFactory.setProperty(XMLInputFactory.SUPPORT_DTD, false);
+            xmlInputFactory.setProperty("javax.xml.stream.isSupportingExternalEntities", false);
+
+            inputStream = new NonCloseableInputStream(in);
+            inputStream.mark(Integer.MAX_VALUE);
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            xmlSchemaInference = new XmlSchemaInference(new TimeValueInference(dateFormat, timeFormat, timestampFormat));
+
+            // Do a streaming pass through the input looking for <Data> tags, then reset the input
+            schema = determineSchema();
+
+            // Restart the XML event stream and advance to the first Event tag
+            inputStream.reset();
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            if (isArray) {
+                skipToNextStartTag();
+            }
+            setNextRecordStartTag();
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);
+        }
+    }
+
+    @Override
+    public Record nextRecord(final boolean coerceTypes, final boolean dropUnknownFields) throws IOException, MalformedRecordException {
+        if (currentRecordStartTag == null) {
+            return null;
+        }
+        try {
+            final Record record = parseRecord(currentRecordStartTag, this.schema, coerceTypes, dropUnknownFields);
+            setNextRecordStartTag();
+            if (record != null) {
+                return record;
+            } else {
+                return new MapRecord(this.schema, Collections.emptyMap());
+            }
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);

Review comment:
       It would be helpful to change this error message to indicate that record parsing failed.  Could the `currentRecordStartTag` be included in the message for additional troubleshooting?

##########
File path: nifi-nar-bundles/nifi-standard-services/nifi-record-serialization-services-bundle/nifi-record-serialization-services/src/main/java/org/apache/nifi/windowsevent/WindowsEventLogRecordReader.java
##########
@@ -0,0 +1,626 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.nifi.windowsevent;
+
+import org.apache.nifi.logging.ComponentLog;
+import org.apache.nifi.schema.inference.TimeValueInference;
+import org.apache.nifi.serialization.MalformedRecordException;
+import org.apache.nifi.serialization.RecordReader;
+import org.apache.nifi.serialization.SimpleRecordSchema;
+import org.apache.nifi.serialization.record.DataType;
+import org.apache.nifi.serialization.record.MapRecord;
+import org.apache.nifi.serialization.record.Record;
+import org.apache.nifi.serialization.record.RecordField;
+import org.apache.nifi.serialization.record.RecordFieldType;
+import org.apache.nifi.serialization.record.RecordSchema;
+import org.apache.nifi.serialization.record.type.ArrayDataType;
+import org.apache.nifi.serialization.record.type.MapDataType;
+import org.apache.nifi.serialization.record.type.RecordDataType;
+import org.apache.nifi.serialization.record.util.DataTypeUtils;
+import org.apache.nifi.stream.io.NonCloseableInputStream;
+import org.apache.nifi.util.StringUtils;
+import org.apache.nifi.xml.inference.XmlSchemaInference;
+
+import javax.xml.stream.XMLEventReader;
+import javax.xml.stream.XMLInputFactory;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.events.Attribute;
+import javax.xml.stream.events.Characters;
+import javax.xml.stream.events.StartElement;
+import javax.xml.stream.events.XMLEvent;
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.text.DateFormat;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.Supplier;
+
+public class WindowsEventLogRecordReader implements RecordReader {
+
+    private final ComponentLog logger;
+    private final RecordSchema schema;
+    private boolean isArray = false;
+    private XMLEventReader xmlEventReader;
+
+    private StartElement currentRecordStartTag;
+    // Utility used to infer <Data> tag data types
+    private final XmlSchemaInference xmlSchemaInference;
+
+    private final Supplier<DateFormat> LAZY_DATE_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIME_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIMESTAMP_FORMAT;
+
+
+    public WindowsEventLogRecordReader(InputStream in, final String dateFormat, final String timeFormat, final String timestampFormat, ComponentLog logger)
+            throws IOException, MalformedRecordException {
+
+        this.logger = logger;
+
+        final DateFormat df = dateFormat == null ? null : DataTypeUtils.getDateFormat(dateFormat);
+        final DateFormat tf = timeFormat == null ? null : DataTypeUtils.getDateFormat(timeFormat);
+        final DateFormat tsf = timestampFormat == null ? null : DataTypeUtils.getDateFormat(timestampFormat);
+
+        LAZY_DATE_FORMAT = () -> df;
+        LAZY_TIME_FORMAT = () -> tf;
+        LAZY_TIMESTAMP_FORMAT = () -> tsf;
+
+        FilterInputStream inputStream;
+        try {
+            final XMLInputFactory xmlInputFactory = XMLInputFactory.newInstance();
+            // Avoid XXE Vulnerabilities
+            xmlInputFactory.setProperty(XMLInputFactory.SUPPORT_DTD, false);
+            xmlInputFactory.setProperty("javax.xml.stream.isSupportingExternalEntities", false);
+
+            inputStream = new NonCloseableInputStream(in);
+            inputStream.mark(Integer.MAX_VALUE);
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            xmlSchemaInference = new XmlSchemaInference(new TimeValueInference(dateFormat, timeFormat, timestampFormat));
+
+            // Do a streaming pass through the input looking for <Data> tags, then reset the input
+            schema = determineSchema();
+
+            // Restart the XML event stream and advance to the first Event tag
+            inputStream.reset();
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            if (isArray) {
+                skipToNextStartTag();
+            }
+            setNextRecordStartTag();
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);
+        }
+    }
+
+    @Override
+    public Record nextRecord(final boolean coerceTypes, final boolean dropUnknownFields) throws IOException, MalformedRecordException {
+        if (currentRecordStartTag == null) {
+            return null;
+        }
+        try {
+            final Record record = parseRecord(currentRecordStartTag, this.schema, coerceTypes, dropUnknownFields);
+            setNextRecordStartTag();
+            if (record != null) {
+                return record;
+            } else {
+                return new MapRecord(this.schema, Collections.emptyMap());
+            }
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);
+        }
+    }
+
+    @Override
+    public RecordSchema getSchema() throws MalformedRecordException {
+        return schema;
+    }
+
+    @Override
+    public void close() throws IOException {
+        try {
+            xmlEventReader.close();
+        } catch (XMLStreamException e) {
+            logger.error("Unable to close XMLEventReader");
+        }
+    }
+
+    private RecordSchema determineSchema() throws XMLStreamException {
+
+        setNextRecordStartTag();
+        if (currentRecordStartTag == null) {
+            throw new XMLStreamException("No root tag found, must be one of <Events> or <Event>");
+        }
+
+        if (currentRecordStartTag.getName().getLocalPart().equals("Events")) {
+            isArray = true;
+            setNextRecordStartTag();
+        }
+
+        // If there was an <Events></Events> tag pair with no Events in it, use the default schema
+        if (currentRecordStartTag == null) {
+            return generateFullSchema(new SimpleRecordSchema(Collections.emptyList()));
+        }
+
+        List<RecordField> dataFields = new ArrayList<>();
+        List<String> dataFieldNames = new ArrayList<>();
+        while (currentRecordStartTag != null) {
+            if (!currentRecordStartTag.getName().getLocalPart().equals("Event")) {
+                // Unknown and invalid tag
+                throw new XMLStreamException("Expecting <Event> tag but found unknown/invalid tag " + currentRecordStartTag.getName().getLocalPart());
+            }
+
+            setNextRecordStartTag();
+            // At an Event tag, skip the event log type tag (System, e.g.), go into EventData tag then add all the Data tags to the partial schema
+            while (currentRecordStartTag != null && !currentRecordStartTag.getName().getLocalPart().equals("EventData")) {
+                skipElement();
+                setNextRecordStartTag();
+            }
+
+            if (currentRecordStartTag == null) {
+                throw new XMLStreamException("Expecting <EventData> tag but found none");
+            }
+
+            setNextRecordStartTag();
+            if (currentRecordStartTag == null) {
+                // There was an <EventData></EventData> tag but no Data/Binary tags, so this record has been fully processed
+                continue;
+            }
+
+            String eventDataElementName = currentRecordStartTag.getName().getLocalPart();
+            while ("Data" .equals(eventDataElementName)) {
+                // Save reference to Data start element so we can continue to get the value/content
+                StartElement dataElement = currentRecordStartTag;
+                String content = getContent();
+
+                // Create field for the data point using attribute "Name"
+                String dataFieldName;
+                final Iterator<?> iterator = dataElement.getAttributes();
+                if (!iterator.hasNext()) {
+                    // If no Name attribute is provided, the Name is the content of the Data tag and there should be a following Binary tag
+                    dataFieldName = content;
+                    setNextRecordStartTag();
+                    eventDataElementName = currentRecordStartTag.getName().getLocalPart();
+                    if (!"Binary" .equals(eventDataElementName)) {
+                        throw new XMLStreamException("Expecting <Binary> tag containing data for element: " + dataFieldName);
+                    }
+                    content = getContent();
+
+                } else {
+                    final Attribute attribute = (Attribute) iterator.next();
+                    final String attributeName = attribute.getName().getLocalPart();
+                    if (!"Name" .equals(attributeName)) {
+                        throw new XMLStreamException("Expecting 'Name' attribute, actual: " + attributeName);
+                    }
+                    dataFieldName = attribute.getValue();
+                }
+                // Skip this if it has been processed in a previous record
+                if (!dataFieldNames.contains(dataFieldName)) {
+                    final DataType dataElementDataType = xmlSchemaInference.inferTextualDataType(content);
+                    RecordField newRecordField = new RecordField(dataFieldName, dataElementDataType, true);
+                    dataFields.add(newRecordField);
+                    dataFieldNames.add(dataFieldName);
+                }
+
+                // Advance to next data point (or end of EventData)
+                setNextRecordStartTag();
+                eventDataElementName = currentRecordStartTag == null ? null : currentRecordStartTag.getName().getLocalPart();
+            }
+        }
+
+        return generateFullSchema(new SimpleRecordSchema(dataFields));
+    }
+
+    private void skipElement() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+
+            if (xmlEvent.isStartElement()) {
+                skipElement();
+            }
+            if (xmlEvent.isEndElement()) {
+                return;
+            }
+        }
+    }
+
+    private void skipToNextStartTag() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isStartElement()) {
+                return;
+            }
+        }
+    }
+
+    private void setNextRecordStartTag() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isStartElement()) {
+                currentRecordStartTag = xmlEvent.asStartElement();
+                return;
+            }
+        }
+        currentRecordStartTag = null;
+    }
+
+    private RecordSchema generateFullSchema(final RecordSchema dataElementsSchema) {
+        final SimpleRecordSchema rootSchema;
+
+        // Generate the full (input) schema even if the output schema is flattened
+        List<RecordField> systemProviderFields = new ArrayList<>();
+        systemProviderFields.add(new RecordField("Guid", RecordFieldType.STRING.getDataType(), false));
+        systemProviderFields.add(new RecordField("Name", RecordFieldType.STRING.getDataType(), false));
+        SimpleRecordSchema systemProviderSchema = new SimpleRecordSchema(systemProviderFields);
+        systemProviderSchema.setSchemaName("Provider");
+
+        List<RecordField> systemTimeCreatedFields = new ArrayList<>(1);
+        systemTimeCreatedFields.add(new RecordField("SystemTime", RecordFieldType.STRING.getDataType(), false));
+        SimpleRecordSchema systemTimeCreatedSchema = new SimpleRecordSchema(systemTimeCreatedFields);
+        systemTimeCreatedSchema.setSchemaName("TimeCreated");
+
+        List<RecordField> systemExecutionFields = new ArrayList<>(2);
+        systemExecutionFields.add(new RecordField("ThreadID", RecordFieldType.INT.getDataType(), true));
+        systemExecutionFields.add(new RecordField("ProcessID", RecordFieldType.INT.getDataType(), true));
+        SimpleRecordSchema systemExecutionSchema = new SimpleRecordSchema(systemExecutionFields);
+        systemExecutionSchema.setSchemaName("Execution");
+
+        List<RecordField> systemFields = new ArrayList<>(14);
+        systemFields.add(new RecordField("Provider", RecordFieldType.RECORD.getRecordDataType(systemProviderSchema)));
+        systemFields.add(new RecordField("EventID", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Version", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Level", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Task", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Opcode", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Keywords", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("TimeCreated", RecordFieldType.RECORD.getRecordDataType(systemTimeCreatedSchema)));
+        systemFields.add(new RecordField("EventRecordID", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Correlation", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("Execution", RecordFieldType.RECORD.getRecordDataType(systemExecutionSchema)));
+        systemFields.add(new RecordField("Channel", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("Computer", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("Security", RecordFieldType.STRING.getDataType(), true));
+
+        SimpleRecordSchema systemSchema = new SimpleRecordSchema(systemFields);
+        systemSchema.setSchemaName("System");
+
+        List<RecordField> fullSchemaFields = new ArrayList<>(2);
+        fullSchemaFields.add(new RecordField("System", RecordFieldType.RECORD.getRecordDataType(systemSchema)));
+        fullSchemaFields.add(new RecordField("EventData", RecordFieldType.RECORD.getRecordDataType(dataElementsSchema)));
+
+        SimpleRecordSchema fullSchema = new SimpleRecordSchema(fullSchemaFields);
+        fullSchema.setSchemaName("Event");
+
+        rootSchema = fullSchema;
+        return rootSchema;
+    }
+
+    private String getContent() throws XMLStreamException {
+        StringBuilder content = new StringBuilder();
+        while (xmlEventReader.hasNext()) {
+            XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isCharacters()) {
+                final Characters characters = xmlEvent.asCharacters();
+                if (!characters.isWhiteSpace()) {
+                    content.append(characters.getData());
+                }
+            } else if (xmlEvent.isEndElement()) {
+                break;
+            } else if (xmlEvent.isStartElement()) {
+                this.skipElement();
+            }
+        }
+        return content.toString();
+    }
+
+    private Record parseRecord(StartElement startElement, RecordSchema schema, boolean coerceTypes, boolean dropUnknown) throws XMLStreamException, MalformedRecordException {
+        final Map<String, Object> recordValues = new HashMap<>();
+
+        // parse attributes
+        final Iterator<?> iterator = startElement.getAttributes();
+        while (iterator.hasNext()) {
+            final Attribute attribute = (Attribute) iterator.next();
+            final String targetFieldName = attribute.getName().toString();
+
+            if (dropUnknown) {
+                final Optional<RecordField> field = schema.getField(targetFieldName);
+                if (field.isPresent()) {
+
+                    // dropUnknown == true && coerceTypes == true
+                    if (coerceTypes) {
+                        final Object value;
+                        final DataType dataType = field.get().getDataType();
+                        if ((value = parseStringForType(attribute.getValue(), targetFieldName, dataType)) != null) {
+                            recordValues.put(targetFieldName, value);
+                        }
+
+                        // dropUnknown == true && coerceTypes == false
+                    } else {
+                        recordValues.put(targetFieldName, attribute.getValue());
+                    }
+                }
+            } else {
+
+                // dropUnknown == false && coerceTypes == true
+                if (coerceTypes) {
+                    final Object value;
+                    final Optional<RecordField> field = schema.getField(targetFieldName);
+                    if (field.isPresent()) {
+                        if ((value = parseStringForType(attribute.getValue(), targetFieldName, field.get().getDataType())) != null) {
+                            recordValues.put(targetFieldName, value);
+                        }
+                    } else {
+                        recordValues.put(targetFieldName, attribute.getValue());
+                    }
+
+                    // dropUnknown == false && coerceTypes == false
+                } else {
+                    recordValues.put(targetFieldName, attribute.getValue());
+                }
+            }
+        }
+
+        // parse fields
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+
+            if (xmlEvent.isStartElement()) {
+                final StartElement subStartElement = xmlEvent.asStartElement();
+                String fieldName = subStartElement.getName().getLocalPart();
+
+                final Optional<RecordField> field = schema.getField(fieldName);
+
+                if (dropUnknown) {
+                    if (field.isPresent()) {
+                        // dropUnknown == true && coerceTypes == true
+                        if (coerceTypes) {
+                            final Object value = parseFieldForType(subStartElement, fieldName, field.get().getDataType(), recordValues, true);
+                            if (value != null) {
+                                recordValues.put(fieldName, value);
+                            }
+
+                            // dropUnknown == true && coerceTypes == false
+                            // subElements of subStartElement can only be known if there is a corresponding field in the schema defined as record
+                        }
+                    } else {
+                        if ("Data" .equals(fieldName)) {
+                            Map<String, Object> namedValue = parseDataField(subStartElement, schema, true);
+                            if(namedValue != null && !namedValue.isEmpty()) {

Review comment:
       It looks like there should be a space after the `if`:
   ```suggestion
                               if (namedValue != null && !namedValue.isEmpty()) {
   ```

##########
File path: nifi-nar-bundles/nifi-standard-services/nifi-record-serialization-services-bundle/nifi-record-serialization-services/src/main/java/org/apache/nifi/windowsevent/WindowsEventLogRecordReader.java
##########
@@ -0,0 +1,626 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.nifi.windowsevent;
+
+import org.apache.nifi.logging.ComponentLog;
+import org.apache.nifi.schema.inference.TimeValueInference;
+import org.apache.nifi.serialization.MalformedRecordException;
+import org.apache.nifi.serialization.RecordReader;
+import org.apache.nifi.serialization.SimpleRecordSchema;
+import org.apache.nifi.serialization.record.DataType;
+import org.apache.nifi.serialization.record.MapRecord;
+import org.apache.nifi.serialization.record.Record;
+import org.apache.nifi.serialization.record.RecordField;
+import org.apache.nifi.serialization.record.RecordFieldType;
+import org.apache.nifi.serialization.record.RecordSchema;
+import org.apache.nifi.serialization.record.type.ArrayDataType;
+import org.apache.nifi.serialization.record.type.MapDataType;
+import org.apache.nifi.serialization.record.type.RecordDataType;
+import org.apache.nifi.serialization.record.util.DataTypeUtils;
+import org.apache.nifi.stream.io.NonCloseableInputStream;
+import org.apache.nifi.util.StringUtils;
+import org.apache.nifi.xml.inference.XmlSchemaInference;
+
+import javax.xml.stream.XMLEventReader;
+import javax.xml.stream.XMLInputFactory;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.events.Attribute;
+import javax.xml.stream.events.Characters;
+import javax.xml.stream.events.StartElement;
+import javax.xml.stream.events.XMLEvent;
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.text.DateFormat;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.Supplier;
+
+public class WindowsEventLogRecordReader implements RecordReader {
+
+    private final ComponentLog logger;
+    private final RecordSchema schema;
+    private boolean isArray = false;
+    private XMLEventReader xmlEventReader;
+
+    private StartElement currentRecordStartTag;
+    // Utility used to infer <Data> tag data types
+    private final XmlSchemaInference xmlSchemaInference;
+
+    private final Supplier<DateFormat> LAZY_DATE_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIME_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIMESTAMP_FORMAT;
+
+
+    public WindowsEventLogRecordReader(InputStream in, final String dateFormat, final String timeFormat, final String timestampFormat, ComponentLog logger)
+            throws IOException, MalformedRecordException {
+
+        this.logger = logger;
+
+        final DateFormat df = dateFormat == null ? null : DataTypeUtils.getDateFormat(dateFormat);
+        final DateFormat tf = timeFormat == null ? null : DataTypeUtils.getDateFormat(timeFormat);
+        final DateFormat tsf = timestampFormat == null ? null : DataTypeUtils.getDateFormat(timestampFormat);
+
+        LAZY_DATE_FORMAT = () -> df;
+        LAZY_TIME_FORMAT = () -> tf;
+        LAZY_TIMESTAMP_FORMAT = () -> tsf;
+
+        FilterInputStream inputStream;
+        try {
+            final XMLInputFactory xmlInputFactory = XMLInputFactory.newInstance();
+            // Avoid XXE Vulnerabilities
+            xmlInputFactory.setProperty(XMLInputFactory.SUPPORT_DTD, false);
+            xmlInputFactory.setProperty("javax.xml.stream.isSupportingExternalEntities", false);
+
+            inputStream = new NonCloseableInputStream(in);
+            inputStream.mark(Integer.MAX_VALUE);
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            xmlSchemaInference = new XmlSchemaInference(new TimeValueInference(dateFormat, timeFormat, timestampFormat));
+
+            // Do a streaming pass through the input looking for <Data> tags, then reset the input
+            schema = determineSchema();
+
+            // Restart the XML event stream and advance to the first Event tag
+            inputStream.reset();
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            if (isArray) {
+                skipToNextStartTag();
+            }
+            setNextRecordStartTag();
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);
+        }
+    }
+
+    @Override
+    public Record nextRecord(final boolean coerceTypes, final boolean dropUnknownFields) throws IOException, MalformedRecordException {
+        if (currentRecordStartTag == null) {
+            return null;
+        }
+        try {
+            final Record record = parseRecord(currentRecordStartTag, this.schema, coerceTypes, dropUnknownFields);
+            setNextRecordStartTag();
+            if (record != null) {
+                return record;
+            } else {
+                return new MapRecord(this.schema, Collections.emptyMap());
+            }
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);
+        }
+    }
+
+    @Override
+    public RecordSchema getSchema() throws MalformedRecordException {
+        return schema;
+    }
+
+    @Override
+    public void close() throws IOException {
+        try {
+            xmlEventReader.close();
+        } catch (XMLStreamException e) {
+            logger.error("Unable to close XMLEventReader");
+        }
+    }
+
+    private RecordSchema determineSchema() throws XMLStreamException {
+
+        setNextRecordStartTag();
+        if (currentRecordStartTag == null) {
+            throw new XMLStreamException("No root tag found, must be one of <Events> or <Event>");
+        }
+
+        if (currentRecordStartTag.getName().getLocalPart().equals("Events")) {
+            isArray = true;
+            setNextRecordStartTag();
+        }
+
+        // If there was an <Events></Events> tag pair with no Events in it, use the default schema
+        if (currentRecordStartTag == null) {
+            return generateFullSchema(new SimpleRecordSchema(Collections.emptyList()));
+        }
+
+        List<RecordField> dataFields = new ArrayList<>();
+        List<String> dataFieldNames = new ArrayList<>();
+        while (currentRecordStartTag != null) {
+            if (!currentRecordStartTag.getName().getLocalPart().equals("Event")) {
+                // Unknown and invalid tag
+                throw new XMLStreamException("Expecting <Event> tag but found unknown/invalid tag " + currentRecordStartTag.getName().getLocalPart());
+            }
+
+            setNextRecordStartTag();
+            // At an Event tag, skip the event log type tag (System, e.g.), go into EventData tag then add all the Data tags to the partial schema
+            while (currentRecordStartTag != null && !currentRecordStartTag.getName().getLocalPart().equals("EventData")) {
+                skipElement();
+                setNextRecordStartTag();
+            }
+
+            if (currentRecordStartTag == null) {
+                throw new XMLStreamException("Expecting <EventData> tag but found none");
+            }
+
+            setNextRecordStartTag();
+            if (currentRecordStartTag == null) {
+                // There was an <EventData></EventData> tag but no Data/Binary tags, so this record has been fully processed
+                continue;
+            }
+
+            String eventDataElementName = currentRecordStartTag.getName().getLocalPart();
+            while ("Data" .equals(eventDataElementName)) {
+                // Save reference to Data start element so we can continue to get the value/content
+                StartElement dataElement = currentRecordStartTag;
+                String content = getContent();
+
+                // Create field for the data point using attribute "Name"
+                String dataFieldName;
+                final Iterator<?> iterator = dataElement.getAttributes();
+                if (!iterator.hasNext()) {
+                    // If no Name attribute is provided, the Name is the content of the Data tag and there should be a following Binary tag
+                    dataFieldName = content;
+                    setNextRecordStartTag();
+                    eventDataElementName = currentRecordStartTag.getName().getLocalPart();
+                    if (!"Binary" .equals(eventDataElementName)) {
+                        throw new XMLStreamException("Expecting <Binary> tag containing data for element: " + dataFieldName);
+                    }
+                    content = getContent();
+
+                } else {
+                    final Attribute attribute = (Attribute) iterator.next();
+                    final String attributeName = attribute.getName().getLocalPart();
+                    if (!"Name" .equals(attributeName)) {
+                        throw new XMLStreamException("Expecting 'Name' attribute, actual: " + attributeName);
+                    }
+                    dataFieldName = attribute.getValue();
+                }
+                // Skip this if it has been processed in a previous record
+                if (!dataFieldNames.contains(dataFieldName)) {
+                    final DataType dataElementDataType = xmlSchemaInference.inferTextualDataType(content);
+                    RecordField newRecordField = new RecordField(dataFieldName, dataElementDataType, true);
+                    dataFields.add(newRecordField);
+                    dataFieldNames.add(dataFieldName);
+                }
+
+                // Advance to next data point (or end of EventData)
+                setNextRecordStartTag();
+                eventDataElementName = currentRecordStartTag == null ? null : currentRecordStartTag.getName().getLocalPart();
+            }
+        }
+
+        return generateFullSchema(new SimpleRecordSchema(dataFields));
+    }
+
+    private void skipElement() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+
+            if (xmlEvent.isStartElement()) {
+                skipElement();
+            }
+            if (xmlEvent.isEndElement()) {
+                return;
+            }
+        }
+    }
+
+    private void skipToNextStartTag() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isStartElement()) {
+                return;
+            }
+        }
+    }
+
+    private void setNextRecordStartTag() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isStartElement()) {
+                currentRecordStartTag = xmlEvent.asStartElement();
+                return;
+            }
+        }
+        currentRecordStartTag = null;
+    }
+
+    private RecordSchema generateFullSchema(final RecordSchema dataElementsSchema) {
+        final SimpleRecordSchema rootSchema;
+
+        // Generate the full (input) schema even if the output schema is flattened
+        List<RecordField> systemProviderFields = new ArrayList<>();
+        systemProviderFields.add(new RecordField("Guid", RecordFieldType.STRING.getDataType(), false));
+        systemProviderFields.add(new RecordField("Name", RecordFieldType.STRING.getDataType(), false));
+        SimpleRecordSchema systemProviderSchema = new SimpleRecordSchema(systemProviderFields);
+        systemProviderSchema.setSchemaName("Provider");
+
+        List<RecordField> systemTimeCreatedFields = new ArrayList<>(1);
+        systemTimeCreatedFields.add(new RecordField("SystemTime", RecordFieldType.STRING.getDataType(), false));
+        SimpleRecordSchema systemTimeCreatedSchema = new SimpleRecordSchema(systemTimeCreatedFields);
+        systemTimeCreatedSchema.setSchemaName("TimeCreated");
+
+        List<RecordField> systemExecutionFields = new ArrayList<>(2);
+        systemExecutionFields.add(new RecordField("ThreadID", RecordFieldType.INT.getDataType(), true));
+        systemExecutionFields.add(new RecordField("ProcessID", RecordFieldType.INT.getDataType(), true));
+        SimpleRecordSchema systemExecutionSchema = new SimpleRecordSchema(systemExecutionFields);
+        systemExecutionSchema.setSchemaName("Execution");
+
+        List<RecordField> systemFields = new ArrayList<>(14);
+        systemFields.add(new RecordField("Provider", RecordFieldType.RECORD.getRecordDataType(systemProviderSchema)));
+        systemFields.add(new RecordField("EventID", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Version", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Level", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Task", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Opcode", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Keywords", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("TimeCreated", RecordFieldType.RECORD.getRecordDataType(systemTimeCreatedSchema)));
+        systemFields.add(new RecordField("EventRecordID", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Correlation", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("Execution", RecordFieldType.RECORD.getRecordDataType(systemExecutionSchema)));
+        systemFields.add(new RecordField("Channel", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("Computer", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("Security", RecordFieldType.STRING.getDataType(), true));
+
+        SimpleRecordSchema systemSchema = new SimpleRecordSchema(systemFields);
+        systemSchema.setSchemaName("System");
+
+        List<RecordField> fullSchemaFields = new ArrayList<>(2);
+        fullSchemaFields.add(new RecordField("System", RecordFieldType.RECORD.getRecordDataType(systemSchema)));
+        fullSchemaFields.add(new RecordField("EventData", RecordFieldType.RECORD.getRecordDataType(dataElementsSchema)));
+
+        SimpleRecordSchema fullSchema = new SimpleRecordSchema(fullSchemaFields);
+        fullSchema.setSchemaName("Event");
+
+        rootSchema = fullSchema;
+        return rootSchema;
+    }
+
+    private String getContent() throws XMLStreamException {
+        StringBuilder content = new StringBuilder();
+        while (xmlEventReader.hasNext()) {
+            XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isCharacters()) {
+                final Characters characters = xmlEvent.asCharacters();
+                if (!characters.isWhiteSpace()) {
+                    content.append(characters.getData());
+                }
+            } else if (xmlEvent.isEndElement()) {
+                break;
+            } else if (xmlEvent.isStartElement()) {
+                this.skipElement();
+            }
+        }
+        return content.toString();
+    }
+
+    private Record parseRecord(StartElement startElement, RecordSchema schema, boolean coerceTypes, boolean dropUnknown) throws XMLStreamException, MalformedRecordException {
+        final Map<String, Object> recordValues = new HashMap<>();
+
+        // parse attributes
+        final Iterator<?> iterator = startElement.getAttributes();
+        while (iterator.hasNext()) {
+            final Attribute attribute = (Attribute) iterator.next();
+            final String targetFieldName = attribute.getName().toString();
+
+            if (dropUnknown) {
+                final Optional<RecordField> field = schema.getField(targetFieldName);
+                if (field.isPresent()) {
+
+                    // dropUnknown == true && coerceTypes == true
+                    if (coerceTypes) {
+                        final Object value;
+                        final DataType dataType = field.get().getDataType();
+                        if ((value = parseStringForType(attribute.getValue(), targetFieldName, dataType)) != null) {
+                            recordValues.put(targetFieldName, value);
+                        }
+
+                        // dropUnknown == true && coerceTypes == false
+                    } else {
+                        recordValues.put(targetFieldName, attribute.getValue());
+                    }
+                }
+            } else {
+
+                // dropUnknown == false && coerceTypes == true
+                if (coerceTypes) {
+                    final Object value;
+                    final Optional<RecordField> field = schema.getField(targetFieldName);
+                    if (field.isPresent()) {
+                        if ((value = parseStringForType(attribute.getValue(), targetFieldName, field.get().getDataType())) != null) {
+                            recordValues.put(targetFieldName, value);
+                        }
+                    } else {
+                        recordValues.put(targetFieldName, attribute.getValue());
+                    }
+
+                    // dropUnknown == false && coerceTypes == false
+                } else {
+                    recordValues.put(targetFieldName, attribute.getValue());
+                }
+            }
+        }
+
+        // parse fields
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+
+            if (xmlEvent.isStartElement()) {
+                final StartElement subStartElement = xmlEvent.asStartElement();
+                String fieldName = subStartElement.getName().getLocalPart();
+
+                final Optional<RecordField> field = schema.getField(fieldName);
+
+                if (dropUnknown) {
+                    if (field.isPresent()) {
+                        // dropUnknown == true && coerceTypes == true
+                        if (coerceTypes) {
+                            final Object value = parseFieldForType(subStartElement, fieldName, field.get().getDataType(), recordValues, true);
+                            if (value != null) {
+                                recordValues.put(fieldName, value);
+                            }
+
+                            // dropUnknown == true && coerceTypes == false
+                            // subElements of subStartElement can only be known if there is a corresponding field in the schema defined as record
+                        }
+                    } else {
+                        if ("Data" .equals(fieldName)) {

Review comment:
       Would it make sense to declare the `"Data"` string as a static variable like `DATA_TAG` and reuse across the class?

##########
File path: nifi-nar-bundles/nifi-standard-services/nifi-record-serialization-services-bundle/nifi-record-serialization-services/src/test/java/org/apache/nifi/windowsevent/TestWindowsEventLogRecordReader.java
##########
@@ -0,0 +1,197 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.nifi.windowsevent;
+
+import org.apache.nifi.logging.ComponentLog;
+import org.apache.nifi.serialization.MalformedRecordException;
+import org.apache.nifi.serialization.record.Record;
+import org.apache.nifi.serialization.record.RecordFieldType;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+import java.io.BufferedInputStream;
+import java.io.ByteArrayInputStream;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+public class TestWindowsEventLogRecordReader {
+
+    private static final String dateFormat = RecordFieldType.DATE.getDefaultFormat();
+    private static final String timeFormat = RecordFieldType.TIME.getDefaultFormat();
+    private static final String timestampFormat = "yyyy-MM-dd'T'18:07:51.SSS";
+
+    @Test
+    public void testSingleEvent() throws IOException, MalformedRecordException {
+        InputStream is = new BufferedInputStream(new FileInputStream("src/test/resources/windowseventlog/single_event.xml"));

Review comment:
       Is there a reason for using the `src/test/resources` path as opposed to using something like `TestWindowsEventLogRecordReader.class.getResourceAsStream("/windowseventlog/single_event.xml")`?

##########
File path: nifi-nar-bundles/nifi-standard-services/nifi-record-serialization-services-bundle/nifi-record-serialization-services/src/main/java/org/apache/nifi/windowsevent/WindowsEventLogRecordReader.java
##########
@@ -0,0 +1,626 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.nifi.windowsevent;
+
+import org.apache.nifi.logging.ComponentLog;
+import org.apache.nifi.schema.inference.TimeValueInference;
+import org.apache.nifi.serialization.MalformedRecordException;
+import org.apache.nifi.serialization.RecordReader;
+import org.apache.nifi.serialization.SimpleRecordSchema;
+import org.apache.nifi.serialization.record.DataType;
+import org.apache.nifi.serialization.record.MapRecord;
+import org.apache.nifi.serialization.record.Record;
+import org.apache.nifi.serialization.record.RecordField;
+import org.apache.nifi.serialization.record.RecordFieldType;
+import org.apache.nifi.serialization.record.RecordSchema;
+import org.apache.nifi.serialization.record.type.ArrayDataType;
+import org.apache.nifi.serialization.record.type.MapDataType;
+import org.apache.nifi.serialization.record.type.RecordDataType;
+import org.apache.nifi.serialization.record.util.DataTypeUtils;
+import org.apache.nifi.stream.io.NonCloseableInputStream;
+import org.apache.nifi.util.StringUtils;
+import org.apache.nifi.xml.inference.XmlSchemaInference;
+
+import javax.xml.stream.XMLEventReader;
+import javax.xml.stream.XMLInputFactory;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.events.Attribute;
+import javax.xml.stream.events.Characters;
+import javax.xml.stream.events.StartElement;
+import javax.xml.stream.events.XMLEvent;
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.text.DateFormat;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.function.Supplier;
+
+public class WindowsEventLogRecordReader implements RecordReader {
+
+    private final ComponentLog logger;
+    private final RecordSchema schema;
+    private boolean isArray = false;
+    private XMLEventReader xmlEventReader;
+
+    private StartElement currentRecordStartTag;
+    // Utility used to infer <Data> tag data types
+    private final XmlSchemaInference xmlSchemaInference;
+
+    private final Supplier<DateFormat> LAZY_DATE_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIME_FORMAT;
+    private final Supplier<DateFormat> LAZY_TIMESTAMP_FORMAT;
+
+
+    public WindowsEventLogRecordReader(InputStream in, final String dateFormat, final String timeFormat, final String timestampFormat, ComponentLog logger)
+            throws IOException, MalformedRecordException {
+
+        this.logger = logger;
+
+        final DateFormat df = dateFormat == null ? null : DataTypeUtils.getDateFormat(dateFormat);
+        final DateFormat tf = timeFormat == null ? null : DataTypeUtils.getDateFormat(timeFormat);
+        final DateFormat tsf = timestampFormat == null ? null : DataTypeUtils.getDateFormat(timestampFormat);
+
+        LAZY_DATE_FORMAT = () -> df;
+        LAZY_TIME_FORMAT = () -> tf;
+        LAZY_TIMESTAMP_FORMAT = () -> tsf;
+
+        FilterInputStream inputStream;
+        try {
+            final XMLInputFactory xmlInputFactory = XMLInputFactory.newInstance();
+            // Avoid XXE Vulnerabilities
+            xmlInputFactory.setProperty(XMLInputFactory.SUPPORT_DTD, false);
+            xmlInputFactory.setProperty("javax.xml.stream.isSupportingExternalEntities", false);
+
+            inputStream = new NonCloseableInputStream(in);
+            inputStream.mark(Integer.MAX_VALUE);
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            xmlSchemaInference = new XmlSchemaInference(new TimeValueInference(dateFormat, timeFormat, timestampFormat));
+
+            // Do a streaming pass through the input looking for <Data> tags, then reset the input
+            schema = determineSchema();
+
+            // Restart the XML event stream and advance to the first Event tag
+            inputStream.reset();
+            xmlEventReader = xmlInputFactory.createXMLEventReader(inputStream);
+            if (isArray) {
+                skipToNextStartTag();
+            }
+            setNextRecordStartTag();
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);
+        }
+    }
+
+    @Override
+    public Record nextRecord(final boolean coerceTypes, final boolean dropUnknownFields) throws IOException, MalformedRecordException {
+        if (currentRecordStartTag == null) {
+            return null;
+        }
+        try {
+            final Record record = parseRecord(currentRecordStartTag, this.schema, coerceTypes, dropUnknownFields);
+            setNextRecordStartTag();
+            if (record != null) {
+                return record;
+            } else {
+                return new MapRecord(this.schema, Collections.emptyMap());
+            }
+        } catch (XMLStreamException e) {
+            throw new MalformedRecordException("Could not parse XML", e);
+        }
+    }
+
+    @Override
+    public RecordSchema getSchema() throws MalformedRecordException {
+        return schema;
+    }
+
+    @Override
+    public void close() throws IOException {
+        try {
+            xmlEventReader.close();
+        } catch (XMLStreamException e) {
+            logger.error("Unable to close XMLEventReader");
+        }
+    }
+
+    private RecordSchema determineSchema() throws XMLStreamException {
+
+        setNextRecordStartTag();
+        if (currentRecordStartTag == null) {
+            throw new XMLStreamException("No root tag found, must be one of <Events> or <Event>");
+        }
+
+        if (currentRecordStartTag.getName().getLocalPart().equals("Events")) {
+            isArray = true;
+            setNextRecordStartTag();
+        }
+
+        // If there was an <Events></Events> tag pair with no Events in it, use the default schema
+        if (currentRecordStartTag == null) {
+            return generateFullSchema(new SimpleRecordSchema(Collections.emptyList()));
+        }
+
+        List<RecordField> dataFields = new ArrayList<>();
+        List<String> dataFieldNames = new ArrayList<>();
+        while (currentRecordStartTag != null) {
+            if (!currentRecordStartTag.getName().getLocalPart().equals("Event")) {
+                // Unknown and invalid tag
+                throw new XMLStreamException("Expecting <Event> tag but found unknown/invalid tag " + currentRecordStartTag.getName().getLocalPart());
+            }
+
+            setNextRecordStartTag();
+            // At an Event tag, skip the event log type tag (System, e.g.), go into EventData tag then add all the Data tags to the partial schema
+            while (currentRecordStartTag != null && !currentRecordStartTag.getName().getLocalPart().equals("EventData")) {
+                skipElement();
+                setNextRecordStartTag();
+            }
+
+            if (currentRecordStartTag == null) {
+                throw new XMLStreamException("Expecting <EventData> tag but found none");
+            }
+
+            setNextRecordStartTag();
+            if (currentRecordStartTag == null) {
+                // There was an <EventData></EventData> tag but no Data/Binary tags, so this record has been fully processed
+                continue;
+            }
+
+            String eventDataElementName = currentRecordStartTag.getName().getLocalPart();
+            while ("Data" .equals(eventDataElementName)) {
+                // Save reference to Data start element so we can continue to get the value/content
+                StartElement dataElement = currentRecordStartTag;
+                String content = getContent();
+
+                // Create field for the data point using attribute "Name"
+                String dataFieldName;
+                final Iterator<?> iterator = dataElement.getAttributes();
+                if (!iterator.hasNext()) {
+                    // If no Name attribute is provided, the Name is the content of the Data tag and there should be a following Binary tag
+                    dataFieldName = content;
+                    setNextRecordStartTag();
+                    eventDataElementName = currentRecordStartTag.getName().getLocalPart();
+                    if (!"Binary" .equals(eventDataElementName)) {
+                        throw new XMLStreamException("Expecting <Binary> tag containing data for element: " + dataFieldName);
+                    }
+                    content = getContent();
+
+                } else {
+                    final Attribute attribute = (Attribute) iterator.next();
+                    final String attributeName = attribute.getName().getLocalPart();
+                    if (!"Name" .equals(attributeName)) {
+                        throw new XMLStreamException("Expecting 'Name' attribute, actual: " + attributeName);
+                    }
+                    dataFieldName = attribute.getValue();
+                }
+                // Skip this if it has been processed in a previous record
+                if (!dataFieldNames.contains(dataFieldName)) {
+                    final DataType dataElementDataType = xmlSchemaInference.inferTextualDataType(content);
+                    RecordField newRecordField = new RecordField(dataFieldName, dataElementDataType, true);
+                    dataFields.add(newRecordField);
+                    dataFieldNames.add(dataFieldName);
+                }
+
+                // Advance to next data point (or end of EventData)
+                setNextRecordStartTag();
+                eventDataElementName = currentRecordStartTag == null ? null : currentRecordStartTag.getName().getLocalPart();
+            }
+        }
+
+        return generateFullSchema(new SimpleRecordSchema(dataFields));
+    }
+
+    private void skipElement() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+
+            if (xmlEvent.isStartElement()) {
+                skipElement();
+            }
+            if (xmlEvent.isEndElement()) {
+                return;
+            }
+        }
+    }
+
+    private void skipToNextStartTag() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isStartElement()) {
+                return;
+            }
+        }
+    }
+
+    private void setNextRecordStartTag() throws XMLStreamException {
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isStartElement()) {
+                currentRecordStartTag = xmlEvent.asStartElement();
+                return;
+            }
+        }
+        currentRecordStartTag = null;
+    }
+
+    private RecordSchema generateFullSchema(final RecordSchema dataElementsSchema) {
+        final SimpleRecordSchema rootSchema;
+
+        // Generate the full (input) schema even if the output schema is flattened
+        List<RecordField> systemProviderFields = new ArrayList<>();
+        systemProviderFields.add(new RecordField("Guid", RecordFieldType.STRING.getDataType(), false));
+        systemProviderFields.add(new RecordField("Name", RecordFieldType.STRING.getDataType(), false));
+        SimpleRecordSchema systemProviderSchema = new SimpleRecordSchema(systemProviderFields);
+        systemProviderSchema.setSchemaName("Provider");
+
+        List<RecordField> systemTimeCreatedFields = new ArrayList<>(1);
+        systemTimeCreatedFields.add(new RecordField("SystemTime", RecordFieldType.STRING.getDataType(), false));
+        SimpleRecordSchema systemTimeCreatedSchema = new SimpleRecordSchema(systemTimeCreatedFields);
+        systemTimeCreatedSchema.setSchemaName("TimeCreated");
+
+        List<RecordField> systemExecutionFields = new ArrayList<>(2);
+        systemExecutionFields.add(new RecordField("ThreadID", RecordFieldType.INT.getDataType(), true));
+        systemExecutionFields.add(new RecordField("ProcessID", RecordFieldType.INT.getDataType(), true));
+        SimpleRecordSchema systemExecutionSchema = new SimpleRecordSchema(systemExecutionFields);
+        systemExecutionSchema.setSchemaName("Execution");
+
+        List<RecordField> systemFields = new ArrayList<>(14);
+        systemFields.add(new RecordField("Provider", RecordFieldType.RECORD.getRecordDataType(systemProviderSchema)));
+        systemFields.add(new RecordField("EventID", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Version", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Level", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Task", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Opcode", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Keywords", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("TimeCreated", RecordFieldType.RECORD.getRecordDataType(systemTimeCreatedSchema)));
+        systemFields.add(new RecordField("EventRecordID", RecordFieldType.INT.getDataType(), true));
+        systemFields.add(new RecordField("Correlation", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("Execution", RecordFieldType.RECORD.getRecordDataType(systemExecutionSchema)));
+        systemFields.add(new RecordField("Channel", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("Computer", RecordFieldType.STRING.getDataType(), true));
+        systemFields.add(new RecordField("Security", RecordFieldType.STRING.getDataType(), true));
+
+        SimpleRecordSchema systemSchema = new SimpleRecordSchema(systemFields);
+        systemSchema.setSchemaName("System");
+
+        List<RecordField> fullSchemaFields = new ArrayList<>(2);
+        fullSchemaFields.add(new RecordField("System", RecordFieldType.RECORD.getRecordDataType(systemSchema)));
+        fullSchemaFields.add(new RecordField("EventData", RecordFieldType.RECORD.getRecordDataType(dataElementsSchema)));
+
+        SimpleRecordSchema fullSchema = new SimpleRecordSchema(fullSchemaFields);
+        fullSchema.setSchemaName("Event");
+
+        rootSchema = fullSchema;
+        return rootSchema;
+    }
+
+    private String getContent() throws XMLStreamException {
+        StringBuilder content = new StringBuilder();
+        while (xmlEventReader.hasNext()) {
+            XMLEvent xmlEvent = xmlEventReader.nextEvent();
+            if (xmlEvent.isCharacters()) {
+                final Characters characters = xmlEvent.asCharacters();
+                if (!characters.isWhiteSpace()) {
+                    content.append(characters.getData());
+                }
+            } else if (xmlEvent.isEndElement()) {
+                break;
+            } else if (xmlEvent.isStartElement()) {
+                this.skipElement();
+            }
+        }
+        return content.toString();
+    }
+
+    private Record parseRecord(StartElement startElement, RecordSchema schema, boolean coerceTypes, boolean dropUnknown) throws XMLStreamException, MalformedRecordException {
+        final Map<String, Object> recordValues = new HashMap<>();
+
+        // parse attributes
+        final Iterator<?> iterator = startElement.getAttributes();
+        while (iterator.hasNext()) {
+            final Attribute attribute = (Attribute) iterator.next();
+            final String targetFieldName = attribute.getName().toString();
+
+            if (dropUnknown) {
+                final Optional<RecordField> field = schema.getField(targetFieldName);
+                if (field.isPresent()) {
+
+                    // dropUnknown == true && coerceTypes == true
+                    if (coerceTypes) {
+                        final Object value;
+                        final DataType dataType = field.get().getDataType();
+                        if ((value = parseStringForType(attribute.getValue(), targetFieldName, dataType)) != null) {
+                            recordValues.put(targetFieldName, value);
+                        }
+
+                        // dropUnknown == true && coerceTypes == false
+                    } else {
+                        recordValues.put(targetFieldName, attribute.getValue());
+                    }
+                }
+            } else {
+
+                // dropUnknown == false && coerceTypes == true
+                if (coerceTypes) {
+                    final Object value;
+                    final Optional<RecordField> field = schema.getField(targetFieldName);
+                    if (field.isPresent()) {
+                        if ((value = parseStringForType(attribute.getValue(), targetFieldName, field.get().getDataType())) != null) {
+                            recordValues.put(targetFieldName, value);
+                        }
+                    } else {
+                        recordValues.put(targetFieldName, attribute.getValue());
+                    }
+
+                    // dropUnknown == false && coerceTypes == false
+                } else {
+                    recordValues.put(targetFieldName, attribute.getValue());
+                }
+            }
+        }
+
+        // parse fields
+        while (xmlEventReader.hasNext()) {
+            final XMLEvent xmlEvent = xmlEventReader.nextEvent();
+
+            if (xmlEvent.isStartElement()) {
+                final StartElement subStartElement = xmlEvent.asStartElement();
+                String fieldName = subStartElement.getName().getLocalPart();
+
+                final Optional<RecordField> field = schema.getField(fieldName);
+
+                if (dropUnknown) {
+                    if (field.isPresent()) {
+                        // dropUnknown == true && coerceTypes == true
+                        if (coerceTypes) {
+                            final Object value = parseFieldForType(subStartElement, fieldName, field.get().getDataType(), recordValues, true);
+                            if (value != null) {
+                                recordValues.put(fieldName, value);
+                            }
+
+                            // dropUnknown == true && coerceTypes == false
+                            // subElements of subStartElement can only be known if there is a corresponding field in the schema defined as record
+                        }
+                    } else {
+                        if ("Data" .equals(fieldName)) {
+                            Map<String, Object> namedValue = parseDataField(subStartElement, schema, true);
+                            if(namedValue != null && !namedValue.isEmpty()) {
+                                final String name = namedValue.keySet().iterator().next();
+                                recordValues.put(name, namedValue.get(name));
+                            }
+                        } else {
+                            skipElement();
+                        }
+                    }
+                } else {
+                    // dropUnknown == false && coerceTypes == true
+                    if (coerceTypes) {
+                        if (field.isPresent()) {
+                            final Object value = parseFieldForType(subStartElement, fieldName, field.get().getDataType(), recordValues, false);
+                            if (value != null) {
+                                recordValues.put(fieldName, value);
+                            }
+                        } else {
+                            if ("Data" .equals(fieldName)) {
+                                Map<String, Object> namedValue = parseDataField(subStartElement, schema, dropUnknown);
+                                if(namedValue != null && !namedValue.isEmpty()) {
+                                    final String name = namedValue.keySet().iterator().next();
+                                    recordValues.put(name, namedValue.get(name));
+                                }
+                            }
+                        }
+
+                        // dropUnknown == false && coerceTypes == false
+                    } else {
+                        if ("Data" .equals(fieldName)) {
+                            Map<String, Object> namedValue = parseDataField(subStartElement, schema, dropUnknown);
+                            if(namedValue != null && !namedValue.isEmpty()) {
+                                final String name = namedValue.keySet().iterator().next();
+                                recordValues.put(name, namedValue.get(name));
+                            }
+                        }
+                    }
+                }
+            } else if (xmlEvent.isEndElement()) {
+                break;
+            }
+        }
+
+        for (final Map.Entry<String, Object> entry : recordValues.entrySet()) {
+            if (entry.getValue() instanceof List) {
+                recordValues.put(entry.getKey(), ((List) entry.getValue()).toArray());
+            }
+        }
+
+        if (recordValues.size() > 0) {
+            return new MapRecord(schema, recordValues);
+        } else {
+            return null;
+        }
+    }
+
+    private Object parseStringForType(String data, String fieldName, DataType dataType) {
+        switch (dataType.getFieldType()) {
+            case BOOLEAN:
+            case BYTE:
+            case CHAR:
+            case DECIMAL:
+            case DOUBLE:
+            case FLOAT:
+            case INT:
+            case LONG:
+            case SHORT:
+            case STRING:
+            case DATE:
+            case TIME:
+            case TIMESTAMP: {
+                return DataTypeUtils.convertType(data, dataType, LAZY_DATE_FORMAT, LAZY_TIME_FORMAT, LAZY_TIMESTAMP_FORMAT, fieldName);
+            }
+        }
+        return null;
+    }
+
+    private Object parseFieldForType(StartElement startElement, String fieldName, DataType dataType, Map<String, Object> recordValues,
+                                     boolean dropUnknown) throws XMLStreamException, MalformedRecordException {
+        switch (dataType.getFieldType()) {
+            case BOOLEAN:
+            case BYTE:
+            case CHAR:
+            case DECIMAL:
+            case DOUBLE:
+            case FLOAT:
+            case INT:
+            case LONG:
+            case SHORT:
+            case STRING:
+            case DATE:
+            case TIME:
+            case TIMESTAMP: {
+
+                StringBuilder content = new StringBuilder();
+
+                while (xmlEventReader.hasNext()) {
+                    XMLEvent xmlEvent = xmlEventReader.nextEvent();
+                    if (xmlEvent.isCharacters()) {
+                        final Characters characters = xmlEvent.asCharacters();
+                        if (!characters.isWhiteSpace()) {
+                            content.append(characters.getData());
+                        }
+                    } else if (xmlEvent.isEndElement()) {
+                        final String contentToReturn = content.toString();
+
+                        if (!StringUtils.isBlank(contentToReturn)) {

Review comment:
       This could be replaced with the Apache Commons `StringUtils.isNotBlank()`

##########
File path: nifi-nar-bundles/nifi-standard-services/nifi-record-serialization-services-bundle/nifi-record-serialization-services/src/test/java/org/apache/nifi/windowsevent/TestWindowsEventLogRecordReader.java
##########
@@ -0,0 +1,197 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.nifi.windowsevent;
+
+import org.apache.nifi.logging.ComponentLog;
+import org.apache.nifi.serialization.MalformedRecordException;
+import org.apache.nifi.serialization.record.Record;
+import org.apache.nifi.serialization.record.RecordFieldType;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+import java.io.BufferedInputStream;
+import java.io.ByteArrayInputStream;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+public class TestWindowsEventLogRecordReader {
+
+    private static final String dateFormat = RecordFieldType.DATE.getDefaultFormat();
+    private static final String timeFormat = RecordFieldType.TIME.getDefaultFormat();
+    private static final String timestampFormat = "yyyy-MM-dd'T'18:07:51.SSS";

Review comment:
       Should this timestamp format also have `HH:mm:ss` in place for the specific value?




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