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Posted to issues@nifi.apache.org by GitBox <gi...@apache.org> on 2022/08/10 18:02:24 UTC

[GitHub] [nifi] exceptionfactory commented on a diff in pull request #6279: NIFI-10230 added FetchSmb

exceptionfactory commented on code in PR #6279:
URL: https://github.com/apache/nifi/pull/6279#discussion_r942729637


##########
nifi-nar-bundles/nifi-smb-bundle/nifi-smb-processors/src/main/java/org/apache/nifi/processors/smb/FetchSmb.java:
##########
@@ -0,0 +1,201 @@
+/*
+ * 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.processors.smb;
+
+import static java.util.Arrays.asList;
+import static org.apache.nifi.processor.util.StandardValidators.NON_EMPTY_EL_VALIDATOR;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import org.apache.nifi.annotation.behavior.InputRequirement;
+import org.apache.nifi.annotation.behavior.WritesAttribute;
+import org.apache.nifi.annotation.behavior.WritesAttributes;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.SeeAlso;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.PropertyDescriptor.Builder;
+import org.apache.nifi.expression.ExpressionLanguageScope;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+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.Record;
+import org.apache.nifi.services.smb.SmbClientProviderService;
+import org.apache.nifi.services.smb.SmbClientService;
+import org.apache.nifi.services.smb.SmbException;
+
+@InputRequirement(InputRequirement.Requirement.INPUT_REQUIRED)
+@Tags({"samba, smb, cifs, files", "fetch"})
+@CapabilityDescription("Fetches files from a SMB Share. Designed to be used in tandem with ListSmb.")
+@SeeAlso({ListSmb.class, PutSmbFile.class, GetSmbFile.class})
+@WritesAttributes({
+        @WritesAttribute(attribute = FetchSmb.ERROR_CODE_ATTRIBUTE, description = "The error code returned by SMB when the fetch of a file fails"),
+        @WritesAttribute(attribute = FetchSmb.ERROR_MESSAGE_ATTRIBUTE, description = "The error message returned by SMB when the fetch of a file fails")
+})
+public class FetchSmb extends AbstractProcessor {
+
+    public static final String ERROR_CODE_ATTRIBUTE = "error.code";
+    public static final String ERROR_MESSAGE_ATTRIBUTE = "error.message";
+
+    public static final PropertyDescriptor FILE_ID = new PropertyDescriptor
+            .Builder().name("file-id")
+            .displayName("File ID")
+            .description("The identifier of the file to fetch.")
+            .required(true)
+            .defaultValue("${identifier}")
+            .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
+            .addValidator(NON_EMPTY_EL_VALIDATOR)
+            .build();
+
+    public static final PropertyDescriptor SMB_CLIENT_PROVIDER_SERVICE = new Builder()
+            .name("smb-client-provider-service")
+            .displayName("SMB Client Provider Service")
+            .description("Specifies the SMB client provider to use for creating SMB connections.")
+            .required(true)
+            .identifiesControllerService(SmbClientProviderService.class)
+            .build();
+
+    public static final Relationship REL_SUCCESS =
+            new Relationship.Builder()
+                    .name("success")
+                    .description("A flowfile will be routed here for each successfully fetched File.")
+                    .build();
+    public static final Relationship REL_FAILURE =
+            new Relationship.Builder().name("failure")
+                    .description(
+                            "A flowfile will be routed here for each File for which fetch was attempted but failed.")
+                    .build();
+    public static final Relationship REL_INPUT_FAILURE =
+            new Relationship.Builder().name("input_failure")
+                    .description("The incoming flowfile will be routed here if its content could not be processed.")
+                    .build();
+    public static final Set<Relationship> relationships = Collections.unmodifiableSet(new HashSet<>(asList(
+            REL_SUCCESS,
+            REL_FAILURE,
+            REL_INPUT_FAILURE
+    )));
+    static final PropertyDescriptor RECORD_READER = new PropertyDescriptor.Builder()

Review Comment:
   This property descriptor declaration should be moved up in the file, following after the `SMB_CLIENT_PROVIDER_SERVICE`.



##########
nifi-nar-bundles/nifi-smb-bundle/nifi-smb-processors/src/main/java/org/apache/nifi/processors/smb/FetchSmb.java:
##########
@@ -0,0 +1,201 @@
+/*
+ * 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.processors.smb;
+
+import static java.util.Arrays.asList;
+import static org.apache.nifi.processor.util.StandardValidators.NON_EMPTY_EL_VALIDATOR;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import org.apache.nifi.annotation.behavior.InputRequirement;
+import org.apache.nifi.annotation.behavior.WritesAttribute;
+import org.apache.nifi.annotation.behavior.WritesAttributes;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.SeeAlso;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.PropertyDescriptor.Builder;
+import org.apache.nifi.expression.ExpressionLanguageScope;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+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.Record;
+import org.apache.nifi.services.smb.SmbClientProviderService;
+import org.apache.nifi.services.smb.SmbClientService;
+import org.apache.nifi.services.smb.SmbException;
+
+@InputRequirement(InputRequirement.Requirement.INPUT_REQUIRED)
+@Tags({"samba, smb, cifs, files", "fetch"})
+@CapabilityDescription("Fetches files from a SMB Share. Designed to be used in tandem with ListSmb.")
+@SeeAlso({ListSmb.class, PutSmbFile.class, GetSmbFile.class})
+@WritesAttributes({
+        @WritesAttribute(attribute = FetchSmb.ERROR_CODE_ATTRIBUTE, description = "The error code returned by SMB when the fetch of a file fails"),
+        @WritesAttribute(attribute = FetchSmb.ERROR_MESSAGE_ATTRIBUTE, description = "The error message returned by SMB when the fetch of a file fails")
+})
+public class FetchSmb extends AbstractProcessor {
+
+    public static final String ERROR_CODE_ATTRIBUTE = "error.code";
+    public static final String ERROR_MESSAGE_ATTRIBUTE = "error.message";
+
+    public static final PropertyDescriptor FILE_ID = new PropertyDescriptor
+            .Builder().name("file-id")
+            .displayName("File ID")
+            .description("The identifier of the file to fetch.")

Review Comment:
   Although the default value aligns with the field from `ListSmb`, it seems like the description could be more intuitive. The actual value is the full path to the remove file, so it would be helpful to incorporate that wording in the description:
   ```suggestion
               .description("The full path of the file to be retrieved from the remote server.")
   ```



##########
nifi-nar-bundles/nifi-smb-bundle/nifi-smb-processors/src/main/java/org/apache/nifi/processors/smb/FetchSmb.java:
##########
@@ -0,0 +1,201 @@
+/*
+ * 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.processors.smb;
+
+import static java.util.Arrays.asList;
+import static org.apache.nifi.processor.util.StandardValidators.NON_EMPTY_EL_VALIDATOR;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import org.apache.nifi.annotation.behavior.InputRequirement;
+import org.apache.nifi.annotation.behavior.WritesAttribute;
+import org.apache.nifi.annotation.behavior.WritesAttributes;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.SeeAlso;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.PropertyDescriptor.Builder;
+import org.apache.nifi.expression.ExpressionLanguageScope;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+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.Record;
+import org.apache.nifi.services.smb.SmbClientProviderService;
+import org.apache.nifi.services.smb.SmbClientService;
+import org.apache.nifi.services.smb.SmbException;
+
+@InputRequirement(InputRequirement.Requirement.INPUT_REQUIRED)
+@Tags({"samba, smb, cifs, files", "fetch"})
+@CapabilityDescription("Fetches files from a SMB Share. Designed to be used in tandem with ListSmb.")
+@SeeAlso({ListSmb.class, PutSmbFile.class, GetSmbFile.class})
+@WritesAttributes({
+        @WritesAttribute(attribute = FetchSmb.ERROR_CODE_ATTRIBUTE, description = "The error code returned by SMB when the fetch of a file fails"),
+        @WritesAttribute(attribute = FetchSmb.ERROR_MESSAGE_ATTRIBUTE, description = "The error message returned by SMB when the fetch of a file fails")
+})
+public class FetchSmb extends AbstractProcessor {
+
+    public static final String ERROR_CODE_ATTRIBUTE = "error.code";
+    public static final String ERROR_MESSAGE_ATTRIBUTE = "error.message";
+
+    public static final PropertyDescriptor FILE_ID = new PropertyDescriptor
+            .Builder().name("file-id")
+            .displayName("File ID")
+            .description("The identifier of the file to fetch.")
+            .required(true)
+            .defaultValue("${identifier}")
+            .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
+            .addValidator(NON_EMPTY_EL_VALIDATOR)
+            .build();
+
+    public static final PropertyDescriptor SMB_CLIENT_PROVIDER_SERVICE = new Builder()
+            .name("smb-client-provider-service")
+            .displayName("SMB Client Provider Service")
+            .description("Specifies the SMB client provider to use for creating SMB connections.")
+            .required(true)
+            .identifiesControllerService(SmbClientProviderService.class)
+            .build();
+
+    public static final Relationship REL_SUCCESS =
+            new Relationship.Builder()
+                    .name("success")
+                    .description("A flowfile will be routed here for each successfully fetched File.")
+                    .build();
+    public static final Relationship REL_FAILURE =
+            new Relationship.Builder().name("failure")
+                    .description(
+                            "A flowfile will be routed here for each File for which fetch was attempted but failed.")
+                    .build();
+    public static final Relationship REL_INPUT_FAILURE =
+            new Relationship.Builder().name("input_failure")
+                    .description("The incoming flowfile will be routed here if its content could not be processed.")
+                    .build();
+    public static final Set<Relationship> relationships = Collections.unmodifiableSet(new HashSet<>(asList(
+            REL_SUCCESS,
+            REL_FAILURE,
+            REL_INPUT_FAILURE
+    )));
+    static final PropertyDescriptor RECORD_READER = new PropertyDescriptor.Builder()
+            .name("record-reader")
+            .displayName("Record Reader")
+            .description(
+                    "Specifies the Controller Service to use for reading incoming NiFi Records. Each record should contain \"identifier\""
+                            + " attribute set to the path and name of the file to fetch."
+                            + " If not set, the Processor expects as attributes of a separate flowfile for each File to fetch.")
+            .identifiesControllerService(RecordReaderFactory.class)
+            .required(false)
+            .build();
+    private static final List<PropertyDescriptor> PROPERTIES = asList(
+            FILE_ID,
+            SMB_CLIENT_PROVIDER_SERVICE,
+            RECORD_READER
+    );
+
+    @Override
+    public Set<Relationship> getRelationships() {
+        return relationships;
+    }
+
+    @Override
+    public void onTrigger(ProcessContext context, ProcessSession session) throws ProcessException {
+        final FlowFile flowFile = session.get();
+        if (flowFile == null) {
+            return;
+        }
+
+        if (context.getProperty(RECORD_READER).isSet()) {
+            final RecordReaderFactory recordReaderFactory =
+                    context.getProperty(RECORD_READER).asControllerService(RecordReaderFactory.class);
+
+            try (InputStream inFlowFile = session.read(flowFile)) {
+                final Map<String, String> flowFileAttributes = flowFile.getAttributes();
+                final RecordReader
+                        reader =
+                        recordReaderFactory.createRecordReader(flowFileAttributes, inFlowFile, flowFile.getSize(),
+                                getLogger());
+
+                Record record;
+                while ((record = reader.nextRecord()) != null) {
+                    final String fileName = record.getAsString("identifier");
+                    final FlowFile outFlowFile = session.create(flowFile);
+                    transferFile(fileName, session, context, outFlowFile);
+                }
+            } catch (Exception e) {
+                handleInputError(e, session, flowFile);
+            } finally {
+                session.remove(flowFile);
+            }
+        } else {
+            final String fileName = context.getProperty(FILE_ID).evaluateAttributeExpressions(flowFile).getValue();
+            transferFile(fileName, session, context, flowFile);
+        }
+        session.commitAsync();
+
+    }
+
+    @Override
+    protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
+        return PROPERTIES;
+    }
+
+    private void transferFile(String fileName, ProcessSession session, ProcessContext context, FlowFile outFlowFile) {
+        final SmbClientProviderService clientProviderService =
+                context.getProperty(SMB_CLIENT_PROVIDER_SERVICE).asControllerService(SmbClientProviderService.class);
+
+        try (SmbClientService client = clientProviderService.getClient()) {
+            session.write(outFlowFile, outputStream -> client.read(fileName, outputStream));
+            session.transfer(outFlowFile, REL_SUCCESS);
+        } catch (Exception e) {
+            session.putAttribute(outFlowFile, ERROR_CODE_ATTRIBUTE, getErrorCode(e));
+            session.putAttribute(outFlowFile, ERROR_MESSAGE_ATTRIBUTE, e.getMessage());
+            session.transfer(outFlowFile, REL_FAILURE);
+        }
+
+    }
+
+    private void handleInputError(Exception exception, ProcessSession session, FlowFile flowFile) {
+        if (exception instanceof IOException || exception instanceof MalformedRecordException || exception instanceof SchemaNotFoundException) {
+            getLogger().error("Couldn't read file metadata content as records from incoming flowfile", exception);

Review Comment:
   Recommend adjusting the wording and including the FlowFile in the log for troubleshooting:
   ```suggestion
               getLogger().error("Failed to read input records {}", flowFile, exception);
   ```



##########
nifi-nar-bundles/nifi-smb-bundle/nifi-smb-processors/src/main/java/org/apache/nifi/processors/smb/FetchSmb.java:
##########
@@ -0,0 +1,201 @@
+/*
+ * 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.processors.smb;
+
+import static java.util.Arrays.asList;
+import static org.apache.nifi.processor.util.StandardValidators.NON_EMPTY_EL_VALIDATOR;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import org.apache.nifi.annotation.behavior.InputRequirement;
+import org.apache.nifi.annotation.behavior.WritesAttribute;
+import org.apache.nifi.annotation.behavior.WritesAttributes;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.SeeAlso;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.PropertyDescriptor.Builder;
+import org.apache.nifi.expression.ExpressionLanguageScope;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+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.Record;
+import org.apache.nifi.services.smb.SmbClientProviderService;
+import org.apache.nifi.services.smb.SmbClientService;
+import org.apache.nifi.services.smb.SmbException;
+
+@InputRequirement(InputRequirement.Requirement.INPUT_REQUIRED)
+@Tags({"samba, smb, cifs, files", "fetch"})
+@CapabilityDescription("Fetches files from a SMB Share. Designed to be used in tandem with ListSmb.")
+@SeeAlso({ListSmb.class, PutSmbFile.class, GetSmbFile.class})
+@WritesAttributes({
+        @WritesAttribute(attribute = FetchSmb.ERROR_CODE_ATTRIBUTE, description = "The error code returned by SMB when the fetch of a file fails"),
+        @WritesAttribute(attribute = FetchSmb.ERROR_MESSAGE_ATTRIBUTE, description = "The error message returned by SMB when the fetch of a file fails")
+})
+public class FetchSmb extends AbstractProcessor {
+
+    public static final String ERROR_CODE_ATTRIBUTE = "error.code";
+    public static final String ERROR_MESSAGE_ATTRIBUTE = "error.message";
+
+    public static final PropertyDescriptor FILE_ID = new PropertyDescriptor
+            .Builder().name("file-id")
+            .displayName("File ID")
+            .description("The identifier of the file to fetch.")
+            .required(true)
+            .defaultValue("${identifier}")
+            .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
+            .addValidator(NON_EMPTY_EL_VALIDATOR)
+            .build();
+
+    public static final PropertyDescriptor SMB_CLIENT_PROVIDER_SERVICE = new Builder()
+            .name("smb-client-provider-service")
+            .displayName("SMB Client Provider Service")
+            .description("Specifies the SMB client provider to use for creating SMB connections.")
+            .required(true)
+            .identifiesControllerService(SmbClientProviderService.class)
+            .build();
+
+    public static final Relationship REL_SUCCESS =
+            new Relationship.Builder()
+                    .name("success")
+                    .description("A flowfile will be routed here for each successfully fetched File.")
+                    .build();
+    public static final Relationship REL_FAILURE =
+            new Relationship.Builder().name("failure")
+                    .description(
+                            "A flowfile will be routed here for each File for which fetch was attempted but failed.")
+                    .build();
+    public static final Relationship REL_INPUT_FAILURE =
+            new Relationship.Builder().name("input_failure")
+                    .description("The incoming flowfile will be routed here if its content could not be processed.")
+                    .build();
+    public static final Set<Relationship> relationships = Collections.unmodifiableSet(new HashSet<>(asList(
+            REL_SUCCESS,
+            REL_FAILURE,
+            REL_INPUT_FAILURE
+    )));
+    static final PropertyDescriptor RECORD_READER = new PropertyDescriptor.Builder()
+            .name("record-reader")
+            .displayName("Record Reader")
+            .description(
+                    "Specifies the Controller Service to use for reading incoming NiFi Records. Each record should contain \"identifier\""
+                            + " attribute set to the path and name of the file to fetch."
+                            + " If not set, the Processor expects as attributes of a separate flowfile for each File to fetch.")
+            .identifiesControllerService(RecordReaderFactory.class)
+            .required(false)
+            .build();
+    private static final List<PropertyDescriptor> PROPERTIES = asList(
+            FILE_ID,
+            SMB_CLIENT_PROVIDER_SERVICE,
+            RECORD_READER
+    );
+
+    @Override
+    public Set<Relationship> getRelationships() {
+        return relationships;
+    }
+
+    @Override
+    public void onTrigger(ProcessContext context, ProcessSession session) throws ProcessException {
+        final FlowFile flowFile = session.get();
+        if (flowFile == null) {
+            return;
+        }
+
+        if (context.getProperty(RECORD_READER).isSet()) {
+            final RecordReaderFactory recordReaderFactory =
+                    context.getProperty(RECORD_READER).asControllerService(RecordReaderFactory.class);
+
+            try (InputStream inFlowFile = session.read(flowFile)) {
+                final Map<String, String> flowFileAttributes = flowFile.getAttributes();
+                final RecordReader
+                        reader =
+                        recordReaderFactory.createRecordReader(flowFileAttributes, inFlowFile, flowFile.getSize(),
+                                getLogger());
+
+                Record record;
+                while ((record = reader.nextRecord()) != null) {
+                    final String fileName = record.getAsString("identifier");
+                    final FlowFile outFlowFile = session.create(flowFile);
+                    transferFile(fileName, session, context, outFlowFile);
+                }
+            } catch (Exception e) {
+                handleInputError(e, session, flowFile);
+            } finally {
+                session.remove(flowFile);
+            }
+        } else {
+            final String fileName = context.getProperty(FILE_ID).evaluateAttributeExpressions(flowFile).getValue();
+            transferFile(fileName, session, context, flowFile);
+        }
+        session.commitAsync();

Review Comment:
   This call should not be necessary since the parent class should commit the session.



##########
nifi-nar-bundles/nifi-smb-bundle/nifi-smb-processors/src/main/java/org/apache/nifi/processors/smb/FetchSmb.java:
##########
@@ -0,0 +1,201 @@
+/*
+ * 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.processors.smb;
+
+import static java.util.Arrays.asList;
+import static org.apache.nifi.processor.util.StandardValidators.NON_EMPTY_EL_VALIDATOR;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import org.apache.nifi.annotation.behavior.InputRequirement;
+import org.apache.nifi.annotation.behavior.WritesAttribute;
+import org.apache.nifi.annotation.behavior.WritesAttributes;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.SeeAlso;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.PropertyDescriptor.Builder;
+import org.apache.nifi.expression.ExpressionLanguageScope;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+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.Record;
+import org.apache.nifi.services.smb.SmbClientProviderService;
+import org.apache.nifi.services.smb.SmbClientService;
+import org.apache.nifi.services.smb.SmbException;
+
+@InputRequirement(InputRequirement.Requirement.INPUT_REQUIRED)
+@Tags({"samba, smb, cifs, files", "fetch"})
+@CapabilityDescription("Fetches files from a SMB Share. Designed to be used in tandem with ListSmb.")
+@SeeAlso({ListSmb.class, PutSmbFile.class, GetSmbFile.class})
+@WritesAttributes({
+        @WritesAttribute(attribute = FetchSmb.ERROR_CODE_ATTRIBUTE, description = "The error code returned by SMB when the fetch of a file fails"),
+        @WritesAttribute(attribute = FetchSmb.ERROR_MESSAGE_ATTRIBUTE, description = "The error message returned by SMB when the fetch of a file fails")
+})
+public class FetchSmb extends AbstractProcessor {
+
+    public static final String ERROR_CODE_ATTRIBUTE = "error.code";
+    public static final String ERROR_MESSAGE_ATTRIBUTE = "error.message";
+
+    public static final PropertyDescriptor FILE_ID = new PropertyDescriptor
+            .Builder().name("file-id")
+            .displayName("File ID")
+            .description("The identifier of the file to fetch.")
+            .required(true)
+            .defaultValue("${identifier}")
+            .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
+            .addValidator(NON_EMPTY_EL_VALIDATOR)
+            .build();
+
+    public static final PropertyDescriptor SMB_CLIENT_PROVIDER_SERVICE = new Builder()
+            .name("smb-client-provider-service")
+            .displayName("SMB Client Provider Service")
+            .description("Specifies the SMB client provider to use for creating SMB connections.")
+            .required(true)
+            .identifiesControllerService(SmbClientProviderService.class)
+            .build();
+
+    public static final Relationship REL_SUCCESS =
+            new Relationship.Builder()
+                    .name("success")
+                    .description("A flowfile will be routed here for each successfully fetched File.")
+                    .build();
+    public static final Relationship REL_FAILURE =
+            new Relationship.Builder().name("failure")
+                    .description(
+                            "A flowfile will be routed here for each File for which fetch was attempted but failed.")
+                    .build();
+    public static final Relationship REL_INPUT_FAILURE =
+            new Relationship.Builder().name("input_failure")
+                    .description("The incoming flowfile will be routed here if its content could not be processed.")
+                    .build();
+    public static final Set<Relationship> relationships = Collections.unmodifiableSet(new HashSet<>(asList(
+            REL_SUCCESS,
+            REL_FAILURE,
+            REL_INPUT_FAILURE
+    )));
+    static final PropertyDescriptor RECORD_READER = new PropertyDescriptor.Builder()
+            .name("record-reader")
+            .displayName("Record Reader")
+            .description(
+                    "Specifies the Controller Service to use for reading incoming NiFi Records. Each record should contain \"identifier\""
+                            + " attribute set to the path and name of the file to fetch."
+                            + " If not set, the Processor expects as attributes of a separate flowfile for each File to fetch.")
+            .identifiesControllerService(RecordReaderFactory.class)
+            .required(false)
+            .build();
+    private static final List<PropertyDescriptor> PROPERTIES = asList(
+            FILE_ID,
+            SMB_CLIENT_PROVIDER_SERVICE,
+            RECORD_READER
+    );
+
+    @Override
+    public Set<Relationship> getRelationships() {
+        return relationships;
+    }
+
+    @Override
+    public void onTrigger(ProcessContext context, ProcessSession session) throws ProcessException {
+        final FlowFile flowFile = session.get();
+        if (flowFile == null) {
+            return;
+        }
+
+        if (context.getProperty(RECORD_READER).isSet()) {
+            final RecordReaderFactory recordReaderFactory =
+                    context.getProperty(RECORD_READER).asControllerService(RecordReaderFactory.class);
+
+            try (InputStream inFlowFile = session.read(flowFile)) {
+                final Map<String, String> flowFileAttributes = flowFile.getAttributes();
+                final RecordReader
+                        reader =
+                        recordReaderFactory.createRecordReader(flowFileAttributes, inFlowFile, flowFile.getSize(),
+                                getLogger());
+
+                Record record;
+                while ((record = reader.nextRecord()) != null) {
+                    final String fileName = record.getAsString("identifier");
+                    final FlowFile outFlowFile = session.create(flowFile);
+                    transferFile(fileName, session, context, outFlowFile);
+                }
+            } catch (Exception e) {
+                handleInputError(e, session, flowFile);
+            } finally {
+                session.remove(flowFile);
+            }
+        } else {
+            final String fileName = context.getProperty(FILE_ID).evaluateAttributeExpressions(flowFile).getValue();
+            transferFile(fileName, session, context, flowFile);
+        }
+        session.commitAsync();
+
+    }
+
+    @Override
+    protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
+        return PROPERTIES;
+    }
+
+    private void transferFile(String fileName, ProcessSession session, ProcessContext context, FlowFile outFlowFile) {
+        final SmbClientProviderService clientProviderService =
+                context.getProperty(SMB_CLIENT_PROVIDER_SERVICE).asControllerService(SmbClientProviderService.class);
+
+        try (SmbClientService client = clientProviderService.getClient()) {
+            session.write(outFlowFile, outputStream -> client.read(fileName, outputStream));
+            session.transfer(outFlowFile, REL_SUCCESS);
+        } catch (Exception e) {
+            session.putAttribute(outFlowFile, ERROR_CODE_ATTRIBUTE, getErrorCode(e));
+            session.putAttribute(outFlowFile, ERROR_MESSAGE_ATTRIBUTE, e.getMessage());
+            session.transfer(outFlowFile, REL_FAILURE);
+        }
+
+    }
+
+    private void handleInputError(Exception exception, ProcessSession session, FlowFile flowFile) {
+        if (exception instanceof IOException || exception instanceof MalformedRecordException || exception instanceof SchemaNotFoundException) {
+            getLogger().error("Couldn't read file metadata content as records from incoming flowfile", exception);
+        } else {
+            getLogger().error("Unexpected error while processing incoming flowfile", exception);

Review Comment:
   Recommend adjusting the wording and including the FlowFile:
   ```suggestion
               getLogger().error("Failed to read input {}", flowFile, exception);
   ```



##########
nifi-nar-bundles/nifi-smb-bundle/nifi-smb-processors/src/main/java/org/apache/nifi/processors/smb/FetchSmb.java:
##########
@@ -0,0 +1,201 @@
+/*
+ * 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.processors.smb;
+
+import static java.util.Arrays.asList;
+import static org.apache.nifi.processor.util.StandardValidators.NON_EMPTY_EL_VALIDATOR;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import org.apache.nifi.annotation.behavior.InputRequirement;
+import org.apache.nifi.annotation.behavior.WritesAttribute;
+import org.apache.nifi.annotation.behavior.WritesAttributes;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.SeeAlso;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.PropertyDescriptor.Builder;
+import org.apache.nifi.expression.ExpressionLanguageScope;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+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.Record;
+import org.apache.nifi.services.smb.SmbClientProviderService;
+import org.apache.nifi.services.smb.SmbClientService;
+import org.apache.nifi.services.smb.SmbException;
+
+@InputRequirement(InputRequirement.Requirement.INPUT_REQUIRED)
+@Tags({"samba, smb, cifs, files", "fetch"})
+@CapabilityDescription("Fetches files from a SMB Share. Designed to be used in tandem with ListSmb.")
+@SeeAlso({ListSmb.class, PutSmbFile.class, GetSmbFile.class})
+@WritesAttributes({
+        @WritesAttribute(attribute = FetchSmb.ERROR_CODE_ATTRIBUTE, description = "The error code returned by SMB when the fetch of a file fails"),
+        @WritesAttribute(attribute = FetchSmb.ERROR_MESSAGE_ATTRIBUTE, description = "The error message returned by SMB when the fetch of a file fails")
+})
+public class FetchSmb extends AbstractProcessor {
+
+    public static final String ERROR_CODE_ATTRIBUTE = "error.code";
+    public static final String ERROR_MESSAGE_ATTRIBUTE = "error.message";
+
+    public static final PropertyDescriptor FILE_ID = new PropertyDescriptor
+            .Builder().name("file-id")
+            .displayName("File ID")
+            .description("The identifier of the file to fetch.")
+            .required(true)
+            .defaultValue("${identifier}")
+            .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
+            .addValidator(NON_EMPTY_EL_VALIDATOR)
+            .build();
+
+    public static final PropertyDescriptor SMB_CLIENT_PROVIDER_SERVICE = new Builder()
+            .name("smb-client-provider-service")
+            .displayName("SMB Client Provider Service")
+            .description("Specifies the SMB client provider to use for creating SMB connections.")
+            .required(true)
+            .identifiesControllerService(SmbClientProviderService.class)
+            .build();
+
+    public static final Relationship REL_SUCCESS =
+            new Relationship.Builder()
+                    .name("success")
+                    .description("A flowfile will be routed here for each successfully fetched File.")
+                    .build();
+    public static final Relationship REL_FAILURE =
+            new Relationship.Builder().name("failure")
+                    .description(
+                            "A flowfile will be routed here for each File for which fetch was attempted but failed.")
+                    .build();
+    public static final Relationship REL_INPUT_FAILURE =
+            new Relationship.Builder().name("input_failure")
+                    .description("The incoming flowfile will be routed here if its content could not be processed.")
+                    .build();
+    public static final Set<Relationship> relationships = Collections.unmodifiableSet(new HashSet<>(asList(
+            REL_SUCCESS,
+            REL_FAILURE,
+            REL_INPUT_FAILURE
+    )));
+    static final PropertyDescriptor RECORD_READER = new PropertyDescriptor.Builder()
+            .name("record-reader")
+            .displayName("Record Reader")
+            .description(
+                    "Specifies the Controller Service to use for reading incoming NiFi Records. Each record should contain \"identifier\""
+                            + " attribute set to the path and name of the file to fetch."
+                            + " If not set, the Processor expects as attributes of a separate flowfile for each File to fetch.")
+            .identifiesControllerService(RecordReaderFactory.class)
+            .required(false)
+            .build();
+    private static final List<PropertyDescriptor> PROPERTIES = asList(
+            FILE_ID,
+            SMB_CLIENT_PROVIDER_SERVICE,
+            RECORD_READER
+    );
+
+    @Override
+    public Set<Relationship> getRelationships() {
+        return relationships;
+    }
+
+    @Override
+    public void onTrigger(ProcessContext context, ProcessSession session) throws ProcessException {
+        final FlowFile flowFile = session.get();
+        if (flowFile == null) {
+            return;
+        }
+
+        if (context.getProperty(RECORD_READER).isSet()) {
+            final RecordReaderFactory recordReaderFactory =
+                    context.getProperty(RECORD_READER).asControllerService(RecordReaderFactory.class);
+
+            try (InputStream inFlowFile = session.read(flowFile)) {
+                final Map<String, String> flowFileAttributes = flowFile.getAttributes();
+                final RecordReader
+                        reader =
+                        recordReaderFactory.createRecordReader(flowFileAttributes, inFlowFile, flowFile.getSize(),
+                                getLogger());
+
+                Record record;
+                while ((record = reader.nextRecord()) != null) {
+                    final String fileName = record.getAsString("identifier");
+                    final FlowFile outFlowFile = session.create(flowFile);
+                    transferFile(fileName, session, context, outFlowFile);
+                }
+            } catch (Exception e) {
+                handleInputError(e, session, flowFile);
+            } finally {
+                session.remove(flowFile);

Review Comment:
   It seems like the original FlowFile should be routed on failures, instead of cloning and creating a new FlowFile. Following this approach, the input FlowFile would be removed only on a successful fetch.



##########
nifi-nar-bundles/nifi-smb-bundle/nifi-smb-processors/src/main/java/org/apache/nifi/processors/smb/FetchSmb.java:
##########
@@ -0,0 +1,201 @@
+/*
+ * 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.processors.smb;
+
+import static java.util.Arrays.asList;
+import static org.apache.nifi.processor.util.StandardValidators.NON_EMPTY_EL_VALIDATOR;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import org.apache.nifi.annotation.behavior.InputRequirement;
+import org.apache.nifi.annotation.behavior.WritesAttribute;
+import org.apache.nifi.annotation.behavior.WritesAttributes;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.SeeAlso;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.PropertyDescriptor.Builder;
+import org.apache.nifi.expression.ExpressionLanguageScope;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+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.Record;
+import org.apache.nifi.services.smb.SmbClientProviderService;
+import org.apache.nifi.services.smb.SmbClientService;
+import org.apache.nifi.services.smb.SmbException;
+
+@InputRequirement(InputRequirement.Requirement.INPUT_REQUIRED)
+@Tags({"samba, smb, cifs, files", "fetch"})
+@CapabilityDescription("Fetches files from a SMB Share. Designed to be used in tandem with ListSmb.")
+@SeeAlso({ListSmb.class, PutSmbFile.class, GetSmbFile.class})
+@WritesAttributes({
+        @WritesAttribute(attribute = FetchSmb.ERROR_CODE_ATTRIBUTE, description = "The error code returned by SMB when the fetch of a file fails"),
+        @WritesAttribute(attribute = FetchSmb.ERROR_MESSAGE_ATTRIBUTE, description = "The error message returned by SMB when the fetch of a file fails")
+})
+public class FetchSmb extends AbstractProcessor {
+
+    public static final String ERROR_CODE_ATTRIBUTE = "error.code";
+    public static final String ERROR_MESSAGE_ATTRIBUTE = "error.message";
+
+    public static final PropertyDescriptor FILE_ID = new PropertyDescriptor
+            .Builder().name("file-id")
+            .displayName("File ID")
+            .description("The identifier of the file to fetch.")
+            .required(true)
+            .defaultValue("${identifier}")
+            .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
+            .addValidator(NON_EMPTY_EL_VALIDATOR)
+            .build();
+
+    public static final PropertyDescriptor SMB_CLIENT_PROVIDER_SERVICE = new Builder()
+            .name("smb-client-provider-service")
+            .displayName("SMB Client Provider Service")
+            .description("Specifies the SMB client provider to use for creating SMB connections.")
+            .required(true)
+            .identifiesControllerService(SmbClientProviderService.class)
+            .build();
+
+    public static final Relationship REL_SUCCESS =
+            new Relationship.Builder()
+                    .name("success")
+                    .description("A flowfile will be routed here for each successfully fetched File.")
+                    .build();
+    public static final Relationship REL_FAILURE =
+            new Relationship.Builder().name("failure")
+                    .description(
+                            "A flowfile will be routed here for each File for which fetch was attempted but failed.")
+                    .build();
+    public static final Relationship REL_INPUT_FAILURE =
+            new Relationship.Builder().name("input_failure")
+                    .description("The incoming flowfile will be routed here if its content could not be processed.")
+                    .build();
+    public static final Set<Relationship> relationships = Collections.unmodifiableSet(new HashSet<>(asList(
+            REL_SUCCESS,
+            REL_FAILURE,
+            REL_INPUT_FAILURE
+    )));
+    static final PropertyDescriptor RECORD_READER = new PropertyDescriptor.Builder()
+            .name("record-reader")
+            .displayName("Record Reader")
+            .description(
+                    "Specifies the Controller Service to use for reading incoming NiFi Records. Each record should contain \"identifier\""
+                            + " attribute set to the path and name of the file to fetch."
+                            + " If not set, the Processor expects as attributes of a separate flowfile for each File to fetch.")
+            .identifiesControllerService(RecordReaderFactory.class)
+            .required(false)
+            .build();
+    private static final List<PropertyDescriptor> PROPERTIES = asList(
+            FILE_ID,
+            SMB_CLIENT_PROVIDER_SERVICE,
+            RECORD_READER
+    );
+
+    @Override
+    public Set<Relationship> getRelationships() {
+        return relationships;
+    }
+
+    @Override
+    public void onTrigger(ProcessContext context, ProcessSession session) throws ProcessException {
+        final FlowFile flowFile = session.get();
+        if (flowFile == null) {
+            return;
+        }
+
+        if (context.getProperty(RECORD_READER).isSet()) {
+            final RecordReaderFactory recordReaderFactory =
+                    context.getProperty(RECORD_READER).asControllerService(RecordReaderFactory.class);
+
+            try (InputStream inFlowFile = session.read(flowFile)) {
+                final Map<String, String> flowFileAttributes = flowFile.getAttributes();
+                final RecordReader
+                        reader =
+                        recordReaderFactory.createRecordReader(flowFileAttributes, inFlowFile, flowFile.getSize(),
+                                getLogger());
+
+                Record record;
+                while ((record = reader.nextRecord()) != null) {
+                    final String fileName = record.getAsString("identifier");

Review Comment:
   This approach requires the input records use the `identifier` field as the remote path. Although this matches the definition of records from `ListSmb`, it might be helpful to make this configurable.
   
   It might be possible to repurpose the `File ID` property and use the value configured, but in that case, the property value would need to be the literal string `identifier`, instead of the expression language reference. It is probably better to have a new property named something like `File ID Field` that depends on the presence of the `Record Reader`. That could be defaulted to `identifier`, but would provide additional flexibility if needed.



##########
nifi-nar-bundles/nifi-smb-bundle/nifi-smb-processors/src/main/java/org/apache/nifi/processors/smb/FetchSmb.java:
##########
@@ -0,0 +1,201 @@
+/*
+ * 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.processors.smb;
+
+import static java.util.Arrays.asList;
+import static org.apache.nifi.processor.util.StandardValidators.NON_EMPTY_EL_VALIDATOR;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import org.apache.nifi.annotation.behavior.InputRequirement;
+import org.apache.nifi.annotation.behavior.WritesAttribute;
+import org.apache.nifi.annotation.behavior.WritesAttributes;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.SeeAlso;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.PropertyDescriptor.Builder;
+import org.apache.nifi.expression.ExpressionLanguageScope;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+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.Record;
+import org.apache.nifi.services.smb.SmbClientProviderService;
+import org.apache.nifi.services.smb.SmbClientService;
+import org.apache.nifi.services.smb.SmbException;
+
+@InputRequirement(InputRequirement.Requirement.INPUT_REQUIRED)
+@Tags({"samba, smb, cifs, files", "fetch"})
+@CapabilityDescription("Fetches files from a SMB Share. Designed to be used in tandem with ListSmb.")
+@SeeAlso({ListSmb.class, PutSmbFile.class, GetSmbFile.class})
+@WritesAttributes({
+        @WritesAttribute(attribute = FetchSmb.ERROR_CODE_ATTRIBUTE, description = "The error code returned by SMB when the fetch of a file fails"),
+        @WritesAttribute(attribute = FetchSmb.ERROR_MESSAGE_ATTRIBUTE, description = "The error message returned by SMB when the fetch of a file fails")
+})
+public class FetchSmb extends AbstractProcessor {
+
+    public static final String ERROR_CODE_ATTRIBUTE = "error.code";
+    public static final String ERROR_MESSAGE_ATTRIBUTE = "error.message";
+
+    public static final PropertyDescriptor FILE_ID = new PropertyDescriptor
+            .Builder().name("file-id")
+            .displayName("File ID")
+            .description("The identifier of the file to fetch.")
+            .required(true)
+            .defaultValue("${identifier}")
+            .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
+            .addValidator(NON_EMPTY_EL_VALIDATOR)
+            .build();
+
+    public static final PropertyDescriptor SMB_CLIENT_PROVIDER_SERVICE = new Builder()
+            .name("smb-client-provider-service")
+            .displayName("SMB Client Provider Service")
+            .description("Specifies the SMB client provider to use for creating SMB connections.")
+            .required(true)
+            .identifiesControllerService(SmbClientProviderService.class)
+            .build();
+
+    public static final Relationship REL_SUCCESS =
+            new Relationship.Builder()
+                    .name("success")
+                    .description("A flowfile will be routed here for each successfully fetched File.")
+                    .build();
+    public static final Relationship REL_FAILURE =
+            new Relationship.Builder().name("failure")
+                    .description(
+                            "A flowfile will be routed here for each File for which fetch was attempted but failed.")
+                    .build();
+    public static final Relationship REL_INPUT_FAILURE =
+            new Relationship.Builder().name("input_failure")
+                    .description("The incoming flowfile will be routed here if its content could not be processed.")
+                    .build();
+    public static final Set<Relationship> relationships = Collections.unmodifiableSet(new HashSet<>(asList(
+            REL_SUCCESS,
+            REL_FAILURE,
+            REL_INPUT_FAILURE
+    )));
+    static final PropertyDescriptor RECORD_READER = new PropertyDescriptor.Builder()
+            .name("record-reader")
+            .displayName("Record Reader")
+            .description(
+                    "Specifies the Controller Service to use for reading incoming NiFi Records. Each record should contain \"identifier\""
+                            + " attribute set to the path and name of the file to fetch."
+                            + " If not set, the Processor expects as attributes of a separate flowfile for each File to fetch.")
+            .identifiesControllerService(RecordReaderFactory.class)
+            .required(false)
+            .build();
+    private static final List<PropertyDescriptor> PROPERTIES = asList(
+            FILE_ID,
+            SMB_CLIENT_PROVIDER_SERVICE,
+            RECORD_READER
+    );
+
+    @Override
+    public Set<Relationship> getRelationships() {
+        return relationships;
+    }
+
+    @Override
+    public void onTrigger(ProcessContext context, ProcessSession session) throws ProcessException {
+        final FlowFile flowFile = session.get();
+        if (flowFile == null) {
+            return;
+        }
+
+        if (context.getProperty(RECORD_READER).isSet()) {
+            final RecordReaderFactory recordReaderFactory =
+                    context.getProperty(RECORD_READER).asControllerService(RecordReaderFactory.class);
+
+            try (InputStream inFlowFile = session.read(flowFile)) {
+                final Map<String, String> flowFileAttributes = flowFile.getAttributes();
+                final RecordReader
+                        reader =
+                        recordReaderFactory.createRecordReader(flowFileAttributes, inFlowFile, flowFile.getSize(),
+                                getLogger());
+
+                Record record;
+                while ((record = reader.nextRecord()) != null) {
+                    final String fileName = record.getAsString("identifier");
+                    final FlowFile outFlowFile = session.create(flowFile);
+                    transferFile(fileName, session, context, outFlowFile);
+                }
+            } catch (Exception e) {
+                handleInputError(e, session, flowFile);
+            } finally {
+                session.remove(flowFile);
+            }
+        } else {
+            final String fileName = context.getProperty(FILE_ID).evaluateAttributeExpressions(flowFile).getValue();
+            transferFile(fileName, session, context, flowFile);
+        }
+        session.commitAsync();
+
+    }
+
+    @Override
+    protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
+        return PROPERTIES;
+    }
+
+    private void transferFile(String fileName, ProcessSession session, ProcessContext context, FlowFile outFlowFile) {
+        final SmbClientProviderService clientProviderService =
+                context.getProperty(SMB_CLIENT_PROVIDER_SERVICE).asControllerService(SmbClientProviderService.class);
+
+        try (SmbClientService client = clientProviderService.getClient()) {
+            session.write(outFlowFile, outputStream -> client.read(fileName, outputStream));
+            session.transfer(outFlowFile, REL_SUCCESS);
+        } catch (Exception e) {
+            session.putAttribute(outFlowFile, ERROR_CODE_ATTRIBUTE, getErrorCode(e));
+            session.putAttribute(outFlowFile, ERROR_MESSAGE_ATTRIBUTE, e.getMessage());

Review Comment:
   The return value from `putAttribute()` needs to be assigned so that the session is working with the most recent FlowFile reference object.
   
   In general, method arguments should be declared as `final`, but in this case, the `outFlowFile` variable could be reassigned:
   ```suggestion
               outFlowFile = session.putAttribute(outFlowFile, ERROR_CODE_ATTRIBUTE, getErrorCode(e));
               outFlowFile = session.putAttribute(outFlowFile, ERROR_MESSAGE_ATTRIBUTE, e.getMessage());
   ```



##########
nifi-nar-bundles/nifi-smb-bundle/nifi-smb-processors/src/main/java/org/apache/nifi/processors/smb/FetchSmb.java:
##########
@@ -0,0 +1,201 @@
+/*
+ * 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.processors.smb;
+
+import static java.util.Arrays.asList;
+import static org.apache.nifi.processor.util.StandardValidators.NON_EMPTY_EL_VALIDATOR;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import org.apache.nifi.annotation.behavior.InputRequirement;
+import org.apache.nifi.annotation.behavior.WritesAttribute;
+import org.apache.nifi.annotation.behavior.WritesAttributes;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.SeeAlso;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.PropertyDescriptor.Builder;
+import org.apache.nifi.expression.ExpressionLanguageScope;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+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.Record;
+import org.apache.nifi.services.smb.SmbClientProviderService;
+import org.apache.nifi.services.smb.SmbClientService;
+import org.apache.nifi.services.smb.SmbException;
+
+@InputRequirement(InputRequirement.Requirement.INPUT_REQUIRED)
+@Tags({"samba, smb, cifs, files", "fetch"})
+@CapabilityDescription("Fetches files from a SMB Share. Designed to be used in tandem with ListSmb.")
+@SeeAlso({ListSmb.class, PutSmbFile.class, GetSmbFile.class})
+@WritesAttributes({
+        @WritesAttribute(attribute = FetchSmb.ERROR_CODE_ATTRIBUTE, description = "The error code returned by SMB when the fetch of a file fails"),
+        @WritesAttribute(attribute = FetchSmb.ERROR_MESSAGE_ATTRIBUTE, description = "The error message returned by SMB when the fetch of a file fails")
+})
+public class FetchSmb extends AbstractProcessor {
+
+    public static final String ERROR_CODE_ATTRIBUTE = "error.code";
+    public static final String ERROR_MESSAGE_ATTRIBUTE = "error.message";
+
+    public static final PropertyDescriptor FILE_ID = new PropertyDescriptor
+            .Builder().name("file-id")
+            .displayName("File ID")
+            .description("The identifier of the file to fetch.")
+            .required(true)
+            .defaultValue("${identifier}")
+            .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
+            .addValidator(NON_EMPTY_EL_VALIDATOR)
+            .build();
+
+    public static final PropertyDescriptor SMB_CLIENT_PROVIDER_SERVICE = new Builder()
+            .name("smb-client-provider-service")
+            .displayName("SMB Client Provider Service")
+            .description("Specifies the SMB client provider to use for creating SMB connections.")
+            .required(true)
+            .identifiesControllerService(SmbClientProviderService.class)
+            .build();
+
+    public static final Relationship REL_SUCCESS =
+            new Relationship.Builder()
+                    .name("success")
+                    .description("A flowfile will be routed here for each successfully fetched File.")
+                    .build();
+    public static final Relationship REL_FAILURE =
+            new Relationship.Builder().name("failure")
+                    .description(
+                            "A flowfile will be routed here for each File for which fetch was attempted but failed.")
+                    .build();
+    public static final Relationship REL_INPUT_FAILURE =
+            new Relationship.Builder().name("input_failure")
+                    .description("The incoming flowfile will be routed here if its content could not be processed.")
+                    .build();
+    public static final Set<Relationship> relationships = Collections.unmodifiableSet(new HashSet<>(asList(
+            REL_SUCCESS,
+            REL_FAILURE,
+            REL_INPUT_FAILURE
+    )));
+    static final PropertyDescriptor RECORD_READER = new PropertyDescriptor.Builder()
+            .name("record-reader")
+            .displayName("Record Reader")
+            .description(
+                    "Specifies the Controller Service to use for reading incoming NiFi Records. Each record should contain \"identifier\""
+                            + " attribute set to the path and name of the file to fetch."
+                            + " If not set, the Processor expects as attributes of a separate flowfile for each File to fetch.")
+            .identifiesControllerService(RecordReaderFactory.class)
+            .required(false)
+            .build();
+    private static final List<PropertyDescriptor> PROPERTIES = asList(
+            FILE_ID,
+            SMB_CLIENT_PROVIDER_SERVICE,
+            RECORD_READER
+    );
+
+    @Override
+    public Set<Relationship> getRelationships() {
+        return relationships;
+    }
+
+    @Override
+    public void onTrigger(ProcessContext context, ProcessSession session) throws ProcessException {
+        final FlowFile flowFile = session.get();
+        if (flowFile == null) {
+            return;
+        }
+
+        if (context.getProperty(RECORD_READER).isSet()) {
+            final RecordReaderFactory recordReaderFactory =
+                    context.getProperty(RECORD_READER).asControllerService(RecordReaderFactory.class);
+
+            try (InputStream inFlowFile = session.read(flowFile)) {
+                final Map<String, String> flowFileAttributes = flowFile.getAttributes();
+                final RecordReader
+                        reader =
+                        recordReaderFactory.createRecordReader(flowFileAttributes, inFlowFile, flowFile.getSize(),
+                                getLogger());
+
+                Record record;
+                while ((record = reader.nextRecord()) != null) {
+                    final String fileName = record.getAsString("identifier");
+                    final FlowFile outFlowFile = session.create(flowFile);
+                    transferFile(fileName, session, context, outFlowFile);
+                }
+            } catch (Exception e) {
+                handleInputError(e, session, flowFile);
+            } finally {
+                session.remove(flowFile);
+            }
+        } else {
+            final String fileName = context.getProperty(FILE_ID).evaluateAttributeExpressions(flowFile).getValue();
+            transferFile(fileName, session, context, flowFile);
+        }
+        session.commitAsync();
+
+    }
+
+    @Override
+    protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
+        return PROPERTIES;
+    }
+
+    private void transferFile(String fileName, ProcessSession session, ProcessContext context, FlowFile outFlowFile) {
+        final SmbClientProviderService clientProviderService =
+                context.getProperty(SMB_CLIENT_PROVIDER_SERVICE).asControllerService(SmbClientProviderService.class);
+
+        try (SmbClientService client = clientProviderService.getClient()) {

Review Comment:
   The current implementation repeatedly calls `getClient()` when using record-oriented processing. It would be more efficient to move the retrieval of the SmbClientService out of this method.



##########
nifi-nar-bundles/nifi-smb-bundle/nifi-smb-processors/src/main/java/org/apache/nifi/processors/smb/FetchSmb.java:
##########
@@ -0,0 +1,201 @@
+/*
+ * 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.processors.smb;
+
+import static java.util.Arrays.asList;
+import static org.apache.nifi.processor.util.StandardValidators.NON_EMPTY_EL_VALIDATOR;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import org.apache.nifi.annotation.behavior.InputRequirement;
+import org.apache.nifi.annotation.behavior.WritesAttribute;
+import org.apache.nifi.annotation.behavior.WritesAttributes;
+import org.apache.nifi.annotation.documentation.CapabilityDescription;
+import org.apache.nifi.annotation.documentation.SeeAlso;
+import org.apache.nifi.annotation.documentation.Tags;
+import org.apache.nifi.components.PropertyDescriptor;
+import org.apache.nifi.components.PropertyDescriptor.Builder;
+import org.apache.nifi.expression.ExpressionLanguageScope;
+import org.apache.nifi.flowfile.FlowFile;
+import org.apache.nifi.processor.AbstractProcessor;
+import org.apache.nifi.processor.ProcessContext;
+import org.apache.nifi.processor.ProcessSession;
+import org.apache.nifi.processor.Relationship;
+import org.apache.nifi.processor.exception.ProcessException;
+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.Record;
+import org.apache.nifi.services.smb.SmbClientProviderService;
+import org.apache.nifi.services.smb.SmbClientService;
+import org.apache.nifi.services.smb.SmbException;
+
+@InputRequirement(InputRequirement.Requirement.INPUT_REQUIRED)
+@Tags({"samba, smb, cifs, files", "fetch"})
+@CapabilityDescription("Fetches files from a SMB Share. Designed to be used in tandem with ListSmb.")
+@SeeAlso({ListSmb.class, PutSmbFile.class, GetSmbFile.class})
+@WritesAttributes({
+        @WritesAttribute(attribute = FetchSmb.ERROR_CODE_ATTRIBUTE, description = "The error code returned by SMB when the fetch of a file fails"),
+        @WritesAttribute(attribute = FetchSmb.ERROR_MESSAGE_ATTRIBUTE, description = "The error message returned by SMB when the fetch of a file fails")
+})
+public class FetchSmb extends AbstractProcessor {
+
+    public static final String ERROR_CODE_ATTRIBUTE = "error.code";
+    public static final String ERROR_MESSAGE_ATTRIBUTE = "error.message";
+
+    public static final PropertyDescriptor FILE_ID = new PropertyDescriptor
+            .Builder().name("file-id")
+            .displayName("File ID")
+            .description("The identifier of the file to fetch.")
+            .required(true)
+            .defaultValue("${identifier}")
+            .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
+            .addValidator(NON_EMPTY_EL_VALIDATOR)
+            .build();
+
+    public static final PropertyDescriptor SMB_CLIENT_PROVIDER_SERVICE = new Builder()
+            .name("smb-client-provider-service")
+            .displayName("SMB Client Provider Service")
+            .description("Specifies the SMB client provider to use for creating SMB connections.")
+            .required(true)
+            .identifiesControllerService(SmbClientProviderService.class)
+            .build();
+
+    public static final Relationship REL_SUCCESS =
+            new Relationship.Builder()
+                    .name("success")
+                    .description("A flowfile will be routed here for each successfully fetched File.")
+                    .build();
+    public static final Relationship REL_FAILURE =
+            new Relationship.Builder().name("failure")
+                    .description(
+                            "A flowfile will be routed here for each File for which fetch was attempted but failed.")
+                    .build();
+    public static final Relationship REL_INPUT_FAILURE =
+            new Relationship.Builder().name("input_failure")
+                    .description("The incoming flowfile will be routed here if its content could not be processed.")
+                    .build();
+    public static final Set<Relationship> relationships = Collections.unmodifiableSet(new HashSet<>(asList(
+            REL_SUCCESS,
+            REL_FAILURE,
+            REL_INPUT_FAILURE
+    )));
+    static final PropertyDescriptor RECORD_READER = new PropertyDescriptor.Builder()
+            .name("record-reader")
+            .displayName("Record Reader")
+            .description(
+                    "Specifies the Controller Service to use for reading incoming NiFi Records. Each record should contain \"identifier\""
+                            + " attribute set to the path and name of the file to fetch."
+                            + " If not set, the Processor expects as attributes of a separate flowfile for each File to fetch.")
+            .identifiesControllerService(RecordReaderFactory.class)
+            .required(false)
+            .build();
+    private static final List<PropertyDescriptor> PROPERTIES = asList(
+            FILE_ID,
+            SMB_CLIENT_PROVIDER_SERVICE,
+            RECORD_READER
+    );
+
+    @Override
+    public Set<Relationship> getRelationships() {
+        return relationships;
+    }
+
+    @Override
+    public void onTrigger(ProcessContext context, ProcessSession session) throws ProcessException {
+        final FlowFile flowFile = session.get();
+        if (flowFile == null) {
+            return;
+        }
+
+        if (context.getProperty(RECORD_READER).isSet()) {
+            final RecordReaderFactory recordReaderFactory =
+                    context.getProperty(RECORD_READER).asControllerService(RecordReaderFactory.class);
+
+            try (InputStream inFlowFile = session.read(flowFile)) {
+                final Map<String, String> flowFileAttributes = flowFile.getAttributes();
+                final RecordReader
+                        reader =
+                        recordReaderFactory.createRecordReader(flowFileAttributes, inFlowFile, flowFile.getSize(),
+                                getLogger());
+
+                Record record;
+                while ((record = reader.nextRecord()) != null) {
+                    final String fileName = record.getAsString("identifier");
+                    final FlowFile outFlowFile = session.create(flowFile);
+                    transferFile(fileName, session, context, outFlowFile);
+                }
+            } catch (Exception e) {
+                handleInputError(e, session, flowFile);
+            } finally {
+                session.remove(flowFile);
+            }
+        } else {
+            final String fileName = context.getProperty(FILE_ID).evaluateAttributeExpressions(flowFile).getValue();
+            transferFile(fileName, session, context, flowFile);
+        }
+        session.commitAsync();
+
+    }
+
+    @Override
+    protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
+        return PROPERTIES;
+    }
+
+    private void transferFile(String fileName, ProcessSession session, ProcessContext context, FlowFile outFlowFile) {
+        final SmbClientProviderService clientProviderService =
+                context.getProperty(SMB_CLIENT_PROVIDER_SERVICE).asControllerService(SmbClientProviderService.class);
+
+        try (SmbClientService client = clientProviderService.getClient()) {
+            session.write(outFlowFile, outputStream -> client.read(fileName, outputStream));
+            session.transfer(outFlowFile, REL_SUCCESS);
+        } catch (Exception e) {
+            session.putAttribute(outFlowFile, ERROR_CODE_ATTRIBUTE, getErrorCode(e));
+            session.putAttribute(outFlowFile, ERROR_MESSAGE_ATTRIBUTE, e.getMessage());
+            session.transfer(outFlowFile, REL_FAILURE);
+        }
+
+    }
+
+    private void handleInputError(Exception exception, ProcessSession session, FlowFile flowFile) {
+        if (exception instanceof IOException || exception instanceof MalformedRecordException || exception instanceof SchemaNotFoundException) {
+            getLogger().error("Couldn't read file metadata content as records from incoming flowfile", exception);
+        } else {
+            getLogger().error("Unexpected error while processing incoming flowfile", exception);
+        }
+        final FlowFile outFlowFile = session.create(flowFile);
+        session.putAttribute(outFlowFile, ERROR_MESSAGE_ATTRIBUTE, exception.getMessage());
+        session.transfer(outFlowFile, REL_INPUT_FAILURE);
+    }
+
+    private String getErrorCode(Exception exception) {
+        return Optional.ofNullable(exception instanceof SmbException ? (SmbException) exception : null)
+                .map(SmbException::getErrorCode)
+                .map(String::valueOf)
+                .orElse("N/A");

Review Comment:
   The use of `N/A` as a placeholder does not seem like the best option. If `-1` does not already have special meaning from the SmbException, that is one option. Otherwise, some other negative number seems best, or perhaps this method should return `null` instead.



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