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components/org.apache.nifi/nifi-ambari-nar/1.9.0/
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URL: http://svn.apache.org/viewvc/nifi/site/trunk/docs/nifi-docs/components/org.apache.nifi/nifi-record-serialization-services-nar/1.9.0/org.apache.nifi.csv.CSVReader/index.html?rev=1854109&view=auto
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+++ nifi/site/trunk/docs/nifi-docs/components/org.apache.nifi/nifi-record-serialization-services-nar/1.9.0/org.apache.nifi.csv.CSVReader/index.html Fri Feb 22 01:03:44 2019
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+<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"></meta><title>CSVReader</title><link rel="stylesheet" href="../../../../../css/component-usage.css" type="text/css"></link></head><script type="text/javascript">window.onload = function(){if(self==top) { document.getElementById('nameHeader').style.display = "inherit"; } }</script><body><h1 id="nameHeader" style="display: none;">CSVReader</h1><h2>Description: </h2><p>Parses CSV-formatted data, returning each row in the CSV file as a separate record. This reader assumes that the first line in the content is the column names and all subsequent lines are the values. See Controller Service's Usage for further documentation.</p><p><a href="additionalDetails.html">Additional Details...</a></p><h3>Tags: </h3><p>csv, parse, record, row, reader, delimited, comma, separated, values</p><h3>Properties: </h3><p>In the list below, the names of required properties appear in <strong>bold</strong>. Any other properties (not in bold) are consi
dered optional. The table also indicates any default values, and whether a property supports the <a href="../../../../../html/expression-language-guide.html">NiFi Expression Language</a>.</p><table id="properties"><tr><th>Name</th><th>Default Value</th><th>Allowable Values</th><th>Description</th></tr><tr><td id="name"><strong>Schema Access Strategy</strong></td><td id="default-value">infer-schema</td><td id="allowable-values"><ul><li>Use 'Schema Name' Property <img src="../../../../../html/images/iconInfo.png" alt="The name of the Schema to use is specified by the 'Schema Name' Property. The value of this property is used to lookup the Schema in the configured Schema Registry service." title="The name of the Schema to use is specified by the 'Schema Name' Property. The value of this property is used to lookup the Schema in the configured Schema Registry service."></img></li><li>Use 'Schema Text' Property <img src="../../../../../html/images/iconInfo.png" alt="The text of the Schema
itself is specified by the 'Schema Text' Property. The value of this property must be a valid Avro Schema. If Expression Language is used, the value of the 'Schema Text' property must be valid after substituting the expressions." title="The text of the Schema itself is specified by the 'Schema Text' Property. The value of this property must be a valid Avro Schema. If Expression Language is used, the value of the 'Schema Text' property must be valid after substituting the expressions."></img></li><li>HWX Schema Reference Attributes <img src="../../../../../html/images/iconInfo.png" alt="The FlowFile contains 3 Attributes that will be used to lookup a Schema from the configured Schema Registry: 'schema.identifier', 'schema.version', and 'schema.protocol.version'" title="The FlowFile contains 3 Attributes that will be used to lookup a Schema from the configured Schema Registry: 'schema.identifier', 'schema.version', and 'schema.protocol.version'"></img></li><li>HWX Content-Encoded Sch
ema Reference <img src="../../../../../html/images/iconInfo.png" alt="The content of the FlowFile contains a reference to a schema in the Schema Registry service. The reference is encoded as a single byte indicating the 'protocol version', followed by 8 bytes indicating the schema identifier, and finally 4 bytes indicating the schema version, as per the Hortonworks Schema Registry serializers and deserializers, found at https://github.com/hortonworks/registry" title="The content of the FlowFile contains a reference to a schema in the Schema Registry service. The reference is encoded as a single byte indicating the 'protocol version', followed by 8 bytes indicating the schema identifier, and finally 4 bytes indicating the schema version, as per the Hortonworks Schema Registry serializers and deserializers, found at https://github.com/hortonworks/registry"></img></li><li>Confluent Content-Encoded Schema Reference <img src="../../../../../html/images/iconInfo.png" alt="The content of t
he FlowFile contains a reference to a schema in the Schema Registry service. The reference is encoded as a single 'Magic Byte' followed by 4 bytes representing the identifier of the schema, as outlined at http://docs.confluent.io/current/schema-registry/docs/serializer-formatter.html. This is based on version 3.2.x of the Confluent Schema Registry." title="The content of the FlowFile contains a reference to a schema in the Schema Registry service. The reference is encoded as a single 'Magic Byte' followed by 4 bytes representing the identifier of the schema, as outlined at http://docs.confluent.io/current/schema-registry/docs/serializer-formatter.html. This is based on version 3.2.x of the Confluent Schema Registry."></img></li><li>Use String Fields From Header <img src="../../../../../html/images/iconInfo.png" alt="The first non-comment line of the CSV file is a header line that contains the names of the columns. The schema will be derived by using the column names in the header an
d assuming that all columns are of type String." title="The first non-comment line of the CSV file is a header line that contains the names of the columns. The schema will be derived by using the column names in the header and assuming that all columns are of type String."></img></li><li>Infer Schema <img src="../../../../../html/images/iconInfo.png" alt="The Schema of the data will be inferred automatically when the data is read. See component Usage and Additional Details for information about how the schema is inferred." title="The Schema of the data will be inferred automatically when the data is read. See component Usage and Additional Details for information about how the schema is inferred."></img></li></ul></td><td id="description">Specifies how to obtain the schema that is to be used for interpreting the data.</td></tr><tr><td id="name">Schema Registry</td><td id="default-value"></td><td id="allowable-values"><strong>Controller Service API: </strong><br/>SchemaRegistry<br/><
strong>Implementations: </strong><a href="../../../nifi-hwx-schema-registry-nar/1.9.0/org.apache.nifi.schemaregistry.hortonworks.HortonworksSchemaRegistry/index.html">HortonworksSchemaRegistry</a><br/><a href="../../../nifi-confluent-platform-nar/1.9.0/org.apache.nifi.confluent.schemaregistry.ConfluentSchemaRegistry/index.html">ConfluentSchemaRegistry</a><br/><a href="../../../nifi-registry-nar/1.9.0/org.apache.nifi.schemaregistry.services.AvroSchemaRegistry/index.html">AvroSchemaRegistry</a></td><td id="description">Specifies the Controller Service to use for the Schema Registry</td></tr><tr><td id="name">Schema Name</td><td id="default-value">${schema.name}</td><td id="allowable-values"></td><td id="description">Specifies the name of the schema to lookup in the Schema Registry property<br/><strong>Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)</strong></td></tr><tr><td id="name">Schema Version</td><td id="default-value"></td
><td id="allowable-values"></td><td id="description">Specifies the version of the schema to lookup in the Schema Registry. If not specified then the latest version of the schema will be retrieved.<br/><strong>Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)</strong></td></tr><tr><td id="name">Schema Branch</td><td id="default-value"></td><td id="allowable-values"></td><td id="description">Specifies the name of the branch to use when looking up the schema in the Schema Registry property. If the chosen Schema Registry does not support branching, this value will be ignored.<br/><strong>Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)</strong></td></tr><tr><td id="name">Schema Text</td><td id="default-value">${avro.schema}</td><td id="allowable-values"></td><td id="description">The text of an Avro-formatted Schema<br/><strong>Supports Expression Language: true (will be evaluated
using flow file attributes and variable registry)</strong></td></tr><tr><td id="name"><strong>CSV Parser</strong></td><td id="default-value">commons-csv</td><td id="allowable-values"><ul><li>Apache Commons CSV <img src="../../../../../html/images/iconInfo.png" alt="The CSV parser implementation from the Apache Commons CSV library." title="The CSV parser implementation from the Apache Commons CSV library."></img></li><li>Jackson CSV <img src="../../../../../html/images/iconInfo.png" alt="The CSV parser implementation from the Jackson Dataformats library." title="The CSV parser implementation from the Jackson Dataformats library."></img></li></ul></td><td id="description">Specifies which parser to use to read CSV records. NOTE: Different parsers may support different subsets of functionality and may also exhibit different levels of performance.</td></tr><tr><td id="name">Date Format</td><td id="default-value"></td><td id="allowable-values"></td><td id="description">Specifies the form
at to use when reading/writing Date fields. If not specified, Date fields will be assumed to be number of milliseconds since epoch (Midnight, Jan 1, 1970 GMT). If specified, the value must match the Java Simple Date Format (for example, MM/dd/yyyy for a two-digit month, followed by a two-digit day, followed by a four-digit year, all separated by '/' characters, as in 01/01/2017).</td></tr><tr><td id="name">Time Format</td><td id="default-value"></td><td id="allowable-values"></td><td id="description">Specifies the format to use when reading/writing Time fields. If not specified, Time fields will be assumed to be number of milliseconds since epoch (Midnight, Jan 1, 1970 GMT). If specified, the value must match the Java Simple Date Format (for example, HH:mm:ss for a two-digit hour in 24-hour format, followed by a two-digit minute, followed by a two-digit second, all separated by ':' characters, as in 18:04:15).</td></tr><tr><td id="name">Timestamp Format</td><td id="default-value"></
td><td id="allowable-values"></td><td id="description">Specifies the format to use when reading/writing Timestamp fields. If not specified, Timestamp fields will be assumed to be number of milliseconds since epoch (Midnight, Jan 1, 1970 GMT). If specified, the value must match the Java Simple Date Format (for example, MM/dd/yyyy HH:mm:ss for a two-digit month, followed by a two-digit day, followed by a four-digit year, all separated by '/' characters; and then followed by a two-digit hour in 24-hour format, followed by a two-digit minute, followed by a two-digit second, all separated by ':' characters, as in 01/01/2017 18:04:15).</td></tr><tr><td id="name"><strong>CSV Format</strong></td><td id="default-value">custom</td><td id="allowable-values"><ul><li>Custom Format <img src="../../../../../html/images/iconInfo.png" alt="The format of the CSV is configured by using the properties of this Controller Service, such as Value Separator" title="The format of the CSV is configured by usi
ng the properties of this Controller Service, such as Value Separator"></img></li><li>RFC 4180 <img src="../../../../../html/images/iconInfo.png" alt="CSV data follows the RFC 4180 Specification defined at https://tools.ietf.org/html/rfc4180" title="CSV data follows the RFC 4180 Specification defined at https://tools.ietf.org/html/rfc4180"></img></li><li>Microsoft Excel <img src="../../../../../html/images/iconInfo.png" alt="CSV data follows the format used by Microsoft Excel" title="CSV data follows the format used by Microsoft Excel"></img></li><li>Tab-Delimited <img src="../../../../../html/images/iconInfo.png" alt="CSV data is Tab-Delimited instead of Comma Delimited" title="CSV data is Tab-Delimited instead of Comma Delimited"></img></li><li>MySQL Format <img src="../../../../../html/images/iconInfo.png" alt="CSV data follows the format used by MySQL" title="CSV data follows the format used by MySQL"></img></li><li>Informix Unload <img src="../../../../../html/images/iconInfo.p
ng" alt="The format used by Informix when issuing the UNLOAD TO file_name command" title="The format used by Informix when issuing the UNLOAD TO file_name command"></img></li><li>Informix Unload Escape Disabled <img src="../../../../../html/images/iconInfo.png" alt="The format used by Informix when issuing the UNLOAD TO file_name command with escaping disabled" title="The format used by Informix when issuing the UNLOAD TO file_name command with escaping disabled"></img></li></ul></td><td id="description">Specifies which "format" the CSV data is in, or specifies if custom formatting should be used.</td></tr><tr><td id="name"><strong>Value Separator</strong></td><td id="default-value">,</td><td id="allowable-values"></td><td id="description">The character that is used to separate values/fields in a CSV Record</td></tr><tr><td id="name"><strong>Treat First Line as Header</strong></td><td id="default-value">false</td><td id="allowable-values"><ul><li>true</li><li>false</li></ul></td><td
id="description">Specifies whether or not the first line of CSV should be considered a Header or should be considered a record. If the Schema Access Strategy indicates that the columns must be defined in the header, then this property will be ignored, since the header must always be present and won't be processed as a Record. Otherwise, if 'true', then the first line of CSV data will not be processed as a record and if 'false',then the first line will be interpreted as a record.</td></tr><tr><td id="name">Ignore CSV Header Column Names</td><td id="default-value">false</td><td id="allowable-values"><ul><li>true</li><li>false</li></ul></td><td id="description">If the first line of a CSV is a header, and the configured schema does not match the fields named in the header line, this controls how the Reader will interpret the fields. If this property is true, then the field names mapped to each column are driven only by the configured schema and any fields not in the schema will be igno
red. If this property is false, then the field names found in the CSV Header will be used as the names of the fields.</td></tr><tr><td id="name"><strong>Quote Character</strong></td><td id="default-value">"</td><td id="allowable-values"></td><td id="description">The character that is used to quote values so that escape characters do not have to be used</td></tr><tr><td id="name"><strong>Escape Character</strong></td><td id="default-value">\</td><td id="allowable-values"></td><td id="description">The character that is used to escape characters that would otherwise have a specific meaning to the CSV Parser.</td></tr><tr><td id="name">Comment Marker</td><td id="default-value"></td><td id="allowable-values"></td><td id="description">The character that is used to denote the start of a comment. Any line that begins with this comment will be ignored.</td></tr><tr><td id="name">Null String</td><td id="default-value"></td><td id="allowable-values"></td><td id="description">Specifies a String
that, if present as a value in the CSV, should be considered a null field instead of using the literal value.</td></tr><tr><td id="name"><strong>Trim Fields</strong></td><td id="default-value">true</td><td id="allowable-values"><ul><li>true</li><li>false</li></ul></td><td id="description">Whether or not white space should be removed from the beginning and end of fields</td></tr><tr><td id="name"><strong>Character Set</strong></td><td id="default-value">UTF-8</td><td id="allowable-values"></td><td id="description">The Character Encoding that is used to encode/decode the CSV file</td></tr></table><h3>State management: </h3>This component does not store state.<h3>Restricted: </h3>This component is not restricted.<h3>System Resource Considerations:</h3>None specified.</body></html>
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+++ nifi/site/trunk/docs/nifi-docs/components/org.apache.nifi/nifi-record-serialization-services-nar/1.9.0/org.apache.nifi.csv.CSVRecordSetWriter/index.html Fri Feb 22 01:03:44 2019
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+<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"></meta><title>CSVRecordSetWriter</title><link rel="stylesheet" href="../../../../../css/component-usage.css" type="text/css"></link></head><script type="text/javascript">window.onload = function(){if(self==top) { document.getElementById('nameHeader').style.display = "inherit"; } }</script><body><h1 id="nameHeader" style="display: none;">CSVRecordSetWriter</h1><h2>Description: </h2><p>Writes the contents of a RecordSet as CSV data. The first line written will be the column names (unless the 'Include Header Line' property is false). All subsequent lines will be the values corresponding to the record fields.</p><h3>Tags: </h3><p>csv, result, set, recordset, record, writer, serializer, row, tsv, tab, separated, delimited</p><h3>Properties: </h3><p>In the list below, the names of required properties appear in <strong>bold</strong>. Any other properties (not in bold) are considered optional. The table also indicates any default va
lues, and whether a property supports the <a href="../../../../../html/expression-language-guide.html">NiFi Expression Language</a>.</p><table id="properties"><tr><th>Name</th><th>Default Value</th><th>Allowable Values</th><th>Description</th></tr><tr><td id="name"><strong>Schema Write Strategy</strong></td><td id="default-value">no-schema</td><td id="allowable-values"><ul><li>Set 'schema.name' Attribute <img src="../../../../../html/images/iconInfo.png" alt="The FlowFile will be given an attribute named 'schema.name' and this attribute will indicate the name of the schema in the Schema Registry. Note that ifthe schema for a record is not obtained from a Schema Registry, then no attribute will be added." title="The FlowFile will be given an attribute named 'schema.name' and this attribute will indicate the name of the schema in the Schema Registry. Note that ifthe schema for a record is not obtained from a Schema Registry, then no attribute will be added."></img></li><li>Set 'avro.s
chema' Attribute <img src="../../../../../html/images/iconInfo.png" alt="The FlowFile will be given an attribute named 'avro.schema' and this attribute will contain the Avro Schema that describes the records in the FlowFile. The contents of the FlowFile need not be Avro, but the text of the schema will be used." title="The FlowFile will be given an attribute named 'avro.schema' and this attribute will contain the Avro Schema that describes the records in the FlowFile. The contents of the FlowFile need not be Avro, but the text of the schema will be used."></img></li><li>HWX Schema Reference Attributes <img src="../../../../../html/images/iconInfo.png" alt="The FlowFile will be given a set of 3 attributes to describe the schema: 'schema.identifier', 'schema.version', and 'schema.protocol.version'. Note that if the schema for a record does not contain the necessary identifier and version, an Exception will be thrown when attempting to write the data." title="The FlowFile will be given
a set of 3 attributes to describe the schema: 'schema.identifier', 'schema.version', and 'schema.protocol.version'. Note that if the schema for a record does not contain the necessary identifier and version, an Exception will be thrown when attempting to write the data."></img></li><li>HWX Content-Encoded Schema Reference <img src="../../../../../html/images/iconInfo.png" alt="The content of the FlowFile will contain a reference to a schema in the Schema Registry service. The reference is encoded as a single byte indicating the 'protocol version', followed by 8 bytes indicating the schema identifier, and finally 4 bytes indicating the schema version, as per the Hortonworks Schema Registry serializers and deserializers, as found at https://github.com/hortonworks/registry. This will be prepended to each FlowFile. Note that if the schema for a record does not contain the necessary identifier and version, an Exception will be thrown when attempting to write the data." title="The conten
t of the FlowFile will contain a reference to a schema in the Schema Registry service. The reference is encoded as a single byte indicating the 'protocol version', followed by 8 bytes indicating the schema identifier, and finally 4 bytes indicating the schema version, as per the Hortonworks Schema Registry serializers and deserializers, as found at https://github.com/hortonworks/registry. This will be prepended to each FlowFile. Note that if the schema for a record does not contain the necessary identifier and version, an Exception will be thrown when attempting to write the data."></img></li><li>Confluent Schema Registry Reference <img src="../../../../../html/images/iconInfo.png" alt="The content of the FlowFile will contain a reference to a schema in the Schema Registry service. The reference is encoded as a single 'Magic Byte' followed by 4 bytes representing the identifier of the schema, as outlined at http://docs.confluent.io/current/schema-registry/docs/serializer-formatter.h
tml. This will be prepended to each FlowFile. Note that if the schema for a record does not contain the necessary identifier and version, an Exception will be thrown when attempting to write the data. This is based on the encoding used by version 3.2.x of the Confluent Schema Registry." title="The content of the FlowFile will contain a reference to a schema in the Schema Registry service. The reference is encoded as a single 'Magic Byte' followed by 4 bytes representing the identifier of the schema, as outlined at http://docs.confluent.io/current/schema-registry/docs/serializer-formatter.html. This will be prepended to each FlowFile. Note that if the schema for a record does not contain the necessary identifier and version, an Exception will be thrown when attempting to write the data. This is based on the encoding used by version 3.2.x of the Confluent Schema Registry."></img></li><li>Do Not Write Schema <img src="../../../../../html/images/iconInfo.png" alt="Do not add any schema-
related information to the FlowFile." title="Do not add any schema-related information to the FlowFile."></img></li></ul></td><td id="description">Specifies how the schema for a Record should be added to the data.</td></tr><tr><td id="name">Schema Cache</td><td id="default-value"></td><td id="allowable-values"><strong>Controller Service API: </strong><br/>RecordSchemaCacheService<br/><strong>Implementation: </strong><a href="../org.apache.nifi.schema.inference.VolatileSchemaCache/index.html">VolatileSchemaCache</a></td><td id="description">Specifies a Schema Cache to add the Record Schema to so that Record Readers can quickly lookup the schema.</td></tr><tr><td id="name"><strong>Schema Access Strategy</strong></td><td id="default-value">inherit-record-schema</td><td id="allowable-values"><ul><li>Use 'Schema Name' Property <img src="../../../../../html/images/iconInfo.png" alt="The name of the Schema to use is specified by the 'Schema Name' Property. The value of this property is use
d to lookup the Schema in the configured Schema Registry service." title="The name of the Schema to use is specified by the 'Schema Name' Property. The value of this property is used to lookup the Schema in the configured Schema Registry service."></img></li><li>Inherit Record Schema <img src="../../../../../html/images/iconInfo.png" alt="The schema used to write records will be the same schema that was given to the Record when the Record was created." title="The schema used to write records will be the same schema that was given to the Record when the Record was created."></img></li><li>Use 'Schema Text' Property <img src="../../../../../html/images/iconInfo.png" alt="The text of the Schema itself is specified by the 'Schema Text' Property. The value of this property must be a valid Avro Schema. If Expression Language is used, the value of the 'Schema Text' property must be valid after substituting the expressions." title="The text of the Schema itself is specified by the 'Schema T
ext' Property. The value of this property must be a valid Avro Schema. If Expression Language is used, the value of the 'Schema Text' property must be valid after substituting the expressions."></img></li></ul></td><td id="description">Specifies how to obtain the schema that is to be used for interpreting the data.</td></tr><tr><td id="name">Schema Registry</td><td id="default-value"></td><td id="allowable-values"><strong>Controller Service API: </strong><br/>SchemaRegistry<br/><strong>Implementations: </strong><a href="../../../nifi-hwx-schema-registry-nar/1.9.0/org.apache.nifi.schemaregistry.hortonworks.HortonworksSchemaRegistry/index.html">HortonworksSchemaRegistry</a><br/><a href="../../../nifi-confluent-platform-nar/1.9.0/org.apache.nifi.confluent.schemaregistry.ConfluentSchemaRegistry/index.html">ConfluentSchemaRegistry</a><br/><a href="../../../nifi-registry-nar/1.9.0/org.apache.nifi.schemaregistry.services.AvroSchemaRegistry/index.html">AvroSchemaRegistry</a></td><td id="des
cription">Specifies the Controller Service to use for the Schema Registry</td></tr><tr><td id="name">Schema Name</td><td id="default-value">${schema.name}</td><td id="allowable-values"></td><td id="description">Specifies the name of the schema to lookup in the Schema Registry property<br/><strong>Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)</strong></td></tr><tr><td id="name">Schema Version</td><td id="default-value"></td><td id="allowable-values"></td><td id="description">Specifies the version of the schema to lookup in the Schema Registry. If not specified then the latest version of the schema will be retrieved.<br/><strong>Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)</strong></td></tr><tr><td id="name">Schema Branch</td><td id="default-value"></td><td id="allowable-values"></td><td id="description">Specifies the name of the branch to use when looking up the schema
in the Schema Registry property. If the chosen Schema Registry does not support branching, this value will be ignored.<br/><strong>Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)</strong></td></tr><tr><td id="name">Schema Text</td><td id="default-value">${avro.schema}</td><td id="allowable-values"></td><td id="description">The text of an Avro-formatted Schema<br/><strong>Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)</strong></td></tr><tr><td id="name">Date Format</td><td id="default-value"></td><td id="allowable-values"></td><td id="description">Specifies the format to use when reading/writing Date fields. If not specified, Date fields will be assumed to be number of milliseconds since epoch (Midnight, Jan 1, 1970 GMT). If specified, the value must match the Java Simple Date Format (for example, MM/dd/yyyy for a two-digit month, followed by a two-digit day, followed by
a four-digit year, all separated by '/' characters, as in 01/01/2017).</td></tr><tr><td id="name">Time Format</td><td id="default-value"></td><td id="allowable-values"></td><td id="description">Specifies the format to use when reading/writing Time fields. If not specified, Time fields will be assumed to be number of milliseconds since epoch (Midnight, Jan 1, 1970 GMT). If specified, the value must match the Java Simple Date Format (for example, HH:mm:ss for a two-digit hour in 24-hour format, followed by a two-digit minute, followed by a two-digit second, all separated by ':' characters, as in 18:04:15).</td></tr><tr><td id="name">Timestamp Format</td><td id="default-value"></td><td id="allowable-values"></td><td id="description">Specifies the format to use when reading/writing Timestamp fields. If not specified, Timestamp fields will be assumed to be number of milliseconds since epoch (Midnight, Jan 1, 1970 GMT). If specified, the value must match the Java Simple Date Format (for e
xample, MM/dd/yyyy HH:mm:ss for a two-digit month, followed by a two-digit day, followed by a four-digit year, all separated by '/' characters; and then followed by a two-digit hour in 24-hour format, followed by a two-digit minute, followed by a two-digit second, all separated by ':' characters, as in 01/01/2017 18:04:15).</td></tr><tr><td id="name"><strong>CSV Format</strong></td><td id="default-value">custom</td><td id="allowable-values"><ul><li>Custom Format <img src="../../../../../html/images/iconInfo.png" alt="The format of the CSV is configured by using the properties of this Controller Service, such as Value Separator" title="The format of the CSV is configured by using the properties of this Controller Service, such as Value Separator"></img></li><li>RFC 4180 <img src="../../../../../html/images/iconInfo.png" alt="CSV data follows the RFC 4180 Specification defined at https://tools.ietf.org/html/rfc4180" title="CSV data follows the RFC 4180 Specification defined at https:/
/tools.ietf.org/html/rfc4180"></img></li><li>Microsoft Excel <img src="../../../../../html/images/iconInfo.png" alt="CSV data follows the format used by Microsoft Excel" title="CSV data follows the format used by Microsoft Excel"></img></li><li>Tab-Delimited <img src="../../../../../html/images/iconInfo.png" alt="CSV data is Tab-Delimited instead of Comma Delimited" title="CSV data is Tab-Delimited instead of Comma Delimited"></img></li><li>MySQL Format <img src="../../../../../html/images/iconInfo.png" alt="CSV data follows the format used by MySQL" title="CSV data follows the format used by MySQL"></img></li><li>Informix Unload <img src="../../../../../html/images/iconInfo.png" alt="The format used by Informix when issuing the UNLOAD TO file_name command" title="The format used by Informix when issuing the UNLOAD TO file_name command"></img></li><li>Informix Unload Escape Disabled <img src="../../../../../html/images/iconInfo.png" alt="The format used by Informix when issuing the
UNLOAD TO file_name command with escaping disabled" title="The format used by Informix when issuing the UNLOAD TO file_name command with escaping disabled"></img></li></ul></td><td id="description">Specifies which "format" the CSV data is in, or specifies if custom formatting should be used.</td></tr><tr><td id="name"><strong>Value Separator</strong></td><td id="default-value">,</td><td id="allowable-values"></td><td id="description">The character that is used to separate values/fields in a CSV Record</td></tr><tr><td id="name"><strong>Include Header Line</strong></td><td id="default-value">true</td><td id="allowable-values"><ul><li>true</li><li>false</li></ul></td><td id="description">Specifies whether or not the CSV column names should be written out as the first line.</td></tr><tr><td id="name"><strong>Quote Character</strong></td><td id="default-value">"</td><td id="allowable-values"></td><td id="description">The character that is used to quote values so that escape characters d
o not have to be used</td></tr><tr><td id="name"><strong>Escape Character</strong></td><td id="default-value">\</td><td id="allowable-values"></td><td id="description">The character that is used to escape characters that would otherwise have a specific meaning to the CSV Parser.</td></tr><tr><td id="name">Comment Marker</td><td id="default-value"></td><td id="allowable-values"></td><td id="description">The character that is used to denote the start of a comment. Any line that begins with this comment will be ignored.</td></tr><tr><td id="name">Null String</td><td id="default-value"></td><td id="allowable-values"></td><td id="description">Specifies a String that, if present as a value in the CSV, should be considered a null field instead of using the literal value.</td></tr><tr><td id="name"><strong>Trim Fields</strong></td><td id="default-value">true</td><td id="allowable-values"><ul><li>true</li><li>false</li></ul></td><td id="description">Whether or not white space should be remov
ed from the beginning and end of fields</td></tr><tr><td id="name"><strong>Quote Mode</strong></td><td id="default-value">MINIMAL</td><td id="allowable-values"><ul><li>Quote All Values <img src="../../../../../html/images/iconInfo.png" alt="All values will be quoted using the configured quote character." title="All values will be quoted using the configured quote character."></img></li><li>Quote Minimal <img src="../../../../../html/images/iconInfo.png" alt="Values will be quoted only if they are contain special characters such as newline characters or field separators." title="Values will be quoted only if they are contain special characters such as newline characters or field separators."></img></li><li>Quote Non-Numeric Values <img src="../../../../../html/images/iconInfo.png" alt="Values will be quoted unless the value is a number." title="Values will be quoted unless the value is a number."></img></li><li>Do Not Quote Values <img src="../../../../../html/images/iconInfo.png" al
t="Values will not be quoted. Instead, all special characters will be escaped using the configured escape character." title="Values will not be quoted. Instead, all special characters will be escaped using the configured escape character."></img></li></ul></td><td id="description">Specifies how fields should be quoted when they are written</td></tr><tr><td id="name"><strong>Record Separator</strong></td><td id="default-value">\n</td><td id="allowable-values"></td><td id="description">Specifies the characters to use in order to separate CSV Records</td></tr><tr><td id="name"><strong>Include Trailing Delimiter</strong></td><td id="default-value">false</td><td id="allowable-values"><ul><li>true</li><li>false</li></ul></td><td id="description">If true, a trailing delimiter will be added to each CSV Record that is written. If false, the trailing delimiter will be omitted.</td></tr><tr><td id="name"><strong>Character Set</strong></td><td id="default-value">UTF-8</td><td id="allowable-valu
es"></td><td id="description">The Character Encoding that is used to encode/decode the CSV file</td></tr></table><h3>State management: </h3>This component does not store state.<h3>Restricted: </h3>This component is not restricted.<h3>System Resource Considerations:</h3>None specified.</body></html>
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+++ nifi/site/trunk/docs/nifi-docs/components/org.apache.nifi/nifi-record-serialization-services-nar/1.9.0/org.apache.nifi.grok.GrokReader/additionalDetails.html Fri Feb 22 01:03:44 2019
@@ -0,0 +1,405 @@
+<!DOCTYPE html>
+<html lang="en">
+ <!--
+ 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.
+ -->
+ <head>
+ <meta charset="utf-8"/>
+ <title>GrokReader</title>
+ <link rel="stylesheet" href="../../../../../css/component-usage.css" type="text/css"/>
+ </head>
+
+ <body>
+ <p>
+ The GrokReader Controller Service provides a means for parsing and structuring input that is
+ made up of unstructured text, such as log files. Grok allows users to add a naming construct to
+ Regular Expressions such that they can be composed in order to create expressions that are easier
+ to manage and work with. This Controller Service consists of one Required Property and a few Optional
+ Properties. The is named <code>Grok Pattern File</code> property specifies the filename of
+ a file that contains Grok Patterns that can be used for parsing log data. If not specified, a default
+ patterns file will be used. Its contents are provided below. There are also properties for specifying
+ the schema to use when parsing data. The schema is not required. However, when data is parsed
+ a Record is created that contains all of the fields present in the Grok Expression (explained below),
+ and all fields are of type String. If a schema is chosen, the field can be declared to be a different,
+ compatible type, such as number. Additionally, if the schema does not contain one of the fields in the
+ parsed data, that field will be ignored. This can be used to filter out fields that are not of interest.
+ </p>
+
+ <p>
+ The Required Property is named <code>Grok Expression</code> and specifies how to parse each
+ incoming record. This is done by providing a Grok Expression such as:
+ <code>%{TIMESTAMP_ISO8601:timestamp} %{LOGLEVEL:level} \[%{DATA:thread}\] %{DATA:class} %{GREEDYDATA:message}</code>.
+ This Expression will parse Apache NiFi log messages. This is accomplished by specifying that a line begins
+ with the <code>TIMESTAMP_ISO8601</code> pattern (which is a Regular Expression defined in the default
+ Grok Patterns File). The value that matches this pattern is then given the name <code>timestamp</code>. As a result,
+ the value that matches this pattern will be assigned to a field named <code>timestamp</code> in the Record that
+ produced by this Controller Service.
+ </p>
+
+ <p>
+ If a line is encountered in the FlowFile that does not match the configured Grok Expression, it is assumed that the line
+ is part of the previous message. If the line is the start of a stack trace, then the entire stack trace is read in and assigned
+ to a field named <code>STACK_TRACE</code>. Otherwise, the line is appended to the last field defined in the Grok Expression. This
+ is done because typically the last field is a 'message' type of field, which can consist of new-lines.
+ </p>
+
+
+ <h2>Schemas and Type Coercion</h2>
+
+ <p>
+ When a record is parsed from incoming data, it is separated into fields. Each of these fields is then looked up against the
+ configured schema (by field name) in order to determine what the type of the data should be. If the field is not present in
+ the schema, that field is omitted from the Record. If the field is found in the schema, the data type of the received data
+ is compared against the data type specified in the schema. If the types match, the value of that field is used as-is. If the
+ schema indicates that the field should be of a different type, then the Controller Service will attempt to coerce the data
+ into the type specified by the schema. If the field cannot be coerced into the specified type, an Exception will be thrown.
+ </p>
+
+ <p>
+ The following rules apply when attempting to coerce a field value from one data type to another:
+ </p>
+
+ <ul>
+ <li>Any data type can be coerced into a String type.</li>
+ <li>Any numeric data type (Byte, Short, Int, Long, Float, Double) can be coerced into any other numeric data type.</li>
+ <li>Any numeric value can be coerced into a Date, Time, or Timestamp type, by assuming that the Long value is the number of
+ milliseconds since epoch (Midnight GMT, January 1, 1970).</li>
+ <li>A String value can be coerced into a Date, Time, or Timestamp type, if its format matches the configured "Date Format," "Time Format,"
+ or "Timestamp Format."</li>
+ <li>A String value can be coerced into a numeric value if the value is of the appropriate type. For example, the String value
+ <code>8</code> can be coerced into any numeric type. However, the String value <code>8.2</code> can be coerced into a Double or Float
+ type but not an Integer.</li>
+ <li>A String value of "true" or "false" (regardless of case) can be coerced into a Boolean value.</li>
+ <li>A String value that is not empty can be coerced into a Char type. If the String contains more than 1 character, the first character is used
+ and the rest of the characters are ignored.</li>
+ <li>Any "date/time" type (Date, Time, Timestamp) can be coerced into any other "date/time" type.</li>
+ <li>Any "date/time" type can be coerced into a Long type, representing the number of milliseconds since epoch (Midnight GMT, January 1, 1970).</li>
+ <li>Any "date/time" type can be coerced into a String. The format of the String is whatever DateFormat is configured for the corresponding
+ property (Date Format, Time Format, Timestamp Format property).</li>
+ </ul>
+
+ <p>
+ If none of the above rules apply when attempting to coerce a value from one data type to another, the coercion will fail and an Exception
+ will be thrown.
+ </p>
+
+
+
+ <h2>
+ Examples
+ </h2>
+
+ <p>
+ As an example, consider that this Controller Service is configured with the following properties:
+ </p>
+
+ <table>
+ <head>
+ <th>Property Name</th>
+ <th>Property Value</th>
+ </head>
+ <body>
+ <tr>
+ <td>Grok Expression</td>
+ <td><code>%{TIMESTAMP_ISO8601:timestamp} %{LOGLEVEL:level} \[%{DATA:thread}\] %{DATA:class} %{GREEDYDATA:message}</code></td>
+ </tr>
+ </body>
+ </table>
+
+ <p>
+ Additionally, let's consider a FlowFile whose contents consists of the following:
+ </p>
+
+ <code><pre>
+2016-08-04 13:26:32,473 INFO [Leader Election Notification Thread-1] o.a.n.c.l.e.CuratorLeaderElectionManager org.apache.nifi.controller.leader.election.CuratorLeaderElectionManager$ElectionListener@1fa27ea5 has been interrupted; no longer leader for role 'Cluster Coordinator'
+2016-08-04 13:26:32,474 ERROR [Leader Election Notification Thread-2] o.apache.nifi.controller.FlowController One
+Two
+Three
+org.apache.nifi.exception.UnitTestException: Testing to ensure we are able to capture stack traces
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_45]
+ at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) [na:1.8.0_45]
+ at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) [na:1.8.0_45]
+ at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) [na:1.8.0_45]
+ at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_45]
+ at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_45]
+ at java.lang.Thread.run(Thread.java:745) [na:1.8.0_45]
+Caused by: org.apache.nifi.exception.UnitTestException: Testing to ensure we are able to capture stack traces
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ ... 12 common frames omitted
+2016-08-04 13:26:35,475 WARN [Curator-Framework-0] org.apache.curator.ConnectionState Connection attempt unsuccessful after 3008 (greater than max timeout of 3000). Resetting connection and trying again with a new connection.
+ </pre></code>
+
+ <p>
+ In this case, the result will be that this FlowFile consists of 3 different records. The first record will contain the following values:
+ </p>
+
+ <table>
+ <head>
+ <th>Field Name</th>
+ <th>Field Value</th>
+ </head>
+ <body>
+ <tr>
+ <td>timestamp</td>
+ <td>2016-08-04 13:26:32,473</td>
+ </tr>
+ <tr>
+ <td>level</td>
+ <td>INFO</td>
+ </tr>
+ <tr>
+ <td>thread</td>
+ <td>Leader Election Notification Thread-1</td>
+ </tr>
+ <tr>
+ <td>class</td>
+ <td>o.a.n.c.l.e.CuratorLeaderElectionManager</td>
+ </tr>
+ <tr>
+ <td>message</td>
+ <td>org.apache.nifi.controller.leader.election.CuratorLeaderElectionManager$ElectionListener@1fa27ea5 has been interrupted; no longer leader for role 'Cluster Coordinator'</td>
+ </tr>
+ <tr>
+ <td>STACK_TRACE</td>
+ <td><i>null</i></td>
+ </tr>
+ </body>
+ </table>
+
+ <p>
+ The second record will contain the following values:
+ </p>
+
+ <table>
+ <head>
+ <th>Field Name</th>
+ <th>Field Value</th>
+ </head>
+ <body>
+ <tr>
+ <td>timestamp</td>
+ <td>2016-08-04 13:26:32,474</td>
+ </tr>
+ <tr>
+ <td>level</td>
+ <td>ERROR</td>
+ </tr>
+ <tr>
+ <td>thread</td>
+ <td>Leader Election Notification Thread-2</td>
+ </tr>
+ <tr>
+ <td>class</td>
+ <td>o.apache.nifi.controller.FlowController</td>
+ </tr>
+ <tr>
+ <td>message</td>
+ <td>One<br />
+Two<br />
+Three</td>
+ </tr>
+ <tr>
+ <td>STACK_TRACE</td>
+ <td>
+<pre>
+org.apache.nifi.exception.UnitTestException: Testing to ensure we are able to capture stack traces
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_45]
+ at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) [na:1.8.0_45]
+ at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) [na:1.8.0_45]
+ at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) [na:1.8.0_45]
+ at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_45]
+ at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_45]
+ at java.lang.Thread.run(Thread.java:745) [na:1.8.0_45]
+Caused by: org.apache.nifi.exception.UnitTestException: Testing to ensure we are able to capture stack traces
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ at org.apache.nifi.cluster.coordination.node.NodeClusterCoordinator.getElectedActiveCoordinatorAddress(NodeClusterCoordinator.java:185)
+ ... 12 common frames omitted
+</pre></td>
+ </tr>
+ </body>
+ </table>
+
+ <p>
+ The third record will contain the following values:
+ </p>
+
+ <table>
+ <head>
+ <th>Field Name</th>
+ <th>Field Value</th>
+ </head>
+ <body>
+ <tr>
+ <td>timestamp</td>
+ <td>2016-08-04 13:26:35,475</td>
+ </tr>
+ <tr>
+ <td>level</td>
+ <td>WARN</td>
+ </tr>
+ <tr>
+ <td>thread</td>
+ <td>Curator-Framework-0</td>
+ </tr>
+ <tr>
+ <td>class</td>
+ <td>org.apache.curator.ConnectionState</td>
+ </tr>
+ <tr>
+ <td>message</td>
+ <td>Connection attempt unsuccessful after 3008 (greater than max timeout of 3000). Resetting connection and trying again with a new connection.</td>
+ </tr>
+ <tr>
+ <td>STACK_TRACE</td>
+ <td><i>null</i></td>
+ </tr>
+ </body>
+ </table>
+
+
+ <h2>
+ </h2>
+
+ <h2>Default Patterns</h2>
+
+ <p>
+ The following patterns are available in the default Grok Pattern File:
+ </p>
+
+ <code>
+ <pre>
+# Log Levels
+LOGLEVEL ([Aa]lert|ALERT|[Tt]race|TRACE|[Dd]ebug|DEBUG|[Nn]otice|NOTICE|[Ii]nfo|INFO|[Ww]arn?(?:ing)?|WARN?(?:ING)?|[Ee]rr?(?:or)?|ERR?(?:OR)?|[Cc]rit?(?:ical)?|CRIT?(?:ICAL)?|[Ff]atal|FATAL|[Ss]evere|SEVERE|EMERG(?:ENCY)?|[Ee]merg(?:ency)?)|FINE|FINER|FINEST|CONFIG
+
+# Syslog Dates: Month Day HH:MM:SS
+SYSLOGTIMESTAMP %{MONTH} +%{MONTHDAY} %{TIME}
+PROG (?:[\w._/%-]+)
+SYSLOGPROG %{PROG:program}(?:\[%{POSINT:pid}\])?
+SYSLOGHOST %{IPORHOST}
+SYSLOGFACILITY <%{NONNEGINT:facility}.%{NONNEGINT:priority}>
+HTTPDATE %{MONTHDAY}/%{MONTH}/%{YEAR}:%{TIME} %{INT}
+
+# Months: January, Feb, 3, 03, 12, December
+MONTH \b(?:Jan(?:uary)?|Feb(?:ruary)?|Mar(?:ch)?|Apr(?:il)?|May|Jun(?:e)?|Jul(?:y)?|Aug(?:ust)?|Sep(?:tember)?|Oct(?:ober)?|Nov(?:ember)?|Dec(?:ember)?)\b
+MONTHNUM (?:0?[1-9]|1[0-2])
+MONTHNUM2 (?:0[1-9]|1[0-2])
+MONTHDAY (?:(?:0[1-9])|(?:[12][0-9])|(?:3[01])|[1-9])
+
+# Days: Monday, Tue, Thu, etc...
+DAY (?:Mon(?:day)?|Tue(?:sday)?|Wed(?:nesday)?|Thu(?:rsday)?|Fri(?:day)?|Sat(?:urday)?|Sun(?:day)?)
+
+# Years?
+YEAR (?>\d\d){1,2}
+HOUR (?:2[0123]|[01]?[0-9])
+MINUTE (?:[0-5][0-9])
+# '60' is a leap second in most time standards and thus is valid.
+SECOND (?:(?:[0-5]?[0-9]|60)(?:[:.,][0-9]+)?)
+TIME (?!<[0-9])%{HOUR}:%{MINUTE}(?::%{SECOND})(?![0-9])
+
+# datestamp is YYYY/MM/DD-HH:MM:SS.UUUU (or something like it)
+DATE_US_MONTH_DAY_YEAR %{MONTHNUM}[/-]%{MONTHDAY}[/-]%{YEAR}
+DATE_US_YEAR_MONTH_DAY %{YEAR}[/-]%{MONTHNUM}[/-]%{MONTHDAY}
+DATE_US %{DATE_US_MONTH_DAY_YEAR}|%{DATE_US_YEAR_MONTH_DAY}
+DATE_EU %{MONTHDAY}[./-]%{MONTHNUM}[./-]%{YEAR}
+ISO8601_TIMEZONE (?:Z|[+-]%{HOUR}(?::?%{MINUTE}))
+ISO8601_SECOND (?:%{SECOND}|60)
+TIMESTAMP_ISO8601 %{YEAR}-%{MONTHNUM}-%{MONTHDAY}[T ]%{HOUR}:?%{MINUTE}(?::?%{SECOND})?%{ISO8601_TIMEZONE}?
+DATE %{DATE_US}|%{DATE_EU}
+DATESTAMP %{DATE}[- ]%{TIME}
+TZ (?:[PMCE][SD]T|UTC)
+DATESTAMP_RFC822 %{DAY} %{MONTH} %{MONTHDAY} %{YEAR} %{TIME} %{TZ}
+DATESTAMP_RFC2822 %{DAY}, %{MONTHDAY} %{MONTH} %{YEAR} %{TIME} %{ISO8601_TIMEZONE}
+DATESTAMP_OTHER %{DAY} %{MONTH} %{MONTHDAY} %{TIME} %{TZ} %{YEAR}
+DATESTAMP_EVENTLOG %{YEAR}%{MONTHNUM2}%{MONTHDAY}%{HOUR}%{MINUTE}%{SECOND}
+
+
+POSINT \b(?:[1-9][0-9]*)\b
+NONNEGINT \b(?:[0-9]+)\b
+WORD \b\w+\b
+NOTSPACE \S+
+SPACE \s*
+DATA .*?
+GREEDYDATA .*
+QUOTEDSTRING (?>(?<!\\)(?>"(?>\\.|[^\\"]+)+"|""|(?>'(?>\\.|[^\\']+)+')|''|(?>`(?>\\.|[^\\`]+)+`)|``))
+UUID [A-Fa-f0-9]{8}-(?:[A-Fa-f0-9]{4}-){3}[A-Fa-f0-9]{12}
+
+USERNAME [a-zA-Z0-9._-]+
+USER %{USERNAME}
+INT (?:[+-]?(?:[0-9]+))
+BASE10NUM (?<![0-9.+-])(?>[+-]?(?:(?:[0-9]+(?:\.[0-9]+)?)|(?:\.[0-9]+)))
+NUMBER (?:%{BASE10NUM})
+BASE16NUM (?<![0-9A-Fa-f])(?:[+-]?(?:0x)?(?:[0-9A-Fa-f]+))
+BASE16FLOAT \b(?<![0-9A-Fa-f.])(?:[+-]?(?:0x)?(?:(?:[0-9A-Fa-f]+(?:\.[0-9A-Fa-f]*)?)|(?:\.[0-9A-Fa-f]+)))\b
+
+# Networking
+MAC (?:%{CISCOMAC}|%{WINDOWSMAC}|%{COMMONMAC})
+CISCOMAC (?:(?:[A-Fa-f0-9]{4}\.){2}[A-Fa-f0-9]{4})
+WINDOWSMAC (?:(?:[A-Fa-f0-9]{2}-){5}[A-Fa-f0-9]{2})
+COMMONMAC (?:(?:[A-Fa-f0-9]{2}:){5}[A-Fa-f0-9]{2})
+IPV6 ((([0-9A-Fa-f]{1,4}:){7}([0-9A-Fa-f]{1,4}|:))|(([0-9A-Fa-f]{1,4}:){6}(:[0-9A-Fa-f]{1,4}|((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){5}(((:[0-9A-Fa-f]{1,4}){1,2})|:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){4}(((:[0-9A-Fa-f]{1,4}){1,3})|((:[0-9A-Fa-f]{1,4})?:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){3}(((:[0-9A-Fa-f]{1,4}){1,4})|((:[0-9A-Fa-f]{1,4}){0,2}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){2}(((:[0-9A-Fa-f]{1,4}){1,5})|((:[0-9A-Fa-f]{1,4}){0,3}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){1}(((:[0-9A-Fa-f]{1,4}){1,6})|((:[0-9A-Fa-f]{1,4}){0,4}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(:(((:[0-9A-Fa-f]{1,4}){1,7})|((:[0-9A-Fa-f]{1,4}){0,5}:((25[0-5
]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:)))(%.+)?
+IPV4 (?<![0-9])(?:(?:25[0-5]|2[0-4][0-9]|[0-1]?[0-9]{1,2})[.](?:25[0-5]|2[0-4][0-9]|[0-1]?[0-9]{1,2})[.](?:25[0-5]|2[0-4][0-9]|[0-1]?[0-9]{1,2})[.](?:25[0-5]|2[0-4][0-9]|[0-1]?[0-9]{1,2}))(?![0-9])
+IP (?:%{IPV6}|%{IPV4})
+HOSTNAME \b(?:[0-9A-Za-z][0-9A-Za-z-]{0,62})(?:\.(?:[0-9A-Za-z][0-9A-Za-z-]{0,62}))*(\.?|\b)
+HOST %{HOSTNAME}
+IPORHOST (?:%{HOSTNAME}|%{IP})
+HOSTPORT %{IPORHOST}:%{POSINT}
+
+# paths
+PATH (?:%{UNIXPATH}|%{WINPATH})
+UNIXPATH (?>/(?>[\w_%!$@:.,-]+|\\.)*)+
+TTY (?:/dev/(pts|tty([pq])?)(\w+)?/?(?:[0-9]+))
+WINPATH (?>[A-Za-z]+:|\\)(?:\\[^\\?*]*)+
+URIPROTO [A-Za-z]+(\+[A-Za-z+]+)?
+URIHOST %{IPORHOST}(?::%{POSINT:port})?
+# uripath comes loosely from RFC1738, but mostly from what Firefox
+# doesn't turn into %XX
+URIPATH (?:/[A-Za-z0-9$.+!*'(){},~:;=@#%_\-]*)+
+#URIPARAM \?(?:[A-Za-z0-9]+(?:=(?:[^&]*))?(?:&(?:[A-Za-z0-9]+(?:=(?:[^&]*))?)?)*)?
+URIPARAM \?[A-Za-z0-9$.+!*'|(){},~@#%&/=:;_?\-\[\]]*
+URIPATHPARAM %{URIPATH}(?:%{URIPARAM})?
+URI %{URIPROTO}://(?:%{USER}(?::[^@]*)?@)?(?:%{URIHOST})?(?:%{URIPATHPARAM})?
+
+# Shortcuts
+QS %{QUOTEDSTRING}
+
+# Log formats
+SYSLOGBASE %{SYSLOGTIMESTAMP:timestamp} (?:%{SYSLOGFACILITY} )?%{SYSLOGHOST:logsource} %{SYSLOGPROG}:
+COMMONAPACHELOG %{IPORHOST:clientip} %{USER:ident} %{USER:auth} \[%{HTTPDATE:timestamp}\] "(?:%{WORD:verb} %{NOTSPACE:request}(?: HTTP/%{NUMBER:httpversion})?|%{DATA:rawrequest})" %{NUMBER:response} (?:%{NUMBER:bytes}|-)
+COMBINEDAPACHELOG %{COMMONAPACHELOG} %{QS:referrer} %{QS:agent}
+ </pre>
+ </code>
+
+ </body>
+</html>
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--- nifi/site/trunk/docs/nifi-docs/components/org.apache.nifi/nifi-record-serialization-services-nar/1.9.0/org.apache.nifi.grok.GrokReader/index.html (added)
+++ nifi/site/trunk/docs/nifi-docs/components/org.apache.nifi/nifi-record-serialization-services-nar/1.9.0/org.apache.nifi.grok.GrokReader/index.html Fri Feb 22 01:03:44 2019
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+<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"></meta><title>GrokReader</title><link rel="stylesheet" href="../../../../../css/component-usage.css" type="text/css"></link></head><script type="text/javascript">window.onload = function(){if(self==top) { document.getElementById('nameHeader').style.display = "inherit"; } }</script><body><h1 id="nameHeader" style="display: none;">GrokReader</h1><h2>Description: </h2><p>Provides a mechanism for reading unstructured text data, such as log files, and structuring the data so that it can be processed. The service is configured using Grok patterns. The service reads from a stream of data and splits each message that it finds into a separate Record, each containing the fields that are configured. If a line in the input does not match the expected message pattern, the line of text is either considered to be part of the previous message or is skipped, depending on the configuration, with the exception of stack traces. A stack trace th
at is found at the end of a log message is considered to be part of the previous message but is added to the 'stackTrace' field of the Record. If a record has no stack trace, it will have a NULL value for the stackTrace field (assuming that the schema does in fact include a stackTrace field of type String). Assuming that the schema includes a '_raw' field of type String, the raw message will be included in the Record.</p><p><a href="additionalDetails.html">Additional Details...</a></p><h3>Tags: </h3><p>grok, logs, logfiles, parse, unstructured, text, record, reader, regex, pattern, logstash</p><h3>Properties: </h3><p>In the list below, the names of required properties appear in <strong>bold</strong>. Any other properties (not in bold) are considered optional. The table also indicates any default values, and whether a property supports the <a href="../../../../../html/expression-language-guide.html">NiFi Expression Language</a>.</p><table id="properties"><tr><th>Name</th><th>Default
Value</th><th>Allowable Values</th><th>Description</th></tr><tr><td id="name"><strong>Schema Access Strategy</strong></td><td id="default-value">string-fields-from-grok-expression</td><td id="allowable-values"><ul><li>Use String Fields From Grok Expression <img src="../../../../../html/images/iconInfo.png" alt="The schema will be derived by using the field names present in the Grok Expression. All fields will be assumed to be of type String. Additionally, a field will be included with a name of 'stackTrace' and a type of String." title="The schema will be derived by using the field names present in the Grok Expression. All fields will be assumed to be of type String. Additionally, a field will be included with a name of 'stackTrace' and a type of String."></img></li><li>Use 'Schema Name' Property <img src="../../../../../html/images/iconInfo.png" alt="The name of the Schema to use is specified by the 'Schema Name' Property. The value of this property is used to lookup the Schema in
the configured Schema Registry service." title="The name of the Schema to use is specified by the 'Schema Name' Property. The value of this property is used to lookup the Schema in the configured Schema Registry service."></img></li><li>Use 'Schema Text' Property <img src="../../../../../html/images/iconInfo.png" alt="The text of the Schema itself is specified by the 'Schema Text' Property. The value of this property must be a valid Avro Schema. If Expression Language is used, the value of the 'Schema Text' property must be valid after substituting the expressions." title="The text of the Schema itself is specified by the 'Schema Text' Property. The value of this property must be a valid Avro Schema. If Expression Language is used, the value of the 'Schema Text' property must be valid after substituting the expressions."></img></li><li>HWX Schema Reference Attributes <img src="../../../../../html/images/iconInfo.png" alt="The FlowFile contains 3 Attributes that will be used to looku
p a Schema from the configured Schema Registry: 'schema.identifier', 'schema.version', and 'schema.protocol.version'" title="The FlowFile contains 3 Attributes that will be used to lookup a Schema from the configured Schema Registry: 'schema.identifier', 'schema.version', and 'schema.protocol.version'"></img></li><li>HWX Content-Encoded Schema Reference <img src="../../../../../html/images/iconInfo.png" alt="The content of the FlowFile contains a reference to a schema in the Schema Registry service. The reference is encoded as a single byte indicating the 'protocol version', followed by 8 bytes indicating the schema identifier, and finally 4 bytes indicating the schema version, as per the Hortonworks Schema Registry serializers and deserializers, found at https://github.com/hortonworks/registry" title="The content of the FlowFile contains a reference to a schema in the Schema Registry service. The reference is encoded as a single byte indicating the 'protocol version', followed by 8
bytes indicating the schema identifier, and finally 4 bytes indicating the schema version, as per the Hortonworks Schema Registry serializers and deserializers, found at https://github.com/hortonworks/registry"></img></li><li>Confluent Content-Encoded Schema Reference <img src="../../../../../html/images/iconInfo.png" alt="The content of the FlowFile contains a reference to a schema in the Schema Registry service. The reference is encoded as a single 'Magic Byte' followed by 4 bytes representing the identifier of the schema, as outlined at http://docs.confluent.io/current/schema-registry/docs/serializer-formatter.html. This is based on version 3.2.x of the Confluent Schema Registry." title="The content of the FlowFile contains a reference to a schema in the Schema Registry service. The reference is encoded as a single 'Magic Byte' followed by 4 bytes representing the identifier of the schema, as outlined at http://docs.confluent.io/current/schema-registry/docs/serializer-formatter.
html. This is based on version 3.2.x of the Confluent Schema Registry."></img></li></ul></td><td id="description">Specifies how to obtain the schema that is to be used for interpreting the data.</td></tr><tr><td id="name">Schema Registry</td><td id="default-value"></td><td id="allowable-values"><strong>Controller Service API: </strong><br/>SchemaRegistry<br/><strong>Implementations: </strong><a href="../../../nifi-hwx-schema-registry-nar/1.9.0/org.apache.nifi.schemaregistry.hortonworks.HortonworksSchemaRegistry/index.html">HortonworksSchemaRegistry</a><br/><a href="../../../nifi-confluent-platform-nar/1.9.0/org.apache.nifi.confluent.schemaregistry.ConfluentSchemaRegistry/index.html">ConfluentSchemaRegistry</a><br/><a href="../../../nifi-registry-nar/1.9.0/org.apache.nifi.schemaregistry.services.AvroSchemaRegistry/index.html">AvroSchemaRegistry</a></td><td id="description">Specifies the Controller Service to use for the Schema Registry</td></tr><tr><td id="name">Schema Name</td><td i
d="default-value">${schema.name}</td><td id="allowable-values"></td><td id="description">Specifies the name of the schema to lookup in the Schema Registry property<br/><strong>Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)</strong></td></tr><tr><td id="name">Schema Version</td><td id="default-value"></td><td id="allowable-values"></td><td id="description">Specifies the version of the schema to lookup in the Schema Registry. If not specified then the latest version of the schema will be retrieved.<br/><strong>Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)</strong></td></tr><tr><td id="name">Schema Branch</td><td id="default-value"></td><td id="allowable-values"></td><td id="description">Specifies the name of the branch to use when looking up the schema in the Schema Registry property. If the chosen Schema Registry does not support branching, this value will be ignored.<br
/><strong>Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)</strong></td></tr><tr><td id="name">Schema Text</td><td id="default-value">${avro.schema}</td><td id="allowable-values"></td><td id="description">The text of an Avro-formatted Schema<br/><strong>Supports Expression Language: true (will be evaluated using flow file attributes and variable registry)</strong></td></tr><tr><td id="name">Grok Pattern File</td><td id="default-value"></td><td id="allowable-values"></td><td id="description">Path to a file that contains Grok Patterns to use for parsing logs. If not specified, a built-in default Pattern file will be used. If specified, all patterns in the given pattern file will override the default patterns. See the Controller Service's Additional Details for a list of pre-defined patterns.<br/><strong>Supports Expression Language: true (will be evaluated using variable registry only)</strong></td></tr><tr><td id="name"><strong>G
rok Expression</strong></td><td id="default-value"></td><td id="allowable-values"></td><td id="description">Specifies the format of a log line in Grok format. This allows the Record Reader to understand how to parse each log line. If a line in the log file does not match this pattern, the line will be assumed to belong to the previous log message.If other Grok expressions are referenced by this expression, they need to be supplied in the Grok Pattern File</td></tr><tr><td id="name"><strong>No Match Behavior</strong></td><td id="default-value">append-to-previous-message</td><td id="allowable-values"><ul><li>Append to Previous Message <img src="../../../../../html/images/iconInfo.png" alt="The line of text that does not match the Grok Expression will be appended to the last field of the prior message." title="The line of text that does not match the Grok Expression will be appended to the last field of the prior message."></img></li><li>Skip Line <img src="../../../../../html/images/i
conInfo.png" alt="The line of text that does not match the Grok Expression will be skipped." title="The line of text that does not match the Grok Expression will be skipped."></img></li></ul></td><td id="description">If a line of text is encountered and it does not match the given Grok Expression, and it is not part of a stack trace, this property specifies how the text should be processed.</td></tr></table><h3>State management: </h3>This component does not store state.<h3>Restricted: </h3>This component is not restricted.<h3>System Resource Considerations:</h3>None specified.</body></html>
\ No newline at end of file
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+++ nifi/site/trunk/docs/nifi-docs/components/org.apache.nifi/nifi-record-serialization-services-nar/1.9.0/org.apache.nifi.json.JsonPathReader/additionalDetails.html Fri Feb 22 01:03:44 2019
@@ -0,0 +1,336 @@
+<!DOCTYPE html>
+<html lang="en">
+ <!--
+ 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.
+ -->
+ <head>
+ <meta charset="utf-8"/>
+ <title>JsonPathReader</title>
+ <link rel="stylesheet" href="../../../../../css/component-usage.css" type="text/css"/>
+ </head>
+
+ <body>
+ <p>
+ The JsonPathReader Controller Service, parses FlowFiles that are in the JSON format. User-defined properties
+ specify how to extract all relevant fields from the JSON in order to create a Record. The Controller
+ Service will not be valid unless at least one JSON Path is provided. Unlike the
+ <a href="../org.apache.nifi.json.JsonTreeReader/additionalDetails.html">JsonTreeReader</a> Controller Service, this
+ service will return a record that contains only those fields that have been configured via JSON Path.
+ </p>
+
+ <p>
+ If the root of the FlowFile's JSON is a JSON Array, each JSON Object found in that array will be treated as a separate
+ Record, not as a single record made up of an array. If the root of the FlowFile's JSON is a JSON Object, it will be
+ evaluated as a single Record.
+ </p>
+
+ <p>
+ Supplying a JSON Path is accomplished by adding a user-defined property where the name of the property becomes the name
+ of the field in the Record that is returned. The value of the property must be a valid JSON Path expression. This JSON Path
+ will be evaluated against each top-level JSON Object in the FlowFile, and the result will be the value of the field whose
+ name is specified by the property name. If any JSON Path is given but no field is present in the Schema with the proper name,
+ then the field will be skipped.
+ </p>
+
+ <p>
+ This Controller Service must be configured with a schema. Each JSON Path that is evaluated and is found in the "root level"
+ of the schema will produce a Field in the Record. I.e., the schema should match the Record that is created by evaluating all
+ of the JSON Paths. It should not match the "incoming JSON" that is read from the FlowFile.
+ </p>
+
+
+ <h2>Schemas and Type Coercion</h2>
+
+ <p>
+ When a record is parsed from incoming data, it is separated into fields. Each of these fields is then looked up against the
+ configured schema (by field name) in order to determine what the type of the data should be. If the field is not present in
+ the schema, that field is omitted from the Record. If the field is found in the schema, the data type of the received data
+ is compared against the data type specified in the schema. If the types match, the value of that field is used as-is. If the
+ schema indicates that the field should be of a different type, then the Controller Service will attempt to coerce the data
+ into the type specified by the schema. If the field cannot be coerced into the specified type, an Exception will be thrown.
+ </p>
+
+ <p>
+ The following rules apply when attempting to coerce a field value from one data type to another:
+ </p>
+
+ <ul>
+ <li>Any data type can be coerced into a String type.</li>
+ <li>Any numeric data type (Byte, Short, Int, Long, Float, Double) can be coerced into any other numeric data type.</li>
+ <li>Any numeric value can be coerced into a Date, Time, or Timestamp type, by assuming that the Long value is the number of
+ milliseconds since epoch (Midnight GMT, January 1, 1970).</li>
+ <li>A String value can be coerced into a Date, Time, or Timestamp type, if its format matches the configured "Date Format," "Time Format,"
+ or "Timestamp Format."</li>
+ <li>A String value can be coerced into a numeric value if the value is of the appropriate type. For example, the String value
+ <code>8</code> can be coerced into any numeric type. However, the String value <code>8.2</code> can be coerced into a Double or Float
+ type but not an Integer.</li>
+ <li>A String value of "true" or "false" (regardless of case) can be coerced into a Boolean value.</li>
+ <li>A String value that is not empty can be coerced into a Char type. If the String contains more than 1 character, the first character is used
+ and the rest of the characters are ignored.</li>
+ <li>Any "date/time" type (Date, Time, Timestamp) can be coerced into any other "date/time" type.</li>
+ <li>Any "date/time" type can be coerced into a Long type, representing the number of milliseconds since epoch (Midnight GMT, January 1, 1970).</li>
+ <li>Any "date/time" type can be coerced into a String. The format of the String is whatever DateFormat is configured for the corresponding
+ property (Date Format, Time Format, Timestamp Format property). If no value is specified, then the value will be converted into a String
+ representation of the number of milliseconds since epoch (Midnight GMT, January 1, 1970).</li>
+ </ul>
+
+ <p>
+ If none of the above rules apply when attempting to coerce a value from one data type to another, the coercion will fail and an Exception
+ will be thrown.
+ </p>
+
+
+ <h2>Schema Inference</h2>
+
+ <p>
+ While NiFi's Record API does require that each Record have a schema, it is often convenient to infer the schema based on the values in the data,
+ rather than having to manually create a schema. This is accomplished by selecting a value of "Infer Schema" for the "Schema Access Strategy" property.
+ When using this strategy, the Reader will determine the schema by first parsing all data in the FlowFile, keeping track of all fields that it has encountered
+ and the type of each field. Once all data has been parsed, a schema is formed that encompasses all fields that have been encountered.
+ </p>
+
+ <p>
+ A common concern when inferring schemas is how to handle the condition of two values that have different types. For example, consider a FlowFile with the following two records:
+ </p>
+ <code><pre>
+[{
+ "name": "John",
+ "age": 8,
+ "values": "N/A"
+}, {
+ "name": "Jane",
+ "age": "Ten",
+ "values": [ 8, "Ten" ]
+}]
+</pre></code>
+
+ <p>
+ It is clear that the "name" field will be inferred as a STRING type. However, how should we handle the "age" field? Should the field be an CHOICE between INT and STRING? Should we
+ prefer LONG over INT? Should we just use a STRING? Should the field be considered nullable?
+ </p>
+
+ <p>
+ To help understand how this Record Reader infers schemas, we have the following list of rules that are followed in the inference logic:
+ </p>
+
+ <ul>
+ <li>All fields are inferred to be nullable.</li>
+ <li>
+ When two values are encountered for the same field in two different records (or two values are encountered for an ARRAY type), the inference engine prefers
+ to use a "wider" data type over using a CHOICE data type. A data type "A" is said to be wider than data type "B" if and only if data type "A" encompasses all
+ values of "B" in addition to other values. For example, the LONG type is wider than the INT type but not wider than the BOOLEAN type (and BOOLEAN is also not wider
+ than LONG). INT is wider than SHORT. The STRING type is considered wider than all other types with the Exception of MAP, RECORD, ARRAY, and CHOICE.
+ </li>
+ <li>
+ If two values are encountered for the same field in two different records (or two values are encountered for an ARRAY type), but neither value is of a type that
+ is wider than the other, then a CHOICE type is used. In the example above, the "values" field will be inferred as a CHOICE between a STRING or an ARRRAY<STRING>.
+ </li>
+ <li>
+ If the "Time Format," "Timestamp Format," or "Date Format" properties are configured, any value that would otherwise be considered a STRING type is first checked against
+ the configured formats to see if it matches any of them. If the value matches the Timestamp Format, the value is considered a Timestamp field. If it matches the Date Format,
+ it is considered a Date field. If it matches the Time Format, it is considered a Time field. In the unlikely event that the value matches more than one of the configured
+ formats, they will be matched in the order: Timestamp, Date, Time. I.e., if a value matched both the Timestamp Format and the Date Format, the type that is inferred will be
+ Timestamp. Because parsing dates and times can be expensive, it is advisable not to configure these formats if dates, times, and timestamps are not expected, or if processing
+ the data as a STRING is acceptable. For use cases when this is important, though, the inference engine is intelligent enough to optimize the parsing by first checking several
+ very cheap conditions. For example, the string's length is examined to see if it is too long or too short to match the pattern. This results in far more efficient processing
+ than would result if attempting to parse each string value as a timestamp.
+ </li>
+ <li>The MAP type is never inferred. Instead, the RECORD type is used.</li>
+ <li>If a field exists but all values are null, then the field is inferred to be of type STRING.</li>
+ </ul>
+
+
+
+ <h2>Caching of Inferred Schemas</h2>
+
+ <p>
+ This Record Reader requires that if a schema is to be inferred, that all records be read in order to ensure that the schema that gets inferred is applicable for all
+ records in the FlowFile. However, this can become expensive, especially if the data undergoes many different transformations. To alleviate the cost of inferring schemas,
+ the Record Reader can be configured with a "Schema Inference Cache" by populating the property with that name. This is a Controller Service that can be shared by Record
+ Readers and Record Writers.
+ </p>
+
+ <p>
+ Whenever a Record Writer is used to write data, if it is configured with a "Schema Cache," it will also add the schema to the Schema Cache. This will result in an
+ identifier for that schema being added as an attribute to the FlowFile.
+ </p>
+
+ <p>
+ Whenever a Record Reader is used to read data, if it is configured with a "Schema Inference Cache", it will first look for a "schema.cache.identifier" attribute on the FlowFile.
+ If the attribute exists, it will use the value of that attribute to lookup the schema in the schema cache. If it is able to find a schema in the cache with that identifier,
+ then it will use that schema instead of reading, parsing, and analyzing the data to infer the schema. If the attribute is not available on the FlowFile, or if the attribute is
+ available but the cache does not have a schema with that identifier, then the Record Reader will proceed to infer the schema as described above.
+ </p>
+
+ <p>
+ The end result is that users are able to chain together many different Processors to operate on Record-oriented data. Typically, only the first such Processor in the chain will
+ incur the "penalty" of inferring the schema. For all other Processors in the chain, the Record Reader is able to simply lookup the schema in the Schema Cache by identifier.
+ This allows the Record Reader to infer a schema accurately, since it is inferred based on all data in the FlowFile, and still allows this to happen efficiently since the schema
+ will typically only be inferred once, regardless of how many Processors handle the data.
+ </p>
+
+
+
+ <h2>Examples</h2>
+
+ <p>
+ As an example, consider a FlowFile whose content contains the following JSON:
+ </p>
+
+ <code>
+ <pre>
+[{
+ "id": 17,
+ "name": "John",
+ "child": {
+ "id": "1"
+ },
+ "siblingIds": [4, 8],
+ "siblings": [
+ { "name": "Jeremy", "id": 4 },
+ { "name": "Julia", "id": 8}
+ ]
+ },
+ {
+ "id": 98,
+ "name": "Jane",
+ "child": {
+ "id": 2
+ },
+ "gender": "F",
+ "siblingIds": [],
+ "siblings": []
+ }]
+ </pre>
+ </code>
+
+ <p>
+ And the following schema has been configured:
+ </p>
+
+ <code>
+ <pre>
+{
+ "namespace": "nifi",
+ "name": "person",
+ "type": "record",
+ "fields": [
+ { "name": "id", "type": "int" },
+ { "name": "name", "type": "string" },
+ { "name": "childId", "type": "long" },
+ { "name": "gender", "type": "string" },
+ { "name": "siblingNames", "type": {
+ "type": "array",
+ "items": "string"
+ }}
+ ]
+}
+ </pre>
+ </code>
+
+ <p>
+ If we configure this Controller Service with the following user-defined properties:
+
+ <table>
+ <tr>
+ <th>Property Name</th>
+ <th>Property Value</th>
+ </tr>
+ <tr>
+ <td>id</td>
+ <td><code>$.id</code></td>
+ </tr>
+ <tr>
+ <td>name</td>
+ <td><code>$.name</code></td>
+ </tr>
+ <tr>
+ <td>childId</td>
+ <td><code>$.child.id</code></td>
+ </tr>
+ <tr>
+ <td>gender</td>
+ <td><code>$.gender</code></td>
+ </tr>
+ <tr>
+ <td>siblingNames</td>
+ <td><code>$.siblings[*].name</code></td>
+ </tr>
+ </table>
+ </p>
+
+ <p>
+ In this case, the FlowFile will generate two Records. The first record will consist of the following key/value pairs:
+
+ <table>
+ <tr>
+ <th>Field Name</th>
+ <th>Field Value</th>
+ </tr>
+ <tr>
+ <td>id</td>
+ <td>17</td>
+ </tr>
+ <tr>
+ <td>name</td>
+ <td>John</td>
+ </tr>
+ <tr>
+ <td>childId</td>
+ <td>1</td>
+ </tr>
+ <tr>
+ <td>gender</td>
+ <td><i>null</i></td>
+ </tr>
+ <tr>
+ <td>siblingNames</td>
+ <td><i>array of two elements: </i><code>Jeremy</code><i> and </i><code>Julia</code></td>
+ </tr>
+ </table>
+ </p>
+
+ <p>
+ The second record will consist of the following key/value pairs:
+
+ <table>
+ <tr>
+ <th>Field Name</th>
+ <th>Field Value</th>
+ </tr>
+ <tr>
+ <td>id</td>
+ <td>98</td>
+ </tr>
+ <tr>
+ <td>name</td>
+ <td>Jane</td>
+ </tr>
+ <tr>
+ <td>childId</td>
+ <td>2</td>
+ </tr>
+ <tr>
+ <td>gender</td>
+ <td>F</td>
+ </tr>
+ <tr>
+ <td>siblingNames</td>
+ <td><i>empty array</i></td>
+ </tr>
+ </table>
+ </p>
+
+ </body>
+</html>