JsonRecordSetWriter

Description:

Writes the results of a RecordSet as a JSON Array. Even if the RecordSet consists of a single row, it will be written as an array with a single element.

Tags:

json, resultset, writer, serialize, record, recordset, row

Properties:

In the list below, the names of required properties appear in bold. Any other properties (not in bold) are considered optional. The table also indicates any default values, and whether a property supports the NiFi Expression Language.

NameDefault ValueAllowable ValuesDescription
Schema Write Strategyschema-name
  • Set 'schema.name' Attribute 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.
  • Set 'avro.schema' Attribute 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.
  • HWX Schema Reference Attributes 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.
  • HWX Content-Encoded Schema Reference 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.
  • Confluent Schema Registry Reference 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.
  • Do Not Write Schema Do not add any schema-related information to the FlowFile.
Specifies how the schema for a Record should be added to the data.
Schema Access Strategyinherit-record-schema
  • Use 'Schema Name' Property 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.
  • Inherit Record Schema The schema used to write records will be the same schema that was given to the Record when the Record was created.
  • Use 'Schema Text' Property 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.
Specifies how to obtain the schema that is to be used for interpreting the data.
Schema RegistryController Service API:
SchemaRegistry
Implementations: AvroSchemaRegistry
ConfluentSchemaRegistry
HortonworksSchemaRegistry		Specifies the Controller Service to use for the Schema Registry
Schema Name${schema.name}Specifies the name of the schema to lookup in the Schema Registry property
Supports Expression Language: true
Schema VersionSpecifies the version of the schema to lookup in the Schema Registry. If not specified then the latest version of the schema will be retrieved.
Supports Expression Language: true
Schema BranchSpecifies the name of the branch to use when looking up the schema in the Schema Registry property. If the chosen Schema Registry does not support branching, this value will be ignored.
Supports Expression Language: true
Schema Text${avro.schema}The text of an Avro-formatted Schema
Supports Expression Language: true
Date FormatSpecifies 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).
Time FormatSpecifies 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).
Timestamp FormatSpecifies 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).
Pretty Print JSONfalse
  • true
  • false
Specifies whether or not the JSON should be pretty printed
Suppress Null Valuesnever-suppress
  • Never Suppress Fields that are missing (present in the schema but not in the record), or that have a value of null, will be written out as a null value
  • Always Suppress Fields that are missing (present in the schema but not in the record), or that have a value of null, will not be written out
  • Suppress Missing Values When a field has a value of null, it will be written out. However, if a field is defined in the schema and not present in the record, the field will not be written out.
Specifies how the writer should handle a null field

State management:

This component does not store state.

Restricted:

This component is not restricted.

System Resource Considerations:

None specified.