Schemaless JSON Source Connector for Confluent Platform

This connector is used to stream JSON files from a directory. It will not try to convert the JSON records to a schema. The recommended converter to use is the StringConverter.

value.converter=org.apache.kafka.connect.storage.StringConverter

To use this connector, use a connector configuration that specifies the name of this connector class in the connector.class configuration property:

connector.class=com.github.jcustenborder.kafka.connect.spooldir.SpoolDirSchemaLessJsonSourceConnector

The other connector-specific configuration properties are described below.

JSON Schemaless Source Connector Example

This example follows the same steps as the Quick Start. Review the Quick Start for help running the Confluent Platform and installing the Spool Dir connectors.

Prerequisites
  1. Generate a JSON dataset using the command below:

    curl "https://api.mockaroo.com/api/17c84440?count=500&key=25fd9c80" > "json-spooldir-source.json"
    
  2. Create a spooldir.properties file with the following contents:

    name=SchemaLessJsonSpoolDir
    tasks.max=1
    connector.class=com.github.jcustenborder.kafka.connect.spooldir.SpoolDirSchemaLessJsonSourceConnector
    input.path=/path/to/data
    input.file.pattern=json-spooldir-source.json
    error.path=/path/to/error
    finished.path=/path/to/finished
    halt.on.error=false
    topic=spooldir-schemaless-json-topic
    value.converter=org.apache.kafka.connect.storage.StringConverter
    
  3. Load the SpoolDir Schemaless JSON Source Connector using the Confluent CLI confluent local load command.

    Caution

    You must include a double dash (--) between the topic name and your flag. For more information, see this post.

    confluent local load spooldir -- -d spooldir.properties
    

    Important

    Don’t use the Confluent CLI commands in production environments.

Configuration Properties

General

topic

The Kafka topic to write the data to.

  • Importance: HIGH
  • Type: STRING
batch.size

The number of records that should be returned with each batch.

  • Importance: LOW
  • Type: INT
  • Default Value: 1000
empty.poll.wait.ms

The amount of time to wait if a poll returns an empty list of records.

  • Importance: LOW
  • Type: LONG
  • Default Value: 500
  • Validator: [1,…,9223372036854775807]

Metadata

metadata.field

The name of the field in the value where the metadata will be stored.

  • Importance: LOW
  • Type: STRING
  • Default Value: metadata
metadata.location

Location that metadata about the input file will be stored. FIELD - Metadata about the file will be stored in a field in the value of the record. HEADERS - Metadata about the input file will be stored as headers on the record. NONE - no metadata about the input file will be stored.

  • Importance: LOW
  • Type: STRING
  • Default Value: HEADERS
  • Validator: Matches: NONE, HEADERS, FIELD

File System

error.path

The directory to place files that have errors. This directory must exist and be writable by the user running Kafka Connect.

  • Importance: HIGH
  • Type: STRING
  • Validator: Absolute path to a directory that exists and is writable.
input.file.pattern

Regular expression to check input file names against. This expression must match the entire filename. The equivalent of Matcher.matches().

  • Importance: HIGH
  • Type: STRING
input.path

The directory where Kafka Connect reads files that are processed. This directory must exist and be writable by the user running Connect.

  • Importance: HIGH
  • Type: STRING
  • Validator: Absolute path to a directory that exists and is writable.
finished.path

The directory where Connect puts files that are successfully processed. This directory must exist and be writable by the user running Connect.

  • Importance: HIGH
  • Type: STRING
halt.on.error

Sets whether the task halts when it encounters an error or continues to the next file.

  • Importance: HIGH
  • Type: BOOLEAN
  • Default Value: true
cleanup.policy

Determines how the connector should cleanup the files that have been successfully processed. NONE leaves the files in place which could cause them to be reprocessed if the connector is restarted. DELETE removes the file from the filesystem. MOVE will move the file to a finished directory. MOVEBYDATE will move the file to a finished directory with subdirectories by date.

  • Importance: MEDIUM
  • Type: STRING
  • Default Value: MOVE
  • Validator: Matches: NONE, DELETE, MOVE, MOVEBYDATE
task.partitioner

The task partitioner implementation is used when the connector is configured to use more than one task. This is used by each task to identify which files will be processed by that task. This ensures that each file is only assigned to one task.

  • Importance: MEDIUM
  • Type: STRING
  • Default Value: ByName
  • Validator: Matches: ByName
file.buffer.size.bytes

The size of buffer for the BufferedInputStream that will be used to interact with the file system.

  • Importance: LOW
  • Type: INT
  • Default Value: 131072
  • Validator: [1,…]
file.minimum.age.ms

The amount of time in milliseconds after the file was last written to before the file can be processed.

  • Importance: LOW
  • Type: LONG
  • Default Value: 0
  • Validator: [0,…]
files.sort.attributes

The attributes each file will use to determine the sort order. Name is name of the file. Length is the length of the file preferring larger files first. LastModified is the LastModified attribute of the file preferring older files first.

  • Importance: LOW
  • Type: LIST
  • Default Value: [NameAsc]
  • Validator: Matches: NameAsc, NameDesc, LengthAsc, LengthDesc, LastModifiedAsc, LastModifiedDesc
processing.file.extension

Before a file is processed, it is renamed to indicate that it is currently being processed. This setting is appended to the end of the file.

  • Importance: LOW
  • Type: STRING
  • Default Value: .PROCESSING
  • Validator: Matches regex( ^.*..+$ )

Timestamps

timestamp.mode

Determines how the connector sets the timestamp for the ConnectRecord. If set to Field, the timestamp is read from a field in the value. This field cannot be optional and must be a Timestamp. Specify the field in timestamp.field. If set to FILE_TIME, the last time the file was modified is used. If set to PROCESS_TIME (the default), the time the record is read is used.

  • Importance: MEDIUM
  • Type: STRING
  • Default Value: PROCESS_TIME
  • Validator: Matches: FIELD, FILE_TIME, PROCESS_TIME