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 services connect connector load command.

    Caution

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

    confluent local services connect connector load spooldir --config 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
  • Valid values: [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
  • Valid values: NONE, HEADERS, FIELD

Auto topic creation

For more information about Auto topic creation, see Configuring Auto Topic Creation for Source Connectors.

Configuration properties accept regular expressions (regex) that are defined as Java regex.

topic.creation.groups

A list of group aliases that are used to define per-group topic configurations for matching topics. A default group always exists and matches all topics.

  • Type: List of String types
  • Default: empty
  • Possible Values: The values of this property refer to any additional groups. A default group is always defined for topic configurations.
topic.creation.$alias.replication.factor

The replication factor for new topics created by the connector. This value must not be larger than the number of brokers in the Kafka cluster. If this value is larger than the number of Kafka brokers, an error occurs when the connector attempts to create a topic. This is a required property for the default group. This property is optional for any other group defined in topic.creation.groups. Other groups use the Kafka broker default value.

  • Type: int
  • Default: n/a
  • Possible Values: >= 1 for a specific valid value or -1 to use the Kafka broker’s default value.
topic.creation.$alias.partitions

The number of topic partitions created by this connector. This is a required property for the default group. This property is optional for any other group defined in topic.creation.groups. Other groups use the Kafka broker default value.

  • Type: int
  • Default: n/a
  • Possible Values: >= 1 for a specific valid value or -1 to use the Kafka broker’s default value.
topic.creation.$alias.include

A list of strings that represent regular expressions that match topic names. This list is used to include topics with matching values, and apply this group’s specific configuration to the matching topics. $alias applies to any group defined in topic.creation.groups. This property does not apply to the default group.

  • Type: List of String types
  • Default: empty
  • Possible Values: Comma-separated list of exact topic names or regular expressions.
topic.creation.$alias.exclude

A list of strings representing regular expressions that match topic names. This list is used to exclude topics with matching values from getting the group’s specfic configuration. $alias applies to any group defined in topic.creation.groups. This property does not apply to the default group. Note that exclusion rules override any inclusion rules for topics.

  • Type: List of String types
  • Default: empty
  • Possible Values: Comma-separated list of exact topic names or regular expressions.
topic.creation.$alias.${kafkaTopicSpecificConfigName}

Any of the Changing Broker Configurations Dynamically for the version of the Kafka broker where the records will be written. The broker’s topic-level configuration value is used if the configuration is not specified for the rule. $alias applies to the default group as well as any group defined in topic.creation.groups.

  • Type: property values
  • Default: Kafka broker value

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
  • Valid values: 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(). For valid syntax definitions, see Class Pattern.

  • 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
  • Valid values: 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. 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
  • Valid values: 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
  • Valid values: 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
  • Valid values: [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
  • Valid values: [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]
  • Valid values: 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
  • Valid values: 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
  • Valid values: FIELD, FILE_TIME, PROCESS_TIME