Kafka batch source that emits a records with user specified schema.
Kafka Batch Source can be used to read events from a kafka topic. It uses kafka consumer 2.6 apis to read events from a kafka topic. The Kafka Batch Source supports providing additional kafka properties for the kafka consumer, reading from kerberos-enabled kafka and limiting the number of records read. Kafka Batch Source converts incoming kafka events into cdap structured records which then can be used for further transformations.
The source will read from the earliest available offset or the initial offset that specified in the config for the first run, remember the last offset it read last run and continue from that offset for the next run.
| Configuration | Required | Default | Description |
|---|---|---|---|
| Kafka Brokers | Y | N/A | List of Kafka brokers specified in host1:port1,host2:port2 form. |
| Kafka Topic | Y | N/A | The Kafka topic to read from. |
| Offset Directory | Y | N/A | A directory path to store the latest Kafka offsets. A file named with the pipeline name will be created under the given directory. |
| Topic Partition | N | N/A | List of topic partitions to read from. If not specified, all partitions will be read. |
| Initial Partition Offsets | N | N/A | The initial offset for each topic partition. If this is not specified, earliest offset will be used. This offset will only be used for the first run of the pipeline. Any subsequent run will read from the latest offset from previous run. Offsets are inclusive. If an offset of 5 is used, the message at offset 5 will be read. |
| Key Field | N | N/A | Optional name of the field containing the message key. If this is not set, no key field will be added to output records. If set, this field must be present in the schema property and must be bytes. |
| Partition Field | N | N/A | Optional name of the field containing the partition the message was read from. If this is not set, no partition field will be added to output records. If set, this field must be present in the schema property and must be an int. |
| Offset Field | N | N/A | Optional name of the field containing the partition offset the message was read from. If this is not set, no offset field will be added to output records. If set, this field must be present in the schema property and must be a long. |
| Max Number Records | N | N/A | The maximum of messages the source will read from each topic partition. If the current topic partition does not have this number of messages, the source will read to the latest offset. Note that this is an estimation, the acutal number of messages the source read may be smaller than this number. |
| Kerberos Principal | N | N/A | The kerberos principal used for the source when kerberos security is enabled for kafka. |
| Keytab Location | N | N/A | The keytab location for the kerberos principal when kerberos security is enabled for kafka. |
| Additional Kafka Consumer Properties | N | N/A | Additional kafka consumer properties to set. |
| Format | N | N/A | Optional format of the Kafka event message. Any format supported by CDAP is supported. For example, a value of 'csv' will attempt to parse Kafka payloads as comma-separated values. If no format is given, Kafka message payloads will be treated as bytes. |
To build this plugin:
mvn clean package
The build will create a .jar and .json file under the target directory.
These files can be used to deploy your plugins.
You can deploy your plugins using the CDAP CLI:
> load artifact <target/kafka-plugins-<version>.jar config-file <target/kafka-plugins<version>.json>
For example, if your artifact is named 'kafka-plugins-':
> load artifact target/kafka-plugins-<version>.jar config-file target/kafka-plugins-<version>.json
CDAP User Group and Development Discussions:
[email protected] <https://groups.google.com/d/forum/cdap-user>
The cdap-user mailing list is primarily for users using the product to develop applications or building plugins for appplications. You can expect questions from users, release announcements, and any other discussions that we think will be helpful to the users.
Copyright © 2017 Cask Data, Inc.
Licensed 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
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