Adapter properties and commands

This section lists the properties supported by the adapter.

In maps:

  • Use adapter commands on input cards and GET functions to configure the adapter to consume messages from Kafka topics.
  • Use adapter commands on output cards and PUT functions to configure the adapter to publish messages to Kafka topics.

Many Kafka adapter commands are based on Apache Kafka consumer or producer configurations. Those adapter command descriptions include the name of the related Apache Kafka configuration. See the Apache Kafka documentation for details.

Apache Kafka adapter command aliases

Use KAFKA as the adapter command alias on input and output cards and in GET and PUT rules. For example:

Input source override execution command -IAKAFKA card_num
Output target override execution command -OAKAFKA card_num

Headers for data payloads

You can specify the optional -HDR command to prepend one of the following header versions to the messages. The numbers in brackets denote the number of bytes:
  • [4] is 32-bit int
  • [8] is 64-bit int
Version
Header structure
1
[4]             Total header size (excluding this field): 2*4 + size(key)
[4]             Header Version: 1
[4]key          Key size followed by the key value
2
[4]             Total header size (excluding this field): 4*4 + 2*8 + size(key) + size(topic)
[4]             Header Version: 2
[4]key          Key size followed by the key value
[4]topic        Topic size followed by the topic
[4]             Partition number
[8]             Offset
[8]             Timestamp
3
[4]             Total header size (excluding this field): 4*4 + 2*8 + size(key) + size(topic) + sum(2*4 + size(hkey_i) + size(hvalue_i))
[4]             Header Version: 3
[4]key          Key size followed by the key value
[4]topic        Topic size followed by the topic
[4]             Partition number
[8]             Offset
[8]             Timestamp
[4]             The size of the Kafka headers section (excluding this field), followed by an array of Kafka header key, value pairs in the following format:
   [4]hkey      Kafka header key size followed by Kafka header key 
   [4]hvalue    Kafka header value size followed by Kafka header value
The message header is always followed by the payload size and payload content:
[4]payload	Payload size followed by payload content