Status

Current state: (4x+1 binding, 1x+1 non-binding)

Discussion thread: here

Vote thread: here

JIRA: 

Pull Request: here

Motivation

Tools kafka-console-producer.sh and kafka-console-consumer.sh have the multiple option --property to setup the MessageReader for Producer (defined by --line-reader) or the MessageFormatter for Consumer (defined by --formatter).

To setup the KafkaProducer/KafkaConsumer they have the multiple option --producer-property/--consumer-property and the config file option --consumer.config/--producer.config.

The idea is to offer the same possibility to use a config file option to setup the MessageReader/MessageFormatter in addition to the existing option --property.

It will be useful in different use cases:

• when having multiple --property (the default reader can have up to 11 properties)
• when passing properties with sensitive data (like schema.registry.ssl.truststrore.password for kafka-avro-console-producer) (could also be mitigated by using env vars)

Public Interfaces

Add an option:

• --reader-config to tool kafka-console-producer.sh
• --formatter-config to tool kafka-console-consumer.sh

As for --producer-property/--consumer-property with --consumer.config/--producer.config, any value from option --property would override value from config file.

Simple example

• Before (multiple --property options):
  

  kafka-console-producer.sh [...] --property print.timestamp=true \ --property print.key=true \ --property print.offset=true \ --property print.partition=true \ --property print.headers=true \ --property print.value=true \ --property key.separator=':' \ --property line.separator=';' \ --property headers.separator='|'

  
  

• After (all properties in one file):
  

  print.timestamp=true print.key=true print.offset=true print.partition=true print.headers=true print.value=true key.separator=: line.separator=; headers.separator=|

  
  

  kafka-console-producer.sh [...] --reader-config reader-config.properties

  
  

Mixed example

When a property is in the config file and as option, option wins.

print.timestamp=true
print.key=true
print.offset=true
print.partition=true
print.headers=true
print.value=true
key.separator=:
line.separator=;
headers.separator=|

kafka-console-producer.sh [...] --reader-config reader-config.properties --property key.separator='/'

Then, the MessageReader will get key.separator=/, not key.separator=:

Proposed Changes

Implement the new options as described in Public Interfaces section:

• ConsoleProducer: new option "reader-config" with description "Config properties file for the message reader. Note that --property takes precedence over this config."
• ConsoleConsumer: new option "formatter-config" with description "Config properties file to initialize the message formatter. Note that --property takes precedence over this config."

Already implemented in pull request #12175.

Compatibility, Deprecation, and Migration Plan

No impact on existing users, just a new possibility available.

Test Plan

Launch the tools with the new config file option and check that properties from config file are applied to the reader/formatter.

Define a property in config file and in options and check that option override config file.

Rejected Alternatives

• Use of generic option --config to avoid confusion in the purpose of this config file (but on the other hand, the current --property is quite generic already, maybe another KIP to change it).
• Use of option name --read.config/--formatter.config, with "." as separator, as it's not consitent with the commonly used option --command-config