KAFKA-724; Allow automatic socket.send.buffer from operating system in SocketServer

[rekhajoshm]

If socket.receive.buffer.bytes/socket.send.buffer.bytes are set to -1, use the OS defaults.

[rekhajoshm]

@ijuma PR #50 was done a while back, changes after rebase.Please have a look. thanks

[ijuma]

This is a change in behaviour (-2 would throw an exception instead of using the OS default) and BlockingChannel is deprecated, so I would prefer not to change it.

[ijuma]

Thanks for the PR @rekhajoshm. I left a couple of minor comments. Also, the PR title and description are used in the merged commit message. Can you please edit them to be:

PR title: KAFKA-724: Allow automatic socket.send.buffer from operating system in SocketServer

PR description: If socket.receive.buffer.bytes/socket.send.buffer.bytes are set to -1, use the OS defaults.

[ijuma]

One more thing: we should also update the documentation in KafkaConfig and CommonClientConfigs stating that if the value is -1, the OS default is used.

[rekhajoshm]

done @ijuma Please have a look. thanks.

[ijuma]

We prefer to avoid wildcard imports.

[rekhajoshm]

Thanks @ijuma Please have a look. thanks

[ijuma]

The PR build failed @rekhajoshm.

[rekhajoshm]

my bad.fixed @ijuma Please have a look. thanks

[ijuma]

Thanks, LGTM. Merged to trunk.

[slaunay]

I am interested in such feature for configuring a producer but using -1 throws the following exception with Kafka clients 0.9.0.1:

Exception in thread "main" org.apache.kafka.common.config.ConfigException: Invalid value -1 for configuration receive.buffer.bytes: Value must be at least 0
    at org.apache.kafka.common.config.ConfigDef$Range.ensureValid(ConfigDef.java:308)
    at org.apache.kafka.common.config.ConfigDef.parse(ConfigDef.java:153)
    at org.apache.kafka.common.config.AbstractConfig.<init>(AbstractConfig.java:49)
    at org.apache.kafka.common.config.AbstractConfig.<init>(AbstractConfig.java:56)
    at org.apache.kafka.clients.producer.ProducerConfig.<init>(ProducerConfig.java:315)
    at org.apache.kafka.clients.producer.KafkaProducer.<init>(KafkaProducer.java:156)
    ...

I believe this is caused by an atLeast(0) validation in ProducerConfig.java that is not present in KafkaConfig for the server configuration:

  .define(SEND_BUFFER_CONFIG, Type.INT, 128 * 1024, atLeast(0), Importance.MEDIUM, CommonClientConfigs.SEND_BUFFER_DOC)
  .define(RECEIVE_BUFFER_CONFIG, Type.INT, 32 * 1024, atLeast(0), Importance.MEDIUM, CommonClientConfigs.RECEIVE_BUFFER_DOC)

I can create a separate PR for this but because CommonClientConfigs.java documentation was modified I am not sure if this feature was targeted at the server only or both the server and the clients.

[ijuma]

@slaunay Yes, please create a PR.