Timestamp is not generated in the key for 0.10 compatibility

[atharvai]

the producer doesn't seem to add a timestamp to the producer record when working with 0.10.0.0 protocol. Actually I couldn't find a way to specify the protocol to use.

Part of Kafka Config:

inter.broker.protocol.version=0.10.0.0
log.message.format.version=0.10.0.0
log.message.timestamp.type=CreateTime

Error from KafkaStreams:

Exception in thread "StreamThread-1" java.lang.IllegalArgumentException: Invalid timestamp -1
    at org.apache.kafka.clients.producer.ProducerRecord.<init>(ProducerRecord.java:60)

This means when I have a Kafka Streams application running, I need to use a WallClockTimestampExtractor which is not ideal.
Not sure if the problem is on python client side or librdkafka side.

[edenhill]

Since the Kafka protocol (<=0.9) is not safely forwards compatible you will need to tell the Python client what version to use.
This is done through two configuration settings:

• broker.version.fallback=YOUR_BROKER_VERSION
• api.version.request=true|false

When using a Kafka 0.10 broker you only need to set api.version.request=true.
If you use Kafka broker 0.9 or 0.8 you should leave api.version.request=false(default) and set broker.version.fallback to your broker version, e.g broker.version.fallback=0.9.0.1.

More info here:
https://github.com/edenhill/librdkafka/wiki/Broker-version-compatibility

[atharvai]

Awesome. Thanks! Can we get that added to the readme in this repo? I think others might find this very useful.