Kpipe

This is a simple script for forwarding/repeating/piping kafka messages from one server/topic to another.
It's inteded to be useful, particularly for binary messages. For text messages I suggest you use kafka-console-producer.sh or, even better, kcat (reff)(formelly kafkacat).
kcat is a great tool, described as a "swiss-army knife of tools" by confdluent themselves, but it does not (easily) support binary messages. This is why I wrote kpipe.

Use this at your own risk, and be sure to check the code.

Running from docker vs directly

This script has a single python dependency, kafka-python. If this dependency is satisfied in your local environment (virtual or otherwise) you can simply run the python script with python pipe.py ...args....
If you can't be bothered, kpipe is packaged in docker, so you can run it with docker run -i cmantas/kpipe ..args....
The rest of this readme assumes an alias is set for kpipe. Either

alias kpipe="/path/to/python /path/top/kpipe/pipe.py"

alias kpipe="docker run -i cmantas/kpipe"

Usage examples

You can test that you can read from your source by setting a stdout sink (specially handled). Set the --source arg to the bootstrap server and specify a --topic

$ kpipe --source a-kafka-bootstrap.domain.com --topic topic_name --sink stdout

Note: no parsing is attempted for binary messages. If the data are in a binary format (which they probably will, otherwise why are you not using kcat) the printout will brobably not be legible.

The following arguments are available

-n : the number of messages we will pipe (default is 10)
--source : the source (input) kafka bootstrap server we will be reading from (optionally with port)
--sink : the sink (output) kafka bootstrap server we will be writing to (optional port). Note: you can use stdout and stdout64
--source-topic : the topic to read from
--sink-topic : the topic to write to
--server : use this as shorthand if --source and --sink are the same server
--topic : use this as shorthand if --source-topic and --sink-topic are the same

So when specifying everything:

$ kpipe \
	--source a-kafka-bootstrap.domain.com \
	--source-topic topic_name \
	--sink another-kafka-bootstrap.foo.com \
	--sink-topic foobar \
	-n 5

Example repating a topic to another topic in the same kafka cluster:

$ kpipe \
	--server a-kafka-bootstrap.domain.com \
	--source-topic src_topic_name \
	--sink-topic sink_topic_name \
	-n 5

Example repating the same topic to another kafka cluster:

$ kpipe \
	--topic topic_name \
	--source a-kafka-bootstrap.domain.com \
	--sink another-kafka-bootstrap.foo.com \
	-n 3

Example writing to stdout in a base64 format

$ kpipe --source a-kafka-bootstrap.domain.com --topic topic_name --sink stdout64