As an example of a simple processing step, we can transform the payload of the HTTP posted data to upper case using the stream definitions

http | transform --expression=payload.toUpperCase() | log

To create this stream enter the following command in the shell

dataflow:> stream create --definition "http | transform --expression=payload.toUpperCase() | log" --name mystream --deploy

Posting some data (using shell command)

dataflow:> http post --target http://localhost:1234 --data "hello"

Will result in an uppercased 'hello' in the log

15:18:21,345  WARN ThreadPoolTaskScheduler-1 logger.myprocstream:141 - HELLO

See the Processors section for more information.