How to batch messages multiple times?

[webfrank]

Hi,
I have a use case where I collect messages from MQTT, enrich them using a cache and then send out to a web service.
Each message has a "serial" field which I use to enrich and on the http output to group_by and calculate the final message to send.
The http service accepts multiple messages separated by newline and I would like to aggregate the resulting messages further to optimize the process.
How can I re-batch them?

[mihaitodor]

The http service accepts multiple messages separated by newline and I would like to aggregate the resulting messages further to optimize the process.

I'd try to use a mapping processor to split that string into an array of substrings like so: root = content().split("\n").map_each(m -> m.string()) (the map_each() part is needed because content() returns bytes instead of string which gets encoded to base64 when serialised as JSON). Then you can add an unarchive processor with format: json_array. This will produce a batch of messages from the original one. Not sure where the group_by you mentioned fits in.