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Version: 0.11

syslog udp

The syslog udp example is demonstrate a number things:

  1. Encoding data in the syslog format.
  2. Sending data over UDP.
  3. Receiving data over UDP.
  4. Decoding syslog formated data.

For digestion it is entirely selfcontained inside a singel tremor instance using multiple paralell pipelines, sinks and sources.



All the code here is available in the git repository as well and can be run with docker compose up.


The sources and sinks we use are:

  • The metronome source - to generate data in one second intervals.
  • The udp sink - to send the data over UDP.
  • The udp source - to receive data via UDP.
  • The stdout sink - to display data decoded and re-formated as JSON.

In addition we have two pipelines.

The producer pipeline takes the tick from metronome and generates a syslog message. It is only handling message rewriting.

The consumer pipeline takes the syslog message and forwards it. It is a passthrough pipeline.

The binding expresses those relations and gives the graph of onramp, pipeline and offramp. We hare left with those two workflows:

metronome -> producer -> syslog-udp-out

syslog-udp-in -> consumer -> stdout-output

Finally the mapping instanciates the binding with the given name and instance variable to activate the elements of the binding.

Business Logic

The only interesting part to look at is the event rewriting, this uses an example syslog message and adds the as a strucuted_data field.

select {
"severity": "notice",
"facility": "local4",
"hostname": "",
"appname": "evntsog",
"msg": "BOMAn application event log entry...",
"procid": null,
"msgid": "ID47",
"protocol": "RFC5424",
"protocol_version": 1,
"structured_data": {
"exampleSDID@32473" :
{"eventSource": "Tremor"},
{"eventID": "#{ }"}
"timestamp": event.ingest_ns
} from in into out


from inside the docker container, custom syslog messages can be send with the logger command:

$ logger -d -n -P 12201 "Weeeeh. It works :D"