Example fluentd configuration for message routing
Fastify logging with pino to standard out from a docker container. Docker logging with docker fluentd logger settings into a fluentd instance. This instance writes messages to the standard out.
Goal: you don't need to add fluent dependency to your code, just logging to standard output. You can route your log messages with dest: journal key, and it will be saved to journal database, any others will be saved to the log database.
Start with docker-compose up -d --build
Log some message with http://localhost:4000/?message=cool
Tail fluentd log with docker logs --follow test_fluentd
Stop with CTRL-C and docker-compose down --remove-orphans
When you logging with dest key with journal value, then output wil be saved into the journal DB.
// saved to journalDB (but not to logDB)
fastify.log.info({dest: 'journal', msg:'journal message'})
// others saved to logDB
fastify.log.info({dest: 'log', msg:'log message'})
fastify.log.info({msg:'log object, but no dest key'})
fastify.log.info('string log message')