elastic/logstash ? reverse-engineered prompt

Build me a working Logstash setup from this repo that I can run locally without a lot of fuss.

I want to be able to start it from source, feed it logs or simple text from stdin, see the event get transformed, and have it print to stdout or send to Elasticsearch. If there are any missing pieces for a smooth first run, please wire them up and make the default experience clear.

Please also make sure the build and test flow is sane for someone following the README, including any needed setup steps, sample config, and a quick way to verify everything works end to end. If you need to check current docs or best practices online, go ahead.

Keep it focused on the core Logstash experience, not plugin development extras.