A new Logstash input plugin called logstash-input-firebase is now available to retrieve data out of your Firebase real-time databases.
This plugin can work in two modes:
1. get mode: Retrieve the value of database references on a fixed schedule (at midnight, every 5 minutes, etc)
2. stream mode: Retrieve the value of database references in real-time as it changes (via the streaming REST API)
We're still working on a few kinks (complex filtering stuff, etc) but aside from that the input is fully functional.
The input is available and documented here: https://github.com/consulthys/logstash-input-firebase
Also watch out for the sister output plugin coming out soon, which will allow you to sink your Logstash events to Firebase: https://github.com/consulthys/logstash-output-firebase
PS: Thanks to the good folks at Codementor for providing the excellent rest-firebase Ruby library to interact with the Firebase REST API.