At work, we use Logstash a lot, and spend way more time than we should creating parsing for complex log format ..
To help us, I created a little web app, that I decided to release lately in open-source, now that it is stable enough.
You may find :
the online instance url here: https://titan-project.transrian.fr/
the Github repository here: https://github.com/GroupePSA/titan-project
more info on the Github Wiki page: https://github.com/GroupePSA/titan-project/wiki
The idea is as following : abstract the I/O part (input & output), to be able to focus on the productive part : the filter = the parsing of the log in itself. Once the filter set-up and working for the log sample you provided, you only need to apply it in your Logstash instance(s) (either manually, or though the central pipeline management)
It's not some clean code, I made some questionable choices ; but it work, and should be pretty stable.
So if that can permit you to speed-up your development process (especially for newcomers in the Logstash world), feel free to check it out, and don't hesitate if you have any questions or suggestions !