Display satis logs in admin panel

[kevindierkx]

Satis gives great feedback when the indexation of a repository fails, unfortunately the indexation of 'all' repositories fail when this happens.

Appending the output of the Satis build job to any kind of log file makes debugging these kind of errors allot easier, but it still requires you to SSH onto the server where Satis is running to look into the logs.
I'm running a cron every minute to keep things up to date, therefore I don't directly see the Satis output when something goes wrong.

My suggestion is to keep logs by default for all kind of application errors and secondly make them visible in the management interface.
ie. something like control-center/serviced does utilising Elasticsearch and Kibana.

I don't think we need a full stack Elasticsearch environment to keep logs, Satis doesn't report that much. A simple rotating file setup and some kind of frontend parser would suffice. (Maybe something like kassner/log-parser?)

I'm open for suggestions!

EDIT: This would partially depend on #54.

[ramunasd]

Might be helpful...
https://github.com/EasyCorp/easy-log-handler