All of this runs on one single server, no big infrastructure, no big data. I am unable to find a SIMPLE tool to collect my logs in some way, parse them, and visualize them in histograms for example.
I know there exist ELK stack, Splunk, Graylog and many others, but all these solutions are much too complex. Especially I do not want to spend weeks setting this up correctly. Further more, most of these solutions need an extra server for aggregating the logdata in some timeseries db.
I would be very happy if you know about any opensource tool which can do this job.
example: goaccess logfile.log -o report.html --log-format=COMBINED
There's also angle-grinder, which has less features, but also pretty useful: https://github.com/rcoh/angle-grinder
For some kinds of logs there are tools for summarization and reports (like awstats for web or pflogsumm for mail servers).
And, of course, for particular queries on existing logs the standard text tools in a linux box let you generate a lot of info.