Alexander Aleksandrovič Klimov

Evaluate a better algorithm for the check scheduler logic

7

## Is your feature request related to a problem? Please describe. How our checks scheduler works:  ## Describe the solution you'd like How our checks scheduler shall work: ...

not just monitoring-plugins, as in the other distros. Read also https://github.com/Icinga/icinga2/pull/9151#issuecomment-1051034393 . closes #9151

ExtractSubjectTag Action: prepend, not append, remote system's subject tag

3

Too long (200+) ticket subjects (produced by this action) are shortened automatically. This could cut off the remote system's subject tag if at the end.

JSONFormatter#Format(): let errors decide their JSON representation by themselves

2

... if they implement json.Marshaler or encoding.TextMarshaler.

if a retryable error ocurred during waiting for the response. Otherwise we could run out of retries despite the XREAD was actually partially successful. fixes #2131

XREADs with BLOCK 0 on multiple consecutive Redis restarts exceed retries

2

@lippserd just had the observation that blocking XREADs without timeouts (BLOCK 0) on multiple consecutive Redis restarts and I/O timeouts exceeds Go-Redis internal retries and eventually leads to errors. @julianbrost...

## How to reproduce 1. Add IRC account: any nick / expired.badssl.com / port 443 / use SSL 2. Wait 3. Error: the server has terminated the connection

Command line: `["/usr/lib/nagios/plugins/check_docker","--containers","elasticsearch","--present","--restarts","23:42","--status","running","--uptime","120:60","--version"]` Container's image: `docker.elastic.co/elasticsearch/elasticsearch:7.5.1` Output: ``` Traceback (most recent call last): File "/usr/local/lib/python3.7/dist-packages/check_docker/check_docker.py", line 985, in main [x.result() for x in futures.as_completed(threads)] File "/usr/local/lib/python3.7/dist-packages/check_docker/check_docker.py", line 985, in [x.result()...