mqtt: enable limiting of logged message length

[satta]

• I have read the contributing guide lines at
  https://docs.suricata.io/en/latest/devguide/contributing/contribution-process.html
• I have signed the Open Information Security Foundation contribution agreement at
  https://suricata.io/about/contribution-agreement/ (note: this is only required once)

Link to redmine ticket: https://redmine.openinfosecfoundation.org/issues/6984

Describe changes:

• Add an msg-log-limit option to enable optional truncation of the message payloads in MQTT.

SV_BRANCH=https://github.com/OISF/suricata-verify/pull/1828

[codecov]

Codecov Report

Attention: Patch coverage is 93.05556% with 5 lines in your changes are missing coverage. Please review.

Project coverage is 83.65%. Comparing base (abb7424) to head (5edd982).

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #11053      +/-   ##
==========================================
+ Coverage   80.63%   83.65%   +3.01%     
==========================================
  Files         922      922              
  Lines      250137   250338     +201     
==========================================
+ Hits       201699   209417    +7718     
+ Misses      48438    40921    -7517     

Flag	Coverage Δ
fuzzcorpus	64.28% <33.33%> (+0.01%)	⬆️
livemode	18.42% <13.33%> (-0.13%)	⬇️
suricata-verify	62.76% <83.33%> (?)
unittests	62.26% <62.50%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

[jlucovsky]

Please add a documentation update to doc/userguide/configuration/suricata-yaml.rst

[satta]

Hmm, it looks like the included file doc/userguide/partials/eve-log.yaml hasn't been updated in some time. I guess that's where you meant the additional options to be listed? Should I bring it up to date with the current state of supported event types?

Also, I don't think that the logging options should go into doc/userguide/configuration/suricata-yaml.rst? The app-layer parser configuration is there, but the changes here only affect logging. I think it would probably be best to add a MQTT section to doc/userguide/output/eve/eve-json-output.rst. What do you think?

[satta]

New PR: #11054 11054

[catenacyber]

Also, I don't think that the logging options should go into doc/userguide/configuration/suricata-yaml.rst? The app-layer parser configuration is there, but the changes here only affect logging. I think it would probably be best to add a MQTT section to doc/userguide/output/eve/eve-json-output.rst. What do you think?

I think doc/userguide/configuration/suricata-yaml.rst is meant to document everything in suricata.yaml
@jufajardini what do you think ?

[jufajardini]

Also, I don't think that the logging options should go into doc/userguide/configuration/suricata-yaml.rst? The app-layer parser configuration is there, but the changes here only affect logging. I think it would probably be best to add a MQTT section to doc/userguide/output/eve/eve-json-output.rst. What do you think?

I think doc/userguide/configuration/suricata-yaml.rst is meant to document everything in suricata.yaml @jufajardini what do you think ?

I see that Sascha has addressed this, but just to answer - it seems to be what we're following, indeed.