[sosreport] /etc/sos.conf to support (more/some/all) command line options

[pmoravec]

Sosreport might be deployed in environments where different command line options might need to be used by default all the time. I.e. limit log size, set some plugin options, skip some plugins etc. It makes sense to store such defaults in /etc/sos.conf.

Shall sos.conf support all or specific types of parameters?

Shall cmdline options take precedence of the options in sos.conf (I think so)?

[pmoravec]

Hm, I can add a new section (say [general] to sos.conf and load sosreport's cmdline options from there - but only after they are loaded from cmdline. And I dont see a simple way to check if just parsed option from config has or has not been provided in cmdline - optparser does not have a method for that :(

So now I would end up with config options preceding cmdline options - something not intended.

[pmoravec]

Since the time of opening this issue, presets were introduced.

I expect the right ordering of evaluation of tunables/settings should be:

1. apply presets
2. apply changes from config file (either /etc/sos.conf or the file from --config-file=.. one), optionally overwrite those set via tunables
3. apply changes from command line, optionally overwrite those set via tunables or from config file

[pmoravec]

OK, now the ordering is different: first cmdline options are loaded, then overwritten by those in sos.conf.

[pmoravec]

There is a bit chicken-egg problem:

• the very first options to load are from presets
• to find preset, we need to know policy
• to set policy and/or preset, we need to evaluate command line options and config file
• but evaluating command line options and config file should be done after evaluating presets

(similar chicken-egg problem is with evaluating non-default config file prior command line options where we need to process cmdline before the config - this can be yet resolved by some trick)

Gladly, SoSOptions.merge method helps here a lot:

• self.opts = "process command line options (to know config file or presets or sysroot)"
• self.cfgfileopts = "process config file from self.opts["config_file"]"
• self.opts.merge(self.cfgfileopts) (but fix the bug in _merge_opt to add src option to the beginning of the list/tuple)
• set policy per sysroot
• self.presetopts = "process preset loaded from self.opts["preset"] and self.opts["sysroot"]"
• self.opts.merge(self.presetopts)