Deprecate conf_2_db feature

[ikedas]

Expected Behavior

The feature to save configuration into database table should be deprecated.

Current Behavior

There are two use cases:

• Content of sympa.conf and/or robot.conf may be imported into conf_table in database with sympa.pl --conf_2_db, and they may override default values of configuration.
  However, configuration in database affects only sympa_msg.pl and sympa_automatic.pl daemons and sympa.pl command line utility. The other daemons and most of command line tools seem not affected.

• Color setting (color_* parameters) on web UI are saved into conf_table, and they override configuration in each robot.conf.
  These settings are shared by possible multiple FastCGI servers through the database.

Possible Solution

• Deprecate conf_2_db feature to import configuration into database table.
• The setting imported into database should be exported to the configuration files during upgrade process.
• Color setting will be kept in the database.

[EDIT] It turned out that this feature has not dealt with the parameters other than CSS colors, so exporting parameters to the configuration files is unnecessary.

Context

This feature was introduced in Sympa 6.1. cf. the initial commit.

Probably it has been rarely used, except for color settings.

Deprecating this, configuration will be independent from database. It will make the code simpler.

[racke]

Sounds good to me 👍

[dverdin]

I precisely just used it for color settings. :-)

It is useful when, like I do, you regularly import new robots, when people are migrating from self hosting to a shared server.
Of course, most of the time, it involves an upgrade because we rarely run the same version of Sympa, so what you propose would probably work.

I remember why the conf_2_db feature had been asked: It was for people running a very large number of virtual hosts (I'm speaking thousands of robots). When reloading Sympa processes, reading the config files seemed to be a problem. I don't know why it was not applied to all Sympa daemons. Just a history note so you get some context.

Anyway, while running this command, I noticed a few bugs (introduced a long time ago). Is it still useful that I propose the fixes?
they are here: sympa-6.2...dverdin:fix-conf_2_db

[ikedas]

OK. It turns out that this is one of the features that was only planned but not working properly.

In these years, I have been working on fixing many of those things to make them really usable or removing them to cleanup code. I am happy to be able to safely remove this (unfinished) feature since it has never been used (except for color settings) in the first place.

[racke]

Yes that makes sense to me.