Add Dockerfiles + Compose

[parkingups69-netizen]

Proposed change

• This PR creates a functional docker container stack based on the current dev branch.
• This stack will boot to a functional instance, ready for installer.pl
• Auto-configuration of the database host in Kernel/Config.pm
• Preconfigured tuning parameters for MariaDB (max_allowed_packet, innodb_log_file_size) based on Znuny installation recommendations.

Type of change

1 - 🚀 feature' - New feature (which adds functionality to an existing integration)

Checklist

• [x ] The code change is tested and works locally.(❗)
• There is no commented out code in this PR.(❕)
• You improved or added new unit tests.(❕)
• Local ZnunyCodePolicy passed.(❕)
• Local UnitTests / Selenium passed.(❕)
• GitHub workflow CI (UnitTests / Selenium) passed.(❗)

[eyazi]

Hey, this is a solid PoC and shows that Znuny can run in Docker, but I see a few structural issues for a default configuration:

1. The entire application directory is mounted as a volume, which makes updates and rollbacks harder because application code and persistent data are mixed; usually only a few paths need to be persistent (e.g. Kernel/Config.pm, attachments, logs).
2. Some environment-specific settings (like the database host and SMTP) are hardcoded.
3. The daemon runs in the background instead of as the main container process, so Docker can’t reliably detect whether the daemon is running or restart it if it fails.

[parkingups69-netizen]

@eyazi Thank you for the feedback, I'll refine the default configuration and post here when i've got news.

[parkingups69-netizen]

@eyazi Hey, i've updated the PR:

The entire application directory is mounted as a volume, which makes updates and rollbacks harder because application code and persistent data are mixed; usually only a few paths need to be persistent (e.g. Kernel/Config.pm, attachments, logs).
Moved Config.pm to a custom directory (/persistent) and symlinking it, this directory is a volume
A seperate volume for these directories:
/opt/znuny/var/log
/opt/znuny/var/article
/opt/znuny/var/httpd/htdocs/custom
I'm personally not aware of more things that would need to be provided as standard, as my knowledge is limited of the inner workings of Znuny.

Some environment-specific settings (like the database host and SMTP) are hardcoded.
Added env vars for DB settings, injected in config.pm during container boot (only when they are default values, to leave any custom config alone)
SMTP settings are saved in the DB i thought?

The daemon runs in the background instead of as the main container process, so Docker can’t reliably detect whether the daemon is running or restart it if it fails.
Moved to using a watchdog script, it will force restart the container if daemon is down for more than 5 minutes
Using the daemon start script wasn't an option as it exits when the daemon is already running. (Had some goofy behaviour)

[parkingups69-netizen]

@rkaldung Have you had a chance to review this yet?

[rkaldung]

@rkaldung Have you had a chance to review this yet?

Only on a high level because we're right in the pre-release of 7.3. The detailed review is on my agenda right after the release.

[rkaldung]

@parkingups69-netizen We won't merge this PR, but use it as the initial commit for https://github.com/znuny/znuny-docker