Make systemd service robust to permission issues

[jollyroger]

In order for facette to successfully start there are some preconditions to be met:

• directory in /run should exist and permissions should allow to write facette user to it
• if facette listens on UNIX socket it should not exist when starting facette service

[vbatoufflet]

Hi @jollyroger,

Thanks for the PR.

I see that you enforce /run/facette creation and permissions, but retrieve the socket location from the configuration file.

What about if the .sock file is not located in /run/facette?

[jollyroger]

@vbatoufflet I tried to avoid putting additional checks and logic for these reasons:

• /run is recreated at boot time so this is where we should really check if the directory exists and create if necessary; there is no harm in creating the directory in /run as well even if no pidfile or socket file is used;
• in case the socket file is stored not in /run it is sufficient to create directory and set its permissions by hand during initial service configuration; creating the directory automatically in this case could do more harm then good because we cannot possibly know the exact directory permissions;
• in either case the service won't start if socket file already exist so we should remove it beforehand