Reloading of Perl modules

[bschmalhofer]

Currently, at least in the PSGI case, there is a two level approach to reloading. By reloading I mean check whether the module file has been updated and reload the module when it has.

1. The files in Kernel/Config/Files are reloaded whenever an new instance of Kernel::Configis created. That is for every request
2. All other modules, that is modules from Core, installed CPAN modules, and OTOBO specific modules, are check every 10s.
3. As of OTOBO 10.1.1 the file Kernel/Config.pm is also checked for every request.

The first case is fine, as only few files are concerned. The second case is not very elegant. Why don't we use a trigger file like it is supported in Apache2::Reload? This could then be done for every request, reducing the dead time between change and reload.

[bschmalhofer]

The solution implemented in #1000 is IMHO good enough for now.

[bschmalhofer]

Note that there are issues when OTOBO packages are deinstalled. Here is a scenaria where failures occured:

• An installation with an OTOBO package having Custom/Kernel/Translation.pm is running without flaws
• That module is deinstalled
• Failures because Kernel::Language::Translatable() is used in loaded modules, but the symbol is gone