Understand Znuny / OTRS / OTOBO traceback

Learn in this article how to analyze, debug and fully understand OTRS / Znuny traceback errors. Let us take a common upgrade issue from Znuny 6.2.x to 6.3.x
Here we are failing on fetching E-Mails and we get this error:

ERROR: OTRS-otrs.Console.pl-Maint::PostMaster::MailAccountFetch-10 Perl

Message: There was an error executing Execute() in Kernel::System::Console::Command::Maint::PostMaster::MailAccountFetch: Console command 'MailAccountFetch' is failed.

Traceback 
Module: Kernel::System::Daemon::DaemonModules::BaseTaskWorker::_HandleError Line: 50
Module: Kernel::System::Daemon::DaemonModules::SchedulerTaskWorker::Cron::Run Line: 175
Module: Kernel::System::Daemon::DaemonModules::SchedulerTaskWorker::Run Line: 233
Module: (eval) Line: 331
Module: main::Start Line: 331
Module: /opt/otrs/bin/otrs.Daemon.pl Line: 152

This message looks really awkward but it has lot of details to track down your error. Here a simple process to find your OTRS / Znuny / OTOBO error:

Prozess to read and understand the traceback lines

For this example here we will use specifically Znuny version 6.3.3.

1. Line 1: ERROR: OTRS-otrs.Console.pl-Maint::PostMaster::MailAccountFetch
   The line is telling you very specific, who is causing the error. Here it is naming Console.pl and the Module Maint::PostMaster::MailAccountFetch
   Now you know how to reproduce or where to search
2. Line 2: Message: There was an error executing Execute()
   Sometimes you get more details from the developed code, if this error is expected. In this case it seems to be an unexpected error
3. Line 3 and following: Traceback
   Traceback is giving you hints to the specific places in code. The topmost entry is showing you there exactly the code terminated expectedly or unexpectedly.
   In this case it seems it is unexpected termination in
   Module: Kernel::System::Daemon::DaemonModules::BaseTaskWorker::_HandleError
   at line 50 in perl file Module: Kernel::System::Daemon::DaemonModules::BaseTaskWorker in function/method _HandleError
4. find the corresponding file of the Module
   this is mostly also very simple by going to your installation (typically /opt/otrs) and you navigate from here to
   Kernel/System/Daemon/DaemonModules and your file has mostly .pm or .pl as file extension.
   In our case it is BaseTaskWorker.pm
5. open the file with an editor
   go to the given line, in our case Line 50

You will find here this code

sub _HandleError {
    my ( $Self, %Param ) = @_;

    $Kernel::OM->Get('Kernel::System::Log')->Log( // our Line 50
        Priority => 'error',
        Message  => $Param{LogMessage},
    );

If you do not have access to the file system you can use github with it’s git repository.

To get the code simply do:

1. open in browser
   https://github.com/znuny/Znuny
2. select tags in the branches dropdown
   
3. select your version 6.3.3
   named in this list as rel-6.3.3
   which will bring you to the tagged sources
   https://github.com/znuny/Znuny/tree/rel-6_3_3
4. Now you navigate also the folders down to
   Kernel/System/Daemon/DaemonModules, which will bring you to this
   https://github.com/znuny/Znuny/tree/rel-6_3_3/Kernel/System/Daemon/DaemonModules
5. Open the source file
   https://github.com/znuny/Znuny/blob/rel-6_3_3/Kernel/System/Daemon/DaemonModules/BaseTaskWorker.pm
6. Go to source file at Line 50
   https://github.com/znuny/Znuny/blob/rel-6_3_3/Kernel/System/Daemon/DaemonModules/BaseTaskWorker.pm#L50

And now you see that the Line 50 is adding something to log:

$Kernel::OM->Get('Kernel::System::Log')->Log( // Line 50
    Priority => 'error',
    Message  => $Param{LogMessage},
);

So the next checks are:

• if your log file is existing
• if your log file can be created (if missing)
• if your log file is writable

The location of your log file is configured in System Configuration > LogModule::LogFile and it is typically

/var/log/otrs/otrs.log