Creating a pid_file while using Proc::Daemon::Init

Question

I've been following the explanation in run a perl script as a daemon. I would like to create the pid_file within the perl script. After going through the documentation I was sure that the following piece of code would do it:

use Proc::Daemon;
Proc::Daemon::Init({ pid_file => "/var/run/theprocess.pid"} );

To make a long story short. Id didn't work. I've also tried with the Proc::Daemon->new() operator and it didn't work either. What could I be missing?

Please provide more details on "didn't work" in both cases. Didn't compile? Runtime error? Error message (and if so what is it)? hanging? etc... — DVK, Oct 01 '11 at 00:23
Didn't create the pid file. Worked perfectly as the daemon detached and it did run. — Ricardo Marimon, Oct 01 '11 at 02:25
No errors on STDERR that I could find. Nothing on the console or /var/log/syslog. — Ricardo Marimon, Oct 01 '11 at 12:55

score 1 · Answer 1 · answered Oct 01 '11 at 00:34

Without knowing any details it's hard to tell, but most likely it's one of 2 things:

Either pid_file doesn't support a full path. This is unlikely but possible considering that POD example involves separate work_dir argument and path-less pid_file value:
```
my $daemon = Proc::Daemon->new(
     work_dir     => '/working/daemon/directory',
     pid_file     => 'pid.txt',
     exec_command => 'perl /home/my_script.pl',
);
```
Based on the current code in the module that's not the case (e.g. the example merely doesn't show a valid usage with full path, but such usage is fine); but it could be a new functionality missing from your older module version. Again, unlikely.
Or, the file you're writing to can't be created, either because the directory is missing or due to permissioning issue. If that's the case there should be something on STDERR looking like "*Can not open pid_file xxxx*" . Just as FYI, the file is opened for read-write mode (+>).

score 1 · Answer 2 · answered Oct 03 '11 at 00:49

Actually the problem was that the debian package that installs Proc::Daemon::Init is for version 0.3 which doesn't have the functionality to create the pid files. I ended up doing something like:

use Proc::Daemon;
use Proc::PID::File;

Proc::Daemon::Init();
if (Proc::PID::File->running()) {
    exit;
}

Creating a pid_file while using Proc::Daemon::Init

2 Answers2