I've never used it, but from the Log::Dispatch SYNOPSIS, it looks like you can set the filename in your Perl code: 
  my $log = Log::Dispatch->new(
      outputs => [
          [ filename => "log/$ENV{HOST}.log" ],
      ],
  );

[download]
Maybe you can set most of your parameters in the config file, and just this one in your Perl code.

In reply to Re: using env vars in Log::Dispatch::Config config files by toolic
in thread using env vars in Log::Dispatch::Config config files by Grafne

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