[dancer-users] Dancer and forking

Johandry Amador Segui johandry at gmail.com
Wed Jul 8 00:58:06 BST 2015

Hi Andy,

I tried to use threads and it did not worked for me (maybe because of non safe thread modules I am using) so I use fork in a production application and it works good. I have some issues some times with MySQL that I have not fixed yet but they do not happen very often.

This is an example of how I use it:

sub execute {

	# These 2 lines below were to eliminate the error that I mentioned before. It did not eliminated them just reduce them
	my $dbh = database();
	$dbh->{InactiveDestroy} = 1;

	my $pid = fork();

	if ($pid) {
		# This is the parent (Dancer) in case you want to do something here
		debug “Process started with PID $pid\n”;

	} elsif ($pid == 0) {
		# This is the child, here is where I do all I need
		$template = ...
	} else {
		debug “Could not fork: $!\n”;

	# I have a variable to know if I’m running this sub from the web or from CLI
	if ($cli) {
		my $output = waitpid($pid, 0);
		print “The process finish with output: $output”;

	return $template;

This is just an example, not the entire code. If someone has a suggestion or improvement, it is welcome.


> On Jul 7, 2015, at 2:58 PM, Andrew Beverley <andy at andybev.com> wrote:
> Dear all,
> Is there anything that I should be aware of if using fork() in a dancer
> application?
> I have some cache update code which can take a while to run, so I'd rather do it
> in the background. I've therefore done something like this:
>    post '/data' => sub {
>        my $template = ...;
>        fork and return $template;
>        update_cache;
>        exit;
>    }
> The actual code is in a module, but you get the idea.
> Thanks,
> Andy
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> dancer-users at dancer.pm
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