Reading the (Perl-based) Mojo config outside of the app

mojo_config.md

I needed to read a Mojo app's config file without being in the Mojo app itself. If I were using YAML or JSON that wouldn't be a problem, but I was using the old-school Perl code format.

I pulled some of the stuff out of Mojolicious::Plugin::Config to write a little script to do it the same way. One thing to note is that mode-specific config files (app.development.conf) overlay the main one rather than merging into it. A later config key at the top level completely replaces the one before it, just as we expect from a Perl hash.

This is also on Reddit.

sub load { $_[0]->parse(decode('UTF-8', path($_[1])->slurp), @_[1, 2, 3]) }

sub parse {
  my ($self, $content, $file, $conf, $app) = @_;

  # Run Perl code in sandbox
  my $config = eval 'package Mojolicious::Plugin::Config::Sandbox; no warnings;'
	. "sub app; local *app = sub { \$app }; use Mojo::Base -strict; $content";
  die qq{Can't load configuration from file "$file": $@} if $@;
  die qq{Configuration file "$file" did not return a hash reference} unless ref $config eq 'HASH';

  return $config;
}

my @files = qw(
	app.conf
	app.development.conf
	);

# load files in order
my $config = {};
foreach my $file ( grep { -e } @file ) {
	my $contents = decode( 'UTF-8', Mojo::File->new($file)->slurp );

	my $this = eval <<~"HERE";
		package Local::Sandbox;
		no warnings;
		$content;
		HERE

	$config = { $config->%*, $this->%* };
	}

say Mojo::Util::dumper($config);