Damien Krotkine home

Mass-Testing Dancer’s Plugins

So, as I said at YAPC::EU 2012, one thing that remains to be done before Dancer 2 can be released : migrating the plugins, making sure they work with it.

To be able to do that, what’s best than an automatic testing facility ?

The goal is to get all Dancer plugins, test them with Dancer1, and Dancer2, and produce a report, to check which one fails and need fixing.

Step 1. Get the list of Dancer plugins.

Easy ! let’s use Metacpan. After searching, I finally got a way to get the list of all modules that depend on Dancer. Then filtering out the ones that don’t contain "Plugin" will do the trick.

#!/usr/bin/env perl

use Modern::Perl;
use ElasticSearch;

my $es = ElasticSearch->new( servers => 'api.metacpan.org', no_refresh => 1 );

my $scroller = $es->scrolled_search(
    query       => { match_all => { } },
    search_type => 'scan',
    scroll      => '5m',
    index       => 'v0',
    type        => 'release',
    size        => 100,
    filter => {
            term => {
                     'release.dependency.module' => 'Dancer'


my $result = $scroller->next;

my %plugins;
while ( my $result = $scroller->next ) {
    $result->{_source}->{name} =~ /Dancer-Plugin/
      or next;
    my $name = $result->{_source}->{name};
    $name =~ s/-\d.*//;
    $name =~ s/-/::/g;
    $plugins{$name} = 1;
say $_ foreach sort keys %plugins;

Cool, let’s save this script as get_modules_list.pl.

Step 2. Prepare two Perl environments

We want two instance of Perl, without polluting anything. We’ll use perlbrew for that. Easy. The small trick is to have PERLBREW_ROOT initialized to a local directory to not polute existing ~/perl5 installation.

Step 3. Have a way to test modules

Well, let’s use cpanm, which has an option --test-only to only test a module without installing it. Oh but plugin modules that we’ll test may require dependances. We’ll install them using cpanm --installdeps, which does just that.

Step 4. Create a result file

I was lazy and just output to a .csv text file, but I may store the results somewhere else later.

Step 5. Let’s glue all that in a Makefile

The beauty of this is that by writing a proper Makefile, we can install this auto-tester anywhere. The requirements are minimal : bash, curl, and perl, with ElasticSearch and Modern::Perl installed.

( This post is intentionally named the same as the one from Yannick, because he proposed a different implementation. We’ll try to merge the good ideas together )


# set up the local Perlbrew location
    && source ${PERLBREW_DIR}/etc/bashrc \

# This will run the cpanm from the local Perlbrew, on each of the 2 perls
CPANM_DANCER1=${PERLBREW} exec --with dancer1_plugin_tests ${PERLBREW_DIR}/bin/cpanm
CPANM_DANCER2=${PERLBREW} exec --with dancer2_plugin_tests ${PERLBREW_DIR}/bin/cpanm

# loop on the plugin list, install the deps and test each plugin and output result
all: got_curl got_bash got_perlbrew_perl plugins_list
	echo "Plugin name,Pass on Dancer 1,Pass on Dancer 2" > result.csv
	@for i in `cat plugins_list`; do pass_d1=0; pass_d2=0; \
	  echo " ---------- TESTING on Dancer 1 : $$i"; \
          ${CPANM_DANCER1} -n --installdeps $$i \
              && ${CPANM_DANCER1} --test-only $$i && pass_d1=1; \
	  echo " ---------- TESTING on Dancer 2 : $$i"; \
          ${CPANM_DANCER2} -n --installdeps $$i \
              && DANCER_FORCE_PLUGIN_REGISTRATION=1 ${CPANM_DANCER2} --test-only $$i \
              && pass_d2=1; \
          echo "$$i,$$pass_d1,$$pass_d2" >> result.csv; \

	rm -rf plugins_list

	rm -rf ${PERLBREW_DIR}

# Get and install Perlbrew locally
	@echo " - creating a local perlbrew"
	export PERLBREW_ROOT=${PERLBREW_DIR} && curl -kL http://install.perlbrew.pl | bash

# Get and install cpanm in the local Perlbrew
	${PERLBREW} install-cpanm

	@which curl >/dev/null \
        || ( echo "you don't have curl, please install it and retry" && false )

	@which bash >/dev/null \
        || ( echo "you don't have bash, please install it and retry" && false )

got_perlbrew_perl: ${PERLBREW_DIR}/bin/perlbrew ${PERLBREW_DIR}/bin/cpanm perlbrew_dancer1_plugin_tests perlbrew_dancer2_plugin_tests

# Build perl from scratch and call this instance dancer1
	${PERLBREW} list | grep dancer1_plugin_tests > /dev/null \
        || ( ${PERLBREW} install -j 2 -n perl-5.16.1 --as dancer1_plugin_tests )

# Build perl from scratch and call this instance dancer2
	${PERLBREW} list | grep dancer2_plugin_tests > /dev/null \
        || ( ${PERLBREW} install -j 2 -n perl-5.16.1 --as dancer2_plugin_tests \
             && ${CPANM_DANCER2} ${HERE}/../.. )

# This gets the list of plugins, as previously described
	${HERE}/get_modules_list.pl > plugins_list

It’s really cool to see what you can do with modern tools of the Perl ecosystem !

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