Perl::Critic is a nifty syntax analyzer able to parse your Perl code, warn you against common mistakes and hint you towards best practices. It’s available either as a Perl module or a standalone shell script (perlcritic). Unfortunately, there is no standard way to integrate it with Jenkins.
Jenkins, the continuous-integration-tool-formerly-known-as-Hudson, is the cornerstone of our continuous building process at work. It checks out the latest build from Git, runs a bunch of tests (mainly Selenium, as we develop a website) and keeps track of what goes wrong and what goes right. We wanted to integrate Perl::Critic to Jenkins’ diagnostics to keep an eye on some errors that could creep in our codebase.
So Jenkins doesn’t do Perl::Critic. However, Jenkins supports TAP. TAP, the Test Anything Protocol, is an awesomely simple format to express test results that goes as follow:
1..4 ok 1 my first test ok 2 another successful test not ok 3 oh, this one failed ok 4 the last one's ok
The first line (the plan) announces how many tests there are, and each following line is a test result beginning by either “ok” or “not ok” depending on what gave.
Based on such a simple format, we can use a bit of shell scripting to mangle perlcritic’s output to be TAP-compatible:
# Perl::Critic \ # with line numbers (nl)... \ # prepend 'ok' for passed files... \ # and 'not ok' for each error... \ # and put everything in a temp file perlcritic $WORKSPACE \ | nl -nln \ | sed 's/\(.*source OK\)$/ok \1/' \ | sed '/source OK$/!s/^.*$/not ok &/' \ > $WORKSPACE/perlcritic_tap.results.tmp # Formatting: add the TAP plan, and output the tap results file. # TAP plan is a line "1..N", N being the number of tests echo 1..`wc -l < $WORKSPACE/perlcritic_tap.results.tmp` \ |cat - $WORKSPACE/perlcritic_tap.results.tmp > $WORKSPACE/perlcritic_tap.results # Cleanup rm -f $WORKSPACE/perlcritic_tap.results.tmp
(Â§WORKSPACE is a Jenkins-set variable referring to where the current build is being worked on.)
And voilÃ ! Jenkins reads the TAP result file and everything runs smoothly.
The only downside of this approach is that the number of tests will vary. For example, a single .pm file containing 5 Perl::Critic violations will show up as 5 failed tests, but fixing these will turn into a single successful test.