Using conditional build steps to speed up your Jenkins PHP builds

At my client Spotney, we have a pretty solid (and common) build infrastructure for our PHP projects; SVN commits are checked out by Jenkins, tests are run by PHPUnit, Sonar runs static code analysis, and artifacts are built and deployed to a staging environment by Phing. However, some of the code relies pretty heavily on (complex) db queries, adding the need for DbUnit style tests. The nature and quantity of the tests, combined with a slow VM (possibly related to this Xdebug issue) meant that our buildtimes were becoming prohibitively long.

An interesting post by @pascaldevink triggered a conversation and sparked an idea. I started working on our build setup, eventually resulting in a 60-70% decrease of our build times!

Here’s how I did it.

Starting point

Let’s assume we have a fairly standard Jenkins job. The job checks out an SVN repository, and periodically scans that repository for changes, triggering a new build if any are detected.

Each build of the job performs three steps:

  • Run phpunit
  • Run phing (target “build”)
  • Invoke Sonar (using the Jenkins Sonar plugin – this plugin also allows invoking Sonar as a post-build action, but that option requires Maven)

After the build steps, the job publishes the test and code coverage reports, and archives the generated artifacts.

Disabling code coverage and Sonar for regular builds

Two of the most obvious optimizations (also suggested by Pascal) are disabling code coverage on all tests and disabling Sonar runs during regular Jenkins builds. We define regular as either manually started by a user, or by an SCM trigger.

Disabling code coverage generation in PHPUnit is easy, simply remove the “coverage-xxx” elements from the logging section of your phpunit.xml configuration file (see this section of the PHPUnit manual). Disabling Sonar is trivial too, just remove the last build step from the job.

However, this is not an ideal solution: we do want to generate code coverage information and run Sonar at some point, such as during nightly builds, preferably without cloning our existing job. This means that we’ll need to skip code coverage and Sonar invocations on all but the scheduled (nightly) builds.

The Sonar plugin supports excluding SCM triggered builds (“Skip if triggered by SCM Changes”), but that only works if you use the post-build action. Additionally, we need to be able to change the PHPUnit configuration – one file to enable code coverage generation, one file to disable it.

Conditional build steps

The Conditional BuildStep plugin wraps one or more build steps in a conditional execution block. One of the possible conditions is the build cause, i.e. was the build triggered by a user, an upstream project, a timer, an SCM change, etc. etc.

First we define the steps that should be taken for each nightly build of our job. These steps should only be executed when the build is trigger by a timer.

We add a “Conditional steps (multiple)” build step, setting the condition to “Build Cause” and the Build Cause to “TimerTrigger”.

Conditional Sonar Build Config [Jenkins]2

Then we add our three (original) build steps:

Conditional Sonar Build Config [Jenkins]3

As stated before, regular builds are those that are triggered by a user or an SCM change.

We again add a “Conditional steps (multiple)” build step. The condition for this step is a little more interesting, as seen below. We combine two Build Cause conditions (one set to “UserCause”, the other to “SCMTrigger”) using the Or condition.

Conditional Sonar Build Config [Jenkins]4

We then add two build steps: the first will run PHPUnit without code coverage (note that we are specifying a different configuration file here), the second one will run Phing.

Conditional Sonar Build Config [Jenkins]5

Note that in the above build steps we’re invoking Phing from the shell instead of using the Phing plugin. Unfortunately this plugin is currently not supported as a conditional build step (probably because of this JIRA issue).

Build schedule

As a final step we need to update our build schedule.

Conditional Sonar Build Config [Jenkins]1

This will ensure our job runs somewhere after midnight (between 12:00 AM and 2:59 AM to be precise).

The end result:

  • A nightly scheduled build, with all the bells and whistles enabled
  • User and SCM triggered builds run (a lot) faster

Please let me know if you think this post is useful, or if you have any other Jenkins/PHP optimization tips!

Michiel Rook

Michiel Rook

Michiel Rook is an experienced, passionate & pragmatic freelance coach, developer & speaker from the Netherlands. He loves helping teams and companies to develop better software and significantly improve their delivery process. When he’s not thinking about continuous deployment, DevOps or event sourcing he enjoys music, cars, sports and movies.

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