Controlled jekyll republishing with git commit messages

November 2, 2015

Relevant XKCD

It’s only fitting to start this little scrapbook with a short snippet for Jekyll. I’m a typical engineer in that I am willing to spend five hours setting something up that will save me 20 seconds about every other month, so I was tempted by the git post-receive hook deployment method from the Jekyll documentation.

Such a complete automatism doesn’t fit my usual workflow, however. I often push unfinished/untested code, mostly for the benefit of a remote backup.And while Jekyll has drafts, that mechanism does not help with changes to the rest of the codebase.

What I wanted was a method to control which pushes lead to redeployments. I’ve settled on the following post-receive hook, which only redeploys if the last commit message contains the string
'p! ' (without quotes). This method is adaptable to perform any conditional post-push action based on commit messages or other information in the git log.

# Republish Jekyll when last commit message
# contains p!

LOG=`git log -1 --pretty=%B HEAD`

if [[ $LOG != *"p! "* ]]
echo "We're keeping this version private."

echo "Publishing... "


jekyll build -s $TMP_GIT_CLONE -d $PUBLIC_WWW
echo "Done. Time to die. How fitting for a damn shell script."


I have a deep hatred for bash scripting and therefore not invested much time. Consider:

Redeploys only happen when the last commit message contains 'p! '. Any intermediate commits that where not pushed are ignored.

The 'p! ' trigger can occure anywhere in the commit message, not just at the beginning.

A better method would be to use branches for intermediate code. But we’re publishing a blog here and avoiding work clearly outranks orthodoxy.

Controlled Jekyll Republishing with git Commit Messages - November 2, 2015 - mw