Prevent mercurial push during a jenkins build - version-control

Question

I have a jenkins job that runs some tests on a mercurial repo, and if successful tags the local repo with a 'stable' tag and then pushes this back to the main repo. The issue I'm having is that if someone pushes changesets while the build is running, then I cannot push the 'stable' tag.
I was wondering if there was a way to set the remote repo to read-only while the build is running, then make it 'push-able' once the build finishes?
Thanks,
Vackar

Answer 1

Preventing the push is probably not what you want (and it's almost pretty much impossible). The promise of a DVCS like Mercurial or git is that there's no locking -- it's a step forward.
Have you considered having Jenkins just pull and update before it merges? You can still tag the proper revision. Something like this:
jenkins checks out the code and notes the revision id it's building
jenkins does the build, runs the tests, etc. and everything goes well
jenkins does a hg pull to get the latest from the server
jenkins does a hg tag -m "build number $BUILD_NUMBER" --revision X --force stable
jenkins does a hg push
Then there's (almost) no time between that final pull, tag, and push, but the tag still goes on the revision that was actually build -- because you saved that revision hash id from when you first pulled.

Answer 2

I've just been looking for something similar. In our case, Jenkins is performing a merge, running an extensive suite of tests and once they all pass, pushing the merged code back to the repository. So it takes ~1 hour and fails if a developer pushes while the job is executing (it can't do the final push).
I couldn't find a ready-made solution, so ended up writing a mercurial hook which checks whether the job is building (using the REST API) before allowing the push.
You'll need access to your remote mercurial repository, but other than that, it's not too complex.
Add the following to your-remote-repo/.hg/hgrc:
[hooks]
pretxnchangegroup.DisablePushDuringJenkinsBuild= python:.hg/disable_push_if_building_hook.py:check_jenkins
[jenkins]
url=http://path-to-jenkins
jobs=jenkins-job-name[,comma-separated, for-multiple, jobs]
And make sure this python script is in your-remote-repo/.hg/
import json, urllib2
from mercurial import util
TEN_SECONDS = 10
def check_jenkins(ui, repo, node, **kwargs):
jenkins_url = ui.config('jenkins', 'url', default=None, untrusted=False)
jenkins_jobs = ui.config('jenkins', 'jobs', default=None, untrusted=False)
if not jenkins_url:
raise util.Abort('Jenkins hook has not been configured correctly. Cannot find Jenkins url in .hg/hgrc.')
if not jenkins_jobs:
raise util.Abort('Jenkins hook has not been configured correctly. Cannot find Jenkins jobs in .hg/hgrc.')
jenkins_jobs = [x.strip() for x in jenkins_jobs.split(',')]
for job in jenkins_jobs:
job_url = jenkins_url + '/job/' + job + '/lastBuild/api/json'
ui.write('Checking if job is running at URL: %s\n' % job_url)
try:
job_metadata = json.load(urllib2.urlopen(job_url, timeout = TEN_SECONDS))
if 'building' in job_metadata and job_metadata['building']:
raise util.Abort('Jenkins build "%s" is in progress. Pushing is disabled until it completes.' % job_metadata['fullDisplayName'])
except urllib2.URLError, e:
raise util.Abort('Error while trying to poll Jenkins: "%s"' % e)
return False # Everything is OK, push can be accepted