How to configure Git post commit hook

Question

How to trigger a build remotely from Jenkins?
How to configure Git post commit hook?

My requirement is whenever changes are made in the Git repository for a particular project it will automatically start Jenkins build for that project.

In Jenkins trigger build section I selected trigger build remotely.
In .git directory, hooks directory is there in that we have to configure post commit file.
I am confusing how to trigger a build from there (I know some part we should use curl command).

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curl cmbuild.aln.com/jenkins/view/project name/job/myproject/buildwithparameters?Branch=feat-con

I have placed this command in my git server hooks directory (post commit hook).
Whenever the changes happen in repository it is running automate build.

I want to check in changeset whether in at least one java file is there the build should start.
Suppose the developers changed only xml files or property files the build should not start.
Along with xml, suppose the .java files is there the build should start.

Answer 1

As mentioned in "Polling must die: triggering Jenkins builds from a git hook", you can notify Jenkins of a new commit:

With the latest Git plugin 1.1.14 (that I just release now), you can now do this more >easily by simply executing the following command:

curl http://yourserver/jenkins/git/notifyCommit?url=<URL of the Git repository>

This will scan all the jobs that’s configured to check out the specified URL, and if they are also configured with polling, it’ll immediately trigger the polling (and if that finds a change worth a build, a build will be triggered in turn.)

This allows a script to remain the same when jobs come and go in Jenkins.
Or if you have multiple repositories under a single repository host application (such as Gitosis), you can share a single post-receive hook script with all the repositories. Finally, this URL doesn’t require authentication even for secured Jenkins, because the server doesn’t directly use anything that the client is sending. It runs polling to verify that there is a change, before it actually starts a build.

As mentioned here, make sure to use the right address for your Jenkins server:

since we're running Jenkins as standalone Webserver on port 8080 the URL should have been without the /jenkins, like this:

http://jenkins:8080/git/notifyCommit?url=git@gitserver:tools/common.git

To reinforce that last point, ptha adds in the comments:

It may be obvious, but I had issues with:

curl http://yourserver/jenkins/git/notifyCommit?url=<URL of the Git repository>. 

The url parameter should match exactly what you have in Repository URL of your Jenkins job.
When copying examples I left out the protocol, in our case ssh://, and it didn't work.

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You can also use a simple post-receive hook like in "Push based builds using Jenkins and GIT"

#!/bin/bash
/usr/bin/curl --user USERNAME:PASS -s \

http://jenkinsci/job/PROJECTNAME/build?token=1qaz2wsx

Configure your Jenkins job to be able to “Trigger builds remotely” and use an authentication token (1qaz2wsx in this example).

However, this is a project-specific script, and the author mentions a way to generalize it.
The first solution is easier as it doesn't depend on authentication or a specific project.

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I want to check in change set whether at least one java file is there the build should start.
Suppose the developers changed only XML files or property files, then the build should not start.

Basically, your build script can:

• put a 'build' notes (see git notes) on the first call
• on the subsequent calls, grab the list of commits between HEAD of your branch candidate for build and the commit referenced by the git notes 'build' (git show refs/notes/build): git diff --name-only SHA_build HEAD.
• your script can parse that list and decide if it needs to go on with the build.
• in any case, create/move your git notes 'build' to HEAD.

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May 2016: cwhsu points out in the comments the following possible url:

you could just use curl --user USER:PWD http://JENKINS_SERVER/job/JOB_NAME/build?token=YOUR_TOKEN if you set trigger config in your item

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June 2016, polaretto points out in the comments:

I wanted to add that with just a little of shell scripting you can avoid manual url configuration, especially if you have many repositories under a common directory.
For example I used these parameter expansions to get the repo name

repository=${PWD%/hooks}; 
repository=${repository##*/} 

and then use it like:

curl $JENKINS_URL/git/notifyCommit?url=$GIT_URL/$repository

Answer 2

Hope this helps: http://nrecursions.blogspot.in/2014/02/how-to-trigger-jenkins-build-on-git.html

It's just a matter of using curl to trigger a Jenkins job using the git hooks provided by git.
The command

curl http://localhost:8080/job/someJob/build?delay=0sec

can run a Jenkins job, where someJob is the name of the Jenkins job.

Search for the hooks folder in your hidden .git folder. Rename the post-commit.sample file to post-commit. Open it with Notepad, remove the : Nothing line and paste the above command into it.

That's it. Whenever you do a commit, Git will trigger the post-commit commands defined in the file.

Answer 3

As the previous answer did show an example of how the full hook might look like here is the code of my working post-receive hook:

#!/usr/bin/python

import sys
from subprocess import call

if __name__ == '__main__':
    for line in sys.stdin.xreadlines():
        old, new, ref = line.strip().split(' ')
        if ref == 'refs/heads/master':
            print "=============================================="
            print "Pushing to master. Triggering jenkins.        "
            print "=============================================="
            sys.stdout.flush()
            call(["curl", "-sS", "http://jenkinsserver/git/notifyCommit?url=ssh://user@gitserver/var/git/repo.git"])

In this case I trigger jenkins jobs only when pushing to master and not other branches.

Answer 4

I want to add to the answers above that it becomes a little more difficult if Jenkins authorization is enabled.

After enabling it I got an error message that anonymous user needs read permission.

I saw two possible solutions:

1: Changing my hook to:

curl --user name:passwd -s http://domain?token=whatevertokenuhave

2: setting project based authorization.

The former solutions has the disadvantage that I had to expose my passwd in the hook file. Unacceptable in my case.

The second works for me. In the global auth settings I had to enable Overall>Read for Anonymous user. In the project I wanted to trigger I had to enable Job>Build and Job>Read for Anonymous.

This is still not a perfect solution because now you can see the project in Jenkins without login. There might be an even better solution using the former approach with http login but I haven't figured it out.