How to trigger a build only if changes happen on p

问题:

How do I tell Jenkins/Hudson to trigger a build only for changes on a particular project in my Git tree?

回答1:

The Git plugin has an option (excluded region) to use regexes to determine whether to skip building based on whether files in the commit match the excluded region regex.

Unfortunately, the stock Git plugin does not have a "included region" feature at this time (1.15). However, someone posted patches on GitHub that work on Jenkins and Hudson that implement the feature you want.

It is a little work to build, but it works as advertised and has been extremely useful since one of my Git trees has multiple independent projects.

https://github.com/jenkinsci/git-plugin/pull/49

Update: The Git plugin (1.16) now has the 'included' region feature.

回答2:

Basically, you need two jobs. One to check whether files changed and one to do the actual build:

Job #1

This should be triggered on changes in your Git repository. It then tests whether the path you specify ("src" here) has changes and then uses Jenkins' CLI to trigger a second job.

export JENKINS_CLI="java -jar /var/run/jenkins/war/WEB-INF/jenkins-cli.jar"
export JENKINS_URL=http://localhost:8080/
export GIT_REVISION=`git rev-parse HEAD`
export STATUSFILE=$WORKSPACE/status_$BUILD_ID.txt

# Figure out, whether "src" has changed in the last commit
git diff-tree --name-only HEAD | grep src

# Exit with success if it didn't
$? || exit 0

# Trigger second job
$JENKINS_CLI build job2 -p GIT_REVISION=$GIT_REVISION -s

Job #2

Configure this job to take a parameter GIT_REVISION like so, to make sure you're building exactly the revision the first job chose to build.

回答3:

While this doesn't affect single jobs, you can use this script to ignore certain steps if the latest commit did not contain any changes:

/*
 * Check a folder if changed in the latest commit.
 * Returns true if changed, or false if no changes.
 */
def checkFolderForDiffs(path) {
    try {
        // git diff will return 1 for changes (failure) which is caught in catch, or
        // 0 meaning no changes 
        sh "git diff --quiet --exit-code HEAD~1..HEAD ${path}"
        return false
    } catch (err) {
        return true
    }
}

if ( checkFolderForDiffs('api/') ) {
    //API folder changed, run steps here
}

回答4:

If the logic for choosing the files is not trivial, I would trigger script execution on each change and then write a script to check if indeed a build is required, then triggering a build if it is.

回答5:

I answered this question in another post:

How to get list of changed files since last build in Jenkins/Hudson

#!/bin/bash

set -e

job_name="whatever"
JOB_URL="http://myserver:8080/job/${job_name}/"
FILTER_PATH="path/to/folder/to/monitor"

python_func="import json, sys
obj = json.loads(sys.stdin.read())
ch_list = obj['changeSet']['items']
_list = [ j['affectedPaths'] for j in ch_list ]
for outer in _list:
  for inner in outer:
    print inner
"

_affected_files=`curl --silent ${JOB_URL}${BUILD_NUMBER}'/api/json' | python -c "$python_func"`

if [ -z "`echo \"$_affected_files\" | grep \"${FILTER_PATH}\"`" ]; then
  echo "[INFO] no changes detected in ${FILTER_PATH}"
  exit 0
else
  echo "[INFO] changed files detected: "
  for a_file in `echo "$_affected_files" | grep "${FILTER_PATH}"`; do
    echo "    $a_file"
  done;
fi;

You can add the check directly to the top of the job's exec shell, and it will exit 0 if no changes are detected... Hence, you can always poll the top level for check-in's to trigger a build.

回答6:

You can use Generic Webhook Trigger Plugin for this.

With a variable like changed_files and expression $.commits[*].['modified','added','removed'][*].

You can have a filter text like $changed_files and filter regexp like "folder/subfolder/[^"]+?" if folder/subfolder is the folder that should trigger builds.