Jenkins with Jenkinsfile Pipeline - Trigger Builds Remotely - jenkins

I have a Jenkinsfile setup for our CI/CD pipeline, and it runs through the pipeline on git actions like Pull Requests, Branch Creation, Tag Pushes, etc..
Prior to this setup, I was used to setting up Jenkins build jobs in the Jenkins UI. The advantage of this, was that I could setup dedicated build jobs that I could trigger remotely, and independently of git webhook actions. I could do a POST to the job endpoint with parameters to trigger various actions.
Documentation for this process would be referenced here - see "Trigger Builds Remotely"
I could also hit the big button that says "Build", or "Build with Parameters" in the UI, which was super nice.
How would one do this with a Jenkinsfile? Is this even possible to define build jobs in a pipeline definition within a Jenkinsfile? I.E. define functions / build jobs that have dedicated URLs that could be called on the Jenkins URL independent of webhook callbacks?
What's the best practice here?
Thanks for any tips, references, suggestions!

I would recommend starting with Multibranch pipelines. In general you get all the things you mentioned, but a little better. Because thhe paramteres can be defined within your Jenkinsfile. In short just do it like this:
Create a Jenkinsfile an check this into a Git Repository.
To create a Multibranch Pipeline: Click New Item on Jenkins home page.
Enter a name for your Pipeline, select Multibranch Pipeline and click OK.
Add a Branch Source (for example, Git) and enter the location of the repository.
Save the Multibranch Pipeline project.
A declarative Jenkinsfile can look like this:
pipeline {
agent any
parameters {
string(name: 'Greeting', defaultValue: 'Hello', description: 'How should I greet the world?')
}
stages {
stage('Example') {
steps {
echo "${params.Greeting} World!"
}
}
}
}
A good tutorial with screenshhots can be found here: https://www.jenkins.io/doc/book/pipeline/multibranch/

Related

Jenkins: how to trigger pipeline on git tag

We want to use Jenkins to generate releases/deployments on specific project milestones. Is it possible to trigger a Jenkins Pipeline (defined in a Jenkinsfile or Groovy script) when a tag is pushed to a Git repository?
We host a private Gitlab server, so Github solutions are not applicable to our case.
This is currently something that is sorely lacking in the pipeline / multibranch workflow. See a ticket around this here: https://issues.jenkins-ci.org/browse/JENKINS-34395
If you're not opposed to using release branches instead of tags, you might find that to be easier. For example, if you decided that all branches that start with release- are to be treated as "release branches", you can go...
if( env.BRANCH_NAME.startsWith("release-") ) {
// groovy code on release goes here
}
And if you need to use the name that comes after release-, such as release-10.1 turning into 10.1, just create a variable like so...
if( env.BRANCH_NAME.startsWith("release-") ) {
def releaseName = env.BRANCH_NAME.drop(8)
}
Both of these will probably require some method whitelisting in order to be functional.
I had the same desire and rolled my own, maybe not pretty but it worked...
In your pipeline job, mark that "This project is parameterized" and add a parameter for your tag. Then in the pipeline script checkout the tag if it is present.
Create a freestyle job that runs a script to:
Checkout
Run git describe --tags --abbrev=0 to get the latest tag.
Check that tag against a running list of builds (like in a file).
If the build hasn't occurred, trigger the pipeline job via a url passing your tag as a parameter (in your pipeline job under "Build Triggers" set "Trigger builds remotely (e.g. from scripts) and it will show the correct url.
Add the tag to your running list of builds so it doesn't get triggered again.
Have this job run frequently.
if you use multibranch pipeline, there is a discover tag. Use that plus Spencer solution

Visualizing build steps in Jenkins pipeline

In my Jenkins pipeline, I trigger several other jobs using the build step and pass some parameters to it. I'm having issues visualizing the different jobs I've triggered in addition to my pipeline. I have set up the Jenkins Delivery Pipeline plugin but the documentation for it is extremely vague and I have only been able to visualize the steps within my pipeline, despite tagging the jobs with both a stage and task name.
Example:
I have two jobs in Jenkins as pipelines/workflow jobs with the following pipeline script:
Job Foo:
stage('Building') {
println 'Triggering job'
build 'Bar'
}
Job Bar:
node('master') {
stage('Child job stage') {
println 'Doing stuff in child job'
}
}
When visualizing this with the Jenkins Pipeline Delivery plugin, I only get this:
How do I make it also show the stage in job Bar in a separate box?
Unfortunately, this use case is currently not supported in the Delivery Pipeline plugin version 1.0.0. The delivery pipeline plugin views for Jenkins pipelines are only rendering what is contained within one pipeline definition at this point. This feature request is tracked in JENKINS-43679.

Jenkins multibranch pipeline with Jenkinsfile from different repository

I have a Git repository with code I'd like to build but I'm not "allowed" to add a Jenkinsfile in its root (it is a Debian package so I can't add files to upstream source). Is there a way to store the Jenkinsfile in one repository and have it build code from another repository? Since my code repository has several branches to build (one for each Debian release) this should be a multibranch pipeline. Commits in either the code or Jenkinsfile repositories should trigger a build.
Bonus complexity: I have several code/packaging repositories like this and I'd like to reuse the same Jenkinsfile for all of them. Thus it should somehow dynamically fetch the right Git URL to use. The branches to build have the same names across all repositories.
Short answer is : you cannot do that with a multibranch pipeline. Multibranch pipelines are only designed (at least for now) to execute a specific pipeline in Pipeline script from SCM style, with a fixed Jenkinsfile at the root of the project.
You can however use the Multi-Branch Project plugin made for multibranch freestyle projects. First, you need to define your multibranch freestyle configuration just like you would with a multibranch pipeline configuration.
Select this new item like shown below :
This type of configuration will behave exactly same as the multibranch pipeline type, i.e. it will create you a folder with the name of your configuration and a sub-project for each branch it automatically detected.
The implementation should then be a piece of cake :
Specify your SCM repository in the multibranch configuration
Call another build as part of your build/post-build as you would do in a standard freestyle project, except that you have to call a parameterized job (let's call it build-job) and give it your repository information, i.e. Git URL and current branch (you can use the pre-defined variables $GIT_URL and $GIT_BRANCH for this purpose)
In your build-job, just define either an inline pipeline or a pipeline script checked out from SCM, and inside this script do a SCM checkout and go on with the steps you need to build. Example of build-job pipeline content :
.
node() {
stage 'Checkout'
checkout scm: [$class: 'GitSCM', branches: [[name: '*/${GIT_BRANCH}']], userRemoteConfigs: [[url: '${GIT_URL}']]]
stage 'Build'
// Build steps...
}
Of course if your different multibranches projects need to be treated a bit differently, you could also use intermediate projects (let's say build-project-A, build-project-B, ...) that would in turn call the generic build-job pipeline)
The one, major drawback of this solution is that you will only have one job responsible for all of your builds, making it harder to debug. You would still have your multibranch projects going blue/red in case of success/error but you will have to go back to called build-job to find the real problem of your build.
The best way I have found is to use the Remote Jenkinsfile Provider plugin. https://plugins.jenkins.io/remote-file/
This will add an option "by Remote Jenkinsfile Provider plugin" under Build Configuration>Mode then you can point to another repo where the Jenkinsfile is. I find this to be a much better solution than the Pipeline Multibranch Defaults Plugin, which makes you store the Jenkins file in Jenkins itself, rather than in source control.
U can make use of this plugin
https://github.com/jenkinsci/pipeline-multibranch-defaults-plugin/blob/master/README.md
Where we need to configure the jenkinsfile on jenkins rather than having it on each branch of your repo
I have version 2.121 and you can do this two ways:
Way 1
In the multibranch pipeline configuration > Build Configuration > Mode > Select "Custom Script" and put in "Marker File" below the name of a file you will use to identify branches that you want to have builds for.
Then, below that in Pipeline > Definition select "Pipeline Script from SCM" and enter the "SCM" information for how to find the "Jenkinsfile" that holds the script you want to run. It can be in the same repo you are finding branches in to create the jobs (if you put in the same GitHub repo's info) but I can't find a way to indicate that you just use the same branch for the file.
Way 2
Same as above, in the multibranch pipeline configuration > Build Configuration > Mode > Select "Custom Script" and put in "Marker File" below the name of a file you will use to identify branches that you want to have builds for.
Then, below that in Pipeline > Definition select "Pipeline Script" and put a bit of Groovy in the text box to load whatever you want or to run some script that already got loaded into the workspace.
In my case, i have an escenario whith a gitlab project based on gradle who has dependencies on another gitlab preject based on gradle too (same dashboard, but differents commits, differents developers).
I have added the following lines into my Jenkinsfile (the one which depends)
stage('Build') {
steps {
git branch: 'dev', credentialsId: 'jenkins-generated-ssh-key', url: 'git#gitlab.project.com:root/coreProject.git'
sh './gradlew clean'
}
}
Note: Be awark on the order on the sentences.
If you have doubt on how to create jenkins-generated-ssh-key please ask me

Jenkins multi-branch pipeline and specifying upstream projects

We currently generate a lot of Jenkins jobs on a per Git branch basis using Jenkins job DSL; the multi-branch pipeline plugin looks like an interesting way to potentially get first-class job generation support using Jenkinsfiles and reduce the amount of Job DSL we maintain.
For example we have libwidget-server and widget-server develop branch projects. When the libwidget-server build finishes then the widget-server job is triggered (for the develop branch). This applies to other branches too.
This makes use of the Build after other projects are built to trigger upon completion of an upstream build (e.g. libwidget-server causes widget-server to be built).
It seems that the multi-branch pipeline plugin lacks the Build after other projects are built setting - how would we accomplish the above in the multi-branch pipeline build?
You should add the branch name to your upstream job (assuming you are using a multi-branch pipeline for the upstream job too).
Suppose you have a folder with two jobs, both multi-branch pipeline jobs: jobA and jobB; jobB should trigger after jobA's master.
You can add this code snippet to jobB's Jenkinsfile:
properties([
pipelineTriggers([
upstream(
threshold: 'SUCCESS',
upstreamProjects: '../jobA/master'
)
])
])
(Mind that any branch of jobB here will trigger after jobA's master!)
I'm currently trying to get this to work for our deployment.
The closest I've got is adding the following to the downstream Jenkinsfile;
properties([
pipelineTriggers([
triggers: [
[
$class: 'jenkins.triggers.ReverseBuildTrigger',
upstreamProjects: "some_project", result: hudson.model.Result.SUCCESS
]
]
]),
])
That at least gets Jenkins to acknowledge that it should be triggering when
'some_project' get's built i.e it appears in the "View Configuration" page.
However so far builds of 'some_project' still don't trigger the downstream
project as expected.
That being said maybe you'll have more luck.
Let me know if it works for you.
(Someone else has asked a similar question here -> Jenkins: Trigger Multi-branch pipeline on upstream change )

Multibranch Pipeline vs Pipeline job

Now that the Multibranch Pipeline job type has matured, is there any reason to use the simple Pipeline job type any longer? Even if you only have one branch today, it's probably wise to account for the possibility of multiple branches in the future, so what would the motivation be to use the Pipeline job type for your Jenkins Pipeline vs. always using the Multibranch Pipeline job type, assuming you are storing your Jenkinsfile in SCM? Is there feature parity between the two job types now?
In my experience with multibranch pipelines, the ONLY downside is that you can't see the last success/failure/duration columns on the Jenkins main page. They just show "NA" on the Jenkins front page since it's technically a 'folder' of sub-jobs.
Other than that I can't think of any other "cons" to using multibranch.
I disagree with the other answer.... that case was that multibranch sends changes for "any" branch. That's not necessarily true. If a Jenkinsfile exists on a random feature branch, but that branch is not defined in the pipeline then you can just not do anything with it using typical if/else conditionals.
For example:
node {
checkout scm
def workspace = pwd()
if (env.BRANCH_NAME == 'master') {
stage ('Some Stage 1 for master') {
sh 'do something'
}
stage ('Another Stage for Master') {
sh 'do something else here'
}
}
else if (env.BRANCH_NAME == 'stage') {
stage ('Some stage branch step') {
sh 'do something'
}
stage ('Deploy to stage target') {
sh 'do something else'
}
}
else {
sh 'echo "Branch not applicable to Jenkins... do nothing"'
}
}
Multibranch Pipeline works well if your Jenkins job deals with a single git repository. On the other hand, the pipeline job can be repository-neutral and branch-neutral and very flexible when working with multiple git repositories with a single Jenkins job.
For example, assume you have artifact-1 from repo-1, artifact-2 from repo-2, and integration tests from repo-3. And artifact-2 depends on artifact-1. A Jenkins job has to build artifact-1, then build artifact-2, and finally run integration tests from repo-3. And assume your code change goes to a feature-1 branch of repo-1 and feature-1 branch for new tests in repo-3. In this case, the Jenkins job builds feature-1 for artifact-1, then uses 'dev' branch as default from repo-2 (if feature-1 is not detected in repo-2), and runs 'feature-1' from repo-3 for new integration tests. As you can see, the job works well with three git repositories. A repo-neutral/branch-neutral pipeline job is ideal in this setting.
In a CI/CD situation, it may not be desirable to send every branch to the target environment. Using pipeline and specifying a single branch would allow you to filter, and send only /master to Staging or Production environments. Multibranch would be useful for sending any change on any branch specifically to a test environment.
On the other hand, if the QA/AutomatedTesting process is thorough enough, the risk with sending any branch to Production could be acceptable.
If you are still developing your flow, the simple pipeline has the added advantage of supporting parameterized projects. This feature is useful for developing the declarative pipelines in the jenkins gui, using the parameter to control what branch/repository you are targeting.

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