We have several Java projects. Each project has its own delivery pipeline.
All pipelines have the following steps in common (simplified):
The project pipelines only differ in project specific properties such as service names or the IP addresses of test and production environment.
The questions are: How could we avoid the boilerplate that all projects have in common? Does Jenkins "Pipeline as code" provide something like pipeline templates?
I could imagine that a template would save a lot of redundant code/steps in our project pipelines. Therefore it would be much easier to setup a new project, maintain the pipeline, keep the pipeline in sync...
An approach that works well for us is to put parts of the pipeline (those that all projects have in common) or even the whole pipeline into a Jenkins shared library.
Example
The following script (template.groovy) is defined as global variable in a Jenkins shared library. The method creates a new declarative pipeline (it also works for scripted pipeline syntax). All project specific properties are provided via the templateParams map.
/**
* Defines a pipeline template (as a sample with one job parameter
* that should be common for all pipelines)
*/
def createMyStandardDeclarativePipeline(Map templateParams) {
pipeline {
agent any
parameters {
string(name: 'myInput', description: 'Some pipeline parameters')
}
stages {
stage('Stage one') {
steps {
script {
echo "Parameter from template creation: " + templateParams.someParam
}
}
}
stage('Stage two') {
steps {
script {
echo "Job input parameter: " + params.myInput
}
}
}
}
}
}
Using this global variable, the following line creates a pipeline from our template:
template.createMyStandardDeclarativePipeline(someParam: 'myParam')
Conclusion
This concept makes it easy to define pipeline templates and reuse them in several projects.
Applied on the example given in the question, you can create a delivery pipeline for a project with a simple one-liner:
template.createMyStandardDeclarativePipeline(serviceName: 'myService',
testEnv: '192.168.99.104',
productionEnv: '192.168.99.105')
Update (30-09-2017): Declaring a pipeline block in a shared library is now officially supported with Declarative Pipelines version 1.2 . See: https://jenkins.io/doc/book/pipeline/shared-libraries/#defining-declarative-pipelines
Update (06-10-2017): An extended example can now be found here: https://jenkins.io/blog/2017/10/02/pipeline-templates-with-shared-libraries/