Working on my 6th or 7th Jenkins script now - and I already noticed they share a bit of code (essentially just the same groovy subroutines over and over again). I wouldn't like to continue with that and rather learn some best practices. It seems that "Shared Libraries" are the thing to do. (Or is there a better way when you just want to share groovy code, not script steps etc.?)

Those scripts are part of a larger repo (that contains the source of the entire project, including the other scripts), stored in a subfolder Jenkins/Library with this structure:

Jenkins/Library
 - vars
|  common_code.groovy

There is only a vars folder, no src. The documentation said

For Shared Libraries which only define Global Variables (vars/), or a Jenkinsfile which only needs a Global Variable, the annotation pattern @Library('my-shared-library') _ may be useful for keeping code concise. In essence, instead of annotating an unnecessary import statement, the symbol _ is annotated.

so I concluded that I wouldn't need a src folder and can do with vars alone.

The library is made available via "Configure Jenkins" > "Global Pipeline Libraries" with SourcePath set to "/Jenkins/Library/" and is brought in with the statement @Library('{name}') _ as first line of the script.

However, when attempting to use the library, I get the error shown in the subject. What's the problem? (I already searched around and found this instance of the problem, but that doesn't seem to fit for my issue - unless I misunderstood something.)

CodePudding user response：

To specify a name of the library you should set the same name in your jenkins settings:

Name. An identifier you pick for this library, to be used in the @Library annotation. An environment variable library.THIS_NAME.version will also be set to the version loaded for a build (whether that comes from the Default version here, or from an annotation after the @ separator).

Your '{name}' parameter inside of @Library() means you should add a library with the same name. Because it's not a variable like "${name}" which is not a built in variable and undefined.

If you wish to set up your library with the same name as your jenkins pipleine you could use env.JOB_NAME variable, or check the all environment and pre-defined variables:

println env.getEnvironment()

Or check job parameters only:

println params

Now step-by-step instructions:

1. Create your library, for example from Git SCM as shown on the screenshot.

2. Put your library code to the project, e.g: <project_root_folder>/vars/common_code.groovy. You don't need your additional path Jenkins/Library. Also you have named your file in 'snake case' style, which is not usual for groovy:

The vars directory hosts scripts that define global variables accessible from Pipeline. The basename of each *.groovy file should be a Groovy (~ Java) identifier, conventionally camelCased.

So your file in 'camel case' should looks CommonCode.groovy.

3. Write your library code:

// vars/commonCode.groovy

// Define your method
def call() {
   // do some stuff
   return 'Some message'
}

4. Write your pipeline. Example of scripted pipeline:

#!/usr/bin/env groovy

// yourPipeline.groovy file in your project

@Library('jenkins-shared-library') _

// Get the message from the method in your library
def messageText = commonCode() as String
println messageText

If you wish to define some global variables this answer also may help you.

PS: Using 'vars' folder allows you to load everything from your vars folder once at the same time. If you wish to load dynamically use import from src folder.