Jenkins Pipeline define and set variables

Question

I am using branch name to pass it into build script. $(env.BRANCH_NAME).

I would like to manipulate the value before using it. For example in case we build from trunk I want suffix for the build output be empty but in case of branch I want it to be -branch name.

currently I am doing it by defining environment section.

environment {
    OUTPUT_NAME_SUFFIX = ($(env.BRANCH_NAME) == 'trunk') ? '': $(env.BRANCH_NAME)
}

I am getting this error:

WorkflowScript: 4: Environment variable values must either be single quoted, double quoted, or function calls. @ line 4, column 62.
   (env.BRANCH_NAME) == 'trunk') ? '': $(en
                                 ^

What the best way to define variables and eval their values in scope of pipeline.

TIA

Answer 1

You can use string interpolation to evaluate the expression:

environment {
    OUTPUT_NAME_SUFFIX = "${env.BRANCH_NAME == 'trunk' ? '': env.BRANCH_NAME}"
}

This will fix the error you're getting, however pipeline does not allow you to have environment variables that are of 0 length, aka empty string (JENKINS-43632).

That means that setting OUTPUT_NAME_SUFFIX to '' is like unseting it. You might want to precalculate the whole name of your output, so that your env variable is never an empty string.