06_environment.md

Lab 6: Environment

In this lab we see how to work with environment variables in pipelines.

Enironment Variable are generally in pipelines available under the env namespace, like env.BUILD_ID

Lab 6.1: Environment

Create a new branch named lab-6.1 from branch lab-3.1 and change the contents of the Jenkinsfile to:

pipeline {
    agent any
    options {
        buildDiscarder(logRotator(numToKeepStr: '5'))
        timeout(time: 10, unit: 'MINUTES')
        timestamps()  // Requires the "Timestamper Plugin"
    }
    environment {
        GREETINGS_TO = 'Jenkins Techlab'
    }
    stages {
        stage('Greeting') {
            steps {
                echo "Hello, ${env.GREETINGS_TO} !"

                // also available as env variable to a process:
                sh 'echo "Hello, $GREETINGS_TO !"'
            }
        }
    }
}

To add values to the path there is a special syntax

    environment {
        PATH+MAVEN = '/path/to/maven'
    }

The PATH+<IDENTIFIER> syntax specifies that the given value should be prepended to the PATH environment variable, where <IDENTIFIER> is an arbitrary unique identifier, used to make the left hand side of the assignment unique.

Lab 6.2: Predefined Environment Variables

Jenkins provides a list of predefined environment variables under the path /pipeline-syntax/globals#env. Visit the corresponding link for the techlab environment and study the list:

https://jenkins-techlab.ose3-lab.puzzle.ch/pipeline-syntax/globals#env

Please note that the list may vary depending on Jenkins version and installed plugins.

Additional Lab: Update the pipelines from Lab 6 so that the output looks something like this:

...
Hello Jenkins Techlab [current build ID]
...

Use the string interpolation functionality you've learnt in a previous Lab.

Verify your scripts with the solution.

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End of Lab 6

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