Handling Environment Variables in Jenkins

Introduction

Environment variables are key-value pairs that can affect the way running processes will behave on a computer. In Jenkins, they are crucial for defining configurations and ensuring secure handling of sensitive data.

What are Environment Variables?

Environment variables are dynamic values that can affect the behavior of processes in the system. They can store data such as configuration settings, paths, and credentials.

Setting Environment Variables

Environment variables can be set in Jenkins in several ways:

1. Through the Jenkins UI.
2. In Pipeline scripts.
3. As part of the Jenkins Job configuration.

Setting in the UI

To set environment variables through the Jenkins UI, follow these steps:

1. Navigate to your Jenkins job.
2. Click on Configure.
3. Scroll down to the Build Environment section.
4. Check Use secret text(s) or file(s) or add Environment variables as needed.

Setting in Pipeline Scripts

You can also define environment variables directly in your Pipeline script as follows:

pipeline {
    agent any
    environment {
        MY_ENV_VAR = 'my_value'
    }
    stages {
        stage('Build') {
            steps {
                echo "The value of MY_ENV_VAR is ${MY_ENV_VAR}"
            }
        }
    }
}

Using Environment Variables in Jenkins

Environment variables can be accessed in various parts of Jenkins jobs and Pipeline scripts:

• Using the ${VARIABLE_NAME} syntax in scripts.
• Within shell scripts executed during the build process.
• For configuring build parameters.

Example Usage in Shell Script

Here’s how you can use an environment variable in a shell script step:

stage('Test') {
    steps {
        sh 'echo "The value of MY_ENV_VAR is $MY_ENV_VAR"'
    }
}

Best Practices

• Use descriptive names for environment variables.
• Keep sensitive values secure using Jenkins credentials.
• Document environment variables used in your projects.
• Regularly review and clean up unused environment variables.

FAQ