Understanding Jenkins Environment Variables: A Comprehensive Guide

If you're working with Jenkins, you've likely encountered environment variables at some point. These variables are a key component of Jenkins, as they allow you to dynamically configure your builds based on the current environment.

In this comprehensive guide, we'll take a deep dive into Jenkins environment variables, covering everything you need to know to use them effectively in your builds.

What are Jenkins Environment Variables?

Environment variables in Jenkins are dynamic values that can be used to configure your build process. These values can be set by Jenkins itself, by plugins, or by scripts that you write.

There are a number of default environment variables that are available in Jenkins, such as WORKSPACE (the path to the workspace directory), JOB_NAME (the name of the current job), and BUILD_NUMBER (the current build number).

In addition to these default variables, you can also define your own custom environment variables. These variables can be set at the global level (for all jobs), or at the job level (for a specific job).

How to Use Jenkins Environment Variables

Using environment variables in Jenkins is fairly straightforward. To access an environment variable, simply reference it using the ${VARIABLE_NAME} syntax.

For example, let's say you want to use the JOB_NAME environment variable in a script. You would reference it like this:

echo "The current job is ${JOB_NAME}"

This would output a message like:

The current job is my-cool-job

You can also use environment variables in other areas of Jenkins, such as build steps, post-build actions, and even in email notifications.

Managing Jenkins Environment Variables

Managing environment variables in Jenkins is easy. To create a new environment variable, simply navigate to the Jenkins dashboard, click on "Manage Jenkins", then click on "Configure System". From there, you can define global environment variables that will be available to all jobs.

If you want to define environment variables for a specific job, simply navigate to the job's configuration page and click on "Configure". From there, you can define job-specific environment variables.

It's important to note that environment variables set at the job level will override any global environment variables with the same name.

Conclusion

Environment variables are a powerful and flexible feature of Jenkins that allow you to customize your builds based on the current environment. By understanding how to use and manage environment variables in Jenkins, you'll be able to create more robust and flexible build processes.