Pipelines can be used to call scripts that are stored in a repo along with a Jenkinsfile.

The sh() build step is used to run shell commands on Linux, Unix, and macOS systems.

The bat() build step is used to run shell commands on Windows systems.

Relative paths can be used to reference files from the root of the repo.

sh(‘./scripts/build.sh’)
bat(‘..\scripts\build.bat’)

Absolute paths can be used to reference files in the workspace or in other locations on the systems where the job is being run.

sh(‘/usr/local/bin/build.sh’)
bat(‘C:\bin\build.bat’)

The dir() build step can be used to change directories for other build steps.

dir("${env.WORKSPACE}/environments/test"){
sh(‘’’
    terraform init
    terraform plan
‘’’)
}

The exercise files for this lesson include a Jenkinsfile and a script that calculates a Fibonacci sequence.

• Create a new GitHub repo and add the exercise files.

  • Add the Jenkinsfile to the root of the repo.
  • Add the fibonacci.sh file to a directory named scripts.

• NOTE: The fibonacci.sh file must be placed in a subdirectory named scripts for the pipeline to run successfully.

• Create a new pipeline project in your Jenkins server.

  • Select New Item
  • Enter item name (use the same name as your repo if possible)
  • Select Pipeline project
  • OK
  • Select GitHub Project and paste in the repo URL.
    • NOTE: This step is optional. It only creates a link to the repo on the project home page.
  • Under Build Triggers, select the checkbox next to GitHub hook trigger for GITScm polling.
  • Under Pipeline, select Pipeline script from SCM.
  • Under SCM, select Git.
  • Under Repository URL, paste in the repo URL.
  • Under Branch Specifier (blank for 'any'), change master to main.
  • Save → Build Now.
  • NOTE: The project must run at least one successful build before connecting to GitHub. This allows Jenkins to read the configuration from the repo.
  • Copy the URL of your Jenkins server.

• Go back to the GitHub repo and configure the settings to create a webhook for the project you just created.

  • Select Settings → Webhooks → Add webhook.
  • Under Payload URL, paste in the URL for your Jenkins server.
  • Immediately after the Jenkins server URL, add /github-webhook/.
  • NOTE: Please be sure to include the trailing slash on github-webhook/. The field should be in a format similar to http://jenkins_url/github-webhook/.
  • Under Content type, select application/json.
  • Add webhook
  • NOTE: GitHub will ping the Jenkins server and indicate a successful connection with a green checkmark next to the webhook name. If your webhook does not indicate that it connected successfully, select Edit and confirm your settings again. If needed, delete the webhook and start over.
  • Select the <>Code tab.
  • Make a change to the README.md file.
    • Click the pencil icon.
    • Make a change to the file.
    • Click Commit changes.
  • Go to the Jenkins server and observe the job being triggered by the change you just made in GitHub.
  • NOTE: If your job is not triggered, review the configuration for the Jenkins job and the GitHub repo, making any adjustments as needed. If needed, start again with a new job in Jenkins or with a new webhook in GitHub.