In this simple hands-on lab, we've been asked to configure a Jenkins project to build the train schedule app. The source code for the application is hosted in the GitHub Repo. The app already has build automation set up using gradle wrapper, and can be built with ./gradlew build. The team wants Jenkins to execute this automated build every time changes are pushed to the GitHub repository.
We will need to:
Configure Jenkins to authenticate with GitHub
Create a freestyle project in Jenkins
Configure the project to build the train schedule app
Set up a webhook to trigger the build whenever changes are made to the repository in GitHub
Configure the build to archive trainSchedule.zip as a build artifact
To confirm, we will make a change in GitHub and commit it. This should trigger a build in Jenkins automatically
Steps:
First, we'll create a personal fork of the sample application.
Create an API key in GitHub that will allow Jenkins to interact with GitHub. Navigate to settings > developer settings > personal access tokens > generate new token.
We'll assign the token the "admin:repo_hook" permission. This will enable Jenkins to utilise github's API to create webhooks for jenkins.
Copy the generated token
Webhooks are event notifications made from one application to another over HTTP.
In Jenkins, setup the connection to github using the API token just created. navigate to Manage Jenkins > Configure Systems > scroll down to GitHub and Add GitHub Server
Add the credentials (select secret text as the kind and paste the api key generated in github)
Leave "Manage hooks" box checked to allow jenkins automatically manage webhooks from github
Click "Test Connections" to verify everything is setup correctly
The Jenkins instance is successfully configured to talk to github.com
Configure the project.
Copy the URL for the project's github repository and use it to setup a "New Item" in jenkins.
select the build trigger to setup a webhook so that everytime changes are commmited to the github repo, github sends webhook to jenkins, this will automatically trigger a build in jenkins
setup build steps. this is a gradle build that uses the gradle wrapper. the task is "build" and this will call the
./gradlew build.
create a post build action to archive the artifact. this will archive the artifact that was produced as a result of this build. the artifact is a zip file that contains all the code that will need to be deployed to a production web server for example.
click on "Build Now" to check and see if the build is working
artifact of the manually triggered build
Test the webhook automatic trigger.
commit changes to github to trigger automatic build. The "README.md" file was edited
build automatically triggered by commit
build successful
artifact of the automatically triggered build
Voila! QED!