Jenkins

Jenkins is a web-based continuous integration (CI) server that can build, test and deploy software automatically based on various triggers.

Once you have created your Spring Boot project and pushed your code to a git server, you can configure jenkins to build and deploy your project to your group's tomcat container.

The address of your group's own jenkins instance and the corresponding container to deploy to, along with the necessary credentials, are available to all group members on the keys page.

Configure your build

On the jenkins dashboard, click "New Item" in the upper left, enter a job name, choose the project type "Maven project" and click "OK"

You are now looking at the project configuration page, where most of the configuration is done.

In order to save disk space, check "Discard old builds"

Git settings

Under "Source code management", choose "git" and enter your project's git URL under "Repository URL" (usually something like git@gitea.dsv.su.se:[ausername]/[aprojectname].git). Make sure you're using the SSH version of the git URL, otherwise you may run into a lot of authentication issues.

If your repo isn't public, jenkins will need to authenticate in order to pull the code.

Under "Credentials", click "Add", followed by "jenkins" in the drop-down
Change "Kind" to "SSH username with private key"
Enter a useful description, e.g "gitea pull key" or similar
Under "Username", fill in "git"
Under "Private key", click "Enter directly" and paste the private key from the keys page
Leave the passphrase blank and click "Add"

Once you have set up the private key in jenkins, you will need to add the public key as a deploy key on the git server. How to do this depends on the server, but this is how to do it in gitea (github works very similarly):

Open your repo in the gitea web interface
Click "Settings" in the upper right (same row as Code and Issues)
Click the "Deploy Keys" heading and choose "Add Deploy Key"
Paste the public key from the keys page into the "Content" box
Click the green "Add Deply Key" button below the form

If you don't give the key a title it will be pulled from the public key itself, using the comment at the end of the key which will be "group-X-Y@pvt".

Maven settings

If your pom.xml file isn't located in the project's root directory, you need to change the default configuration in the field "Root POM" under "Build".

At this point the build configuration should be complete enough to build (but not yet deploy) your project. You may try to run your job - it should finish successfully if your git and maven configurations are correct. The job will not deploy anything yet though, it only compiles according to your pom.xml.

Deployment settings

In order to actually deploy your compiled code, click "Add post-build action" at the very bottom of the configuration page and choose "Deploy war/ear to a container".

In the field "WAR/EAR files" you need to point to the war file you want to deploy. If your project only produces a single WAR file, you can use the shorthand "**/*.war" here. Otherwise, enter the path to your WAR file, relative to the project's root directory.

In the field "Context path" you should enter "/". You can also enter a different path such as "/myproject", but deploying directly to the root context is a good default behaviour.

Tomcat settings

Click "Add Container" and choose "Tomcat 9.x Remote".

You will need to store credentials in a similar way to the git pull key:

Under "Credentials", click "Add", followed by "jenkins" in the drop-down
Under "Username", fill in "tomcat"
Under "Password", paste the tomcat manager password from the keys page
Enter a useful description, e.g "tomcat deploy credentials" or similar

Under "Tomcat URL", enter the container URL listed on the keys page.

Finished

Your job should now be fully set up. Given that everything is set up correctly and your code compiles and passes any tests you may have, your application should be running in your container once the job has finished.

Any failures will be indicated by the job status (it wil be shown as failed), and the log will contain details about what exactly went wrong.