README

This is a Keptn Service Template written in GoLang.

Quick start:

1. In case you want to contribute your service to keptn-sandbox or keptn-contrib, make sure you have read and understood the Contributing Guidelines.
2. Click Use this template on top of the repository, or download the repo as a zip-file, extract it into a new folder named after the service you want to create (e.g., simple-service)
3. Replace every occurrence of (docker) image names and tags from keptnsandbox/keptn-service-template-go to your docker organization and image name (e.g., yourorganization/simple-service)
4. Replace every occurrence of keptn-service-template-go with the name of your service (e.g., simple-service)
5. Optional (but recommended): Create a git repo (e.g., on github.com/your-username/simple-service)
6. Àdapt the go.mod file and change example.com/ to the actual package name (e.g., github.com/your-username/simple-service)
7. Add yourself to the CODEOWNERS file
8. Initialize a git repository:

• git init .
• git add .
• git commit -m "Initial Commit"

1. Optional: Push your code an upstream git repo (e.g., GitHub) and adapt all links that contain github.com (e.g., to github.com/your-username/simple-service)
2. Figure out whether your Kubernetes Deployment requires any RBAC rules or a different service-account, and adapt deploy/service.yaml accordingly (initial setup is serviceAccountName: keptn-default).
3. Last but not least: Remove this intro within the README file and make sure the README file properly states what this repository is about

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keptn-service-template-go

This implements a keptn-service-template-go for Keptn. If you want to learn more about Keptn visit us on keptn.sh

Compatibility Matrix

Please fill in your versions accordingly

Keptn Version	Keptn-Service-Template-Go Docker Image
0.6.1	keptnsandbox/keptn-service-template-go:0.1.0
0.7.1	keptnsandbox/keptn-service-template-go:0.1.1
0.7.2	keptnsandbox/keptn-service-template-go:0.1.2

Installation

The keptn-service-template-go can be installed as a part of Keptn's uniform.

Deploy in your Kubernetes cluster

To deploy the current version of the keptn-service-template-go in your Keptn Kubernetes cluster, apply the deploy/service.yaml file:

kubectl apply -f deploy/service.yaml

This should install the keptn-service-template-go together with a Keptn distributor into the keptn namespace, which you can verify using

kubectl -n keptn get deployment keptn-service-template-go -o wide
kubectl -n keptn get pods -l run=keptn-service-template-go

Up- or Downgrading

Adapt and use the following command in case you want to up- or downgrade your installed version (specified by the $VERSION placeholder):

kubectl -n keptn set image deployment/keptn-service-template-go keptn-service-template-go=keptnsandbox/keptn-service-template-go:$VERSION --record

Uninstall

To delete a deployed keptn-service-template-go, use the file deploy/*.yaml files from this repository and delete the Kubernetes resources:

kubectl delete -f deploy/service.yaml

Development

Development can be conducted using any GoLang compatible IDE/editor (e.g., Jetbrains GoLand, VSCode with Go plugins).

It is recommended to make use of branches as follows:

• master contains the latest potentially unstable version
• release-* contains a stable version of the service (e.g., release-0.1.0 contains version 0.1.0)
• create a new branch for any changes that you are working on, e.g., feature/my-cool-stuff or bug/overflow
• once ready, create a pull request from that branch back to the master branch

When writing code, it is recommended to follow the coding style suggested by the Golang community.

Where to start

If you don't care about the details, your first entrypoint is eventhandlers.go. Within this file you can add implementation for pre-defined Keptn Cloud events.

To better understand all variants of Keptn CloudEvents, please look at the Keptn Spec.

If you want to get more insights into processing those CloudEvents or even defining your own CloudEvents in code, please look into main.go (specifically processKeptnCloudEvent), deploy/service.yaml, consult the Keptn docs as well as existing Keptn Core and Keptn Contrib services.

Common tasks

• Build the binary: go build -ldflags '-linkmode=external' -v -o keptn-service-template-go
• Run tests: go test -race -v ./...
• Build the docker image: docker build . -t keptnsandbox/keptn-service-template-go:dev (Note: Ensure that you use the correct DockerHub account/organization)
• Run the docker image locally: docker run --rm -it -p 8080:8080 keptnsandbox/keptn-service-template-go:dev
• Push the docker image to DockerHub: docker push keptnsandbox/keptn-service-template-go:dev (Note: Ensure that you use the correct DockerHub account/organization)
• Deploy the service using kubectl: kubectl apply -f deploy/
• Delete/undeploy the service using kubectl: kubectl delete -f deploy/
• Watch the deployment using kubectl: kubectl -n keptn get deployment keptn-service-template-go -o wide
• Get logs using kubectl: kubectl -n keptn logs deployment/keptn-service-template-go -f
• Watch the deployed pods using kubectl: kubectl -n keptn get pods -l run=keptn-service-template-go
• Deploy the service using Skaffold: skaffold run --default-repo=your-docker-registry --tail (Note: Replace your-docker-registry with your DockerHub username; also make sure to adapt the image name in skaffold.yaml)

Testing Cloud Events

We have dummy cloud-events in the form of RFC 2616 requests in the test-events/ directory. These can be easily executed using third party plugins such as the Huachao Mao REST Client in VS Code.

Automation

GitHub Actions: Automated Pull Request Review

This repo uses reviewdog for automated reviews of Pull Requests.

You can find the details in .github/workflows/reviewdog.yml.

GitHub Actions: Unit Tests

This repo has automated unit tests for pull requests.

You can find the details in .github/workflows/tests.yml.

GH Actions/Workflow: Build Docker Images

This repo uses GH Actions and Workflows to test the code and automatically build docker images.

Docker Images are automatically pushed based on the configuration done in .ci_env and the two GitHub Secrets

• REGISTRY_USER - your DockerHub username
• REGISTRY_PASSWORD - a DockerHub access token (alternatively, your DockerHub password)

How to release a new version of this service

It is assumed that the current development takes place in the master branch (either via Pull Requests or directly).

To make use of the built-in automation using GH Actions for releasing a new version of this service, you should

• branch away from master to a branch called release-x.y.z (where x.y.z is your version),
• write release notes in the releasenotes/ folder,
• check the output of GH Actions builds for the release branch,
• verify that your image was built and pushed to DockerHub with the right tags,
• update the image tags in [deploy/service.yaml], and
• test your service against a working Keptn installation.

If any problems occur, fix them in the release branch and test them again.

Once you have confirmed that everything works and your version is ready to go, you should

• create a new release on the release branch using the GitHub releases page, and
• merge any changes from the release branch back to the master branch.

License

Please find more information in the LICENSE file.