Kubernetes Event Listener by Serve

The Kubernetes Event Listener by Serve is a service designed to monitor changes in Kubernetes and automatically send the latest information to another application for processing. This README provides detailed instructions on how to run the service on both a host machine and within a Docker container.

Development

In this repo, we work Trunk based, which means that we bypass the dev branch.

Create short-lived branches from main:

git checkout main
git pull
git checkout -b feature/xyz

Keep your branch fresh:

git fetch
git rebase origin/main

Verify that the code adheres to the style guidelines and code analysis rules:

flake8 .
black . --check
hadolint Dockerfile

When the work is ready to be merged to main, create a PR to merge your feature branch into the main branch.

To release a new version of the event-listener, first tag the latest commit. When the tag is pushed to origin, a github action is run automatically and publishes a new package which is a docker image called event-listener.

Host Machine Setup

Prerequisites

Make sure you have the following prerequisites installed on your host machine:

• Python 3.x
• Kubernetes cluster configuration file (cluster.conf)

Configuration

Set the KUBECONFIG environment variable to point to your Kubernetes cluster configuration:

export KUBECONFIG=/path/to/cluster.conf
export BASE_URL=<Retriever URL (Serve) (no trailing slash)>
export TOKEN_API_ENDPOINT=<end point for fetching token> (optional, is set to BASE_URL + "/api/v1/token-auth/" if not defined)
export APP_STATUS_API_ENDPOINT=<end point for status updates> (optional, is set to BASE_URL + "/api/v1/app-status/" if not defined)
export USERNAME=<admin username (Serve)>
export PASSWORD=<admin password (Serve)>

To retrieve additional log messages, set:

export DEBUG=True
export TEST_LOG_STREAM=sys.stdout

Running the Service

Navigate to the project directory and execute the following command to run the service:

python3 ./serve_event_listener/main.py --namespace <some-namespace> --label-selector <some label selector>

Running the unit tests

python -m unittest discover -s tests

Docker Container Setup

Build the Docker Image

Build the Docker container image using the following command. Replace <image name> and <image tag> with your desired values.

docker build -t <image name>:<image tag> .

Running the Docker Container

Run the Docker container with the mounted cluster.conf file and provide necessary environment variables:

docker run --rm -v $PWD/cluster.conf:/home/serve/cluster.conf \
    --env KUBECONFIG=/home/serve/cluster.conf \
    --env [email protected] \
    ...(set all env from above) \
     <image name>:<image tag> \
     --namespace <some-namespace> \
     --label-selector <some label selector>

Program Arguments

The following are the main function arguments that can be passed to run the program:

• --namespace: Kubernetes namespace to watch (default: default).
• --label-selector: Label selector for filtering pods (default: type=app).