My Connected API

The aim of this project is to provide a test web application using Spring Boot that can be used within a Kubernetes cluster.

It was created to experiment with using private APIs within a Kubernetes cluster along with the my-connected-app Next.js web application.

You can find a more detailed explanation of the project in my associated Medium article.

Profiles

The application has been created with a single Spring Boot profile: dev

You should add your own profiles for other scenarios.

What does it do?

As a bit of fun, the API provides a set of basic API endpoints to allow you to manage fishes in fish tanks.

The features include the ability to:

• Manage a set of fish tanks (GET, POST, PUT, DELETE)
• Create and manage fishes (GET, POST, PUT, DELETE)
• Add and remove fish to/from a tank (PUT, DELETE)

The REST API end points are at:

/api/v1/fish-tanks
/api/v1/fish-tanks/{id}
/api/v1/fish-tanks/{id}/fishes/{id}
/api/v1/fish-types
/api/v1/fish-types/{id}
/api/v1/fishes
/api/v1/fishes/{id}

Additional documentation

You can find more documentation about the project in my medium article. You will also find references in this article to other articles that explain how to set up a local Kubernetes cluster using Kind.

Setting up a local Kind Kubernetes cluster

The files to set up a 3 node cluster are included in this repository (1 master and 2 workers).

From the project root, assuming you have Kind and Helm installed, create a base-level KInd cluster with:

 kind create cluster --config kind/kind-config.yml

Once this has been created, set up the required Helm repositories:

helm repo add grafana https://grafana.github.io/helm-charts
helm repo add cnpg https://cloudnative-pg.github.io/charts
helm repo add hashicorp https://helm.releases.hashicorp.com
helm repo add external-secrets https://charts.external-secrets.io
helm repo update

Now install Grafana, Loki, and Postgres (note that some steps can take up to 2 minutes to start):

kubectl create namespace monitoring
helm install loki grafana/loki-stack -n monitoring -f kind/loki-config.yml
kubectl apply -f kind/grafana-svc.yml

kubectl create namespace pg
helm install cnpg cnpg/cloudnative-pg -n pg --wait
kubectl apply -f kind/db-user-config.yml
kubectl apply -f kind/db-config.yml

Running this application

You can run this application using the dev profile mentioned earlier.

In this profile, the application runs in the Kubernetes cluster as a JAR file in a Docker image. It connects to the cluster database.

You can build this and create the image with:

gradle jar
docker build -t my-connected-apis .

You can now upload it to your cluster with:

kind load docker-image my-connected-apis .

Before you can deploy it, you need to create the username and password in a Kubernetes secret:

kubectl create secret generic static-db-credentials --from-literal username=app-user --from-literal password=app-secret

The API will be available on http://localhost:30080 You can connect a DB client to the database on http://localhost:32321

Test Pod

To test internal services, there is an included Ubuntu deployment. Deploy it with:

kubectl apply -f k8s/test-deployment.yml

You can then get a command line on the pod with:

kubectl exec -it ubunutu -- bash