qultist / quest-log

A playground for my bachelor's thesis

Quest Log

Simple distributed app built and packaged with Docker to be deployed on Kubernetes as playground/demo for my bachelor's thesis. The project is intended to test tools like Skaffold and Telepresence in interaction with different communication mechanisms between the services.

The app consists of three services which all do the same but are differently integrated. The HTTP service can be found here.

Requirements

Development	Deployment	Additional services
Go	Docker	Kafka
protoc	Docker-Compose	Redis
protoc plugin for Go	Kubernetes

In order to test Skaffold and others, they have to be installed as well.

Build, Package and Run

You can simply run the services locally or build and package them with Docker. Using multi-stage builds and the new Go modules the build process is fairly quick. In any case make sure a Redis instance is running. If you want to use Kafka, make sure it's set up. I've included Redis and Kafka in the docker-compose file. On Kubernetes I'm using Strimzi to run Kafka and a simple Deployment and Service (see deployments/k8s/redis) to run Redis.

By default the services are expected at these locations:

Service	Location
gRPC service	grpc-service:50051
HTTP service	http-service:8080
Kafka	ql-kafka-bootstrap:9092
Zookeeper	ql-zookeper-client:2181
Redis	redis:6379

The values are used in the following files:

• internal/app/gateway/*-handler.go
• cmd/kafka-service/main.go
• build/package/kafka-service/docker-entrypoint.sh
• internal/pkg/reposistory/repository.go.
• cmd/grpc-service/main.go (port of the grpc-service)

Run locally

Not recommended!

1. Change the addresses of the above mentioned services to match your local setup.
2. Spin up the services using go run.

Build and run with Docker

You can build each image individually:

# For example the gateway
cd deployments/docker-compose
docker-compose build gateway
# Omit service name to build all

… or build and run them all at once:

cd deployments/docker-compose
docker-compose up -d --build
# --build forces a rebuild if the images already exist.

Note: You probably want to change the image names in the compose file.

Run on Kubernetes

1. Build the images (see section above).
2. Push your images.
3. Change the image names in the manifests (deployment/k8s/*) to your image names.
4. Create the objects.
5. Profit. :)

Develop on Kubernetes with Skaffold

The project comes with individual Skaffold configs for each service. Don't forget to change the image names!

Local build

# For example the gateway
skaffold dev -f developlemt/skaffold/locally/gateway/skaffold.yaml

In-cluster build

You can use Skaffold in combination with kaniko to run builds in the cluster. You can find an example for the gateway in development/skaffold/kaniko/gateway. The configuration uses the localDir build context.

Although not using the GCS build context we must provide a secret. Simply create an empty secret with the following command:

kubectl create secret generic kaniko-secret --from-literal=

Additionally to push to other secured registries you must provide a Docker config.json as a secret.

# config.json
{
    "auths": {
        "https://index.docker.io/v1/": {
            "auth": "dXNlcjpwYXNzd29yZAo="
	    }
    }
}

auth is your username and password separated by a colon and base64 encoded.

echo -n "user:password" | base64

Development

Compile protos

cd internal/pkg/protos
protoc quest-service.proto --go_out=plugins=grpc:.