Hello World API

• Hello World API
  • Kubernetes
    • Prerequisites
    • Create secret to pull image from Github
    • Local dev using Skaffold
    • Run locally using kubectl
  • Local Docker commands
  • Publishing Docker Images
  • Unit Tests

Kubernetes

Prerequisites

• minikube
• kubectl
• Skaffold

Create secret to pull image from Github

1. Create new Github Personal Access Token with read:packages scope at https://github.com/settings/tokens/new

2. Base-64 encode :

   $ echo -n <github-username>:<TOKEN> | base64
   <AUTH>

3. Manually create the secret:

   $ echo '{"auths":{"docker.pkg.github.com":{"auth":"<AUTH>"}}}' | kubectl create secret generic dockerconfigjson-github-com --type=kubernetes.io/dockerconfigjson --from-file=.dockerconfigjson=/dev/stdin

4. Now, you can reference the above secret from your pod's spec definition via imagePullSecrets field:

   spec:
     containers:
     - name: your-container-name
       image: docker.pkg.github.com/<ORG>/<REPO>/<PKG>:<TAG>
     imagePullSecrets:
     - name: dockerconfigjson-github-com

Local dev using Skaffold

Skaffold watches for file changes and rebuilds thereby allowing for quicker local development.

# start minikube
$ minikube start

# switch to using an existing namespace
$ kubectl config set-context --current --namespace <NAMESPACE>

$ skaffold dev --port-forward

Port forwarding service/helloworld-api-load-balancer in namespace devsam, remote port 8080 -> address 127.0.0.1 port 8080

# In a separate terminal, test the endpoint (below example uses HTTPie)
$ http localhost:8080

HTTP/1.1 200 OK
Content-Length: 39
Content-Type: application/json
Date: Fri, 11 Dec 2020 12:12:45 GMT

{
    "Message": "Hello, World",
    "Status": 200
}

Run locally using kubectl

Instructions for running on macOS using minikube

# start minikube
$ minkube start

# switch to using a namespace
$ kubectl config set-context --current --namespace <NAMESPACE>

# apply Kubernetes config
$ kubectl apply -f k8s

# Start minikube tunnel service
$ minikube service helloworld-api-load-balancer -n <NAMESPACE>
# outputs something like:

|-----------|------------------------------|-------------|-------------------------|
| NAMESPACE |             NAME             | TARGET PORT |           URL           |
|-----------|------------------------------|-------------|-------------------------|
| devsam    | helloworld-api-load-balancer |        8080 | http://172.17.0.2:32464 |
|-----------|------------------------------|-------------|-------------------------|
🏃  Starting tunnel for service helloworld-api-load-balancer.
|-----------|------------------------------|-------------|------------------------|
| NAMESPACE |             NAME             | TARGET PORT |          URL           |
|-----------|------------------------------|-------------|------------------------|
| devsam    | helloworld-api-load-balancer |             | http://127.0.0.1:62282 |
|-----------|------------------------------|-------------|------------------------|
🎉  Opening service devsam/helloworld-api-load-balancer in default browser...
❗  Because you are using a Docker driver on darwin, the terminal needs to be open to run it.

# To also test on the command line
$ http http://127.0.0.1:62282

Local Docker commands

# build
$ docker build -t helloworldapi .

# run using local image
$ docker run -p 8080:8080 -it helloworldapi

Publishing Docker Images

Merges to the main branch will trigger the CI action to test the code and if the tests are green to publish a "latest" image.

In order to tag an image, add a git tag against the main branch and push. This will trigger CI and publish the versioned image.

# add a tag
git tag <tag e.g. v0.3.0> -am <tag>

# push the tag to remote which will trigger CI
git push --follow-tags

Unit Tests

go test -v -cover