mycompany-docker-flask-gunicorn

• Example Python3 app using flask and gunicorn
• Note: I used an arbitrary name: myapp in this example--use your service and repo name instead.
• This was done to create an internal company/cloud specific template for developers at my present employer.
  • As noted in the Dockerfile, this project was created for our internal use based on:
    • dockerizing-flask-with-postgres-gunicorn-and-nginx
  • were we configure and use:
    • Ingress Nginx L7 TLS on ELB
    • External DNS manged Route53 (via ingress annotations)
    • etc.

Requirements

• For mycompany environments we should have all of these in place:
  • Cloud: Kube cluster with Ingress Nginx and requisite certs for L7 term at ELB/ingress.
  • Client: Terraform, tfenv, docker, etc.
  • Global recursive replace mycompany.com and myapp with your working top-level domain and requisite app/service name.
  • External DNS configured in your K8S cluster, etc.

Build tag and push to remote AWS ECS repo (locally)

• build script requires one arg which is the version to build/tag/push, etc.
  • Note: this would be for one-off builds, regular builds should be done in CI/CD (jenkins) using dedicated project.

./build 0.1.1

• Push tagged one-off local build to Dev Kube cluster

k apply --recursive -f ./k8s -n myapp

NOTE: Apps should have at least dummy '/alive' and '/ready' routes

This allows kube to know if the app is healthy/available

• I.e. see ./services/web/project/__init__.py

# define your app/service routes here
@app.route("/")
def hello_world():
    return jsonify(hello="world")

# Liveliness check
@app.route("/alive")
def alive():
    return 'OK'

# Mock readiness check
@app.route("/ready")
def ready():
    return jsonify(
        backend='ready',
        db='ready',
        queue='ready'
    )

• This also allows us to curl the above URI's and get the expected output:
  • I.e.:
    • curl https://myapp.dev.mycompany.com/alive
    • curl https://myapp.dev.mycompany.com/ready

myapp app Kube resources should look like this:

k get all -n myapp
NAME                         READY   STATUS    RESTARTS   AGE
pod/myapp-754b4c46bf-whml2   1/1     Running   0          29m
pod/myapp-754b4c46bf-zq77v   1/1     Running   0          29m

NAME            TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE
service/myapp   ClusterIP   172.20.226.37   <none>        80/TCP    29m

NAME                    READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/myapp   2/2     2            2           29m

NAME                               DESIRED   CURRENT   READY   AGE
replicaset.apps/myapp-754b4c46bf   2         2         2       29m

myapp Ingress looks like this

k get ing -A | grep myapp
myapp                 myapp                  myapp.dev.mycompany.com                 a123laa2asd6adsa9asdasdasdsadasd-123456789.us-west-2.elb.amazonaws.com   80      128m

Refactoring Options

• enable the provided commented out HPA horizontal pod autoscaler
• add nginx, and other layers/requirements as needed, etc.