Add app and workflow

Author: peter-evans

.github/workflows/push.yml

@@ -0,0 +1,11 @@
+name: Docker Compose Actions Workflow
+on: push
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@master
+    - name: Build the stack
+      run: docker-compose up -d
+    - name: Test
+      run: docker run --network container:webapp-frontend appropriate/curl -s --retry 10 --retry-connrefused http://localhost:5000/

Dockerfile

@@ -0,0 +1,9 @@
+FROM python:3.7-alpine
+WORKDIR /code
+ENV FLASK_APP app.py
+ENV FLASK_RUN_HOST 0.0.0.0
+RUN apk add --no-cache gcc musl-dev linux-headers
+COPY requirements.txt requirements.txt
+RUN pip install -r requirements.txt
+COPY . .
+CMD ["flask", "run"]

README.md

@@ -1,2 +1,26 @@
 # docker-compose-actions-workflow
-GitHub Actions workflow example using Docker Compose to build and test a multi-container stack
+
+This is a GitHub Actions workflow example to demonstrate building and testing a multi-container stack using `docker-compose`.
+
+This sample is based on the [Get started with Docker Compose](https://docs.docker.com/compose/gettingstarted/) documentation.
+
+## GitHub Actions Workflow
+
+**push.yml**
+```yml
+name: Docker Compose Actions Workflow
+on: push
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@master
+    - name: Build the stack
+      run: docker-compose up -d
+    - name: Test
+      run: docker run --network container:webapp-frontend appropriate/curl -s --retry 10 --retry-connrefused http://localhost:5000/
+```
+
+## License
+
+MIT License - see the [LICENSE](LICENSE) file for details

app.py

@@ -0,0 +1,25 @@
+import time
+
+import redis
+from flask import Flask
+
+app = Flask(__name__)
+cache = redis.Redis(host='redis', port=6379)
+
+
+def get_hit_count():
+    retries = 5
+    while True:
+        try:
+            return cache.incr('hits')
+        except redis.exceptions.ConnectionError as exc:
+            if retries == 0:
+                raise exc
+            retries -= 1
+            time.sleep(0.5)
+
+
+@app.route('/')
+def hello():
+    count = get_hit_count()
+    return 'Hello World! I have been seen {} times.\n'.format(count)

docker-compose.yml

@@ -0,0 +1,10 @@
+version: '3'
+services:
+  web:
+    container_name: webapp-frontend
+    build: .
+    ports:
+      - "5000:5000"
+  redis:
+    container_name: redis-backend
+    image: "redis:alpine"

requirements.txt

@@ -0,0 +1,2 @@
+flask
+redis