Finish docker compose

Dockerfile

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+# syntax=docker/dockerfile:1
+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
+EXPOSE 5000
+COPY . .
+CMD ["flask", "run"]

app.py

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+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

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+version: '3.9'
+services:
+  web:
+    build: .
+    ports:
+      - '5000:5000'
+    volumes:
+      - '.:/code'
+    environment:
+      FLASK_ENV: development
+  redis:
+    image: 'redis:alpine'

requirements.txt

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+flask
+redis