Simple one step setup for: https://docs.docker.com/get-started/part2

app.py

from flask import Flask
from redis import Redis, RedisError
import os
import socket

# Connect to Redis
redis = Redis(host="redis", db=0, socket_connect_timeout=2, socket_timeout=2)

app = Flask(__name__)

@app.route("/")
def hello():
    try:
        visits = redis.incr("counter")
    except RedisError:
        visits = "<i>cannot connect to Redis, counter disabled</i>"

    html = "<h3>Hello {name}!</h3>" \
           "<b>Hostname:</b> {hostname}<br/>" \
           "<b>Visits:</b> {visits}"
    return html.format(name=os.getenv("NAME", "world"), hostname=socket.gethostname(), visits=visits)

if __name__ == "__main__":
    app.run(host='0.0.0.0', port=80)

Dockerfile

# Use an official Python runtime as a parent image
FROM python:2.7-slim

# Set the working directory to /app
WORKDIR /app

# Copy the current directory contents into the container at /app
ADD . /app

# Install any needed packages specified in requirements.txt
RUN pip install --trusted-host pypi.python.org -r requirements.txt

# Make port 80 available to the world outside this container
EXPOSE 80

# Define environment variable
ENV NAME World

# Run app.py when the container launches
CMD ["python", "app.py"]

requirements.txt

Flask
Redis

Created for: https://stackoverflow.com/questions/47630767/docker-get-startedpython-not-working/47655089

To run this, do: (this will download all 3 files shown here, build the docker image, run the container, curl the url, then exit)

mkdir -p dockerapp && \
curl -sL https://gist.github.com/kingbuzzman/b48be91757fc60e97f6a9a189d006bd8/download | tar -xvz -C dockerapp --strip-components=1 && \
docker build -t friendlyhello dockerapp && \
docker run --rm -p 4000:80 --name friendlyhello -d friendlyhello && \
sleep 2 && \
curl -s http://localhost:4000/ && \
docker kill friendlyhello  

if you want to keep it running for longer:

docker run --rm -p 4000:80 friendlyhello

and then do whatever you want -- use curl/browser what have you..., when you're done, kill it (CTRL-C)