I read the official document a few days ago. in the second part, I finished it.app.pywithdockerfile, andrequirements.txt.

2. Run-time input:docker bulid -t dockerdemo .

In the end, I made a mistake. Don’t know why, remember to report the error message is roughlydocker Collecting Flask (from -r requirements.txt (line 1))

3. Then enter it nowdocker bulid -t friendlyhello .It will run through.

Ask big brothers to explain why.

Operating environment: Docker for Mac
Version: dockerversion 17.06.1-ce, build874a737

Focus:app.pyAnddockerfilein additionrequirements.txtThere has been no change.

Attachapp.pyCode

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)

AttachdockerfileCode

# 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 -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"]

Attachrequirements.txt

Flask
 Redis

Ask the bosses to explain the problems