Styjun

I have been stuck trying to figure out how to edit a python flask code after pulling from a Docker Hub repository on a different computer. I want to create a Folder in my Linux Desktop that contains all of the packages the image has when running as a container (Dockerfile, requirements.txt, app.py) that way I can edit the app.py regardless of what computer I have or even if my classmates want to edit it they can simply just pull my image, run the container, and be able to have a copy of the code saved on their local machine for them to open it using Visual Studio Code (or any IDE) and edit it. This is what I tried.
I first pulled from the Docker hub:

sudo docker pull woonx/dockertester1

Then used this command to run the image as a container and create a directory:

sudo docker run --name=test1 -v ~/testfile:/var/lib/docker -p 4000:80 woonx/dockertester1

I was able to create a local directory called testfile but it was an empty folder when I opened it. No app.py, dockerfile, nothing.

The example code I am using to test is from following the example guide on the Docker website: https://docs.docker.com/get-started/part2/

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
COPY . /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

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)

What I do is;
First, I issue docker run command.

sudo docker run --name=test1 -v ~/testfile:/var/lib/docker -p 4000:80 woonx/dockertester1

At this stage, files are created in container. Then I stop the container (lets say container id is 0101010101) .

docker container stop 0101010101

What I do is simply copying those files from container to the appropriate directory on my machine by using :

 docker cp <container_name>:/path/in/container /path/of/host 

 or 

 cd ~/testfile
 docker cp <container_name>:/path/in/container . 

So, You have the files craeted by docker run on you local host. Now you can use them with -v option.

sudo docker run --name=test1 -v ~/testfile:/var/lib/docker -p 4000:80 woonx/dockertester1

Normally, when you change a setting in your configuration, it should be enough to stop/start container to take in action.

I hope this approach solves your problem.

Regards