How to update code from Git to a Docker container

Question

I have a Docker file trying to deploy Django code to a container

FROM ubuntu:latest MAINTAINER { myname }  #RUN echo "deb http://archive.ubuntu.com/ubuntu/ $(lsb_release -sc) main universe" >> /etc/apt/sou$  RUN apt-get update  RUN DEBIAN_FRONTEND=noninteractive apt-get install -y tar git curl dialog wget net-tools nano buil$ RUN DEBIAN_FRONTEND=noninteractive apt-get install -y python python-dev python-distribute python-p$  RUN mkdir /opt/app WORKDIR /opt/app  #Pull Code RUN git clone [email protected]/{user}/{repo}  RUN pip install -r website/requirements.txt  #EXPOSE = ["8000"] CMD python website/manage.py runserver 0.0.0.0:8000 

And then I build my code as docker build -t dockerhubaccount/demo:v1 ., and this pulls my code from Bitbucket to the container. I run it as docker run -p 8000:8080 -td felixcheruiyot/demo:v1 and things appear to work fine.

Now I want to update the code i.e since I used git clone ..., I have this confusion:

• How can I update my code when I have new commits and upon Docker containers build it ships with the new code (note: when I run build it does not fetch it because of cache).
• What is the best workflow for this kind of approach?

Answer 1

There are a couple of approaches you can use.

1. You can use docker build --no-cache to avoid using the cache of the Git clone.
2. The startup command calls git pull. So instead of running python manage.py, you'd have something like CMD cd /repo && git pull && python manage.py or use a start script if things are more complex.

I tend to prefer 2. You can also run a cron job to update the code in your container, but that's a little more work and goes somewhat against the Docker philosophy.