Discussion on: Getting Started with Flask and Docker 🐳🚀

Nice article.

One point of optimization for your final Dockerfile example is to run the pip install piece after the requirements.txt is COPYed, instead of as far down as you put it.

Because of the layers, if requirements.txt doesn't change, the container will build faster by using the cache. But in your current set up, the second COPY command has a high likelihood of changing.

What you want to do is:

...
COPY ./requirements.txt /app/requirements.txt
RUN pip install -r /app/requirements.txt
COPY . /app
...

Check out pythonspeed.com/articles/docker-ca... for more info.