I'm trying to run a simple Flask app locally from a docker and I seem to be stuck...

 

I have the following Dockerfile:

FROM python:3.11-slim
WORKDIR /usr/src/app
RUN python -m pip install flask
COPY . .
EXPOSE 5000
CMD [ "flask", "run"]

 

and a basic flask app defined in app.py:

import flask
app = flask.Flask(__name__)

@app.route('/')
def helloworld():
return 'HELLO, WORLD'

 

I copied these two files to my Unraid server and ran `docker build -t myapp .` then `docker run -it myapp`, which yields the expected message:

* Debug mode: off
WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
* Running on http://127.0.0.1:5000
Press CTRL+C to quit

 

Based on instructions from here, I set up a local private Docker registry `myrepo` and I then created the following `myapp.xml` file:

<?xml version="1.0" encoding="utf-8"?>
<Container>
<Beta>False</Beta>
<Category>HomeAutomation:</Category>
<Date>2024-11-03</Date>
<Changes>
[b]3.NOV.2024:[/b]Added[br]
</Changes>
<Support>http://forums.unraid.net</Support>
<Name>myapp</Name>
<Description>
myapp server
</Description>
<Registry>http://unraid:5000/myapp/</Registry>
<GitHub>https://github.com/</GitHub>
<Repository>localhost:5000/myapp</Repository>
<BindTime>true</BindTime>
<Privileged>false</Privileged>
<Networking>
  <Mode>bridge</Mode>
  <Publish>
    <Port>
      <HostPort>3016</HostPort>
      <ContainerPort>5000</ContainerPort>
      <Protocol>tcp</Protocol>
    </Port>
  </Publish>
</Networking>
<WebUI>http://[IP]:[PORT:3016]</WebUI>
<Banner>http://i.imgur.com/zXpacAF.png</Banner>
<Icon>http://i.imgur.com/zXpacAF.png</Icon>
</Container>

 

I then copied `myapp.xml` to `/boot/config/plugins/community.applications/private/myrepo`, stop and restart Docker, and install `myapp` from Unraid Apps.

 

Then in Docker, clicking on `myapp`'s log yields the expected message again, so at least my app is running:

WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
* Running on http://127.0.0.1:5000
Press CTRL+C to quit
* Debug mode: off

 

In the list of Docker containers, `myapp` is listed with the following port mappings: `172.17.0.6:5000/TCP <=> 192.168.1.50:3016`.

 

When I point my browser to http://192.168.1.50:3016/, I get an error ("Unable to connect"), and the logs don't show any activity within the container.

 

I've tried various different settings but I seem to be stuck. Is it a matter of telling flask to run from host 172.17.0.6 instead of 127.0.0.1? I'd greatly appreciate some suggestions at this point.

Got it! It was indeed a host setting. For whoever this might help, this is what worked:

CMD [ "python", "-m", "flask", "run", "-h", "0.0.0.0"]

Now I'm wondering if there is a way to specify, in the myapp.xml configuration file, that container path /usr/src/app/data should be mapped to a specific host path. I was able to change this using the GUI aftr installing myapp, but how can I specify this as a default preset?