Can't access docker application from localhost using docker-compose - docker

Question

before I start: I have searched this question already and implemented what the "Solutions" were and it did not help (setting host to 0.0.0.0). So, with that out of the way,
Directory structure
|-- osr
| |-- __init__.py
|-- requirements.txt
|-- Dockerfile
|-- docker-compose.yml
Dockerfile:
FROM python:3.7.5-buster
EXPOSE 5000 # i have tried with and without this
ENV INSTALL_PATH /osr
ENV FLASK_APP osr
ENV FLASK_ENV development
RUN mkdir -p $INSTALL_PATH
COPY requirements.txt requirements.txt
RUN pip install -r requirements.txt
COPY . .
CMD [ "flask", "run", "--host=0.0.0.0"]
docker-compose.yml:
version: '3.8'
services:
web:
build: .
ports:
- '5000:5000'
expose:
- '5000'
volumes:
- .:/osr
__ init __.py
import os
from flask import Flask
def create_app(test_config=None):
app = Flask(__name__, instance_relative_config=True)
app.config.from_mapping(
SECRET_KEY='dev'
)
#app.route('/hello')
def hello():
return 'Hello, World!'
return app
docker-compose build web
docker-compose run web
* Serving Flask app "osr" (lazy loading)
* Environment: development
* Debug mode: on
* Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
* Restarting with stat
* Debugger is active!
* Debugger PIN: 225-441-434
all of the below return "hmm can't reach this page"
http://localhost
http://localhost:5000/hello
http://127.0.0.1:5000/hello
I've even tried going to the containers IP with
docker exec -it 49e677 bash
ip add | grep global
inet 172.21.0.2/16 brd 172.21.255.255 scope global eth0
http://127.21.0.2:5000/hello # nothing
Nothing.
I'm sure the app itself works fine as I can simply run the app directly.
$env:FLASK_APP="osr"
$env:FLASK_ENV="development"
flask run --host=0.0.0.0
And it runs fine
EDIT: UPDATE
I am actually able to get to the container when I run it through simply the Dockerfile... using
docker run -it -p 5000:5000 osr_web # the container built by docker-compose build
With this, I am able to access the endpoint through localhost:5000/hello
So the issue appears to lie in spinning it up through docker-compose run
Does this help at all?
UPDATE 2
I have discovered that when I run docker ps -a I can see that Docker run actually exposes the port, but docker-compose run does not:

Answer 1

Are you sure app works fine itself? I tried to run your python __init__.py file and ended up with an error.
python osr/__init__.py
File "osr/__init__.py", line 11
def hello():
^
IndentationError: unexpected indent
It works after fixing the indentation error.
#app.route('/hello')
def hello():
return 'Hello, World!'
$ docker run -d -p 5000:5000 harik8/osr:latest
76628f86fecb61c0be4a969d3c91c5c575702ad8063b594a6c1c90b498ea25f1
$ curl http://127.0.0.1:5000/hello
Hello, World!
You can't run both docker and docker-compose in port 5000 at the same time. Either run one at a time or change the docker-compose/dockerfile host port.
$ docker ps -a | grep osr
8b885c4a9654 harik8/osr:latest "flask run --host=0.…" 12 seconds ago Up 11 seconds 0.0.0.0:5000->5000/tcp
$ docker ps -a | grep q5
70f38bf11e26 q5_web "flask run --host=0.…" About a minute ago Up 10 seconds 0.0.0.0:5001->5000/tcp
$ docker ps -a | grep q5
f9f6ba999109 q5_web "flask run --host=0.…" 5 minutes ago Up 5 minutes 0.0.0.0:5000->5000/tcp q5_web_1
$ docker ps -a | grep osr
93fb421333e4 harik8/osr:latest "flask run --host=0.…" 18 seconds ago Up 18 seconds 5000/tcp

Answer 2

I found the issue. For reference, I am running these versions:
docker-compose version 1.25.5, build 8a1c60f6
Docker version 19.03.8, build afacb8b
There were a couple issues: First and foremost to get the ports exposed I needed to run one of two options.
docker-compose up web
or
docker-compose run --service-ports web
Simply running docker-compose run web would not expose the ports.
Once this was finished, I was able to access the endpoint. However I started getting another odd error,
flask.cli.NoAppException
flask.cli.NoAppException: Failed to find Flask application or factory in module
"osr". Use "FLASK_APP=osr:name to specify one.
I had not experienced this simply using docker run -it -p 5000:5000 osr_web which was odd. However I noticed I had not set the work directory in the Dockerfile.
I changed the Dockerfile to this:
FROM python:3.7.5-buster
EXPOSE 5000
ENV INSTALL_PATH /osr
ENV FLASK_APP osr
ENV FLASK_ENV development
RUN mkdir -p $INSTALL_PATH
COPY requirements.txt requirements.txt
RUN pip install -r requirements.txt
# added this line
WORKDIR $INSTALL_PATH
COPY . .
CMD [ "flask", "run", "--host=0.0.0.0"]
I believe you could get away without setting the WORK_DIR if you turn the flask application into a package and install it.