Pytgon Request Library and Docker Container-CodePudding

Wrote basic flask app like this:

import flask
from flask import request, jsonify,render_template

app = flask.Flask(__name__)
app.config["DEBUG"] = False



@app.route('/')
def home():
    a=dict()
    a["araba"]="tyt"
    a["araba2"]="rnt"
    return a

if __name__ == "__main__":
    app.run(host='0.0.0.0')

It's working with docker container localhost:50003. Also its basic request code here:

import requests as req

resp = req.get("http://localhost:5003/")

print(resp.text)

When i use this request code with PyCharm can request and getting response. But when i want to use it with docker container i am getting this fail:

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/urllib3/connection.py", line 174, in _new_conn
    conn = connection.create_connection(
  File "/usr/local/lib/python3.8/site-packages/urllib3/util/connection.py", line 96, in create_connection
    raise err
  File "/usr/local/lib/python3.8/site-packages/urllib3/util/connection.py", line 86, in create_connection
    sock.connect(sa)
ConnectionRefusedError: [Errno 111] Connection refused

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/urllib3/connectionpool.py", line 699, in urlopen
    httplib_response = self._make_request(
  File "/usr/local/lib/python3.8/site-packages/urllib3/connectionpool.py", line 394, in _make_request
    conn.request(method, url, **httplib_request_kw)
  File "/usr/local/lib/python3.8/site-packages/urllib3/connection.py", line 239, in request
    super(HTTPConnection, self).request(method, url, body=body, headers=headers)
  File "/usr/local/lib/python3.8/http/client.py", line 1256, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/usr/local/lib/python3.8/http/client.py", line 1302, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
  File "/usr/local/lib/python3.8/http/client.py", line 1251, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "/usr/local/lib/python3.8/http/client.py", line 1011, in _send_output
    self.send(msg)
  File "/usr/local/lib/python3.8/http/client.py", line 951, in send
    self.connect()
  File "/usr/local/lib/python3.8/site-packages/urllib3/connection.py", line 205, in connect
    conn = self._new_conn()
  File "/usr/local/lib/python3.8/site-packages/urllib3/connection.py", line 186, in _new_conn
    raise NewConnectionError(
urllib3.exceptions.NewConnectionError: <urllib3.connection.HTTPConnection object at 0x7f1cb4cebac0>: Failed to establish a new connection: [Errno 111] Connection refused

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/requests/adapters.py", line 439, in send
    resp = conn.urlopen(
  File "/usr/local/lib/python3.8/site-packages/urllib3/connectionpool.py", line 755, in urlopen
    retries = retries.increment(
  File "/usr/local/lib/python3.8/site-packages/urllib3/util/retry.py", line 574, in increment
    raise MaxRetryError(_pool, url, error or ResponseError(cause))
urllib3.exceptions.MaxRetryError: HTTPConnectionPool(host='localhost', port=5003): Max retries exceeded with url: / (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7f1cb4cebac0>: Failed to establish a new connection: [Errno 111] Connection refused'))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "./request.py", line 3, in <module>
    resp = req.get("http://localhost:5003/")
  File "/usr/local/lib/python3.8/site-packages/requests/api.py", line 75, in get
    return request('get', url, params=params, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/requests/api.py", line 61, in request
    return session.request(method=method, url=url, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/requests/sessions.py", line 542, in request
    resp = self.send(prep, **send_kwargs)
  File "/usr/local/lib/python3.8/site-packages/requests/sessions.py", line 655, in send
    r = adapter.send(request, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/requests/adapters.py", line 516, in send
    raise ConnectionError(e, request=request)
requests.exceptions.ConnectionError: HTTPConnectionPool(host='localhost', port=5003): Max retries exceeded with url: / (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7f1cb4cebac0>: Failed to establish a new connection: [Errno 111] Connection refused'))

Can not understand the problem. Thanks for help..

CodePudding user response：

How to fix

In your Dockerfile, ensure that you are running the Flask app by setting the FLASK_APP environment variable to the name of your app file (request.py in your case, default is app.py) and overriding the default port that Flask listens on:

ENV FLASK_APP=request.py
ENV FLASK_RUN_PORT=5003

CMD [ "python3", "-m" , "flask", "run", "--host=0.0.0.0"]

Build your Docker container:

$ docker build -t request-example:latest .

Run your Docker image as a container, symmetrically exposing 5003 as the port for simplicity:

$ docker run -p 5003:5003 request-example:latest

Test that the Flask app is now accessible on your local machine's localhost:

$ curl http://localhost:5003/

import requests as req

resp = req.get("http://localhost:5003/")

print(resp.text)

Suggestions

Create a requirements.txt that includes all your third-party libraries:

flask
requests
jsonify

Rewrite your Dockerfile to install whatever is in requirements.txt, rather than just the requests library:

FROM python:3.8

WORKDIR /request

COPY requirements.txt requirements.txt
COPY request.py request.py

RUN pip install -r requirements.txt

ENV FLASK_APP=request.py
ENV FLASK_RUN_PORT=5003

CMD [ "python", "-m" , "flask", "run", "--host=0.0.0.0"]