My flask application is below:

from flask import Flask, request, jsonify
import docker
import os
import uuid
app = Flask(__name__)
client = docker.from_env()
@app.route('/run', methods=['POST'])
def run_code():
    data = request.json
    code = data.get('code')
    try:
        output = execute_code("python", code)
        return jsonify({'output': output})
    except Exception as e:
        return jsonify({'error': str(e)}), 500
def execute_code(language, code):
    code_file, command = create_code_file(language, code) # just writes the code to a file and path to that is code_file
    container = client.containers.run(
        "python:3.9-slim",
        command,
        volumes={os.path.abspath(code_file): {'bind': f'/code/{code_file}', 'mode': 'ro'}},
        working_dir='/code',
        detach=True
    )
    result = container.wait()
    output = container.logs().decode('utf-8')
    container.remove()
    os.remove(code_file)
    if result['StatusCode'] != 0:
        raise Exception(output)
    return output

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=5000)

I want to deploy the above by building a dockerfile. Can someone give me a docker file that will be suitable for this.

I tried the below docker file:

FROM docker:19.03.12

RUN apk add --no-cache python3-dev py3-pip gcc musl-dev libffi-dev openssl-dev

WORKDIR /app

COPY . /app

RUN pip3 install flask docker

CMD ["sh", "-c", "dockerd-entrypoint.sh & python3 test_code.py"]

It is building successfully, but not running at all. I am getting the below error:

sh: dockerd-entrypoint.sh: not found
Traceback (most recent call last):
  File "/usr/lib/python3.8/site-packages/urllib3/connection.py", line 198, in _new_conn
    sock = connection.create_connection(
  File "/usr/lib/python3.8/site-packages/urllib3/util/connection.py", line 60, in create_connection
    for res in socket.getaddrinfo(host, port, family, socket.SOCK_STREAM):
  File "/usr/lib/python3.8/socket.py", line 918, in getaddrinfo
    for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
socket.gaierror: [Errno -3] Try again

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/lib/python3.8/site-packages/urllib3/connectionpool.py", line 793, in urlopen
    response = self._make_request(
  File "/usr/lib/python3.8/site-packages/urllib3/connectionpool.py", line 496, in _make_request
    conn.request(
  File "/usr/lib/python3.8/site-packages/urllib3/connection.py", line 400, in request
    self.endheaders()
  File "/usr/lib/python3.8/http/client.py", line 1247, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "/usr/lib/python3.8/http/client.py", line 1007, in _send_output
    self.send(msg)
  File "/usr/lib/python3.8/http/client.py", line 947, in send
    self.connect()
  File "/usr/lib/python3.8/site-packages/urllib3/connection.py", line 238, in connect
    self.sock = self._new_conn()
  File "/usr/lib/python3.8/site-packages/urllib3/connection.py", line 205, in _new_conn
    raise NameResolutionError(self.host, self, e) from e
urllib3.exceptions.NameResolutionError: <urllib3.connection.HTTPConnection object at 0x7b6a0588d100>: Failed to resolve 'docker' ([Errno -3] Try again)

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/lib/python3.8/site-packages/requests/adapters.py", line 667, in send
    resp = conn.urlopen(
  File "/usr/lib/python3.8/site-packages/urllib3/connectionpool.py", line 847, in urlopen
    retries = retries.increment(
  File "/usr/lib/python3.8/site-packages/urllib3/util/retry.py", line 515, in increment
    raise MaxRetryError(_pool, url, reason) from reason  # type: ignore[arg-type]
urllib3.exceptions.MaxRetryError: HTTPConnectionPool(host='docker', port=2375): Max retries exceeded with url: /version (Caused by NameResolutionError("<urllib3.connection.HTTPConnection object at 0x7b6a0588d100>: Failed to resolve 'docker' ([Errno -3] Try again)"))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.8/site-packages/docker/api/client.py", line 223, in _retrieve_server_version
    return self.version(api_version=False)["ApiVersion"]
  File "/usr/lib/python3.8/site-packages/docker/api/daemon.py", line 181, in version
    return self._result(self._get(url), json=True)
  File "/usr/lib/python3.8/site-packages/docker/utils/decorators.py", line 44, in inner
    return f(self, *args, **kwargs)
  File "/usr/lib/python3.8/site-packages/docker/api/client.py", line 246, in _get
    return self.get(url, **self._set_request_timeout(kwargs))
  File "/usr/lib/python3.8/site-packages/requests/sessions.py", line 602, in get
    return self.request("GET", url, **kwargs)
  File "/usr/lib/python3.8/site-packages/requests/sessions.py", line 589, in request
    resp = self.send(prep, **send_kwargs)
  File "/usr/lib/python3.8/site-packages/requests/sessions.py", line 703, in send
    r = adapter.send(request, **kwargs)
  File "/usr/lib/python3.8/site-packages/requests/adapters.py", line 700, in send
    raise ConnectionError(e, request=request)
requests.exceptions.ConnectionError: HTTPConnectionPool(host='docker', port=2375): Max retries exceeded with url: /version (Caused by NameResolutionError("<urllib3.connection.HTTPConnection object at 0x7b6a0588d100>: Failed to resolve 'docker' ([Errno -3] Try again)"))

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "test_code.py", line 6, in <module>
    client = docker.from_env()
  File "/usr/lib/python3.8/site-packages/docker/client.py", line 94, in from_env
    return cls(
  File "/usr/lib/python3.8/site-packages/docker/client.py", line 45, in __init__
    self.api = APIClient(*args, **kwargs)
  File "/usr/lib/python3.8/site-packages/docker/api/client.py", line 207, in __init__
    self._version = self._retrieve_server_version()
  File "/usr/lib/python3.8/site-packages/docker/api/client.py", line 230, in _retrieve_server_version
    raise DockerException(
docker.errors.DockerException: Error while fetching server API version: HTTPConnectionPool(host='docker', port=2375): Max retries exceeded with url: /version (Caused by NameResolutionError("<urllib3.connection.HTTPConnection object at 0x7b6a0588d100>: Failed to resolve 'docker' ([Errno -3] Try again)"))

If anyone is having any experience building docker-in-docker type of things or have previously build an online compiler you may help me here.