Docker容器中的Python服務器腳本不接收來自主機操作系統的請求

Question

我寫了一個上傳/下載文件的腳本。 它適用於系統（這里是Win10），但不適用於我放入的docker容器。

我使用了另一個Python項目的Dockerfile和docker-compose.yml（一個剪切版本），它是Django REST Framework的一個，它們工作得很好。 Python版本3.7.0。 僅使用標准庫模塊。 Docker圖像是官方的python-3.7-alpine。

Python腳本（跳過導入）：

ADDRESS, PORT = 'localhost', 5050

DATABASE = 'db.sqlite'
FILEDIR = 'Uploads'

class HttpHandler(BaseHTTPRequestHandler):
    '''A tiny request handler for uploading and downloading files.'''

    def __init__(self: '__main__.HttpHandler', *args, **kwargs) -> None:
        '''
        The handler class constructor. Before initialization checks if
        the DATABASE file and the FILEDIR directory/folder both exist,
        otherwise creates them.
        '''
        makedirs(FILEDIR, exist_ok=True)

        if not path.isfile(DATABASE):
            conn = sqlite3.connect(DATABASE)
            with conn:
                conn.execute('''CREATE TABLE filepaths (
                                    uuid CHARACTER(36) PRIMARY KEY,
                                    filepath TEXT NOT NULL,
                                    filename TEXT NOT NULL,
                                    extension TEXT,
                                    upload_date TEXT
                                );''')
            conn.close()
            print(f'Database {DATABASE} created')

        super().__init__(*args, **kwargs)

    def read_from_db(self: '__main__.HttpHandler',
                     file_id: str) -> Union[tuple, None]:
        '''Fetch the file record from the database.'''
        try:
            conn = sqlite3.connect(DATABASE)
            with closing(conn):
                cursor = conn.cursor()
                query = f'''SELECT filepath, filename, extension, upload_date
                            FROM filepaths
                            WHERE uuid=:id;
                        '''
                cursor.execute(query, {'id': file_id})
                return cursor.fetchone()

        except sqlite3.DatabaseError as error:
            self.send_response(code=500, message='Database error')
            self.end_headers()
            print('Database error :', error)

    def send_file(self: '__main__.HttpHandler',
                  file_id: str,
                  filepath: str,
                  filename: str,
                  extension: str) -> None:
        '''Send the requested file to user.'''
        try:
            with open(filepath, 'rb') as file:
                self.send_response(code=200)
                self.send_header(
                    'Content-Disposition',
                    f'attachment; filename="{filename}.{extension}"'
                )
                self.end_headers()
                data = file.read()
                self.wfile.write(data)

        except FileNotFoundError:
            self.send_response(
                code=410,
                message=f'File with id {file_id} was deleted.'
            )
            self.end_headers()

    def do_GET(self: '__main__.HttpHandler') -> None: # pylint: disable=C0103
        '''
        Check if a record for the given id exists in the DATABASE and
        send the respective response to user; if 'download' parameter
        provided, download the existing file to user from FILEPATH.
        Usage is as follows:

        CHECK
        http://<ADDRESS>:<PORT>/?id=<file_id>

        DOWNLOAD
        http://<ADDRESS>:<PORT>/?id=<file_id>&download=1
        '''
        get_query = urlsplit(self.path).query
        params = dict(parse_qsl(get_query))

        if 'id' not in params:
            self.send_response_only(code=200)
            self.end_headers()
            return

        file_id = params['id']

        db_response = self.read_from_db(file_id)

        if not db_response:
            self.send_response(code=204,
                               message=f'No files found with id {file_id}')
            self.end_headers()
            return

        filepath, filename, extension, upload_date = db_response

        if 'download' not in params:
            self.send_response(
                code=200,
                message=f'{filename}.{extension} was uploaded at {upload_date}'
            )
            self.end_headers()
        else:
            self.send_file(file_id, filepath, filename, extension)

    def do_POST(self: '__main__.HttpHandler') -> None: # pylint: disable=C0103
        '''
        Upload a file to FILEPATH and create the record for that
        in the DATABASE, then send it's id in the response message.
        Usage is as follows:

        UPLOAD
        POST request containing the file body to http://<ADDRESS>:<PORT>/
        Content-Length must be provided in the headers;
        If Content-Disposition is absent, the file will be saved as
        "filename.not_provided"
        '''
        content_length = int(self.headers.get('Content-Length', 0))

        if content_length == 0:
            self.send_response(code=411, message='Length required')
            self.end_headers()
            return

        content_disposition = self.headers.get('Content-Disposition',
                                               'name="filename.not_provided"')
        filename, extension = re.findall(r'name="(.+)\.(\S+)"',
                                         content_disposition)[0]

        file_content = self.rfile.read(content_length)
        uuid = uuid4()
        filepath = path.join(getcwd(), FILEDIR, f'{uuid}.{extension}')

        with open(filepath, 'wb') as file:
            file.write(file_content)

        try:
            with sqlite3.connect(DATABASE) as conn:
                query = '''INSERT INTO filepaths VALUES (
                               :uuid,
                               :filepath,
                               :filename,
                               :extension,
                               :upload_date
                           );'''
                conn.execute(query, {'uuid': str(uuid),
                                     'filepath': filepath,
                                     'filename': filename,
                                     'extension': extension,
                                     'upload_date': datetime.now()})
            conn.close()

            self.send_response(code=201, message=uuid)
            self.end_headers()

        except sqlite3.DatabaseError as error:
            self.send_response(code=500, message='Database error')
            self.end_headers()
            print('Database error :', error)


if __name__ == "__main__":
    with ThreadingTCPServer((ADDRESS, PORT), HttpHandler) as httpd:
        print('Serving on port', PORT)
        SERVER_THREAD = Thread(httpd.serve_forever(), daemon=True)
        SERVER_THREAD.start()

Dockerfile：

FROM python:3.7-alpine

ENV PYTHONUNBUFFERED 1

RUN mkdir /server
WORKDIR /server
COPY . /server

RUN adduser -D user
RUN chown -R user:user /server
RUN chmod -R 755 /server
USER user

泊塢窗，compose.yml：

version: "3"

services:
  server:
    build:
      context: .
    ports:
      - "5050:5050"
    volumes:
      - .:/server
    command: >
      sh -c "python server_threaded.py"

我使用請求庫來制作......呃......請求，代碼很簡單：

import requests

print(requests.get('http://localhost:5050/'))

服務器端的輸出不會改變：

$ docker-compose up
Recreating servers_server_1 ... done
Attaching to servers_server_1
server_1  | Serving on port 5050

基本上它無論如何都不會響應。 客戶端錯誤消息：

requests.exceptions.ConnectionError: ('Connection aborted.', RemoteDisconnected('Remote end closed connection without response'))

如果我在系統上運行腳本，則為客戶端消息：

<Response [200]>

我嘗試擺弄端口，在這里和那里更改它們，使用Postman和telnet，從Dockerfile中刪除'ENV PYTHONUNBUFFERED 1'。 什么都行不通。 我顯然不是Docker隊長，但配置看起來非常基本。 我究竟做錯了什么？ 謝謝。

Answer 1

如果Windows是主機，Docker正在使用Linux虛擬機來托管其環境，因此來自Windows的“localhost”或反之亦然，它們是不同的主機。

您可以獲取有關VM docker正在使用docker-machine 。

Answer 2

使用ADDRESS ='0.0.0.0'解決了問題。 感謝David Maze。