在Docker中运行应用程序时的ModuleNotFound

Question

我有一个Python3 Flask应用程序，我想把它放到容器中。我已经在requirements.txt中添加了Flask，它可以在本地工作，但在容器中找不到"flask“模块。我做错了什么？

requirements.txt：

aniso8601==7.0.0
certifi==2019.6.16
chardet==3.0.4
Click==7.0
Flask==1.1.1
Flask-RESTful==0.3.7
idna==2.8
itsdangerous==1.1.0
Jinja2==2.10.1
MarkupSafe==1.1.1
pymongo==3.8.0
pytz==2019.1
requests==2.22.0
six==1.12.0
urllib3==1.25.3
Werkzeug==0.15.4

最小工作app.py

from flask import Flask
from flask_restful import Api
app = Flask(__name__)
api = Api(app)

if __name__ == '__main__':
    app.run(host="0.0.0.0", port=8080)

Dockerfile：

FROM python:3.7-alpine
WORKDIR /usr/src/app
RUN apk add --no-cache \
        uwsgi-python3
COPY . .
ENV TESTING TRUE
RUN pip3 install --no-cache-dir -r requirements.txt
CMD [ "uwsgi", "--socket", "0.0.0.0:3031", \
               "--uid", "uwsgi", \
               "--plugins", "python3", \
               "--protocol", "uwsgi", \
               "--wsgi", "app:app", \
               "-p", "4", \
               "--enable-threads"]

错误：

*** Operational MODE: preforking ***
Traceback (most recent call last):
  File "./app.py", line 5, in <module>
    from flask import Flask, request, Response
ModuleNotFoundError: No module named 'flask'
unable to load app 0 (mountpoint='') (callable not found or import error)
*** no app loaded. going in full dynamic mode ***
*** uWSGI is running in multiple interpreter mode ***

app.py的Example (太大，无法添加到问题中)

项目结构：

├── app.py
├── docker-compose.yml
├── Dockerfile
├── LICENSE
├── logging_config.ini
├── nginx.conf
├── __pycache__
│   └── utils.cpython-37.pyc
├── README.md
├── requirements.txt
├── testing_data
│   ├─- some jsons here
├── tests.py
└── utils.py

Answer 1

尝试使用pip而不是pip3，并尝试将requirements.txt显式复制到Docker根目录。此外，您还需要在使用它之前创建一个workdir。

类似于：

FROM python:3.7-alpine

COPY requirements.txt /
RUN pip install --no-cache-dir -r requirements.txt

RUN mkdir /app
WORKDIR /app
COPY . app/

# not sure what this is doing
RUN apk add --no-cache \
        uwsgi-python3

# ENV TESTING TRUE

CMD [ "uwsgi", "--socket", "0.0.0.0:3031", \
               "--uid", "uwsgi", \
               "--plugins", "python3", \
               "--protocol", "uwsgi", \
               "--wsgi", "app:app", \
               "-p", "4", \
               "--enable-threads"]```

Answer 2

我已经尝试复制这个错误(没有运气)，但您可能仍然会发现这一点很有用。如果您可以使用app.py第1-5行编辑您的问题，我也许可以复制它并更新我的答案。

我已经修改了您的Dockerfile，添加了bash (第5行)，这样您就可以进入容器并查看发生了什么-

FROM python:3.7-alpine
WORKDIR /usr/src/app
RUN apk add --no-cache \
        uwsgi-python3 \
        bash
COPY . .
ENV TESTING TRUE
RUN pip3 install --no-cache-dir -r requirements.txt
CMD [ "uwsgi", "--socket", "0.0.0.0:3031", \
               "--uid", "uwsgi", \
               "--plugins", "python3", \
               "--protocol", "uwsgi", \
               "--wsgi", "app:app", \
               "-p", "4", \
               "--enable-threads"]

重建镜像

$ docker build . -t soflask

将容器作为守护进程运行

$ docker run -d --rm soflask
$ docker ps

CONTAINER ID ...
96f341e998d4 ...

$ docker exec -i -t 96f bash
$ python
>>> from flask import Flask
>>>

无错误...app.py第1-5行是什么样子？

Answer 3

好吧，运行Python :3.10会有所帮助，但是因为它目前是随Python3.6一起提供的(我需要3.7)，所以我以这样一个Dockerfile结束：

FROM alpine:3.10
VOLUME /usr/src/app/public
WORKDIR /usr/src/app
RUN apk add --no-cache python3 && \
    if [ ! -e /usr/bin/python ]; then ln -sf python3 /usr/bin/python ; fi && \
    python3 -m ensurepip && \
    rm -r /usr/lib/python*/ensurepip && \
    pip3 install --no-cache --upgrade pip setuptools wheel && \
    if [ ! -e /usr/bin/pip ]; then ln -s pip3 /usr/bin/pip ; fi
RUN apk add --no-cache \
        uwsgi-python3
COPY . .
RUN rm -rf public/*
ENV TESTING TRUE
RUN pip3 install --no-cache-dir -r requirements.txt
CMD [ "uwsgi", "--socket", "0.0.0.0:3031", \
               "--uid", "uwsgi", \
               "--plugins", "python3", \
               "--protocol", "uwsgi", \
               "--wsgi", "app:app", \
               "-p", "4", \
               "--enable-threads"]

这个运行apk add --no-cache python3...魔法是从here那里夺走的。不知道是怎么回事，但就是行得通。