尝试为 flask 应用程序构建 docker 时出错

Question

我正在尝试构建 docker 来运行 flask 应用程序。 我以前从来没有这样做过。 我有 flask 应用程序在本地工作。 这是我的方法：

我的项目目录结构如下所示：

model.pkl  README.md          images/            static/
Dockerfile         flaskapp.py        requirements.txt   templates/

我可以通过运行python flaskapp.py来启动 flask 应用程序，它在我的浏览器（本地）中运行。

我想创建一个 Docker 以便其他机器可以在不处理所有依赖项的情况下运行这个项目。 为此，我做了以下事情：

• 我在里面创建了一个 Dockerfile ：

FROM python:3
COPY requirements.txt /tmp
COPY flaskapp.py /tmp
COPY model.pkl /tmp
COPY images /tmp
COPY static /tmp
COPY templates /tmp
WORKDIR /tmp
ADD flaskapp.py /
RUN pip install -r requirements.txt
CMD [ "python", "flaskapp.py" ]

• 运行命令docker build -t python-barcode.

• 那行得通，所以。 我跑了docker run python-barcode 。 终端打印出* Running on http://0.0.0.0:5000/ (Press CTRL+C to quit) ，但它不起作用，我在浏览器上收到此错误：

This site can’t be reached0.0.0.0 refused to connect.
Try:

Checking the connection
Checking the proxy and the firewall
ERR_CONNECTION_REFUSED

所以我做了一些挖掘，并将我的 Dockerfile 更新到这个（添加最后一行）：

FROM python:3
COPY requirements.txt /tmp
COPY flaskapp.py /tmp
COPY model.pkl /tmp
COPY images /tmp
COPY static /tmp
COPY templates /tmp
WORKDIR /tmp
ADD flaskapp.py /
RUN pip install -r requirements.txt
CMD [ "python", "flaskapp.py" ]
CMD ["flask", "run", "--host", "0.0.0.0" ]

• 然后运行docker run python-barcode ，我得到这个错误：

Usage: flask run [OPTIONS]

Error: Could not locate Flask application. You did not provide the FLASK_APP environment variable.

For more information see http://flask.pocoo.org/docs/latest/quickstart/

我应该如何进行？

如果它相关，我的flaskapp.py看起来像这样：

model = load_learner('', 'model.pkl')

app = Flask(__name__)
app.config['SEND_FILE_MAX_AGE_DEFAULT'] = 0

def classify(document):
    X = document
    y = model.predict(X)
   
    return y

class ReviewForm(Form):
    pred = TextAreaField('',[validators.DataRequired(),validators.length(min=1)])

@app.route('/')
def index():
    form = ReviewForm(request.form)
    return render_template('reviewform.html', form=form)

@app.route('/results', methods=['POST'])
def results():
    form = ReviewForm(request.form)
    if request.method == 'POST' and form.validate():
        sequence = request.form['pred']
        y = classify(sequence)
        return render_template('results.html',
        y = y)
    return render_template('reviewform.html', form=form)

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

编辑 1

现在我收到此错误：

[2020-07-03 00:29:51,222] ERROR in app: Exception on / [GET]
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/flask/app.py", line 1988, in wsgi_app
    response = self.full_dispatch_request()
  File "/usr/local/lib/python3.8/site-packages/flask/app.py", line 1641, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/usr/local/lib/python3.8/site-packages/flask/app.py", line 1544, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/local/lib/python3.8/site-packages/flask/_compat.py", line 33, in reraise
    raise value
  File "/usr/local/lib/python3.8/site-packages/flask/app.py", line 1639, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/local/lib/python3.8/site-packages/flask/app.py", line 1625, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "flaskapp.py", line 94, in index
    return render_template('reviewform.html', form=form)
  File "/usr/local/lib/python3.8/site-packages/flask/templating.py", line 133, in render_template
    return _render(ctx.app.jinja_env.get_or_select_template(template_name_or_list),
  File "/usr/local/lib/python3.8/site-packages/jinja2/environment.py", line 930, in get_or_select_template
    return self.get_template(template_name_or_list, parent, globals)
  File "/usr/local/lib/python3.8/site-packages/jinja2/environment.py", line 883, in get_template
    return self._load_template(name, self.make_globals(globals))
  File "/usr/local/lib/python3.8/site-packages/jinja2/environment.py", line 857, in _load_template
    template = self.loader.load(self, name, globals)
  File "/usr/local/lib/python3.8/site-packages/jinja2/loaders.py", line 115, in load
    source, filename, uptodate = self.get_source(environment, name)
  File "/usr/local/lib/python3.8/site-packages/flask/templating.py", line 57, in get_source
    return self._get_source_fast(environment, template)
  File "/usr/local/lib/python3.8/site-packages/flask/templating.py", line 85, in _get_source_fast
    raise TemplateNotFound(template)
jinja2.exceptions.TemplateNotFound: reviewform.html

Answer 1

每个 Dockerfile 只能有CMD 。 所以很可能会被忽略。

CMD [ "python", "flaskapp.py" ]
CMD ["flask", "run", "--host", "0.0.0.0" ]

只需删除第二个，因为您已经监听了代码中的所有接口。

CMD [ "python", "flaskapp.py" ]

现在使用此命令运行 Docker 容器。

docker run -p 5000:5000 -it python-barcode

然后你就可以到达终点

http://localhost:5000

Answer 2

您需要将端口暴露给外部世界

docker run -p 8000:8000 python-barcode将 docker 容器内的端口 8000 映射到 Z05B6053C41A2130AFD6FC3B158BDA4 容器外的端口 8000。

然后你可以在主机上 go 到http://127.0.0.1:8000

您还可以将端口重定向到不同的端口

docker run -p 8000:9000 python-barcode然后在主机系统上的http://127.0.0.1:9000访问它