Heroku Flask 教程 Procfile 含义

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问题描述

在 heroku 教程中，有一段代码

In the heroku tutorial, there is a piece of code

hello.py

import os
from flask import Flask

app = Flask(__name__)

@app.route('/')
def hello():
    return 'Hello World!'

和Procfile:

web: gunicorn hello:app --log-file=-

真正令人困惑的部分是 hello:app 部分；hello 是指 hello() 函数还是 hello.py 脚本?根据其含义，整个 Procfile 语句是什么意思?

The part that's really confusing is the hello:app part; does hello refer to the hello() function or the hello.py script? Depending on the meaning of that, what does the whole Procfile statement mean?

推荐答案

tl;dr: hello 指的是 hello.py 和 app指的是 app = Flask(__name__)

tl;dr: hello refers to hello.py and app refers to app = Flask(__name__)

提到的 Heroku 教程不再可用，但是 Gunicorn 的文档给出了一个很好的最小例子:

The mentioned Heroku tutorial is no more available, however Gunicorn's doc gives a good minimal example :

测试应用示例:

def app(environ, start_response):
    """Simplest possible application object"""
    data = b'Hello, World!
'
    status = '200 OK'
    response_headers = [
        ('Content-type', 'text/plain'),
        ('Content-Length', str(len(data)))
    ]
    start_response(status, response_headers)
    return iter([data])

您现在可以使用以下命令运行应用程序:

You can now run the app with the following command:

$ gunicorn --workers=2 test:app

让我们试试，我的测试目录看起来像这样:

(.venv) 14:41 ~/testgunicorn % tree
.
├── requirements.txt
└── testpkg
    ├── __init__.py
    └── testfile.py

__init__.py :

from flask import Flask
from .testfile import app

testfile.py :

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

def app(environ, start_response):
    """Simplest possible application object"""
    data = b'Hello, World!
'
    status = '200 OK'
    response_headers = [
        ('Content-type', 'text/plain'),
        ('Content-Length', str(len(data)))
    ]
    start_response(status, response_headers)
    return iter([data])

错误调用:

(.venv) 14:41 ~/testgunicorn % gunicorn testfile:app
[2018-08-24 14:41:44 +0200] [27248] [INFO] Starting gunicorn 19.9.0
[2018-08-24 14:41:44 +0200] [27248] [INFO] Listening at: http://127.0.0.1:8000 (27248)
[2018-08-24 14:41:44 +0200] [27248] [INFO] Using worker: sync
[2018-08-24 14:41:44 +0200] [27251] [INFO] Booting worker with pid: 27251
[2018-08-24 14:41:44 +0200] [27251] [ERROR] Exception in worker process
Traceback (most recent call last):
  File "~/testgunicorn/.venv/lib/python3.6/site-packages/gunicorn/arbiter.py", line 583, in spawn_worker
    worker.init_process()
  File "~/testgunicorn/.venv/lib/python3.6/site-packages/gunicorn/workers/base.py", line 129, in init_process
    self.load_wsgi()
  File "~/testgunicorn/.venv/lib/python3.6/site-packages/gunicorn/workers/base.py", line 138, in load_wsgi
    self.wsgi = self.app.wsgi()
  File "~/testgunicorn/.venv/lib/python3.6/site-packages/gunicorn/app/base.py", line 67, in wsgi
    self.callable = self.load()
  File "~/testgunicorn/.venv/lib/python3.6/site-packages/gunicorn/app/wsgiapp.py", line 52, in load
    return self.load_wsgiapp()
  File "~/testgunicorn/.venv/lib/python3.6/site-packages/gunicorn/app/wsgiapp.py", line 41, in load_wsgiapp
    return util.import_app(self.app_uri)
  File "~/testgunicorn/.venv/lib/python3.6/site-packages/gunicorn/util.py", line 350, in import_app
    __import__(module)
ModuleNotFoundError: No module named 'testfile'
[2018-08-24 14:41:44 +0200] [27251] [INFO] Worker exiting (pid: 27251)
[2018-08-24 14:41:44 +0200] [27248] [INFO] Shutting down: Master
[2018-08-24 14:41:44 +0200] [27248] [INFO] Reason: Worker failed to boot.
zsh: exit 3     gunicorn testfile:app

良好的呼唤:

(.venv) 14:43 ~/testgunicorn % gunicorn testpkg:app
[2018-08-24 14:43:56 +0200] [27302] [INFO] Starting gunicorn 19.9.0
[2018-08-24 14:43:56 +0200] [27302] [INFO] Listening at: http://127.0.0.1:8000 (27302)
[2018-08-24 14:43:56 +0200] [27302] [INFO] Using worker: sync
[2018-08-24 14:43:56 +0200] [27305] [INFO] Booting worker with pid: 27305
^C
(…)

(.venv) 15:03 ~/testgunicorn % cd testpkg
(.venv) 15:03 fred@susa ~/git/ocp7/testpkg % gunicorn testfile:app
[2018-08-24 15:03:22 +0200] [27494] [INFO] Starting gunicorn 19.9.0
[2018-08-24 15:03:22 +0200] [27494] [INFO] Listening at: http://127.0.0.1:8000 (27494)
[2018-08-24 15:03:22 +0200] [27494] [INFO] Using worker: sync
[2018-08-24 15:03:22 +0200] [27497] [INFO] Booting worker with pid: 27497
^C
(…)

然后对于这个 Procfile :

web: gunicorn hello:app --log-file=-

hello 是指 hello() 函数还是 hello.py 脚本?

到 hello.py 脚本

根据其含义，整个 Procfile 语句是什么意思?

Heroku 的 Procfile 格式文档说:

Heroku's Procfile format documentation says :

Procfile 在单独的行上声明它的进程类型，每一行都有以下格式:

:

是您的命令的字母数字名称，例如 web、worker、emergencyworker、clock 等.
表示进程类型的每个 dyno 在启动时应该执行的命令，例如 rake jobs:work.

<process type> is an alphanumeric name for your command, such as web, worker, urgentworker, clock, and so on.
<command> indicates the command that every dyno of the process type should execute on startup, such as rake jobs:work.

--logfile=- 选项似乎已被弃用，我在文档中没有找到有关它的任何内容，如果我使用它，我会收到此错误:

The --logfile=- option seems to be deprecated, I did not find anything about it in documentation and if I use it I get this error :

(.venv) 15:34 ~/testgunicorn % heroku local web
[WARN] No ENV file found
15:34:30 web.1   |  usage: gunicorn [OPTIONS] [APP_MODULE]
15:34:30 web.1   |  gunicorn: error: unrecognized arguments: --logfile=-
15:34:30 web.1   Exited with exit code 2

根据这个答案，这是登录 Heroku 标准输出的一个选项.

According to this answer it was an option for logging in Heroku's stdout.

这篇关于Heroku Flask 教程 Procfile 含义的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！