在这个例子中，main.py还是app.yaml决定App Engine定时任务使用的URL？

Question

在这个示例代码中，应用的URL似乎是由应用内部的这一行决定的：

application = webapp.WSGIApplication([('/mailjob', MailJob)], debug=True)

同时，也由app.yaml文件中的这一行决定：

- url: /.*
  script: main.py

不过，定时任务的URL是由这一行设置的：

url: /tasks/summary

所以看起来，定时任务工具会调用"/tasks/summary"，而由于应用处理程序的关系，这会导致main.py被执行。这是否意味着，对于定时任务来说，应用中设置URL的那一行是多余的：

application = webapp.WSGIApplication([('/mailjob', MailJob)], debug=True)

……因为定时任务只需要app.yaml中定义的那个URL。

app.yaml
application: yourappname
version: 1
runtime: python
api_version: 1

handlers:

- url: /.*
  script: main.py

cron.yaml
cron:
    - description: daily mailing job
    url: /tasks/summary
    schedule: every 24 hours

main.py
#!/usr/bin/env python  

import cgi
from google.appengine.ext import webapp
from google.appengine.api import mail
from google.appengine.api import urlfetch 

class MailJob(webapp.RequestHandler):
    def get(self):

        # Call your website using URL Fetch service ...
        url = "http://www.yoursite.com/page_or_service"
        result = urlfetch.fetch(url)

        if result.status_code == 200:
            doSomethingWithResult(result.content)

        # Send emails using Mail service ...
        mail.send_mail(sender="admin@gmail.com",
                to="someone@gmail.com",
                subject="Your account on YourSite.com has expired",
                body="Bla bla bla ...")
        return

application = webapp.WSGIApplication([
        ('/mailjob', MailJob)], debug=True)

def main():
    wsgiref.handlers.CGIHandler().run(application)

if __name__ == '__main__':
    main()

Answer 1

看起来你正在阅读这个页面（虽然你没有给我们网址）。根据你提供的配置和代码，运行起来可能会出问题：定时任务会尝试访问路径 /tasks/summary，而 app.yaml 会让它执行 main.py，但 main.py 只设置了一个处理器来处理 /mailjob，所以定时任务的访问会失败，返回404错误。

Answer 2

你可以这样做：

app.yaml
application: yourappname
version: 1
runtime: python
api_version: 1

handlers:

- url: /tasks/.*
  script: main.py

cron.yaml
cron:
    - description: daily mailing job
    url: /tasks/summary
    schedule: every 24 hours

main.py
#!/usr/bin/env python  

import cgi
from google.appengine.ext import webapp
from google.appengine.api import mail
from google.appengine.api import urlfetch 

class MailJob(webapp.RequestHandler):
    def get(self):

        # Call your website using URL Fetch service ...
        url = "http://www.yoursite.com/page_or_service"
        result = urlfetch.fetch(url)

        if result.status_code == 200:
                doSomethingWithResult(result.content)

        # Send emails using Mail service ...
        mail.send_mail(sender="admin@gmail.com",
                        to="someone@gmail.com",
                        subject="Your account on YourSite.com has expired",
                        body="Bla bla bla ...")
        return

application = webapp.WSGIApplication([
        ('/tasks/summary', MailJob)], debug=True)

def main():
    wsgiref.handlers.CGIHandler().run(application)

if __name__ == '__main__':
    main()