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目前,我的 Google App Engine 设计有一个前端通过 URL 获取与常驻后端通信。新设计将使用模块而不是后端。这是谷歌希望人们前进的方向,所以这应该不难,但让它在生产中运行已经让我难了好几天。“ manual_scaling ”对我不起作用。dev_appserver.py(1.8.3)中的“manual_scaling”工作正常,但在生产中不起作用。我已经尽可能地简化了这个问题。这是应该复制问题的四个文件:

源代码

应用程序.yaml

api_version: 1
application: myapp
version: 123456
runtime: python27
threadsafe: true
handlers:
- url: /send_hello/.*
  script: send_hello.app
- url: /hello/.*
  script: hello.app

你好.yaml

api_version: 1
application: myapp
module: hello
version: 123456
runtime: python27
threadsafe: true
#comment out these next two lines and it works!!!
manual_scaling:
  instances: 1
handlers:
- url: /_ah/start
  script: hello.app
- url: /hello/.*
  script: hello.app

你好.py

import webapp2
import logging
from google.appengine.api import modules

class HelloHandler(webapp2.RequestHandler):
  def get(self):
      who = modules.get_current_module_name() 
      logging.info("Hello from the '%s' module" %  who)
      self.response.headers['Content-Type'] = 'text/plain'
      self.response.out.write("Hello from the '%s' module!\n" % who)

mappings = [
   (r'/_ah/start', HelloHandler),
   (r'/hello/.*', HelloHandler)
   ]

app = webapp2.WSGIApplication(mappings, debug=True)

send_hello.py

import logging
import webapp2
from google.appengine.api import urlfetch
from google.appengine.api import modules

class SendHelloHandler(webapp2.RequestHandler):
   def get(self):
       url = "http://%s/hello/world" % modules.get_hostname(module="hello")

       logging.info('backend url: %s' % url)
       response = urlfetch.fetch(url=url, method=urlfetch.GET)

       reply = 'backend response: %d %s' % (response.status_code, response.content))
       logging.info(reply)

       self.response.headers['Content-Type'] = 'text/plain'
       self.response.out.write(reply)


mappings = [
    (r'/send_hello/.*', SendHelloHandler)
    ]

app = webapp2.WSGIApplication(mappings, debug=True)

使用开发服务器进行测试效果很好

启动它运行良好,您可以看到手动扩展实例启动

$ dev_appserver.py app.yaml hello.yaml
WARNING  2013-08-17 00:19:37,131 api_server.py:317] Could not initialize images API; you are likely missing the Python "PIL" module.
INFO     2013-08-17 00:19:37,134 api_server.py:138] Starting API server at: http://localhost:34319
INFO     2013-08-17 00:19:37,147 dispatcher.py:164] Starting module "default" running at: http://localhost:8080
INFO     2013-08-17 00:19:37,157 dispatcher.py:164] Starting module "hello" running at: http://localhost:8081
INFO     2013-08-17 00:19:37,160 admin_server.py:117] Starting admin server at: http://localhost:8000
INFO     2013-08-17 00:19:39,575 hello.py:9] Hello from the 'hello' module
INFO     2013-08-17 00:19:39,581 module.py:593] hello: "GET /_ah/start HTTP/1.1" 200 31

调用调用模块的前端,它按预期工作:

$ curl "http://localhost:8080/send_hello/world"
backend response: 200 Hello from the 'hello' module!

直接调用模块,按预期工作

$ curl "http://localhost:8081/hello/world"
Hello from the 'hello' module!

使用生产服务器进行测试失败

将应用加载到生产环境中

$ appcfg.py update app.yaml hello.yaml

调用调用模块的前端..并获得404

$ curl "http://123456.myapp.appspot.com/send_hello/world"
backend response: 404
<html><head>
<meta http-equiv="content-type" content="text/html;charset=utf-8">
<title>404 Not Found</title>
</head>
<body text=#000000 bgcolor=#ffffff>
<h1>Error: Not Found</h1>
<h2>The requested URL <code>/hello/world</code> was not found on this server.</h2>
<h2></h2>
</body></html>

直接调用模块报503错误

$ curl "http://hello.myapp.appspot.com/hello/world"

<html><head>
<meta http-equiv="content-type" content="text/html;charset=utf-8">
<title>503 Server Error</title>
</head>
<body text=#000000 bgcolor=#ffffff>
<h1>Error: Server Error</h1>
<h2>The service you requested is not available yet.<p>Please try again in 30 seconds. </h2>
<h2></h2>
</body></html>

使用版本说明符调用模块并得到 404 错误:

$ curl "http://123456.hello.myapp.appspot.com/hello/world"

<html><head>
<meta http-equiv="content-type" content="text/html;charset=utf-8">
<title>404 Not Found</title>
</head>
<body text=#000000 bgcolor=#ffffff>
<h1>Error: Not Found</h1>
<h2>The requested URL <code>/hello/world</code> was not found on this server.</h2>
<h2></h2>
</body></html>

问题...

为什么生产 manual_scaling 实例不在生产服务器(即实际的 Google 服务器)上启动?请注意,如果您在“app.yaml”中注释掉手动缩放行,则应用程序在生产环境中按预期工作。

另一个线索是 Google App Engine 控制台没有显示“hello”模块的日志记录,也没有显示任何活动实例。奇怪的是appcfg.py start hello.yaml,它说它已经在运行了。

回答这个问题的另一种方法是向我指出一个使用模块的“手动缩放”的完整工作示例(来自 Google 的片段还不够)。

4

1 回答 1

6

想通了我自己的问题...

version: 123456将 .yaml 文件中的更改为version: v123456,它在生产中按预期工作。

在“manual_scaling”模块类型的情况下,似乎不支持对版本使用整数。也许它使特定实例的 URL不明确。

于 2013-08-24T00:28:21.443 回答