python 如何在 Google App Engine 中为 urlfetch 设置超时？
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How to set timeout for urlfetch in Google App Engine?
提问by GRex
I'm trying to have Django (on top of GAE) fetch data from another web service. I'm often hit with error like this:
我正在尝试让 Django（在 GAE 之上）从另一个 Web 服务获取数据。我经常遇到这样的错误：
ApplicationError: 2 timed out Request
Method: GET
Request URL:http://localhost:8080/
Exception Type: DownloadError
Exception Value: ApplicationError: 2 timed out
Exception Location: /google_appengine/google/appengine/api/urlfetch.py in _get_fetch_result, line 325
应用程序错误：2 超时请求
方法：获取
异常类型：下载错误
异常值：ApplicationError：2 超时
异常位置：/google_appengine/google/appengine/api/urlfetch.py in _get_fetch_result, line 325
It feels as if it will time out only after 12 seconds (I'm not sure, but it's really short).
感觉好像它只会在 12 秒后超时（我不确定，但它真的很短）。
Question: how can I set a longer timeout?
问题：如何设置更长的超时时间？
回答by Alex Young
Seeing as this is a Pythonquestion, I thought I'd provide a Python answer for anyone who comes across this problem.
看到这是一个Python问题，我想我会为遇到此问题的任何人提供 Python 答案。
Just import urlfetchand then define a deadline before doing anything else in your code:
只需导入urlfetch然后在代码中执行任何其他操作之前定义一个截止日期：
from google.appengine.api import urlfetch
urlfetch.set_default_fetch_deadline(60)
回答by Mark Bell
You can set it using the deadlineargument of the fetch function. From the docs:
您可以使用fetch 函数的deadline参数来设置它。从文档：
The deadline can be up to a maximum of 60 seconds for request handlers and 10 minutes for tasks queue and cron job handlers. If deadline is None, the deadline is set to 5 seconds.
请求处理程序的截止时间最长为 60 秒，任务队列和 cron 作业处理程序的截止时间最长为 10 分钟。如果截止时间为无，则截止时间设置为 5 秒。
Edit:looks like this has changed now. From here:
编辑：看起来现在已经改变了。从这里：
You can set a deadline for a request, the most amount of time the service will wait for a response. By default, the deadline for a fetch is 5 seconds. You can adjust the default deadline for requests using the
urlfetch.set_default_fetch_deadline()function.
您可以为请求设置截止时间，即服务等待响应的最长时间。默认情况下，获取的截止时间为 5 秒。您可以使用该
urlfetch.set_default_fetch_deadline()功能调整请求的默认截止日期。
And this pagelists the default timeout values:
而此页面列出了默认的超时值：
Currently, there are several errors named DeadlineExceededError for the Python runtime:
google.appengine.runtime.DeadlineExceededError: raised if the overall request times out, typically after 60 seconds, or 10 minutes for task queue requests.google.appengine.runtime.apiproxy_errors.DeadlineExceededError: raised if an RPC exceeded its deadline. This is typically 5 seconds, but it is settable for some APIs using the 'deadline' option.google.appengine.api.urlfetch_errors.DeadlineExceededError: raised if the URLFetch times out.
目前，Python 运行时有几个名为 DeadlineExceededError 的错误：
google.appengine.runtime.DeadlineExceededError：如果整个请求超时，通常在 60 秒后或任务队列请求 10 分钟后引发。google.appengine.runtime.apiproxy_errors.DeadlineExceededError: 如果 RPC 超过其截止日期，则引发。这通常是 5 秒，但对于某些使用 'deadline' 选项的 API，它是可设置的。google.appengine.api.urlfetch_errors.DeadlineExceededError: 如果 URLFetch 超时则引发。
回答by gosharplite
For Go, you might want to try below code.
对于 Go，您可能想尝试以下代码。
// createClient is urlfetch.Client with Deadline
func createClient(context appengine.Context, t time.Duration) *http.Client {
return &http.Client{
Transport: &urlfetch.Transport{
Context: context,
Deadline: t,
},
}
}
Here is how to use it.
这是如何使用它。
// urlfetch
client := createClient(c, time.Second*60)
回答by gosharplite
It seems short but you have to know that the timeout of a request on GAE is around 30 seconds. As you probably need to do some operations on the response of your urlfetch, there's no need to have a timeout more than 10 seconds I think.
看起来很短，但您必须知道 GAE 上的请求超时约为 30 秒。由于您可能需要对 urlfetch 的响应进行一些操作，因此我认为没有必要超时超过 10 秒。
