python - Google App Engine - 使用任务队列或延迟作业

Question

Google App Engine 有两种稍后运行作业的方法，Task Queues和 Deferred jops

据我所知，它们支持所有相同的功能(例如，延迟作业可以放在特定的任务队列中，这样您就可以限制执行)——但延迟作业看起来更容易实现，也更灵活。

有人知道每种方法的优缺点吗？在任何情况下您都希望对延迟作业使用任务队列？

Answer 1

我不确定你是否注意到了，但是 deferreds 的文档最后有这个部分:

You may be wondering when to use ext.deferred, and when to stick with the built-in task queue API. Here are our suggestions.

You may want to use the deferred library if:

• You only use the task queue lightly.
• You want to refactor existing code to run on the Task Queue with a minimum of changes.
• You're writing a one off maintenance task, such as schema migration.
• Your app has many different types of background task, and writing a separate handler for each would be burdensome.
• Your task requires complex arguments that aren't easily serialized without using Pickle.
• You are writing a library for other apps that needs to do background work.

You may want to use the Task Queue API if:

• You need complete control over how tasks are queued and executed.
• You need better queue management or monitoring than deferred provides.
• You have high throughput, and overhead is important.
• You are building larger abstractions and need direct control over tasks.
• You like the webhook model better than the RPC model.

Naturally, you can use both the Task Queue API and the deferred library side-by-side, if your app has requirements that fit into both groups.