一次使用Python初始化的Azure函数应用 [英] Azure function apps with Python one time initialization

问题描述

我正在将Azure函数应用与Python结合使用。我有两个功能应用程序，全部使用Postgres DB和Custom Vision。所有功能应用程序都设置为HttpTriggers。现在，当一个函数被触发时，一个新的数据库处理程序（或自定义视觉处理程序）对象将在函数应用程序调用完成后创建，使用和终止。

I'm using Azure function apps with Python. I have two dozen function apps that all use a Postgres DB and Custom Vision. All function apps are setup as HttpTriggers. Right now, when a function is triggered, a new database handler (or custom vision handler) object is created, used and terminated when the function app call is done.

它在传入的每个请求中实例化一个新对象似乎非常适得其反。是否有一种方法可以实例化共享对象一次，然后在调用它们时将其传递给函数？

It seems to be very counterproductive to instantiate a new objects on every single request that comes in. Is there a way to instantiate shared objects once and then pass them to a function when they are called?

推荐答案

通常，Azure Functions旨在为无状态，并且不会在一次调用中共享对象下一个。但是，也有一些例外。

In general, Azure Functions are intended to be stateless and not share objects from one invocation to the next. However, there are some exceptions.

共享连接对象

Azure文档推荐不当实例化模式，用于共享打算在应用程序中一次打开并一次又一次使用的连接对象。

Azure Docs recommend the Improper Instantiation Pattern for sharing of connection objects that are intended in an application to be opened once and used again and again.

需要牢记一些注意事项为此，主要是：

There are some things to keep in mind for this to work for you, mainly:

此反模式的关键要素是反复创建和销毁可共享对象的实例。如果一个类不是可共享的（不是线程安全的），那么该反模式将不适用。

The key element of this antipattern is repeatedly creating and destroying instances of a shareable object. If a class is not shareable (not thread-safe), then this antipattern does not apply.

他们在那里有一些演练可能会帮助您。由于您的问题相当笼统，因此我最好的建议是建议您通读它，看看是否会对您有所帮助。

They have some walkthroughs there that will probably help you. Since your question is fairly generic, the best I can do is recommend you read through it and see if that will help you.

持久功能

另一种方法是考虑耐用功能代替标准。它们旨在能够在函数之间传递对象，从而使它们并非完全无状态。

The alternative is to consider the Durable Functions instead of the standard. They are intended to be able to pass objects between functions making them not quite stateless.

持久函数是Azure函数的高级扩展，不适用于所有应用程序。本文假定您对 Azure函数中的概念非常熟悉以及无服务器应用程序开发所涉及的挑战。

Durable Functions is an advanced extension for Azure Functions that isn't appropriate for all applications. This article assumes that you have a strong familiarity with concepts in Azure Functions and the challenges involved in serverless application development.

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