Azure Functions [JavaScript/Node.js] - HTTP 调用，良好实践

问题描述

从我的 Azure 函数(在 Node.js 中运行，由 EventHub 消息触发)我想向某个外部页面发出发布请求.比如:

From my Azure Function (which runs in Node.js, triggered by EventHub message) I would like to make a post request to some external page. Something like:

module.exports = function (context, eventHubMessages) {

var http = require("http");

context.log('JavaScript Function triggered by eventHub messages ');

http.request(post_options, function(res){
    ...
})

context.done();

上面的代码可能会起作用，但我怀疑这是否不是反模式.

The code above will probably work but I have a doubt if that is not an antipattern.

想象一下在短时间内触发了数千个函数的情况 - 对于每次执行，我们都需要创建一个 HTTP 客户端并创建一个连接......

Imagine situation when there are thousands of functions triggered in short period of time - for each execution we would need to create an HTTP client and create a connection...

从简短的研究中，我发现了一些针对 C# Azure Functions 的解决方案建议:https://docs.microsoft.com/en-us/azure/architecture/antipatterns/improper-instantiation/它使用静态 HttpClient 类.

From short research I have found some solution proposal for C# Azure Functions: https://docs.microsoft.com/en-us/azure/architecture/antipatterns/improper-instantiation/ which uses static HttpClient class.

我有一个问题，Node.js Azure Function 中是否有类似的方法?或者任何其他方法来避免这个问题，在 Node.js Azure 函数执行之间共享一个对象?

I have a question, is there any similar approach in Node.js Azure Function? Or any other way to avoid this problem, to share an object between Node.js Azure Function executions?

推荐答案

如果短时间内触发了数千个函数，你应该通过修改 http.globalAgent 或传递一个实例来限制套接字一个新的 代理

If thousands of functions triggered in short period of time you should limit the sockets by modifying the http.globalAgent or by passing an instance of a new Agent

代理负责管理连接持久性和重用对于 HTTP 客户端.它维护一个给定的待处理请求队列主机和端口，为每个重用一个套接字连接，直到队列为空，此时套接字要么被销毁，要么被放置进入一个池，在那里它被保存以再次用于相同的请求主机和端口.是销毁还是池化取决于keepAlive 选项.

An Agent is responsible for managing connection persistence and reuse for HTTP clients. It maintains a queue of pending requests for a given host and port, reusing a single socket connection for each until the queue is empty, at which time the socket is either destroyed or put into a pool where it is kept to be used again for requests to the same host and port. Whether it is destroyed or pooled depends on the keepAlive option.

来源:https://nodejs.org/api/http.html#http_class_http_agent

http.globalAgent.maxSockets 默认为无穷大，因此除非您限制此值，否则您的函数将耗尽套接字，您将看到您的请求开始失败.此外，如果您计划连接到同一主机，则应在 globalAgent/Agent 上启用 keep-alive 以启用池连接.

http.globalAgent.maxSockets defaults to infinity so unless you limit this value your function will run out of sockets and you'll see your requests start to fail. Additionally if you are planning on connecting to the same host you should enable keep-alive on the globalAgent/Agent to enable pooled connections.

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