如何按需运行后台服务-不在应用程序启动或计时器上运行 [英] How to run a background service on demand - not on application startup or on a timer

问题描述

在.Net 5 Web API中，我想运行一个后台任务，该任务发送大量电子邮件和SMS.我知道我可以创建一个从BackgroundService继承的服务，然后将其添加到Startup.ConfigureServices方法中的DI容器中，如下所示:

In a .Net 5 Web API, I would like to run a background task that sends out bulk emails and SMSes. I know I can create a service that inherits from BackgroundService, and then add it to the DI Container in the Startup.ConfigureServices method like this:

services.AddHostedService<EmailAndSmsService>();

但这将立即运行服务-即在应用程序启动时.当API从前端收到请求时，我想运行该服务.即采用控制器的操作方法.

But that runs the service immediately - i.e. on application startup. I would like to run the service when the API receives a request from the front-end. i.e. in a controller's action method.

我一直在研究具有托管服务的后台任务"Microsoft的文档上，如果我没记错的话，这就是我需要做的(请查看标题为在后台任务中使用作用域服务"的部分):

I've been looking at "Background tasks with hosted services" on Microsoft's documentation, and if I'm not mistaken, this is what i need to do (Look at the section titled "Consuming a scoped service in a background task"):

这是正确的吗?我是否基本上需要创建两个服务，一个可以执行实际工作，而另一个调用可以执行实际工作的服务?我在正确的道路上吗?

Is this correct? Do I basically need to create two services, one that does the actual work, and one that calls the service that does the actual work? Am I on the right path?

谢谢

推荐答案

您需要查看排队后台服务".您可以在其中提交职位"它将在后台队列中执行这些作业.

You need to look at a "queued background service" where you can submit "jobs" to it and it will perform those jobs in a background queue.

工作流程如下:

1. 呼叫者使用一些参数向服务发送请求
2. 服务生成职位"对象并通过202(接受)响应立即返回ID
3. Service将此作业放入由 BackgroundService
维护的队列中
4. 呼叫者可以查询作业状态，并获取有关使用此作业ID完成了多少工作以及还有多少要做的信息
服务完成工作，将工作置于完成"状态.状态，然后返回等待队列以产生更多工作

1. Caller sends a request to the service with some parameters
2. Service generates a "job" object and returns an ID immediately via 202 (accepted) response
3. Service places this job in to a queue that is being maintained by a BackgroundService
4. Caller can query the job status and get information about how much has been done and how much is left to go using this job ID
5. Service finishes the job, puts the job in to a "completed" state and goes back to waiting on the queue to produce more jobs

以下是有关其工作原理的非常冗长的解释: https://stackoverflow.com/a/63429262/1204153

Here is a very long-winded explanation on how it works: https://stackoverflow.com/a/63429262/1204153

这是我前一阵子的例子: https://github.com/sonicmouse/ComputationService

Here is an example I made a while back: https://github.com/sonicmouse/ComputationService

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