如何在 ServiceBusTrigger azure function 中进行持久的后调用？

Question

嘿，我正在使用ServiceBusTrigger azure function 来获取在队列中接收到的消息，然后将它们发送到我的 webapi，它将对该内容做一些事情

[FunctionName("MyAzureFunction")]
public async void Run(
    [ServiceBusTrigger("<MyQueue>", Connection = "<MyConnectionString>")] Message myQueueItem, ILogger log)
{
    log.LogInformation($"C# ServiceBus queue trigger function processed message: {myQueueItem.ToString()}");
    var client = new HttpClient();
    // Retrieving the string content from the message
    var bodyMessage = Encoding.UTF8.GetString(myQueueItem.Body);
    // Calling my API to do something based on the message content
    var response = await client.PostAsync("<MyAPIUrl>", new StringContent(bodyMessage, Encoding.UTF8, "application/json"));
    // doing something based on the response
}

我一直在阅读有关 azure 功能的文章，为了它变得更便宜，我阅读了有关持久功能的文章，我期待如何使用它们，以便我可以根据我的响应做出决定，我可以让它与这个ServiceBusTrigger一起工作

Answer 1

需要更改当前的ServiceBusTrigger function 所以它会调用另一个 Function 来实际完成这项工作：

[FunctionName("MyAzureFunction")] public async void Run(
    [ServiceBusTrigger("<MyQueue>", Connection = "<MyConnectionString>")] Message myQueueItem,
    [DurableClient] IDurableOrchestrationClient orchestratorClient,
    ILogger log) {

    log.LogInformation($"C# ServiceBus queue trigger function processed message: {myQueueItem.ToString()}");

    // Here is where you need to specify in the first parameter the name of the function to be called
    // and the last parameter are the params you'll send to that one
    var instanceId = await orchestratorClient.StartNewAsync("MyPostFunction", null, myQueueItem);

    log.LogInformation($"C# ServiceBus queue trigger function created an async instance of 'MyPostFunction' with the ID: {instanceId}");
}

然后需要创建另一个 function，它将是OrchestrationTrigger类型，如下所示：

[FunctionName("MyPostFunction")] public async void RunOrchestrator([OrchestrationTrigger] IDurableOrchestrationContext context) {
    // using the context can be retrieved the parammeters passed in the function above
    // in this case I just specify the type of that one and that's it
    var myQueueItem = context.GetInput<Message>();
    var bodyMessage = Encoding.UTF8.GetString(myQueueItem.Body);

    // Create a URI of your API url
    var postUri = new Uri($"<MyAPIUrl>");

    // depending on your WebAPI you'll need to specify the content type in the headers
    var headers = new Dictionary<string, StringValues>() { { "Content-Type", "application/json" } };
    // creating durable http request
    var request = new DurableHttpRequest(HttpMethod.Post, postUri, headers, bodyMessage);

    // Doing the http call async, in this context you'll save money since your function will not be completely waiting for a response
    // this one will keep just checking to see if there's a response available or not
    var response = await context.CallHttpAsync(request);

    // do your stuffs depending in the response
}

在我的情况下，我必须在请求中指定标头，否则我曾经获得415 Unsupported Media Type可以通过这种方式完成，或者只是创建请求而不在开始时指定任何 header 然后添加如下内容：

var request = new DurableHttpRequest(HttpMethod.Post, postUri, null, bodyMessage);
request.Headers.Add("Content-Type", "application/json");

两种选择都有效