如何在ServiceBusTrigger Azure函数中进行持久的后期调用?

时间:2020-06-25 13:52:34

标签: c# azure azure-functions azure-durable-functions

嘿,我正在使用一个ServiceBusTrigger天蓝色函数来获取队列中接收到的消息,然后将它们发送到我的webapi,它将对该内容进行一些处理

[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
}

我一直在阅读有关天蓝色函数的信息,为了使它便宜一些,我阅读了关于持久函数的信息,我期待着如何使用它们,以便我可以根据自己的回答做出决定,并可以将其用于此工作。 ServiceBusTrigger

1 个答案:

答案 0 :(得分:1)

需要更改当前的ServiceBusTrigger函数,以便它调用实际上可以完成工作的另一个Function:

[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OrchestrationTrigger类型的函数,它看起来像这样:

[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,我必须指定请求中的标头,否则我可以用这种方式完成415 Unsupported Media Type的操作,或者只创建请求而无需在开头指定任何标头,然后添加类似这个:

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

两个选项都有效