Azure Function App Azure Service Bus trigger 触发两次

Question

我正在使用带有服务总线触发器的 Azure Function Apps 来读取服务总线并对服务总线消息的内容进行操作。服务总线接收到一个 JSON 序列化对象，然后我将 JSON 消息反序列化回 Function App 中的对象。但是，出于某种原因，每当有东西被发送到服务总线时，触发器都会触发两次，一次是 JSON 消息，一次是包含文本 "Service Bus Message".

的消息

我不知道是什么导致了第二条消息，所以我想到的只是反序列化服务总线消息，当它因 "Service Bus Message" 而失败时，我将捕获异常并忽略它。但是，我认为这不是处理此问题的正确方法，JSON 反序列化中的实际错误将被忽略。处理第二条消息的正确方法是什么？

示例代码：

using Newtonsoft.Json;

public static void Run(string myQueueItem, ILogger log, out SendGridMessage mailMessage)
{
    MyClass myObject = null;
    try
    {
        myObject = JsonConvert.DeserializeObject<MyClass>(myQueueItem);
        // do stuff
    }
    catch (JsonException je)
    {
        // ignore this exception
    }
    catch (Exception e)
    {
        // handle the other exceptions and send an alert
    }
}

编辑：我在原文 post 中遗漏的一件事是我也有一个 SendGrid 输出。我不明白为什么这会对触发器产生任何影响，这就是我将其排除在外的原因。但是，我现在添加它以防万一它可能是某些奇怪原因的原因。

编辑 2：添加了突出问题的完整工作代码

// Sender
using System;
using System.Text;
using System.Threading.Tasks;
using Microsoft.Azure.ServiceBus;
using Newtonsoft.Json;

namespace myapp
{
    class Program
    {
        static void Main(string[] args) => MainAsync().GetAwaiter().GetResult();

        static async Task MainAsync()
        {
            string serviceBusConnectionString = "<your servicebus connectionstring>";
            string queueName = "<your queue name>";
            IQueueClient queueClient = new QueueClient(serviceBusConnectionString, queueName);
            string messageBody = JsonConvert.SerializeObject(new Test());
            var message = new Message(Encoding.UTF8.GetBytes(messageBody));
            await queueClient.SendAsync(message);
            await queueClient.CloseAsync();
        }

        class Test
        {
            public string Text { get; set; } = "test";
        }
    }
}

// Receiver
#r "Newtonsoft.Json"

using System;
using System.Threading.Tasks;
using Newtonsoft.Json;

public static void Run(string myQueueItem, ILogger log)
{
    try
    {
        Test test = JsonConvert.DeserializeObject<Test>(myQueueItem);
        log.LogInformation($"C# ServiceBus queue trigger function processed message: {test.Text}");
    }
    catch (Exception e)
    {
        log.LogInformation($"Exception: {e.Message}");
    }
}

class Test
{
    public string Text { get; set; } = "test";
}

结果：

2019-11-04T08:38:10.544 [Information] Executing 'Functions.test' (Reason='This function was programmatically called via the host APIs.', Id=06e10006-baa6-430f-b5db-9a5eae5c154c)
2019-11-04T08:38:10.659 [Information] Exception: Unexpected character encountered while parsing value: S. Path '', line 0, position 0. // This here is caused by "Service bus message"
2019-11-04T08:38:10.659 [Information] Executed 'Functions.test' (Succeeded, Id=06e10006-baa6-430f-b5db-9a5eae5c154c)
2019-11-04T08:39:02.582 [Information] Executing 'Functions.test' (Reason='New ServiceBus message detected on 'test'.', Id=5d7622a7-cc8d-44c9-8720-626fdbb8cabb)
2019-11-04T08:39:02.583 [Information] Trigger Details: MessageId: 13bba779fd524fa1a0098acd6634aded, DeliveryCount: 1, EnqueuedTime: 11/4/2019 8:39:02 AM, LockedUntil: 11/4/2019 8:39:07 AM
2019-11-04T08:39:02.584 [Information] C# ServiceBus queue trigger function processed message: test // This here is the actual message
2019-11-04T08:39:02.584 [Information] Executed 'Functions.test' (Succeeded, Id=5d7622a7-cc8d-44c9-8720-626fdbb8cabb)

Answer 1

根据我的测试，触发器不会被触发两次。

namespace ServiceBusTrigger
{
    public static class Function1
    {
        [FunctionName("Function1")]
        public static void Run([ServiceBusTrigger("myqueue", Connection = "ServiceBusConnection")]string myQueueItem, ILogger log)
        {
            log.LogInformation($"C# ServiceBus queue trigger function processed message: {myQueueItem}");

            var myMessage = JsonConvert.DeserializeObject<MyMessage>(myQueueItem);

            log.LogInformation($"ID: {myMessage.id}\tContent:{myMessage.content}");
        }
    }
}

手动发送消息，得到如下输出：


Pause Clear Expand

2019-11-04T08:18:56.837 [Information] Executing 'Function1' (Reason='New ServiceBus message detected on 'myqueue'.', Id=7fb37483-b9a3-4c19-baa3-235b419bb585)
2019-11-04T08:18:56.837 [Information] Trigger Details: MessageId: c00a8e41-d883-4620-992f-6b9b4fdae320, DeliveryCount: 1, EnqueuedTime: 11/4/2019 8:18:56 AM, LockedUntil: 11/4/2019 8:19:26 AM
2019-11-04T08:18:56.838 [Information] C# ServiceBus queue trigger function processed message: {"id":"1","content":"abc"}
2019-11-04T08:18:56.838 [Information] ID: 1 Content:abc
2019-11-04T08:18:56.839 [Information] Executed 'Function1' (Succeeded, Id=7fb37483-b9a3-4c19-baa3-235b419bb585)

那么，能否请您检查一下您的服务总线生产商，看看是否发送了任何其他消息。

您可以停止函数应用程序，手动发送消息并在门户上查看：

如果一切正常，那么应该只有 1 条活动消息。

更新

Azure Function App Azure Service Bus trigger 触发两次

Azure Function App Azure Service Bus trigger triggers twice

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