如何在异步 Azure 函数 HTTP 触发函数中捕获 Azure 表抛出的异常 [英] How to catch an Exception throw by Azure Table in an async Azure Function HTTP Triggered function

问题描述

我有一个 Azure 函数 HTTP 触发函数，它写入可能以重复条目结尾的 Azure 表.我注意到即使我尝试/捕获了整个函数，仍然会有一个异常泄漏"到函数运行器，从而返回 HTTP 500.有什么办法可以捕获这种异常?

I have an Azure Function HTTP triggered function which writes to Azure Table that may end in duplicated entries. I noticed that even if I try/catch'd the whole function, there will still be an Exception "leaked" to the function runner thus returning HTTP 500. Is there any way to catch this kind of exception?

这是代码的缩小版本:

using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;
using Microsoft.WindowsAzure.Storage;

namespace FunctionTest
{
    public class Entry
    {
        public string PartitionKey { get; set; }
        public string RowKey { get; set; }
    }
    public static class Debug
    {
        [FunctionName("Debug")]
        public static async Task<IActionResult> Run(
            [HttpTrigger(AuthorizationLevel.Anonymous, "get", "post", Route = null)]
            HttpRequest req,
            [Table("Debug")]
            IAsyncCollector<Entry> tableBinding,
            ILogger log)
        {
            try
            {
                await tableBinding.AddAsync(new Entry()
                {
                    PartitionKey = "1111",
                    RowKey = "1111",
                });
                await tableBinding.FlushAsync();
            }
            catch (StorageException)
            {
                // we expect an Exception "The specified entity already exists"
                return new OkObjectResult("This passes test");
            }

            return new OkObjectResult("This passes test too");
        }
    }
}

代码是在 Azure Function 运行时 2.0(.NET Core 之一)下编写的.

The code is written under Azure Function runtime 2.0 (the .NET Core one).

触发 /api/debug 两次或更多次，你会看到:

Trigger /api/debug twice or more and you will see:

• HTTP 500
• 输入了 catch{} 代码，但仍返回 HTTP 500(!)
• 在 Application Insights 中，每个请求有两个表依赖项调用(不应该发生，文档说表没有自动重试)

• HTTP 500
• The catch{} code is entered, and still returns an HTTP 500(!)
• In Application Insights, two table dependency call per request (shouldn't happen, the documentation says table do not have auto retry)

推荐答案

我想，使用 IAsyncCollector<> 会破坏这里的事情.如果你想避免此类问题，请尝试交换以下绑定:

I guess, that using IAsyncCollector<> breaks things here. If you want to avoid such problems, try to exchange the following binding:

[Table("Debug")] IAsyncCollector<Entry> tableBinding

到:

[Table("Debug")] CloudTable tableBinding

然后，不要使用 tableBinding.AddAsync() 使用以下代码段:

Then, instead of using tableBinding.AddAsync() use the following snippet:

var op = TableOperation.Insert(new Entry());
await tableBinding.ExecuteAsync(op);

使用这种方法，您应该能够捕获异常，而不会将其泄漏到 Functions 运行时.

With that approach, you should be able to catch the exception, without leaking it to the Functions runtime.

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