azure - 找不到 blob 文件时出现 FunctionInitationException

Question

我正在创建一个函数来读取存储中的自定义文件。 function.json 与此类似:

{
  "disabled": false,
  "bindings": [
    {
      "authLevel": "anonymous",
      "type": "httpTrigger",
      "direction": "in",
      "name": "req",
      "route": "resource/{code}",
      "methods": [
        "get"
      ]
    },
    {
      "type": "blob",
      "name": "item",
      "path": "data/20171003/{code}.json",
      "connection": "blog_STORAGE",
      "direction": "in"
    },
    {
      "type": "http",
      "direction": "out",
      "name": "res"
    }
  ]
}

在 postman 中，如果我键入现有文件，它将正确调用该函数。另一方面，如果该文件不存在，azure 运行时将抛出错误:

{ "id": "4ef77dcd-f8ed-4327-9447-969da6b328a9", "requestId": "0a9874dd-6a7b-4717-ae9f-c3c1e3bb16c8", "statusCode": 500, "errorCode": 0, "message": "Exception while executing function: Functions.func_ativos -> Valor não pode ser nulo.\r\nNome do parâmetro: stream", "errorDetails": "Microsoft.Azure.WebJobs.Host.FunctionInvocationException : Exception while executing function: Functions.func_ativos ---> System.ArgumentNullException : Valor não pode ser nulo.\r\nNome do parâmetro: stream\r\n at System.IO.StreamReader..ctor(Stream stream,Encoding encoding,Boolean detectEncodingFromByteOrderMarks,Int32 bufferSize,Boolean leaveOpen)\r\n at System.IO.StreamReader..ctor(Stream stream)\r\n
at Microsoft.Azure.WebJobs.Script.Binding.FunctionBinding.ConvertStreamToValue(Stream stream,DataType dataType,Object& converted)\r\n at async Microsoft.Azure.WebJobs.Script.Binding.FunctionBinding.BindStreamAsync(BindingContext context,FileAccess access)\r\n at async Microsoft.Azure.WebJobs.Script.Binding.ExtensionBinding.BindAsync(BindingContext context)\r\n at async Microsoft.Azure.WebJobs.Script.Description.NodeFunctionInvoker.ProcessInputBindingsAsync(Binder binder,Dictionary2 executionContext,Dictionary2 bindingData)\r\n
at async Microsoft.Azure.WebJobs.Script.Description.NodeFunctionInvoker.InvokeCore(Object[] parameters,FunctionInvocationContext context)\r\n at async Microsoft.Azure.WebJobs.Script.Description.FunctionInvokerBase.Invoke(Object[] parameters)\r\n at async Microsoft.Azure.WebJobs.Host.Executors.VoidTaskMethodInvoker2.InvokeAsync[TReflected,TReturnType](TReflected instance,Object[] arguments)\r\n at async Microsoft.Azure.WebJobs.Host.Executors.FunctionInvoker2.InvokeAsync[TReflected,TReturnValue](Object[] arguments)\r\n at async Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.InvokeAsync(IFunctionInvoker invoker,ParameterHelper parameterHelper,CancellationTokenSource timeoutTokenSource,CancellationTokenSource functionCancellationTokenSource,Boolean throwOnTimeout,TimeSpan timerInterval,IFunctionInstance instance)\r\n at async Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.ExecuteWithWatchersAsync(IFunctionInstance instance,ParameterHelper parameterHelper,TraceWriter traceWriter,ILogger logger,CancellationTokenSource functionCancellationTokenSource)\r\n at async Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.ExecuteWithLoggingAsync(??)\r\n at async Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.ExecuteWithLoggingAsync(??) \r\n End of inner exception\r\n at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()\r\n
at async Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.ExecuteWithLoggingAsync(??)\r\n at async Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor.TryExecuteAsync(IFunctionInstance functionInstance,CancellationToken cancellationToken)\r\n at Microsoft.Azure.WebJobs.Host.Executors.ExceptionDispatchInfoDelayedException.Throw()\r\n at async Microsoft.Azure.WebJobs.JobHost.CallAsync(??)\r\n at async Microsoft.Azure.WebJobs.Script.ScriptHost.CallAsync(String method,Dictionary2 arguments,CancellationToken cancellationToken)\r\n at async Microsoft.Azure.WebJobs.Script.WebHost.WebScriptHostManager.HandleRequestAsync(FunctionDescriptor function,HttpRequestMessage request,CancellationToken cancellationToken)\r\n at async Microsoft.Azure.WebJobs.Script.WebHost.Controllers.FunctionsController.ProcessRequestAsync(HttpRequestMessage request,FunctionDescriptor function,CancellationToken cancellationToken)\r\n at async Microsoft.Azure.WebJobs.Script.WebHost.Controllers.FunctionsController.<>c__DisplayClass3_0.<ExecuteAsync>b__0(??)\r\n at async Microsoft.Azure.WebJobs.Extensions.Http.HttpRequestManager.ProcessRequestAsync(HttpRequestMessage request,Func3 processRequestHandler,CancellationToken cancellationToken)\r\n at async Microsoft.Azure.WebJobs.Script.WebHost.Controllers.FunctionsController.ExecuteAsync(HttpControllerContext controllerContext,CancellationToken cancellationToken)\r\n at async System.Web.Http.Dispatcher.HttpControllerDispatcher.SendAsync(HttpRequestMessage request,CancellationToken cancellationToken)\r\n at async System.Web.Http.Dispatcher.HttpControllerDispatcher.SendAsync(HttpRequestMessage request,CancellationToken cancellationToken)\r\n at async Microsoft.Azure.WebJobs.Script.WebHost.Handlers.SystemTraceHandler.SendAsync(HttpRequestMessage request,CancellationToken cancellationToken)\r\n at async Microsoft.Azure.WebJobs.Script.WebHost.Handlers.WebScriptHostHandler.SendAsync(HttpRequestMessage request,CancellationToken cancellationToken)\r\n at async System.Web.Http.HttpServer.SendAsync(HttpRequestMessage request,CancellationToken cancellationToken)" }

我想在找不到文件时发送 404 状态代码，而不是像那样丑陋的堆栈(以及错误 500)。我应该遵循的最佳方法是什么？

==更新

请注意，FunctionInitationException 发生在调用我的函数之前。 Azure Functions Runtime 中似乎存在一个错误，我不知道这是错误还是预期错误。

Answer 1

我们还可以在Azure函数应用程序中捕获异常。在您的情况下，您可以捕获异常并返回 http 状态代码 HttpStatusCode.NotFound

 public static HttpResponseMessage Run([HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)]HttpRequestMessage req, TraceWriter log)
        {
            log.Info("C# HTTP trigger function processed a request.");

            try
            {
                //Todo ：Add your own logic
            }
            catch (Exception ex)
            {
                return req.CreateResponse(HttpStatusCode.NotFound);
            }
            return req.CreateResponse(HttpStatusCode.OK);
        }

编辑:

正如您提到的，它发生在调用函数之前，似乎是由Azure函数集成SDK返回的。这也许是设计好的。我们也可以将我们的想法发送给azure function team .

如果我们想控制逻辑，我的解决方法是我们可以删除输入 blob 并自己实现自定义逻辑。我们可以从 Microsoft Azure Storage SDK for Node.js 获取示例代码.