Setting "maxConcurrentRequests" on http trigger for python function leads to error

[bas001]

We're using Python 3.9 Azure Functions with http-trigger in a premium plan and maximum burst set to 10.

This is the host.json file { "version": "2.0", "logging": { "applicationInsights": { "samplingSettings": { "isEnabled": true, "excludedTypes": "Request" } } }, "extensionBundle": { "id": "Microsoft.Azure.Functions.ExtensionBundle", "version": "[2.*, 3.0.0)" } }

Adding maxConcurrentRequests like this leads to an error, when receiving requests faster than can be consumed (e.g. total of 50 requests with 10 req / sec): , "extensions": { "http": { "routePrefix": "api", "maxOutstandingRequests": 200, "maxConcurrentRequests": 1, "dynamicThrottlesEnabled": true }

Leads to error before entering the function code: Exception while executing function: Functions.orchestrator Exception binding parameter 'req' Unexpected end of request content.

CallStack: Microsoft.Azure.WebJobs.Host.FunctionInvocationException: at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<ExecuteWithLoggingAsync>d__26.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.34.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.cs:352) at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<TryExecuteAsync>d__18.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.34.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.cs:108) Inner exception System.InvalidOperationException handled at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw: at Microsoft.Azure.WebJobs.Host.Executors.DelayedException.Throw (Microsoft.Azure.WebJobs.Host, Version=3.0.34.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\DelayedException.cs:27) at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+ParameterHelper+<PrepareParametersAsync>d__36.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.34.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.cs:922) at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<ExecuteWithWatchersAsync>d__32.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.34.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.cs:492) at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at Microsoft.Azure.WebJobs.Host.Executors.FunctionExecutor+<ExecuteWithLoggingAsync>d__26.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.34.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Executors\FunctionExecutor.cs:306) Inner exception Microsoft.AspNetCore.Server.Kestrel.Core.BadHttpRequestException handled at Microsoft.Azure.WebJobs.Host.Executors.DelayedException.Throw: at Microsoft.AspNetCore.Server.Kestrel.Core.KestrelBadHttpRequestException.Throw (Microsoft.AspNetCore.Server.Kestrel.Core, Version=6.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60) at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.Http1ContentLengthMessageBody+<ReadAsyncInternal>d__9.MoveNext (Microsoft.AspNetCore.Server.Kestrel.Core, Version=6.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60) at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Threading.Tasks.Sources.ManualResetValueTaskSourceCore1.ThrowForFailedGetResult (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Threading.Tasks.Sources.ManualResetValueTaskSourceCore1.GetResult (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.PoolingAsyncValueTaskMethodBuilder1+StateMachineBox1.System.Threading.Tasks.Sources.IValueTaskSource<TResult>.GetResult (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpRequestStream+<ReadAsyncInternal>d__29.MoveNext (Microsoft.AspNetCore.Server.Kestrel.Core, Version=6.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60) at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at Microsoft.AspNetCore.WebUtilities.FileBufferingReadStream+<ReadAsync>d__40.MoveNext (Microsoft.AspNetCore.WebUtilities, Version=6.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60) at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.IO.StreamReader+<ReadBufferAsync>d__71.MoveNext (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.IO.StreamReader+<ReadToEndAsyncInternal>d__65.MoveNext (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at Microsoft.Azure.WebJobs.Extensions.Http.HttpRequestExtensions+<ReadAsStringAsync>d__4.MoveNext (Microsoft.Azure.WebJobs.Extensions.Http, Version=3.1.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\azure-webjobs-sdk-extensions\src\WebJobs.Extensions.Http\Extensions\HttpRequestExtensions.cs:39) at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at Microsoft.Azure.WebJobs.Extensions.Http.HttpTriggerAttributeBindingProvider+HttpTriggerBinding+<BindAsync>d__10.MoveNext (Microsoft.Azure.WebJobs.Extensions.Http, Version=3.1.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\azure-webjobs-sdk-extensions\src\WebJobs.Extensions.Http\HttpTriggerAttributeBindingProvider.cs:162) at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Private.CoreLib, Version=6.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e) at Microsoft.Azure.WebJobs.Host.Triggers.TriggeredFunctionBinding1+d__8.MoveNext (Microsoft.Azure.WebJobs.Host, Version=3.0.34.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35: C:\projects\azure-webjobs-sdk-rqm4t\src\Microsoft.Azure.WebJobs.Host\Triggers\TriggeredFunctionBinding.cs:57)`

[bas001]

As a workaround the maxOutstandingRequests attribute must match the maxConcurrentRequests

[Ved2806]

Hi @vrdmr could you please help with this issue?

[PeterAndrewGilbert]

Hi @Ved2806 and @vrdmr, I can confirm seeing the same thing, using Python 3.8 runtime in Azure Functions Premium.

Any updates on a fix? Thanks

[blochstrinity]

This is a large issue, and results in a significant loss of productivity.