[.NET 5 RC1] "HttpRequestException: Address family not supported by protocol (127.0.0.1:9001)" thrown when Lambda invoked

[martincostello]

Description

I have a Lambda function that uses the .NET Core custom runtime via the Amazon.Lambda.RuntimeSupport NuGet package, so with the release of .NET 5.0 RC1 as a "go live" release I updated it to target net5.0 using RC1 to try it out.

The tests passed as expected in CI, however when the Lambda was deployed to the Lambda environment it failed with the exception:

System.Net.Http.HttpRequestException: Address family not supported by protocol (127.0.0.1:9001)

The error comes from the HTTP call made here:

aws-lambda-dotnet/Libraries/src/Amazon.Lambda.RuntimeSupport/Client/InternalClientAdapted.cs

Line 233 in c306036

var response_ = await client_.SendAsync(request_, System.Net.Http.HttpCompletionOption.ResponseHeadersRead, cancellationToken).ConfigureAwait(false);

Reproduction Steps

Clone the Lambda function from martincostello/alexa-london-travel@d5d7618 and deploy to AWS Lambda and invoke the function.

Logs

  | 2020-09-14T23:10:37.855+01:00 | Unhandled exception. System.Net.Http.HttpRequestException: Address family not supported by protocol (127.0.0.1:9001)
  | 2020-09-14T23:10:37.855+01:00 | ---> System.Net.Sockets.SocketException (97): Address family not supported by protocol
  | 2020-09-14T23:10:37.855+01:00 | at System.Net.Sockets.Socket..ctor(AddressFamily addressFamily, SocketType socketType, ProtocolType protocolType)
  | 2020-09-14T23:10:37.855+01:00 | at System.Net.Connections.SocketsConnectionFactory.CreateSocket(AddressFamily addressFamily, SocketType socketType, ProtocolType protocolType, EndPoint endPoint, IConnectionProperties options)
  | 2020-09-14T23:10:37.855+01:00 | at System.Net.Connections.SocketsConnectionFactory.ConnectAsync(EndPoint endPoint, IConnectionProperties options, CancellationToken cancellationToken)
  | 2020-09-14T23:10:37.855+01:00 | at System.Net.Http.ConnectHelper.ConnectAsync(ConnectionFactory factory, DnsEndPoint endPoint, IConnectionProperties options, CancellationToken cancellationToken)
  | 2020-09-14T23:10:37.855+01:00 | --- End of inner exception stack trace ---
  | 2020-09-14T23:10:37.855+01:00 | at System.Net.Http.ConnectHelper.ConnectAsync(ConnectionFactory factory, DnsEndPoint endPoint, IConnectionProperties options, CancellationToken cancellationToken)
  | 2020-09-14T23:10:37.855+01:00 | at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
  | 2020-09-14T23:10:37.855+01:00 | at System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
  | 2020-09-14T23:10:37.855+01:00 | at System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
  | 2020-09-14T23:10:37.855+01:00 | at System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)
  | 2020-09-14T23:10:37.855+01:00 | at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)
  | 2020-09-14T23:10:37.855+01:00 | at System.Net.Http.HttpClient.SendAsyncCore(HttpRequestMessage request, HttpCompletionOption completionOption, Boolean async, Boolean emitTelemetryStartStop, CancellationToken cancellationToken)
  | 2020-09-14T23:10:37.855+01:00 | at Amazon.Lambda.RuntimeSupport.InternalRuntimeApiClient.NextAsync(CancellationToken cancellationToken)
  | 2020-09-14T23:10:37.855+01:00 | at Amazon.Lambda.RuntimeSupport.RuntimeApiClient.GetNextInvocationAsync(CancellationToken cancellationToken)
  | 2020-09-14T23:10:37.855+01:00 | at Amazon.Lambda.RuntimeSupport.LambdaBootstrap.InvokeOnceAsync(CancellationToken cancellationToken)
  | 2020-09-14T23:10:37.855+01:00 | at Amazon.Lambda.RuntimeSupport.LambdaBootstrap.RunAsync(CancellationToken cancellationToken)
  | 2020-09-14T23:10:37.855+01:00 | at MartinCostello.LondonTravel.Skill.FunctionEntrypoint.RunAsync(HttpClient httpClient, CancellationToken cancellationToken) in /_/src/LondonTravel.Skill/FunctionEntrypoint.cs:line 42
  | 2020-09-14T23:10:37.855+01:00 | at MartinCostello.LondonTravel.Skill.FunctionEntrypoint.Main() in /_/src/LondonTravel.Skill/FunctionEntrypoint.cs:line 52
  | 2020-09-14T23:10:37.855+01:00 | at MartinCostello.LondonTravel.Skill.FunctionEntrypoint.<Main>()
  | 2020-09-14T23:10:37.939+01:00 | START RequestId: e9f44aa6-1849-46e8-9fd7-60b2cb95620b Version: $LATEST

While not yet supported by AWS Lambda itself, I thought I'd raise this here in the first instance in case this is an issue that stems from the Lambda runtime. If it is not, then I can open the issue against the dotnet/runtime repo for investigation.

Environment

• Build Version: 1.1.1
• OS Info: AmazonLinux
• Build Environment: dotnet SDK
• Targeted .NET Platform:

Resolution

The Lambda successfully receives requests to process from the Lambda runtime.

---

This is a 🐛 bug-report

[normj]

Interesting that it does work correctly with .NET 5 preview 8 which was what I lasted tested and just confirmed it does still work with preview 8. I get the same error for RC1.

[normj]

I do think this is regression with .NET 5 RC. I have opened an issue on their repository to work with them to get the issue fixed or come up with a work around. dotnet/runtime#42233

[normj]

I confirmed using the nightly builds of .NET 5 RC2 the issue is fixed. So you will either have to use the nightly builds or wait till RC2 is released. Thanks so much for alerting us of the issue.

[martincostello]

Awesome - thanks for the detective work Norm 🕵🏻‍♂️

I think I'll hold out for RC2 for now.

[martincostello]

FYI the fix came about here: dotnet/runtime#41955 (comment)

[martincostello]

FYI I've confirmed the fix myself via updating my Lambda to use 5.0.100-rc.2.20464.14 (martincostello/alexa-london-travel#275).

[ashishdhingra]

Closing based on last comment.

[github-actions]

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