Fiddler with dotnet-isolated Az Function - Error starting gRPC call

user_41169 0
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I have a C# dotnet 5 Azure Function in VS2019 configured with "FUNCTIONS_WORKER_RUNTIME": "dotnet-isolated".

If I run the function in the dev environment (ctrl + F5) while Fiddler is running then I get the following error:

Grpc.Core.RpcException: Status(StatusCode="Internal", Detail="Error starting gRPC call. HttpRequestException: Requesting HTTP version 2.0 with version policy RequestVersionOrHigher while HTTP/2 is not enabled.

The function will run fine if Fiddler is not running.

Anyone know how to resolve this?

azure-functions-core-tools azure-functions .net-core fiddler
2 Answers

I've made Fiddler work with an Azure Function project with two additions to the standard setup:

  1. Add 127.0.0.1 to the bypass list
  2. Add tls1.1 and tls1.2 to the supported protocols and skip decryption for 127.0.0.1

Bypass list

HTTPS Decryption options

user_45528190

I am using CharlesProxy and issue is the same. Adding HttpClient.DefaultProxy = new WebProxy(); in Program.cs fixes the problem and function starts. However you won't see the outgoing requests made by the function. That's the idea why I want proxy running, to check all outgoing requests. Maybe someone solve it?

user_67000820
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