[Bug Report] Proxy settings are ignored when connecting to IoT Hub over AMQP

[backspacer80]

Context

• OS, version, SKU and CPU architecture used: Windows 10 Desktop x64
• Application's .NET Target Framework : netcoreapp3.1, net6.0
• Device: Laptop
• SDK version used: Microsoft.Azure.Devices.Client 1.39.0

Description of the issue

An application that is located on premises of a customer connects over AMQP to IoT Hub. The customer uses a corporate proxy.
In the application I'm creating a DeviceClient instance and opening a connection to IoT Hub over AMQP.
No matter what I enter for property AmqpTransportSettings.Proxy it seems to be ignored.
Regardless if I enter the correct address of the corporate proxy or a fake address, the SDK behaves the same:
It always manages to connect to the IoT Hub. Is the Proxy property respected at all? See minimal example below.

Code sample exhibiting the issue

// dotnet 6.0
using System.Net;
using Microsoft.Azure.Devices.Client;

RunExample();

void RunExample()
{
    using (DeviceClient deviceClient = CreateDeviceClient())
    {
        try
        {
            deviceClient.OpenAsync().GetAwaiter().GetResult();
        }
        catch (Exception e)
        {
            if (e.Message.Contains("IotHub") && e.Message.Contains("not registered"))
            {
                // We expect an exception because the device ID is made up: If that's the actual error message then we're connected!
                Console.WriteLine("Connected to IoT Hub successfully!");
            }
            else
            {
                Console.WriteLine("Not connected to IoT Hub :-(");
                throw;
            }
        }
    }
}

DeviceClient CreateDeviceClient()
{
    string deviceId = "Y2N0ZXN1";
    string authToken = "Y2N0ZXN2";
    string hostName = "example.azure-devices.net";
    string proxyHost = "10.11.12.13";
    int proxyPort = 3128;
    string? proxyUser = "***";
    string proxyPassword = "***";

    return DeviceClient.Create(
        hostName,
        new DeviceAuthenticationWithRegistrySymmetricKey(deviceId, authToken),
        new ITransportSettings[]
        {
            new AmqpTransportSettings(TransportType.Amqp_Tcp_Only)
            {
                Proxy = new WebProxy(proxyHost, proxyPort)
                {
                    Credentials = new NetworkCredential(proxyUser, proxyPassword)
                }
            }
        });
}

Console log of the issue

Connected to IoT Hub successfully!

[jamdavi]

@backspacer80 It looks like you're using Amqp_Tcp_Only. Proxy support is only for WebSocket connections. Can you try again using Amqp_WebSocket_Only and see it it honors the proxy setting.

https://docs.microsoft.com/en-us/dotnet/api/microsoft.azure.devices.client.transporttype?view=azure-dotnet

[jamdavi]

@backspacer80 Please have a look at the linked PR and let me know if this documentation would have helped when writing the code. Here is what it looks like in Visual Studio.

[backspacer80]

@backspacer80 It looks like you're using Amqp_Tcp_Only. Proxy support is only for WebSocket connections. Can you try again using Amqp_WebSocket_Only and see it it honors the proxy setting.

https://docs.microsoft.com/en-us/dotnet/api/microsoft.azure.devices.client.transporttype?view=azure-dotnet

Yes, I switched to Amqp_WebSocket_Only and it does the job! Thank you.

[backspacer80]

@backspacer80 Please have a look at the linked PR and let me know if this documentation would have helped when writing the code. Here is what it looks like in Visual Studio.

Yes, definitely it would have helped. I'm looking forward to the PR. I consider this one here solved and will close it. Thanks.