Allow passing custom HttpClient

[carlos-the-ai]

Motivation and Context

My company network needs more custom set up in HttpClient to make calls, but SK OpenAI code only allows me to pass a hander delegate factory. I cannot use SK without more settings in HttpClient and I want to pass in my own instances anyway so I can manage them from my application.

I think I am not the only one to need this:

• Concerns with Connector Classes: Improper Use of HttpClient and the Risk of Port/Socket Exhaustion #527
• Allow Custom httpClientHandler #133

See https://learn.microsoft.com/en-us/dotnet/fundamentals/networking/http/httpclient-guidelines.

Description

Changes included:

• The OpenAI and AzureOpenAI connectors take optional HttpClient? in the constructor methods instead of IDelegatingHandlerFactory
  • Note first approach was adding two new constructor methods to each type so you could choose. But two constructors could not be there together with optional HttpClient? in one and optional IDelegatingHandlerFactory? in the other because it made calls ambiguous. Then I tried making HttpClient not optional, but that made the parameter order different because in some there are also other optional parameters like openai string? organization = null. So the not optional HttpClient would have to come BEFORE optional openai organization in one constructor, but the optional IDelegatingHandlerFactory comes AFTER optional openai organization in another constructor. In the end it seemed better to just take HttpClient and do the custom client creation in the extension methods. I hope this is okay I know it is a bigger change than I planned.
  • IDelegatingHandlerFactory is not being used as a factory in these Open AI connector classes anyway. They use it one to create an HttpClient instance in the constructor method anyway and never call it again so it's just as easy to pass in the HttpClient you want.
• Updated the extension methods in KernelConfigOpenAIExtensions so that they can optionally pass in a custom HttpClient and ILogger. If null then it uses the same defaults as before.
• There was some mix use of Logger log and ILogger logger in different places so on the parts I changed I set these all to "logger" because it makes it more clear that it is a object and not a "log" method. I can undo if you don't like this.
• Changed "credentials" to "credential" to match this is one TokenCredenial not a credential collection. I can undo if you don't like this.
• Made the default HttpClientHandler static and shared for new HttpClients with disposeHandler: false What's the recommended approach for reusing/disposing new HttpClient handlers? dotnet/runtime#16255
• Updated a sample Program
• I can add more tests if required

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows SK Contribution Guidelines (https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
• The code follows the .NET coding conventions (https://learn.microsoft.com/dotnet/csharp/fundamentals/coding-style/coding-conventions) verified with dotnet format
• All unit tests pass, and I have added new tests where possible
  • Most tests pass but it skips some because I don't have keys for all these model types so I hope your github build will run this and double check.
• I didn't break anyone 😄
  • I changed the constructor method args in the OpenAI code, and the will break your users that are creating these open ai classes using their constructors directly. If the users are using the extension methods (AddAzureOpenAI) then they should not have problems.
  • If you want I can put back all of the constructor methods so they can be created with HttpClient or IDelegatingHandlerFactory but with parameters orders different as explained
  • I don't think those classes need to be aware of IDelegatingHandlerFactory or have it included in the constructor methods, since the extension method or calling code can always convert to HttpClient before calling.

[carlos-the-ai]

@microsoft-github-policy-service agree

[adrianwyatt]

LGTM - waiting for build break fixes.

[lemillermicrosoft]

It might be useful to add a kernel-syntax-examples to demonstrate supplying a custom httpclient.

[shawncal]

IDelegatingHandlerFactory is not being used as a factory in these Open AI connector classes anyway. They use it one to create an HttpClient instance in the constructor method anyway and never call it again so it's just as easy to pass in the HttpClient you want.

Yup, you are right. I think we can actually take this further and remove the IDelegatingHandlerFactory interface altogether. That will take more work and planning. This change is a huge step in the right direction, and we should close on it before doing more.

It might be useful to add a kernel-syntax-examples to demonstrate supplying a custom httpclient.

@lemillermicrosoft I agree with the above. I'll take a note to do that when we finish the change -- if we are able to remove IDelegatingHandlerFactory as noted above, we can likely update "Example08_RetryHandler". There is an example in "KernelBuilder".