Fixed google ai default endpoint

[ljgago]

Hello!

In the ChatGoogleAI is wrong the default endpoint.

langchain/lib/chat_models/chat_google_ai.ex

Lines 24 to 26 in 48add20

	@default_base_url "https://generativelanguage.googleapis.com"
	@default_api_version "v1beta"
	@default_endpoint "#{@default_base_url}/#{@default_api_version}"

langchain/lib/chat_models/chat_google_ai.ex

Lines 32 to 36 in 48add20

	embedded_schema do
	field :endpoint, :string, default: @default_endpoint
	# The version of the API to use.
	field :version, :string, default: @default_api_version

Then, when the final url is geneated, the version is added again:

langchain/lib/chat_models/chat_google_ai.ex

Lines 338 to 342 in 48add20

	@spec build_url(t()) :: String.t()
	defp build_url(%ChatGoogleAI{endpoint: endpoint, version: version, model: model} = google_ai) do
	"#{endpoint}/#{version}/models/#{model}:#{get_action(google_ai)}?key=#{get_api_key(google_ai)}"
	|> use_sse(google_ai)
	end

This PR only define @default_endpoint with the base url without the api version.

Thanks!

[yeshan333]

I also encountered the same problem and solved it according to this modification.

[brainlid]

Thanks @ljgago! I'm not a Google AI user so I rely on others to help support and understand the issues.

Is this related to #85?

If so, I think the problem is there are two separate Google APIs that use the same structure/format for their messages and communication, but connections are made differently.

[ljgago]

Hi @brainlid!

I checked and Google has two platforms:

• Google AI Gemini API
• Google Cloud Vertex AI Gemini API

Google AI Gemini API is public and can be used for free (with limitations) with any google account. API REST and the base endpoint is https://generativelanguage.googleapis.com

Google Cloud Vertex AI Gemini API is for Google Cloud platform API REST and the endpoint depends from the region, etc and the api may be different.

I think that ChatGoogleAI module is for Google AI Gemini API and the issue here is that the final url adds the version twice and the call fails.

Thanks!

[brainlid]

Thanks @ljgago for digging into that. What is needed to work well for both systems? Is it just a URL change? Or is there more?

[ljgago]

Here some comparatives:

Google AI Gemini API

• Auth: api key in url
• Generate Content
• Response

Google Cloud Vertex AI Gemini API

• Auth: via Bearer token
• Generate Content
• Response

The two are very similar with the request model and response model, the main difference is with the url and the auth method.

[raulchedrese]

@brainlid, @ljgago I had a bunch of trouble getting the existing ChatGoogleAI to work with Vertex AI. There are subtle differences in the request formats. For example Vertex seems to have stricter validation on which properties are included in the request and what their values are. I ended up writing a separate module that is working quite well for Gemini through Vertex AI.

I'm happy to contribute some of that code if you think it's helpful but thus far I'm not convinced it is feasible to have a single module handle both APIs.

[brainlid]

I had a bunch of trouble getting the existing ChatGoogleAI to work with Vertex AI. There are subtle differences in the request formats. For example Vertex seems to have stricter validation on which properties are included in the request and what their values are.

Leave it to Google to create two competing and incompatible tools to do the same thing. 🙄

From what you say @raulchedrese, it sounds like two separate versions may work out best. Can we base the new one on your implementation?

[raulchedrese]

@brainlid yep. I can clean it up and open a PR if you like or feel free to grab the code yourself. Whatever is easiest.

[brainlid]

@raulchedrese I'd really appreciate it as a PR. Also, if you can write some tests around it that would be fantastic.

[raulchedrese]

@brainlid created a PR here.

[brainlid]

@ljgago @raulchedrese contributed a specific VertextAI chat module to handle both the URL difference and other peculiarities between the two implementations.

#124

The PR has been merged. Would you please try it out and see if it meets your needs as well?

[ljgago]

@ljgago @raulchedrese contributed a specific VertextAI chat module to handle both the URL difference and other peculiarities between the two implementations.

#124

The PR has been merged. Would you please try it out and see if it meets your needs as well?

Hello! I don't have Google Cloud access credentials to try VertexAI, I'm sorry. 😦

[brainlid]

Hello! I don't have Google Cloud access credentials to try VertexAI, I'm sorry. 😦

No worries! My mistake. I thought that what you were asking about.

[brainlid]

The ChatGoogleAI URL issues have been fixed in PR #152 and merged to main.