variant.go

Overview

variant.go defines constants and a utility function to determine which Google Large Language Model (LLM) variant should be used by the application. It distinguishes between two Google LLM variants:

• Vertex AI: Uses credentials from Google Vertex AI.

• Gemini API: Uses an API key from Google AI Studio.

The file's primary responsibility is to read environment configuration and select the appropriate LLM variant string accordingly. This selection guides downstream components on how to interact with the Google LLM backend, influencing authentication and API usage.

Constants

const (
	GoogleLLMVariantVertexAI = "VERTEX_AI"
	GoogleLLMVariantGeminiAPI = "GEMINI_API"
)

• GoogleLLMVariantVertexAI
  A string constant representing the usage of Google Vertex AI credentials for accessing Google's language models.

• GoogleLLMVariantGeminiAPI
  A string constant representing the usage of API key authentication via Google AI Studio's Gemini API.

These constants act as identifiers for variant selection and are returned by the core function GetGoogleLLMVariant().

Functions

GetGoogleLLMVariant

func GetGoogleLLMVariant() string

• Purpose: Determines which Google LLM variant to use based on the environment variable GOOGLE_GENAI_USE_VERTEXAI.

• Parameters: None.

• Returns:
  A string value, either GoogleLLMVariantVertexAI or GoogleLLMVariantGeminiAPI.

Detailed Behavior

1. It reads the environment variable GOOGLE_GENAI_USE_VERTEXAI using os.LookupEnv.

2. It checks if the environment variable's value is either "1" or "true" (case sensitive).

3. If the value matches, it returns GoogleLLMVariantVertexAI.

4. Otherwise, it returns GoogleLLMVariantGeminiAPI.

Usage Example

variant := GetGoogleLLMVariant()
if variant == GoogleLLMVariantVertexAI {
    // Initialize client with Vertex AI credentials
} else if variant == GoogleLLMVariantGeminiAPI {
    // Initialize client with API key for Gemini API
}

This function is a simple utility used during initialization or configuration phases to decide which authentication and API interaction method to employ for Google LLM access.

Implementation Details

• Uses os.LookupEnv to fetch environment variables safely without causing runtime errors if undefined.

• Uses slices.Contains from the Go standard library (slices package) to check membership within a string slice.

• The environment variable check is explicit for the values "1" and "true", reflecting common boolean environment flag conventions.

Interaction with Other System Components

• This file is part of the googlellm package, which likely contains code for interacting with Google LLM services.

• The selected variant string returned by GetGoogleLLMVariant() controls which authentication mechanism and API endpoint the client components will use.

• Downstream components responsible for LLM calls will query this function to configure themselves appropriately.

• It integrates with environment-based configuration management, allowing runtime flexibility without code changes.

• This utility supports LLM Integration and Agents, as it helps configure the underlying LLM backend.

Diagram: Structure and Function Flow of variant.go

flowchart TD
A[Start] --> B[Read env GOOGLE_GENAI_USE_VERTEXAI]
B --> C{Is value "1" or "true"?}
C -->|Yes| D[Return "VERTEX_AI"]
C -->|No| E[Return "GEMINI_API"]

• The flowchart shows the decision path within GetGoogleLLMVariant.

• The environment variable determines which variant string is returned.

References

• For environment variable usage patterns and configuration management, refer to Agent Invocation Context.

• For LLM authentication and usage patterns, see LLM Integration and Agents.

• For how this variant selection affects agent configuration, see LLM Agent Configuration.