Add support for Gemini models

[kevinmingtarja]

API References:

• https://ai.google.dev/api/generate-content
• https://github.com/google-gemini/generative-ai-js

Out of scope (for another PR):

• Functions calling
• Code execution

Example usage:

import { JSON } from "json-as";
import { models } from "@hypermode/functions-as";

import {
  GeminiGenerateModel,
  UserTextContent,
  ModelTextContent,
  SystemTextContent,
  GenerationConfig,
  FinishReason
} from "@hypermode/models-as/models/gemini/generate";

// This model name should match the one defined in the hypermode.json manifest file.
const modelName: string = "text-generator";

// This function generates some text based on the instruction and prompt provided.
export function generateText(instruction: string, prompt: string): string {
  // The imported ChatModel interface follows the OpenAI Chat completion model input format.
  const model = models.getModel<GeminiGenerateModel>(modelName);
  const input = model.createInput([
    new UserTextContent("Hello"),
    new ModelTextContent("Great to meet you. What would you like to know?"),
    new UserTextContent(prompt), // equivalent to new UserContent([{ text: prompt }]),
  ]);
  input.systemInstruction = new SystemTextContent(instruction);

  input.generationConfig = <GenerationConfig>{
    stopSequences: ["."],
    maxOutputTokens: 100,
    temperature: 2,
    topK: 40,
    topP: 1.0,
  };

  const output = model.invoke(input);
  const resp = output.candidates[0]
  if (resp.finishReason === FinishReason.SAFETY) {
    return JSON.stringify(resp.safetyRatings)
  }

  return output.candidates[0].content!.parts[0].text.trim();
}

Example hypermode.json

{
  "$schema": "https://manifest.hypermode.com/hypermode.json",
  "models": {
    "text-generator": {
      "sourceModel": "gemini-1.5-flash",
      "host": "gemini",
      "path": "v1beta/models/gemini-1.5-flash:generateContent"
    }
  },
  "hosts": {
    "gemini": {
      "baseUrl": "https://generativelanguage.googleapis.com/",
      "headers": {
        "X-goog-api-key": "{{API_KEY}}"
      }
    }
  }
}

[mattjohnsonpint]

Looks great. Thanks! 🎉