Genkit in Node, Building a Weather Service with AI Integration (English)

28 Feb 2025 in Firebase / Google Cloud Platform (GCP) on Firebase, Gcp

Building a weather service using Genkit in Node.js with AI integration

1. Overview
2. Prerequisites
3. Technical Deep Dive
   1. AI Configuration
   2. Weather Tool Implementation
   3. AI Flow Definition
   4. Express Server Configuration
4. Full Code
5. Setup & Development
6. Dependencies
   1. Core Dependencies
   2. Development Dependencies
7. Project Configuration
8. License
9. Resources
10. Conclusion

Overview

This project demonstrates how to build an AI-enhanced weather service using Genkit, TypeScript, OpenWeatherAPI and Github Models. The application showcases modern Node.js patterns and AI integration techniques.

Prerequisites

Before you begin, ensure you have the following:

1. Node.js installed on your machine.
2. GitHub account and access token for GitHub APIs.
3. An OpenWeatherAPI key for fetching weather data.
4. Genkit CLI installed on your machine.

Technical Deep Dive

AI Configuration

The core AI setup is initialized with Genkit and GitHub plugin integration. In this case we are going to use the OpenAI o3-mini model:

const ai = genkit({
  plugins: [
    github({ githubToken: process.env.GITHUB_TOKEN }),
  ],
  model: openAIO3Mini,
});

Weather Tool Implementation

The application defines a custom weather tool using Zod schema validation:

const getWeather = ai.defineTool(
  {
    name: 'getWeather',
    description: 'Gets the current weather in a given location',
    inputSchema: weatherToolInputSchema,
    outputSchema: z.string(),
  },
  async (input) => {

    const weather = new OpenWeatherAPI({
        key: process.env.OPENWEATHER_API_KEY,
        units: "metric"
    })

    const data = await weather.getCurrent({locationName: input.location});

    return `The current weather in ${input.location} is: ${data.weather.temp.cur} Degrees in Celsius`;
  }
);

AI Flow Definition

The service exposes an AI flow that processes weather requests:

const helloFlow = ai.defineFlow(
  {
    name: 'helloFlow',
    inputSchema: z.object({ location: z.string() }),
    outputSchema: z.string(),
  },
  async (input) => {
    const response = await ai.generate({
      tools: [getWeather],
      prompt: `What's the weather in ${input.location}?`
    });
    return response.text;
  }
);

Express Server Configuration

The application uses the Genkit Express plugin to create an API server:

const app = express({
  flows: [helloFlow],
});

Full Code

The full code for the weather service is as follows:

/* eslint-disable  @typescript-eslint/no-explicit-any */

import { genkit, z } from 'genkit';
import { startFlowServer } from '@genkit-ai/express';
import { openAIO3Mini, github } from 'genkitx-github';
import {OpenWeatherAPI } from 'openweather-api-node';
import dotenv from 'dotenv';

dotenv.config();

const ai = genkit({
  plugins: [
    github({ githubToken: process.env.GITHUB_TOKEN }),
  ],
  model: openAIO3Mini,
});

const weatherToolInputSchema = z.object({ 
  location: z.string().describe('The location to get the current weather for')
});

const getWeather = ai.defineTool(
  {
    name: 'getWeather',
    description: 'Gets the current weather in a given location',
    inputSchema: weatherToolInputSchema,
    outputSchema: z.string(),
  },
  async (input) => {

    const weather = new OpenWeatherAPI({
        key: process.env.OPENWEATHER_API_KEY,
        units: "metric"
    })

    const data = await weather.getCurrent({locationName: input.location});

    return `The current weather in ${input.location} is: ${data.weather.temp.cur} Degrees in Celsius`;
  }
);

const helloFlow = ai.defineFlow(
  {
    name: 'helloFlow',
    inputSchema: z.object({ location: z.string() }),
    outputSchema: z.string(),
  },
  async (input) => {

    const response  = await ai.generate({
      tools: [getWeather],
      prompt: `What's the weather in ${input.location}?`
    });

    return response.text;
  }
);

startFlowServer({
  flows: [helloFlow]
});

Setup & Development

1. Install dependencies:

   npm install
   

2. Configure environment variables:

   GITHUB_TOKEN=your_token
   OPENWEATHER_API_KEY=your_key
   

3. Start development server:

   npm run genkit:start
   

4. To run the project in debug mode and set breakpoints, you can run:

   npm run genkit:start:debug
   

   And then launch the debugger in your IDE. See the .vscode/launch.json file for the configuration.

5. If you want to build the project, you can run:

   npm run build
   

6. Run the project in production mode:

   npm run start:production
   

Dependencies

Core Dependencies

• genkit: ^1.0.5
• @genkit-ai/express: ^1.0.5
• openweather-api-node: ^3.1.5
• genkitx-github: ^1.13.1
• dotenv: ^16.4.7

Development Dependencies

• tsx: ^4.19.2
• typescript: ^5.7.2

Project Configuration

• Uses ES Modules ("type": "module")
• TypeScript with NodeNext module resolution
• Output directory: lib
• Full TypeScript support with type definitions

License

Apache 2.0

Resources

• Firebase Genkit
• GitHub Models
• Firebase Express Plugin

Conclusion

This project demonstrates how to build a weather service using Genkit in Node.js with AI integration. The application showcases modern Node.js patterns and AI integration techniques.

You can find the full code of this example in the GitHub repository

Happy coding!