openai

Genkit OpenAI Sample

This sample demonstrates basic integration with OpenAI models using Genkit Java.

Features Demonstrated

• OpenAI Plugin Setup - Configure Genkit with OpenAI models
• Flow Definitions - Create observable, traceable AI workflows
• Tool Usage - Define and use tools with automatic execution
• Text Generation - Generate text with GPT-4o and GPT-4o-mini
• Streaming - Real-time response streaming
• Vision Models - Process images with vision capabilities
• Image Generation - Generate images with DALL-E

Prerequisites

• Java 21+
• Maven 3.6+
• OpenAI API key

Running the Sample

Option 1: Direct Run

# Set your OpenAI API key
export OPENAI_API_KEY=your-api-key-here

# Navigate to the sample directory
cd java/samples/openai

# Run the sample
./run.sh
# Or: mvn compile exec:java

Option 2: With Genkit Dev UI (Recommended)

# Set your OpenAI API key
export OPENAI_API_KEY=your-api-key-here

# Navigate to the sample directory
cd java/samples/openai

# Run with Genkit CLI
genkit start -- ./run.sh

The Dev UI will be available at http://localhost:4000

Available Flows

Flow	Input	Output	Description
greeting	String (name)	String	Simple greeting flow
tellJoke	String (topic)	String	Generate a joke about a topic
chat	String (message)	String	Chat with GPT-4o
weatherAssistant	String (query)	String	Weather assistant using tools

Example API Calls

Once the server is running on port 8080:

Simple Greeting

curl -X POST http://localhost:8080/greeting \
  -H 'Content-Type: application/json' \
  -d '"World"'

Generate a Joke

curl -X POST http://localhost:8080/tellJoke \
  -H 'Content-Type: application/json' \
  -d '"programming"'

Chat

curl -X POST http://localhost:8080/chat \
  -H 'Content-Type: application/json' \
  -d '"What is the capital of France?"'

Weather Assistant (with Tool)

curl -X POST http://localhost:8080/weatherAssistant \
  -H 'Content-Type: application/json' \
  -d '"What is the weather in Paris?"'

Available Models

The OpenAI plugin provides access to:

Model	Description
openai/gpt-4o	Most capable model, best for complex tasks
openai/gpt-4o-mini	Faster and more cost-effective
openai/gpt-4-turbo	Previous generation GPT-4
openai/gpt-3.5-turbo	Fast and economical
openai/dall-e-3	Image generation
openai/text-embedding-3-small	Text embeddings
openai/text-embedding-3-large	High-dimension text embeddings

Code Highlights

Setting Up Genkit with OpenAI

Genkit genkit = Genkit.builder()
    .options(GenkitOptions.builder()
        .devMode(true)
        .reflectionPort(3100)
        .build())
    .plugin(OpenAIPlugin.create())
    .plugin(new JettyPlugin(JettyPluginOptions.builder()
        .port(8080)
        .build()))
    .build();

Defining a Flow

Flow<String, String, Void> jokeFlow = genkit.defineFlow(
    "tellJoke", String.class, String.class,
    (ctx, topic) -> {
        ModelResponse response = genkit.generate(
            GenerateOptions.builder()
                .model("openai/gpt-4o-mini")
                .prompt("Tell me a short, funny joke about: " + topic)
                .config(GenerationConfig.builder()
                    .temperature(0.9)
                    .maxOutputTokens(200)
                    .build())
                .build());
        return response.getText();
    });

Defining and Using Tools

Tool<Map<String, Object>, Map<String, Object>> weatherTool = genkit.defineTool(
    "getWeather",
    "Gets the current weather for a location",
    Map.of("type", "object", "properties",
        Map.of("location", Map.of("type", "string")),
        "required", new String[]{"location"}),
    (Class<Map<String, Object>>) (Class<?>) Map.class,
    (ctx, input) -> {
        String location = (String) input.get("location");
        return Map.of("location", location, "temperature", "72°F");
    });

// Use tool in generation
ModelResponse response = genkit.generate(
    GenerateOptions.builder()
        .model("openai/gpt-4o")
        .prompt("What's the weather in Paris?")
        .tools(List.of(weatherTool))
        .build());

Development UI

When running with genkit start, access the Dev UI at http://localhost:4000 to:

• Browse all registered flows, tools, and models
• Run flows with test inputs
• View execution traces and logs
• Inspect tool calls and responses

See Also

• Genkit Java README
• OpenAI API Documentation