feat(go): add OpenAI plugin

go/README.md

@@ -499,6 +499,7 @@ Genkit provides a unified interface across all major AI providers. Use whichever
 | **Google AI** | `googlegenai.GoogleAI` | Gemini 2.5 Flash, Gemini 2.5 Pro, and more |
 | **Vertex AI** | `vertexai.VertexAI` | Gemini models via Google Cloud |
 | **Anthropic** | `anthropic.Anthropic` | Claude 3.5, Claude 3 Opus, and more |
+| **OpenAI** | `openai.OpenAI` | GPT-5, GPT-5-mini, GPT-5-nano, GPT-4o and more |
 | **Ollama** | `ollama.Ollama` | Llama, Mistral, and other open models |
 | **OpenAI Compatible** | `compat_oai` | Any OpenAI-compatible API |
 
@@ -509,6 +510,9 @@ g := genkit.Init(ctx, genkit.WithPlugins(&googlegenai.GoogleAI{}))
 // Anthropic
 g := genkit.Init(ctx, genkit.WithPlugins(&anthropic.Anthropic{}))
 
+// OpenAI
+g := genkit.Init(ctx, genkit.WithPlugins(&openai.OpenAI{}))
+
 // Ollama (local models)
 g := genkit.Init(ctx, genkit.WithPlugins(&ollama.Ollama{
     ServerAddress: "http://localhost:11434",

go/go.mod

@@ -28,6 +28,7 @@ require (
 	github.com/jba/slog v0.2.0
 	github.com/lib/pq v1.10.9
 	github.com/mark3labs/mcp-go v0.29.0
+	github.com/openai/openai-go/v3 v3.16.0
 	github.com/pgvector/pgvector-go v0.3.0
 	github.com/weaviate/weaviate v1.30.0
 	github.com/weaviate/weaviate-go-client/v5 v5.1.0

go/go.sum

@@ -308,6 +308,8 @@ github.com/oklog/ulid v1.3.1 h1:EGfNDEx6MqHz8B3uNV6QAib1UR2Lm97sHi3ocA6ESJ4=
 github.com/oklog/ulid v1.3.1/go.mod h1:CirwcVhetQ6Lv90oh/F+FBtV6XMibvdAFo93nm5qn4U=
 github.com/openai/openai-go v1.8.2 h1:UqSkJ1vCOPUpz9Ka5tS0324EJFEuOvMc+lA/EarJWP8=
 github.com/openai/openai-go v1.8.2/go.mod h1:g461MYGXEXBVdV5SaR/5tNzNbSfwTBBefwc+LlDCK0Y=
+github.com/openai/openai-go/v3 v3.16.0 h1:VdqS+GFZgAvEOBcWNyvLVwPlYEIboW5xwiUCcLrVf8c=
+github.com/openai/openai-go/v3 v3.16.0/go.mod h1:cdufnVK14cWcT9qA1rRtrXx4FTRsgbDPW7Ia7SS5cZo=
 github.com/opentracing/opentracing-go v1.2.0 h1:uEJPy/1a5RIPAJ0Ov+OIO8OxWu77jEv+1B0VhjKrZUs=
 github.com/opentracing/opentracing-go v1.2.0/go.mod h1:GxEUsuufX4nBwe+T+Wl9TAgYrxe9dPLANfrWvHYVTgc=
 github.com/pelletier/go-toml v1.7.0/go.mod h1:vwGMzjaWMwyfHwgIBhI2YUM4fB6nL6lVAvS1LBMMhTE=

go/plugins/openai/README.md

@@ -0,0 +1,268 @@
+# OpenAI Plugin for Genkit
+
+The OpenAI plugin for Genkit provides integration with the [OpenAI API](https://platform.openai.com/docs/api-reference), allowing you to use models like GPT-4o, GPT-4 Turbo, and embeddings within your Genkit applications.
+
+> [!NOTE]
+> This plugin uses the modern OpenAI **Responses API**. For applications requiring the legacy **Chat Completions API**, please use the [`compat_oai`](../compat_oai) plugin.
+
+This plugin uses the official [openai-go](https://github.com/openai/openai-go) SDK.
+
+## Setup
+
+First, ensure you have your OpenAI API key set in your environment variables:
+
+```bash
+export OPENAI_API_KEY=your-api-key
+```
+
+Then, initialize the plugin in your Genkit application:
+
+```go
+import (
+ "context"
+ "log"
+
+ "github.com/firebase/genkit/go/genkit"
+ "github.com/firebase/genkit/go/plugins/openai"
+)
+
+func main() {
+ ctx := context.Background()
+
+ // Initialize Genkit with the OpenAI plugin
+ g := genkit.Init(ctx, genkit.WithPlugins(&openai.OpenAI{}))
+
+ // ...
+}
+```
+
+## OpenAI-Compatible Providers
+
+You can use this plugin with other providers that support the OpenAI API by configuring the `BaseURL` and `Provider` fields.
+
+### Groq
+
+```go
+g := genkit.Init(ctx, genkit.WithPlugins(&openai.OpenAI{
+ BaseURL:  "https://api.groq.com/openai/v1",
+ APIKey:   os.Getenv("GROQ_API_KEY"),
+ Provider: "groq",
+}))
+
+model := openai.Model(g, "llama-3.3-70b-versatile")
+```
+
+### Mistral
+
+```go
+g := genkit.Init(ctx, genkit.WithPlugins(&openai.OpenAI{
+ BaseURL:  "https://api.mistral.ai/v1",
+ APIKey:   os.Getenv("MISTRAL_API_KEY"),
+ Provider: "mistral",
+}))
+
+model := openai.Model(g, "mistral-large-latest")
+```
+
+### xAI (Grok)
+
+```go
+g := genkit.Init(ctx, genkit.WithPlugins(&openai.OpenAI{
+ BaseURL:  "https://api.x.ai/v1",
+ APIKey:   os.Getenv("XAI_API_KEY"),
+ Provider: "xai",
+}))
+
+model := openai.Model(g, "grok-4-1-fast-reasoning")
+```
+
+### OpenRouter
+
+```go
+g := genkit.Init(ctx, genkit.WithPlugins(&openai.OpenAI{
+ BaseURL:  "https://openrouter.ai/api/v1",
+ APIKey:   os.Getenv("OPENROUTER_API_KEY"),
+ Provider: "openrouter",
+}))
+
+model := openai.Model(g, "deepseek/deepseek-r1")
+```
+
+## Usage
+
+### Generative Models
+
+You can reference OpenAI models using the `openai.Model` helper.
+
+```go
+import (
+ "context"
+ "fmt"
+ "log"
+
+ "github.com/firebase/genkit/go/ai"
+ "github.com/firebase/genkit/go/genkit"
+ "github.com/firebase/genkit/go/plugins/openai"
+)
+
+func main() {
+ ctx := context.Background()
+ g := genkit.Init(ctx, genkit.WithPlugins(&openai.OpenAI{}))
+
+ // Reference a model (e.g., gpt-4o)
+ model := openai.Model(g, "gpt-4o")
+
+ // Generate text
+ resp, err := genkit.GenerateText(ctx, g,
+  ai.WithModel(model),
+  ai.WithPrompt("Tell me a joke about Go programming."),
+ )
+ if err != nil {
+  log.Fatal(err)
+ }
+
+ fmt.Println(resp)
+}
+```
+
+### Model Configuration
+
+Pass configuration options like temperature and max output tokens using `ai.WithConfig`:
+
+```go
+import (
+ "github.com/openai/openai-go/v3"
+ "github.com/openai/openai-go/v3/responses"
+)
+
+// ...
+
+resp, err := genkit.Generate(ctx, g,
+ ai.WithModel(model),
+ ai.WithPrompt("Write a creative story."),
+ ai.WithConfig(&responses.ResponseNewParams{
+  Temperature:     openai.Float(1.2),
+  MaxOutputTokens: openai.Int(500),
+ }),
+)
+```
+
+### Streaming
+
+Stream responses for real-time interactions:
+
+```go
+import (
+ "context"
+ "fmt"
+
+ "github.com/firebase/genkit/go/ai"
+ "github.com/firebase/genkit/go/genkit"
+ "github.com/firebase/genkit/go/plugins/openai"
+)
+
+// ...
+
+model := openai.Model(g, "gpt-4o")
+
+_, err := genkit.Generate(ctx, g,
+ ai.WithModel(model),
+ ai.WithPrompt("Write a long poem about the sea."),
+ ai.WithStreaming(func(ctx context.Context, chunk *ai.ModelResponseChunk) error {
+  fmt.Print(chunk.Text())
+  return nil
+ }),
+)
+```
+
+### Structured Output
+
+Request structured data (JSON) using `WithOutputType`. This leverages OpenAI's structured output capabilities.
+
+```go
+type MovieReview struct {
+ Title  string `json:"title"`
+ Rating int    `json:"rating"`
+ Reason string `json:"reason"`
+}
+
+// ...
+
+model := openai.Model(g, "gpt-4o")
+
+resp, err := genkit.Generate(ctx, g,
+ ai.WithModel(model),
+ ai.WithPrompt("Review the movie 'Inception'"),
+ ai.WithOutputType(MovieReview{}),
+)
+if err != nil {
+ log.Fatal(err)
+}
+
+var review MovieReview
+if err := resp.Output(&review); err != nil {
+ log.Fatal(err)
+}
+
+fmt.Printf("Rating: %d/10\nReason: %s\n", review.Rating, review.Reason)
+```
+
+### Tool Calling
+
+Register tools and provide them to the model.
+
+```go
+// Define a tool
+weatherTool := genkit.DefineTool(g, "weather", "Returns the weather for the given location",
+ func(ctx *ai.ToolContext, input struct {
+  Location string `json:"location"`
+ }) (string, error) {
+  // Call actual weather API here
+  return fmt.Sprintf("The weather in %s is sunny", input.Location), nil
+ },
+)
+
+// Use the tool in generation
+resp, err := genkit.Generate(ctx, g,
+ ai.WithModel(model),
+ ai.WithPrompt("What is the weather in San Francisco?"),
+ ai.WithTools(weatherTool),
+)
+```
+
+### Multimodal Input
+
+Pass images to models that support vision (like `gpt-4o`).
+
+```go
+import "github.com/firebase/genkit/go/ai"
+
+// ...
+
+resp, err := genkit.Generate(ctx, g,
+ ai.WithModel(model),
+ ai.WithMessages(
+  ai.NewUserMessage(
+   ai.NewTextPart("Describe this image"),
+   ai.NewMediaPart("image/jpeg", "data:image/jpeg;base64,iVBORw0KGgo..."),
+  ),
+ ),
+)
+```
+
+### Embeddings
+
+Use OpenAI embedding models for vector search tasks.
+
+```go
+import "github.com/firebase/genkit/go/plugins/openai"
+
+// ...
+
+embedder := openai.Embedder(g, "text-embedding-3-small")
+
+res, err := ai.Embed(ctx, g,
+ ai.WithEmbedder(embedder),
+ ai.WithTextDocs("Genkit is awesome!"),
+)
+```