[azopenai/openai-go] Azure Image Generation fails: URL routing mismatch and model field validation error

### **Bug Report** **Import path of package in question** `github.com/Azure/azure-sdk-for-go/sdk/ai/azopenai` (Issue originates in the underlying `github.com/openai/openai-go/v3/azure` middleware) **SDK version** `github.com/openai/openai-go/v3 v3.30.0` / `azopenai` latest (0.8.0) **Go version** `go version go1.25.0 linux/amd64` **What happened?** When attempting to use the Go SDK for Azure OpenAI Image Generation (DALL-E 3 / GPT-Image-1.5), the request fails in two specific ways depending on configuration: 1. **404 Not Found (DeploymentNotFound):** If the client is initialized normally, the SDK hits `POST /images/generations`. Azure requires deployment-scoped routing: `/openai/deployments/<deployment-name>/images/generations`. 2. **400 Bad Request:** If we attempt to fix the routing by setting `ImageGenerateParams.Model` to the **Azure Deployment Name**, the Azure middleware correctly rewrites the URL path, but the SDK also sends the deployment name in the JSON body's `"model"` field. Azure rejects this because it expects a canonical model name (e.g., `gpt-image-1.5`) in the body, or no model field at all, resulting in: `"Model not supported with Responses API. Supported models are: ['gpt-image-1', 'gpt-image-1-mini', 'gpt-image-1.5']"` **What did you expect or want to happen?** The SDK should allow for Azure-compliant image generation requests where: * The deployment name is used for URL path construction. * The JSON body either omits the `model` field or allows it to remain a canonical name (like `gpt-image-1.5`) while the URL path uses the deployment identifier. **How can we reproduce it?** 1. Initialize the client using Azure configuration: ```go client := openai.NewClient( azure.WithEndpoint("https://<resource>.openai.azure.com/", "deployment-name"), azure.WithAPIKey("apiKey"), ) ``` 2. Call `client.Images.Generate()` with `Model` set to the deployment name. 3. Observe the 400 error from Azure due to the `model` field in the JSON payload. 4. Call `client.Images.Generate()` with `Model` set to `gpt-image-1.5`. 5. Observe the 404 error because the middleware fails to inject the deployment name into the path. **Technical References (Internal Bottlenecks):** The issue stems from `ImageService.Generate` hardcoding the path and the way `requestconfig` executes: * **Hardcoded Path:** The path is fixed to `images/generations`, which doesn't account for Azure's deployment prefix requirements: ```go // vendor/github.com/openai/openai-go/v3/image.go:82 func (r *ImageService) Generate(...) { path := "images/generations" err = requestconfig.ExecuteNewRequest(ctx, http.MethodPost, path, body, &res, opts...) } ``` * **Model Field Conflict:** The `model` field is strictly validated against canonical names, making it unusable as a "deployment name" carrier for routing without triggering a 400 error: ```go // vendor/github.com/openai/openai-go/v3/image.go:1189 // The model to use for image generation. One of `dall-e-2`, `dall-e-3`, or a GPT // image model (`gpt-image-1`, `gpt-image-1-mini`, `gpt-image-1.5`). Model ImageModel `json:"model,omitzero"` ``` * **Execution Order:** `BaseURL` is parsed before middleware application, meaning the path rewrite happens late in the stack and is dependent on the body content: ```go // vendor/github.com/openai/openai-go/v3/internal/requestconfig/requestconfig.go:387 cfg.Request.URL, err = cfg.BaseURL.Parse(strings.TrimLeft(cfg.Request.URL.String(), "/")) // ... middleware applied after URL parsing ``` ### **Reference to Official Confirmation** **Microsoft Q&A Validation** This issue was discussed and confirmed by Microsoft External Staff (Moderator) 'https://learn.microsoft.com/en-us/users/karnamvenkatarajeswari/' in the official Microsoft Q&A forum. The moderator acknowledged that the Go SDK currently lacks the abstraction to align with Azure's deployment-based routing for image generation and suggested that the current behavior is a known limitation of the SDK layer. * **Discussion Link:** [https://learn.microsoft.com/en-us/answers/questions/5847418/i-cannot-perform-image-generation-with-model-gpt-i?comment=question&translated=false#newest-question-comment](url) * **Key Confirmation:** > *"Your understanding is correct... At present, there is no Microsoft-published Azure Go SDK example or abstraction that aligns with this REST pattern for image generation... The limitation is at the SDK layer."* — **Karnam Venkata Rajeswari, Microsoft Moderator** **Anything we should know about your environment.** This was tested against Azure OpenAI in `eastus2` using `api-version=2024-12-01-preview`. Direct REST/Curl calls using the deployment-scoped URL and a minimal body (no `model` field) work perfectly, confirming the issue is isolated to the SDK's request construction.