fix(#338): Don't instantiate OpenAI client with missing API key

- Skip client initialization when OPENAI_API_KEY not configured
- Set openai property to null instead of creating with dummy key
- Methods return gracefully when embeddings not available
- Updated tests to verify client is not instantiated without key

Refs #338

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/api/src/knowledge/services/embedding.service.spec.ts

@@ -1,12 +1,28 @@
-import { describe, it, expect, beforeEach, vi } from "vitest";
+import { describe, it, expect, beforeEach, vi, afterEach } from "vitest";
 import { EmbeddingService } from "./embedding.service";
 import { PrismaService } from "../../prisma/prisma.service";
 
+// Mock OpenAI with a proper class
+const mockEmbeddingsCreate = vi.fn();
+vi.mock("openai", () => {
+  return {
+    default: class MockOpenAI {
+      embeddings = {
+        create: mockEmbeddingsCreate,
+      };
+    },
+  };
+});
+
 describe("EmbeddingService", () => {
   let service: EmbeddingService;
   let prismaService: PrismaService;
+  let originalEnv: string | undefined;
 
   beforeEach(() => {
+    // Store original env
+    originalEnv = process.env.OPENAI_API_KEY;
+
     prismaService = {
       $executeRaw: vi.fn(),
       knowledgeEmbedding: {
@@ -14,36 +30,65 @@ describe("EmbeddingService", () => {
       },
     } as unknown as PrismaService;
 
-    service = new EmbeddingService(prismaService);
+    // Clear mock call history
+    vi.clearAllMocks();
   });
 
+  afterEach(() => {
+    // Restore original env
+    if (originalEnv) {
+      process.env.OPENAI_API_KEY = originalEnv;
+    } else {
+      delete process.env.OPENAI_API_KEY;
+    }
+  });
+
+  describe("constructor", () => {
+    it("should not instantiate OpenAI client when API key is missing", () => {
+      delete process.env.OPENAI_API_KEY;
+
+      service = new EmbeddingService(prismaService);
+
+      // Verify service is not configured (client is null)
+      expect(service.isConfigured()).toBe(false);
+    });
+
+    it("should instantiate OpenAI client when API key is provided", () => {
+      process.env.OPENAI_API_KEY = "test-api-key";
+
+      service = new EmbeddingService(prismaService);
+
+      // Verify service is configured (client is not null)
+      expect(service.isConfigured()).toBe(true);
+    });
+  });
+
+  // Default service setup (without API key) for remaining tests
+  function createServiceWithoutKey(): EmbeddingService {
+    delete process.env.OPENAI_API_KEY;
+    return new EmbeddingService(prismaService);
+  }
+
   describe("isConfigured", () => {
     it("should return false when OPENAI_API_KEY is not set", () => {
-      const originalEnv = process.env["OPENAI_API_KEY"];
-      delete process.env["OPENAI_API_KEY"];
+      service = createServiceWithoutKey();
 
       expect(service.isConfigured()).toBe(false);
-
-      if (originalEnv) {
-        process.env["OPENAI_API_KEY"] = originalEnv;
-      }
     });
 
     it("should return true when OPENAI_API_KEY is set", () => {
-      const originalEnv = process.env["OPENAI_API_KEY"];
-      process.env["OPENAI_API_KEY"] = "test-key";
+      process.env.OPENAI_API_KEY = "test-key";
+      service = new EmbeddingService(prismaService);
 
       expect(service.isConfigured()).toBe(true);
-
-      if (originalEnv) {
-        process.env["OPENAI_API_KEY"] = originalEnv;
-      } else {
-        delete process.env["OPENAI_API_KEY"];
-      }
     });
   });
 
   describe("prepareContentForEmbedding", () => {
+    beforeEach(() => {
+      service = createServiceWithoutKey();
+    });
+
     it("should combine title and content with title weighting", () => {
       const title = "Test Title";
       const content = "Test content goes here";
@@ -68,20 +113,19 @@ describe("EmbeddingService", () => {
 
   describe("generateAndStoreEmbedding", () => {
     it("should skip generation when not configured", async () => {
-      const originalEnv = process.env["OPENAI_API_KEY"];
-      delete process.env["OPENAI_API_KEY"];
+      service = createServiceWithoutKey();
 
       await service.generateAndStoreEmbedding("test-id", "test content");
 
       expect(prismaService.$executeRaw).not.toHaveBeenCalled();
-
-      if (originalEnv) {
-        process.env["OPENAI_API_KEY"] = originalEnv;
-      }
     });
   });
 
   describe("deleteEmbedding", () => {
+    beforeEach(() => {
+      service = createServiceWithoutKey();
+    });
+
     it("should delete embedding for entry", async () => {
       const entryId = "test-entry-id";
 
@@ -95,8 +139,7 @@ describe("EmbeddingService", () => {
 
   describe("batchGenerateEmbeddings", () => {
     it("should return 0 when not configured", async () => {
-      const originalEnv = process.env["OPENAI_API_KEY"];
-      delete process.env["OPENAI_API_KEY"];
+      service = createServiceWithoutKey();
 
       const entries = [
         { id: "1", content: "content 1" },
@@ -106,10 +149,16 @@ describe("EmbeddingService", () => {
       const result = await service.batchGenerateEmbeddings(entries);
 
       expect(result).toBe(0);
+    });
+  });
 
-      if (originalEnv) {
-        process.env["OPENAI_API_KEY"] = originalEnv;
-      }
+  describe("generateEmbedding", () => {
+    it("should throw error when not configured", async () => {
+      service = createServiceWithoutKey();
+
+      await expect(service.generateEmbedding("test text")).rejects.toThrow(
+        "OPENAI_API_KEY not configured"
+      );
     });
   });
 });

apps/api/src/knowledge/services/embedding.service.ts

@@ -20,7 +20,7 @@ export interface EmbeddingOptions {
 @Injectable()
 export class EmbeddingService {
   private readonly logger = new Logger(EmbeddingService.name);
-  private readonly openai: OpenAI;
+  private readonly openai: OpenAI | null;
   private readonly defaultModel = "text-embedding-3-small";
 
   constructor(private readonly prisma: PrismaService) {
@@ -28,18 +28,17 @@ export class EmbeddingService {
 
     if (!apiKey) {
       this.logger.warn("OPENAI_API_KEY not configured - embedding generation will be disabled");
+      this.openai = null;
+    } else {
+      this.openai = new OpenAI({ apiKey });
     }
-
-    this.openai = new OpenAI({
-      apiKey: apiKey ?? "dummy-key", // Provide dummy key to allow instantiation
-    });
   }
 
   /**
    * Check if the service is properly configured
    */
   isConfigured(): boolean {
-    return !!process.env.OPENAI_API_KEY;
+    return this.openai !== null;
   }
 
   /**
@@ -51,7 +50,7 @@ export class EmbeddingService {
    * @throws Error if OpenAI API key is not configured
    */
   async generateEmbedding(text: string, options: EmbeddingOptions = {}): Promise<number[]> {
-    if (!this.isConfigured()) {
+    if (!this.openai) {
       throw new Error("OPENAI_API_KEY not configured");
     }