Implement asynchronous database initialization: add init_db function to create collections and indexes in MongoDB, update get_db to support async, and modify main.py to await database initialization during startup.

app/db.py

@@ -6,6 +6,7 @@ from motor.motor_asyncio import AsyncIOMotorClient
 from pymongo.errors import ConnectionFailure
 from dotenv import load_dotenv
 import certifi
+from datetime import datetime
 
 # Load environment variables
 load_dotenv()
@@ -20,6 +21,47 @@ DB_NAME = os.getenv("DB_NAME", "tts_api")
 # MongoDB client instance
 client: Optional[AsyncIOMotorClient] = None
 
+async def init_db():
+    """Initialize the database with required collections and indexes."""
+    try:
+        # Get database instance
+        db = await get_db()
+        
+        # Create collections if they don't exist
+        collections = await db.list_collection_names()
+        
+        # Audiobooks collection
+        if AUDIOBOOKS_COLLECTION not in collections:
+            logger.info(f"Creating collection: {AUDIOBOOKS_COLLECTION}")
+            await db.create_collection(AUDIOBOOKS_COLLECTION)
+            # Create indexes
+            await db[AUDIOBOOKS_COLLECTION].create_index("id", unique=True)
+            await db[AUDIOBOOKS_COLLECTION].create_index("created_at")
+            await db[AUDIOBOOKS_COLLECTION].create_index("status")
+        
+        # Voices collection
+        if VOICES_COLLECTION not in collections:
+            logger.info(f"Creating collection: {VOICES_COLLECTION}")
+            await db.create_collection(VOICES_COLLECTION)
+            # Create indexes
+            await db[VOICES_COLLECTION].create_index("id", unique=True)
+            await db[VOICES_COLLECTION].create_index("name")
+            await db[VOICES_COLLECTION].create_index("type")
+        
+        # Audio cache collection
+        if AUDIO_CACHE_COLLECTION not in collections:
+            logger.info(f"Creating collection: {AUDIO_CACHE_COLLECTION}")
+            await db.create_collection(AUDIO_CACHE_COLLECTION)
+            # Create indexes
+            await db[AUDIO_CACHE_COLLECTION].create_index("hash", unique=True)
+            await db[AUDIO_CACHE_COLLECTION].create_index("created_at")
+        
+        logger.info("Database initialization completed successfully")
+        
+    except Exception as e:
+        logger.error(f"Error initializing database: {str(e)}")
+        raise
+
 async def connect_to_mongo():
     """Connect to MongoDB."""
     global client
@@ -46,10 +88,11 @@ async def close_mongo_connection():
         client.close()
         logger.info("MongoDB connection closed")
 
-def get_db():
+async def get_db():
     """Get database instance."""
+    global client
     if not client:
-        raise ConnectionError("MongoDB client not initialized")
+        await connect_to_mongo()
     return client[DB_NAME]
 
 # Collection names

app/main.py

@@ -57,7 +57,7 @@ async def lifespan(app: FastAPI):
     # Initialize database
     from app.db import init_db
     logger.info("Initializing database...")
-    init_db()
+    await init_db()
     logger.info("Database initialized")
     
     # Create necessary directories - use persistent locations