Phase 3 (Part 1): API Infrastructure - FastAPI, Database, Redis, gRPC Client

Completed Tasks (T027-T032):
- ✅ FastAPI application with structured logging, CORS, global error handlers
- ✅ Pydantic Settings for environment configuration
- ✅ SQLAlchemy async engine with session management
- ✅ Alembic migration environment setup
- ✅ Redis async client with connection pooling
- ✅ gRPC SDK Bridge client (placeholder - awaiting protobuf generation)

Next: JWT utilities, middleware, database models

🤖 Generated with Claude Code

src/api/models/__init__.py

@@ -0,0 +1,69 @@
+"""
+SQLAlchemy database setup with async support
+"""
+from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession, async_sessionmaker
+from sqlalchemy.orm import DeclarativeBase
+from config import settings
+import structlog
+
+logger = structlog.get_logger()
+
+# Create async engine
+engine = create_async_engine(
+    settings.DATABASE_URL,
+    echo=settings.ENVIRONMENT == "development",
+    pool_size=settings.DATABASE_POOL_SIZE,
+    max_overflow=settings.DATABASE_MAX_OVERFLOW,
+    pool_pre_ping=True,  # Verify connections before using
+)
+
+# Create async session factory
+AsyncSessionLocal = async_sessionmaker(
+    engine,
+    class_=AsyncSession,
+    expire_on_commit=False,
+)
+
+# Base class for models
+class Base(DeclarativeBase):
+    """Base class for all database models"""
+    pass
+
+# Dependency for FastAPI routes
+async def get_db() -> AsyncSession:
+    """
+    Dependency that provides database session to FastAPI routes
+    Usage: db: AsyncSession = Depends(get_db)
+    """
+    async with AsyncSessionLocal() as session:
+        try:
+            yield session
+            await session.commit()
+        except Exception:
+            await session.rollback()
+            raise
+        finally:
+            await session.close()
+
+# Database initialization
+async def init_db():
+    """Initialize database connection (call on startup)"""
+    try:
+        logger.info("database_init", url=settings.DATABASE_URL.split("@")[-1])  # Hide credentials
+        async with engine.begin() as conn:
+            # Test connection
+            await conn.run_sync(lambda _: None)
+        logger.info("database_connected")
+    except Exception as e:
+        logger.error("database_connection_failed", error=str(e))
+        raise
+
+async def close_db():
+    """Close database connections (call on shutdown)"""
+    try:
+        logger.info("database_closing")
+        await engine.dispose()
+        logger.info("database_closed")
+    except Exception as e:
+        logger.error("database_close_failed", error=str(e))
+        raise