Initial commit: WealthWise financial analytics platform

backend/app/main.py

@@ -0,0 +1,130 @@
+"""WealthWise FastAPI application factory.
+
+This module initializes and configures the FastAPI application with:
+- Middleware configuration (CORS, logging, error handling)
+- API router registration
+- Lifecycle event handlers (startup/shutdown)
+- Exception handlers
+"""
+
+import time
+from contextlib import asynccontextmanager
+
+from fastapi import FastAPI, Request, status
+from fastapi.middleware.cors import CORSMiddleware
+from fastapi.middleware.gzip import GZipMiddleware
+from fastapi.responses import JSONResponse
+
+from app.api.v1.api import api_router
+from app.core.config import get_settings
+from app.core.db import check_db_connection, close_engine
+
+settings = get_settings()
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    """Application lifespan context manager.
+    
+    Handles startup and shutdown events:
+    - Startup: Verify database connectivity, initialize caches
+    - Shutdown: Close database connections, cleanup resources
+    
+    Args:
+        app: FastAPI application instance
+        
+    Yields:
+        None: Application runs during this period
+    """
+    # Startup
+    print(f"Starting {settings.PROJECT_NAME} v{settings.VERSION}")
+    
+    # Verify database connectivity on startup
+    db_healthy = await check_db_connection()
+    if not db_healthy:
+        print("WARNING: Database connection failed on startup!")
+    else:
+        print("Database connection established")
+    
+    yield
+    
+    # Shutdown
+    print(f"Shutting down {settings.PROJECT_NAME}")
+    await close_engine()
+    print("Database connections closed")
+
+
+def create_application() -> FastAPI:
+    """Create and configure FastAPI application.
+    
+    Returns:
+        Configured FastAPI application instance
+    """
+    application = FastAPI(
+        title=settings.PROJECT_NAME,
+        description="Production-grade financial analytics platform API",
+        version=settings.VERSION,
+        openapi_url=f"{settings.API_V1_STR}/openapi.json",
+        docs_url=f"{settings.API_V1_STR}/docs",
+        redoc_url=f"{settings.API_V1_STR}/redoc",
+        lifespan=lifespan,
+    )
+    
+    # CORS Middleware
+    # Explicitly allow Authorization header for JWT Bearer tokens
+    application.add_middleware(
+        CORSMiddleware,
+        allow_origins=settings.cors_origins_list,
+        allow_credentials=True,
+        allow_methods=["*"],
+        allow_headers=["*"],  # Includes Authorization header
+        expose_headers=["X-Process-Time"],  # Expose custom headers
+    )
+    
+    # Gzip compression for responses
+    application.add_middleware(GZipMiddleware, minimum_size=1000)
+    
+    # Request timing middleware
+    @application.middleware("http")
+    async def add_process_time_header(request: Request, call_next):
+        """Add X-Process-Time header to all responses."""
+        start_time = time.time()
+        response = await call_next(request)
+        process_time = time.time() - start_time
+        response.headers["X-Process-Time"] = str(process_time)
+        return response
+    
+    # Include API routers
+    application.include_router(
+        api_router,
+        prefix=settings.API_V1_STR,
+    )
+    
+    # Root endpoint
+    @application.get("/")
+    async def root():
+        """Root endpoint - API information."""
+        return {
+            "name": settings.PROJECT_NAME,
+            "version": settings.VERSION,
+            "docs": f"{settings.API_V1_STR}/docs",
+            "health": f"{settings.API_V1_STR}/health",
+        }
+    
+    # Global exception handlers
+    @application.exception_handler(Exception)
+    async def global_exception_handler(request: Request, exc: Exception):
+        """Handle uncaught exceptions."""
+        return JSONResponse(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            content={
+                "error": "Internal server error",
+                "message": str(exc) if settings.DEBUG else "An unexpected error occurred",
+            },
+        )
+    
+    return application
+
+
+# Create the application instance
+app = create_application()