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/main.py

@@ -0,0 +1,136 @@
+"""
+Geutebruck Cross-Switching API
+FastAPI application entry point
+"""
+from fastapi import FastAPI, Request, status
+from fastapi.middleware.cors import CORSMiddleware
+from fastapi.responses import JSONResponse
+from fastapi.exceptions import RequestValidationError
+import structlog
+import sys
+from pathlib import Path
+
+# Add src/api to Python path for imports
+sys.path.insert(0, str(Path(__file__).parent))
+
+from config import settings
+
+# Configure structured logging
+structlog.configure(
+    processors=[
+        structlog.processors.TimeStamper(fmt="iso"),
+        structlog.stdlib.add_log_level,
+        structlog.processors.JSONRenderer() if settings.LOG_FORMAT == "json" else structlog.dev.ConsoleRenderer()
+    ],
+    wrapper_class=structlog.stdlib.BoundLogger,
+    context_class=dict,
+    logger_factory=structlog.stdlib.LoggerFactory(),
+)
+
+logger = structlog.get_logger()
+
+# Create FastAPI app
+app = FastAPI(
+    title=settings.API_TITLE,
+    version=settings.API_VERSION,
+    description="REST API for Geutebruck GeViScope/GeViSoft Cross-Switching Control",
+    docs_url="/docs",
+    redoc_url="/redoc",
+    openapi_url="/openapi.json"
+)
+
+# CORS middleware
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=settings.CORS_ORIGINS,
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Global exception handlers
+@app.exception_handler(RequestValidationError)
+async def validation_exception_handler(request: Request, exc: RequestValidationError):
+    """Handle validation errors"""
+    logger.warning("validation_error", errors=exc.errors(), body=exc.body)
+    return JSONResponse(
+        status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
+        content={
+            "error": "Validation Error",
+            "detail": exc.errors(),
+        },
+    )
+
+@app.exception_handler(Exception)
+async def global_exception_handler(request: Request, exc: Exception):
+    """Handle unexpected errors"""
+    logger.error("unexpected_error", exc_info=exc)
+    return JSONResponse(
+        status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+        content={
+            "error": "Internal Server Error",
+            "message": "An unexpected error occurred" if settings.ENVIRONMENT == "production" else str(exc),
+        },
+    )
+
+# Startup event
+@app.on_event("startup")
+async def startup_event():
+    """Initialize services on startup"""
+    logger.info("startup",
+                api_title=settings.API_TITLE,
+                version=settings.API_VERSION,
+                environment=settings.ENVIRONMENT)
+
+    # TODO: Initialize database connection pool
+    # TODO: Initialize Redis connection
+    # TODO: Initialize gRPC SDK Bridge client
+
+    logger.info("startup_complete")
+
+# Shutdown event
+@app.on_event("shutdown")
+async def shutdown_event():
+    """Cleanup on shutdown"""
+    logger.info("shutdown")
+
+    # TODO: Close database connections
+    # TODO: Close Redis connections
+    # TODO: Close gRPC connections
+
+# Health check endpoint
+@app.get("/health", tags=["system"])
+async def health_check():
+    """Health check endpoint"""
+    return {
+        "status": "healthy",
+        "version": settings.API_VERSION,
+        "environment": settings.ENVIRONMENT
+    }
+
+# Root endpoint
+@app.get("/", tags=["system"])
+async def root():
+    """API root endpoint"""
+    return {
+        "name": settings.API_TITLE,
+        "version": settings.API_VERSION,
+        "docs": "/docs",
+        "health": "/health"
+    }
+
+# Register routers (TODO: will add as we implement phases)
+# from routers import auth, cameras, monitors, crossswitch
+# app.include_router(auth.router, prefix="/api/v1/auth", tags=["authentication"])
+# app.include_router(cameras.router, prefix="/api/v1/cameras", tags=["cameras"])
+# app.include_router(monitors.router, prefix="/api/v1/monitors", tags=["monitors"])
+# app.include_router(crossswitch.router, prefix="/api/v1", tags=["crossswitch"])
+
+if __name__ == "__main__":
+    import uvicorn
+    uvicorn.run(
+        "main:app",
+        host=settings.API_HOST,
+        port=settings.API_PORT,
+        reload=settings.ENVIRONMENT == "development"
+    )