Initial microservices setup from artifacts

gateway/app/middleware/rate_limit.py

@@ -0,0 +1,85 @@
+"""
+Rate limiting middleware for gateway
+"""
+
+import logging
+from fastapi import Request, HTTPException
+from fastapi.responses import JSONResponse
+import redis.asyncio as redis
+from datetime import datetime, timedelta
+import hashlib
+
+from app.core.config import settings
+
+logger = logging.getLogger(__name__)
+
+# Redis client for rate limiting
+redis_client = redis.from_url(settings.REDIS_URL)
+
+async def rate_limit_middleware(request: Request, call_next):
+    """Rate limiting middleware"""
+    
+    # Skip rate limiting for health checks
+    if request.url.path in ["/health", "/metrics"]:
+        return await call_next(request)
+    
+    # Get client identifier (IP address or user ID)
+    client_id = _get_client_id(request)
+    
+    # Check rate limit
+    if await _is_rate_limited(client_id):
+        return JSONResponse(
+            status_code=429,
+            content={
+                "detail": "Rate limit exceeded",
+                "retry_after": settings.RATE_LIMIT_WINDOW
+            }
+        )
+    
+    # Process request
+    response = await call_next(request)
+    
+    # Update rate limit counter
+    await _update_rate_limit(client_id)
+    
+    return response
+
+def _get_client_id(request: Request) -> str:
+    """Get client identifier for rate limiting"""
+    # Use user ID if authenticated, otherwise use IP
+    if hasattr(request.state, 'user') and request.state.user:
+        return f"user:{request.state.user.get('user_id', 'unknown')}"
+    else:
+        # Hash IP address for privacy
+        ip = request.client.host
+        return f"ip:{hashlib.md5(ip.encode()).hexdigest()}"
+
+async def _is_rate_limited(client_id: str) -> bool:
+    """Check if client is rate limited"""
+    try:
+        key = f"rate_limit:{client_id}"
+        current_count = await redis_client.get(key)
+        
+        if current_count is None:
+            return False
+        
+        return int(current_count) >= settings.RATE_LIMIT_REQUESTS
+        
+    except Exception as e:
+        logger.error(f"Rate limit check failed: {e}")
+        return False
+
+async def _update_rate_limit(client_id: str):
+    """Update rate limit counter"""
+    try:
+        key = f"rate_limit:{client_id}"
+        
+        # Increment counter
+        current_count = await redis_client.incr(key)
+        
+        # Set TTL on first request
+        if current_count == 1:
+            await redis_client.expire(key, settings.RATE_LIMIT_WINDOW)
+            
+    except Exception as e:
+        logger.error(f"Rate limit update failed: {e}")