add rate limiter

rate_limiter.py

@@ -0,0 +1,57 @@
+# rate_limiter.py
+import time
+from datetime import datetime, timedelta
+from typing import Optional
+import logging
+
+logger = logging.getLogger(__name__)
+
+class RateLimiter:
+    """A rate limiter that enforces a maximum number of requests per time period."""
+    
+    def __init__(self, max_requests: int, time_window: int):
+        """
+        Initialize the rate limiter.
+        
+        Args:
+            max_requests: Maximum number of requests allowed in the time window
+            time_window: Time window in seconds
+        """
+        self.max_requests = max_requests
+        self.time_window = time_window
+        self.requests = []
+        self.last_cleanup = datetime.now()
+        
+    def _cleanup_old_requests(self) -> None:
+        """Remove requests older than the time window."""
+        now = datetime.now()
+        if (now - self.last_cleanup).total_seconds() > self.time_window:
+            cutoff = now - timedelta(seconds=self.time_window)
+            self.requests = [req for req in self.requests if req > cutoff]
+            self.last_cleanup = now
+            
+    def wait_if_needed(self) -> Optional[float]:
+        """
+        Wait if necessary to respect the rate limit.
+        
+        Returns:
+            Optional[float]: The number of seconds waited, or None if no wait was needed
+        """
+        self._cleanup_old_requests()
+        
+        if len(self.requests) >= self.max_requests:
+            oldest_request = self.requests[0]
+            wait_time = (datetime.now() - oldest_request).total_seconds()
+            if wait_time < self.time_window:
+                sleep_time = self.time_window - wait_time
+                logger.info(f"Rate limit reached. Waiting {sleep_time:.2f} seconds...")
+                time.sleep(sleep_time)
+                return sleep_time
+                
+        self.requests.append(datetime.now())
+        return None
+        
+    def reset(self) -> None:
+        """Reset the rate limiter's request history."""
+        self.requests = []
+        self.last_cleanup = datetime.now()