Added some more tests + formatted code

rate_limiters/fixed_window.py

@@ -39,6 +39,7 @@ def make_requests(number: int, limiter: FixedWindowLimiter) -> None:
             print("Request limit reached!")
             sleep(0.5)
 
+
 # lim_1 = FixedWindowLimiter(window_duration=10, window_size=10)
 
 # make_requests(100, lim_1)

rate_limiters/leaky_bucket.py

@@ -15,19 +15,16 @@ class LeakyBucketLimiter:
         self.metrics = {
             "processed_count": 0,
             "total_dwell_time": 0.0,  # Total time tasks waited in queue
-            "dropped_tasks": 0
+            "dropped_tasks": 0,
         }
 
-
     def _calculate_delay(self):
         self.delay = 1.0 / self.rate
 
-
     @property
     def queue_depth(self) -> int:
         return self._queue.qsize()
 
-    
     async def start(self):
         if not self._running:
             self._running = True
@@ -35,14 +32,12 @@ class LeakyBucketLimiter:
             self._monitor_task = asyncio.create_task(self._monitor())
             print("Limiter started!")
 
-
     async def stop(self):
         self._running = False
         if self._worker_task:
             await self._worker_task
             print("Limiter stopped!")
 
-    
     async def set_rate(self, new_rate: float):
         if new_rate <= 0:
             raise ValueError("Rate must be a positive number!")
@@ -51,12 +46,14 @@ class LeakyBucketLimiter:
         self.rate = new_rate
         self._calculate_delay()
 
-
     async def _monitor(self):
         while self._running:
             await asyncio.sleep(2)
-            avg_dwell = (self.metrics["total_dwell_time"] / self.metrics["processed_count"] 
+            avg_dwell = (
-                         if self.metrics["processed_count"] > 0 else 0)
+                self.metrics["total_dwell_time"] / self.metrics["processed_count"]
+                if self.metrics["processed_count"] > 0
+                else 0
+            )
 
             print("\n--- [METRICS REPORT] ---")
             print(f"  Queue Depth: {self.queue_depth} tasks")
@@ -65,7 +62,6 @@ class LeakyBucketLimiter:
             print(f"  Drops:       {self.metrics['dropped_tasks']}")
             print("-------------------------\n")
 
-
     async def _worker(self):
         while self._running or not self._queue.empty():
             try:
@@ -132,7 +128,6 @@ async def make_requests(number: int, limiter_rate: float, limiter_max_queue_size
 
     end_time = time()
 
-
     success = 0
     failures = 0
 
@@ -149,7 +144,9 @@ async def make_requests(number: int, limiter_rate: float, limiter_max_queue_size
         f"Total execution time: {execution_time:.2f}\nEffective rate: {effective_rate:.2f}"
     )
 
-    print(f"Operation complete with {success} successful requests and {failures} failures.")
+    print(
+        f"Operation complete with {success} successful requests and {failures} failures."
+    )
 
     await limiter.stop()
 

rate_limiters/lint_and_format.sh

@@ -0,0 +1,4 @@
+#!/bin/bash
+
+ruff format .
+ruff check --select I --fix .

rate_limiters/middleware_starlette.py

@@ -2,13 +2,15 @@ from typing import Optional
 
 from cachetools import TTLCache
 from starlette.applications import Starlette
+from starlette.datastructures import Headers
+from starlette.middleware import Middleware
 from starlette.requests import Request
 from starlette.responses import Response
 from starlette.routing import Route
-from starlette.middleware import Middleware
 
 from token_bucket import AsyncTokenBucketLimiter, RateLimitExceeded
 
+
 class RateLimiterMiddleware:
     def __init__(self, app):
         self.app = app
@@ -18,13 +20,21 @@ class RateLimiterMiddleware:
         if scope["type"] != "http":
             await self.app(scope, receive, send)
 
+        # Check for "X-Forwarded-For" header - as passed by reverse proxies.
+        # Need it for testing
+
+        headers = Headers(raw=scope["headers"])
+
+        if (client_ip := headers.get("X-Forwarded-For")) is None:
             client_data = scope["client"]
             client_ip = client_data[0] if client_data else "UNKNOWN"
 
         limiter: Optional[AsyncTokenBucketLimiter] = self.clients.get(client_ip)
 
         if not limiter:
-            limiter = self.clients.setdefault(client_ip, AsyncTokenBucketLimiter(10, 10))
+            limiter = self.clients.setdefault(
+                client_ip, AsyncTokenBucketLimiter(10, 10)
+            )
 
         try:
             async with limiter:
@@ -34,7 +44,7 @@ class RateLimiterMiddleware:
             response = Response(
                 content=f"Rate limit exceeded! Retry after: {retry_after}",
                 headers={"Retry-After": retry_after},
-                status_code=429
+                status_code=429,
             )
             return await response(scope, receive, send)
 

rate_limiters/pyproject.toml

@@ -12,3 +12,6 @@ dependencies = [
     "starlette>=1.0.0",
     "uvicorn>=0.46.0",
 ]
+
+[tool.isort]
+profile = "ruff"

rate_limiters/tests/test_fixed_window.py

@@ -2,6 +2,7 @@ import pytest
 
 from fixed_window import FixedWindowLimiter
 
+
 def test_limit_respected():
     limiter = FixedWindowLimiter(10, 10)
     try:
@@ -11,6 +12,7 @@ def test_limit_respected():
     except RuntimeError as e:
         assert False, f"Limiter raised an exception -> {e}"
 
+
 def test_limit_enforced():
     limiter = FixedWindowLimiter(10, 10)
     with pytest.raises(RuntimeError) as e:

rate_limiters/tests/test_leaky_bucket.py

@@ -5,12 +5,12 @@ import pytest
 
 from leaky_bucket import LeakyBucketLimiter
 
+
 @pytest.mark.asyncio
 async def test_duration() -> None:
     async def test_function():
         pass
 
-
     limiter = LeakyBucketLimiter(10, 100)
     await limiter.start()
 

rate_limiters/tests/test_middleware_starlette.py

@@ -1,10 +1,15 @@
 from time import sleep
 
+from cachetools import TTLCache
+from starlette.applications import Starlette
 from starlette.testclient import TestClient
 
-from middleware_starlette import app
+from middleware_starlette import RateLimiterMiddleware, create_app, routes
+
 
 def test_app_runs():
+    app = create_app()
+
     client = TestClient(app)
 
     response = client.get("/")
@@ -14,6 +19,8 @@ def test_app_runs():
 
 
 def test_below_rate_limit():
+    app = create_app()
+
     client = TestClient(app)
 
     # Limit is 10/s
@@ -26,6 +33,8 @@ def test_below_rate_limit():
 
 
 def test_above_rate_limit():
+    app = create_app()
+
     client = TestClient(app)
 
     successful = 0
@@ -46,3 +55,96 @@ def test_above_rate_limit():
     assert successful != 0
     assert rate_limited != 0
 
+
+def find_middleware(stack, middleware_cls):
+    current = stack
+
+    while hasattr(current, "app"):
+        if isinstance(current, middleware_cls):
+            return current
+        current = current.app
+
+    return None
+
+
+def test_rate_limiter_cache():
+    app = create_app()
+
+    client = TestClient(app)
+
+    client.get("/")
+
+    middleware = find_middleware(
+        app.middleware_stack,
+        RateLimiterMiddleware,
+    )
+
+    assert middleware is not None
+
+    assert "testclient" in middleware.clients
+    assert len(middleware.clients) == 1
+
+
+def test_cache_ttl():
+    # Setup app with a short TTL
+    class ShortTTLLimiterMiddleware(RateLimiterMiddleware):
+        def __init__(self, app):
+            super().__init__(app)
+            self.clients = TTLCache(maxsize=10, ttl=2)  # Clear after 2 seconds
+
+    app = Starlette(routes=routes)
+    app.add_middleware(ShortTTLLimiterMiddleware)
+
+    client = TestClient(app)
+
+    client.get("/")
+
+    middleware = find_middleware(
+        app.middleware_stack,
+        RateLimiterMiddleware,
+    )
+
+    assert middleware is not None
+
+    client.get("/", headers={"X-Forwarded-For": "1.1.1.1"})
+
+    assert middleware.clients.get("1.1.1.1") is not None
+
+    sleep(2)
+
+    assert middleware.clients.get("1.1.1.1") is None
+
+
+def test_cache_eviction():
+    # Setup app with a tiny cache for testing
+    class TinyLimiterMiddleware(RateLimiterMiddleware):
+        def __init__(self, app):
+            super().__init__(app)
+            self.clients = TTLCache(maxsize=2, ttl=10)  # Only space for 2 IPs
+
+    app = Starlette(routes=routes)
+    app.add_middleware(TinyLimiterMiddleware)
+
+    client = TestClient(app)
+
+    client.get("/")
+
+    middleware = find_middleware(
+        app.middleware_stack,
+        RateLimiterMiddleware,
+    )
+
+    assert middleware is not None
+
+    client.get("/", headers={"X-Forwarded-For": "1.1.1.1"})
+    client.get("/", headers={"X-Forwarded-For": "2.2.2.2"})
+
+    assert middleware.clients.get("1.1.1.1") is not None
+    assert middleware.clients.get("2.2.2.2") is not None
+    assert middleware.clients.get("3.3.3.3") is None
+
+    client.get("/", headers={"X-Forwarded-For": "3.3.3.3"})
+
+    assert middleware.clients.get("1.1.1.1") is None
+    assert middleware.clients.get("2.2.2.2") is not None
+    assert middleware.clients.get("3.3.3.3") is not None

rate_limiters/tests/test_token_bucket.py

@@ -1,6 +1,9 @@
-import pytest
 from time import sleep
-from token_bucket import TokenBucketLimiter, RateLimitExceeded
+
+import pytest
+
+from token_bucket import RateLimitExceeded, TokenBucketLimiter
+
 
 def test_limit_respected() -> None:
     limiter = TokenBucketLimiter(10, 10)
@@ -22,4 +25,3 @@ def test_limit_exceeded() -> None:
                 continue
 
     assert "Rate exceeded" in str(e.value)
-

rate_limiters/token_bucket.py

@@ -1,6 +1,6 @@
+import asyncio
 import threading
 from time import sleep, time
-import asyncio
 
 
 class RateLimiterException(Exception):
@@ -42,6 +42,7 @@ class TokenBucketLimiter:
     def __exit__(self, exc_type, exc_value, exc_traceback) -> bool:
         return False
 
+
 class AsyncTokenBucketLimiter:
     def __init__(self, capacity: int, refill_rate: int):
         self.capacity = float(capacity)