commit 29656c8d158badeb1b2843c9ca55949b4c14f797 Author: V Date: Sat May 9 13:15:44 2026 +0100 looking at rate-limiting implementations diff --git a/rate_limiters/.gitignore b/rate_limiters/.gitignore new file mode 100644 index 0000000..1ec2cdc --- /dev/null +++ b/rate_limiters/.gitignore @@ -0,0 +1,5 @@ +# Python-generated files +__pycache__/ +.venv +.ruff_cache +.pytest_cache \ No newline at end of file diff --git a/rate_limiters/.python-version b/rate_limiters/.python-version new file mode 100644 index 0000000..2c07333 --- /dev/null +++ b/rate_limiters/.python-version @@ -0,0 +1 @@ +3.11 diff --git a/rate_limiters/README.md b/rate_limiters/README.md new file mode 100644 index 0000000..e69de29 diff --git a/rate_limiters/fixed_window.py b/rate_limiters/fixed_window.py new file mode 100644 index 0000000..6b363e0 --- /dev/null +++ b/rate_limiters/fixed_window.py @@ -0,0 +1,44 @@ +import threading +from datetime import datetime, timedelta +from time import sleep + + +class FixedWindowLimiter: + def __init__(self, window_size: int, window_duration: int): + self.window_size = window_size + self.window_duration = window_duration + self.count = 0 + self.last_reset_time = datetime.now() + self._lock = threading.Lock() + + def __enter__(self): + with self._lock: + if datetime.now() - self.last_reset_time > timedelta( + seconds=self.window_duration + ): + self.count = 0 + self.last_reset_time = datetime.now() + if self.count < self.window_size: + self.count += 1 + print("ALLOWED") + return self + else: + raise RuntimeError("Rate exceeded!") + + def __exit__(self, exc_type, exc_value, exc_traceback): + return False + + +def make_requests(number: int, limiter: FixedWindowLimiter) -> None: + for i in range(1, number): + try: + with limiter as lim: + print(f"PRE-BUDGET: {lim.window_size - lim.count}") + print("REQUEST MADE!") + except RuntimeError: + print("Request limit reached!") + sleep(0.5) + +# lim_1 = FixedWindowLimiter(window_duration=10, window_size=10) + +# make_requests(100, lim_1) diff --git a/rate_limiters/main.py b/rate_limiters/main.py new file mode 100644 index 0000000..72d791b --- /dev/null +++ b/rate_limiters/main.py @@ -0,0 +1,6 @@ +def main(): + print("Hello from rate-limiters!") + + +if __name__ == "__main__": + main() diff --git a/rate_limiters/pyproject.toml b/rate_limiters/pyproject.toml new file mode 100644 index 0000000..70ecdfc --- /dev/null +++ b/rate_limiters/pyproject.toml @@ -0,0 +1,9 @@ +[project] +name = "rate-limiters" +version = "0.1.0" +description = "Add your description here" +readme = "README.md" +requires-python = ">=3.11" +dependencies = [ + "pytest>=9.0.3", +] diff --git a/rate_limiters/tests/test_fixed_window.py b/rate_limiters/tests/test_fixed_window.py new file mode 100644 index 0000000..7f60ace --- /dev/null +++ b/rate_limiters/tests/test_fixed_window.py @@ -0,0 +1,20 @@ +import pytest + +from fixed_window import FixedWindowLimiter + +def test_limit_respected(): + limiter = FixedWindowLimiter(10, 10) + try: + for i in range(9): + with limiter: + pass + 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: + for i in range(11): + with limiter: + pass + assert "Rate exceeded" in str(e.value) diff --git a/rate_limiters/tests/test_token_bucket.py b/rate_limiters/tests/test_token_bucket.py new file mode 100644 index 0000000..ba2a68f --- /dev/null +++ b/rate_limiters/tests/test_token_bucket.py @@ -0,0 +1,25 @@ +import pytest +from time import sleep +from token_bucket import TokenBucketLimiter, RateLimitExceeded + +def test_limit_respected() -> None: + limiter = TokenBucketLimiter(10, 10) + + try: + for i in range(30): + with limiter: + sleep(0.1) + except RateLimitExceeded: + assert False, "Rate limit exceeded!" + + +def test_limit_exceeded() -> None: + limiter = TokenBucketLimiter(10, 10) + + with pytest.raises(RateLimitExceeded) as e: + for i in range(20): + with limiter: + continue + + assert "Rate exceeded" in str(e.value) + diff --git a/rate_limiters/token_bucket.py b/rate_limiters/token_bucket.py new file mode 100644 index 0000000..448e453 --- /dev/null +++ b/rate_limiters/token_bucket.py @@ -0,0 +1,82 @@ +import threading +from time import sleep, time + + +class RateLimiterException(Exception): + pass + + +class RateLimitExceeded(RateLimiterException): + def __init__(self, retry_after: float, current_tokens: float): + self.retry_after = retry_after + self.current_tokens = current_tokens + super().__init__(f"Rate exceeded! Retry after {retry_after:.2f} seconds.") + + +class TokenBucketLimiter: + def __init__(self, capacity: int, refill_rate: int): + self.capacity = float(capacity) + self.refill_rate = float(refill_rate) + self.tokens = float(capacity) + self.last_refill_time = time() + self._lock = threading.Lock() + + def __enter__(self): + with self._lock: + now = time() + + elapsed = now - self.last_refill_time + new_tokens = elapsed * self.refill_rate + + self.tokens = min(self.tokens + new_tokens, self.capacity) + self.last_refill_time = time() + + if self.tokens < 1: + retry_after = (1 - self.tokens) / self.refill_rate + raise RateLimitExceeded(retry_after, self.tokens) + + self.tokens -= 1 + return self + + def __exit__(self, exc_type, exc_value, exc_traceback) -> bool: + return False + + +def make_requests(number: int, limiter: TokenBucketLimiter) -> None: + start_time = time() + + successful = 0 + rate_limited = 0 + failed = 0 + + print(f"Starting request cycle with {number} requests...") + + for i in range(1, number): + try: + with limiter: + successful += 1 + except RateLimitExceeded as e: + rate_limited += 1 + sleep(e.retry_after) + try: + with limiter: + successful += 1 + except RuntimeError: + failed += 1 + print("Retry failed! Request limit reached!") + + end_time = time() + + execution_time = end_time - start_time + effective_rate = number / execution_time + + print( + f"Results: \n\nSuccessfull: {successful}\nRate limited: {rate_limited}\nFailed: {failed}\n" + ) + print( + f"Total execution time: {execution_time:.2f}\nEffective rate: {effective_rate:.2f}" + ) + + +# limiter = TokenBucketLimiter(10, 10) +# make_requests(100, limiter) diff --git a/rate_limiters/uv.lock b/rate_limiters/uv.lock new file mode 100644 index 0000000..cc32065 --- /dev/null +++ b/rate_limiters/uv.lock @@ -0,0 +1,75 @@ +version = 1 +revision = 3 +requires-python = ">=3.11" + +[[package]] +name = "colorama" +version = "0.4.6" +source = { registry = "https://pypi.org/simple" } +sdist = { url = "https://files.pythonhosted.org/packages/d8/53/6f443c9a4a8358a93a6792e2acffb9d9d5cb0a5cfd8802644b7b1c9a02e4/colorama-0.4.6.tar.gz", hash = "sha256:08695f5cb7ed6e0531a20572697297273c47b8cae5a63ffc6d6ed5c201be6e44", size = 27697, upload-time = 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