metrics/counters.py

"""
Global monotonic counters — cache hits/misses, requests, errors.
"""

from __future__ import annotations

import threading
from collections import defaultdict
from typing import Dict


class CounterRegistry:
    """Named integer counters."""

    def __init__(self) -> None:
        self._lock = threading.RLock()
        self._counters: Dict[str, int] = defaultdict(int)

    def inc(self, name: str, amount: int = 1) -> None:
        with self._lock:
            self._counters[name] += amount

    def get(self, name: str) -> int:
        with self._lock:
            return self._counters.get(name, 0)

    def snapshot(self) -> Dict[str, int]:
        with self._lock:
            return dict(self._counters)

    def reset(self) -> None:
        with self._lock:
            self._counters.clear()