Track Success Rates and Latency in Python: SRE Metrics Helper

import random
import time
from collections import defaultdict


class MetricsTracker:
    """Simple helper to track success rates and latencies for SRE beginners."""

    def __init__(self):
        self.successes = 0
        self.failures = 0
        self.latencies = []

    def record(self, success, latency_ms):
        if success:
            self.successes += 1
        else:
            self.failures += 1
        self.latencies.append(latency_ms)

    def report(self):
        total = self.successes + self.failures
        success_rate = (self.successes / total * 100) if total else 0.0
        avg_latency = sum(self.latencies) / len(self.latencies) if self.latencies else 0.0
        p99 = sorted(self.latencies)[int(len(self.latencies) * 0.99) - 1] if self.latencies else 0.0
        return {
            "total_requests": total,
            "success_rate": round(success_rate, 2),
            "avg_latency_ms": round(avg_latency, 2),
            "p99_latency_ms": p99,
        }


if __name__ == "__main__":
    tracker = MetricsTracker()
    for _ in range(100):
        tracker.record(
            success=random.random() > 0.1,
            latency_ms=random.uniform(20, 200),
        )
        time.sleep(0.001)
    print(tracker.report())