Adaptive Rate Limiting

How it works

1. Monitor system metrics (CPU, memory, event loop latency)
2. Calculate load factor from metrics
3. Scale rate limits down when load is high

Formula:

scaled_limit = base_limit * (1.0 - load_factor * scale_factor)

Enable

from drogue.core.config import DrogueConfig

config = DrogueConfig(
    adaptive_enabled=True,
    adaptive_scale_factor=0.5,
    adaptive_cpu_threshold=0.8,
    adaptive_memory_threshold=0.8,
    adaptive_check_interval=5.0,
)

Configuration

Option	Default	Description
adaptive_enabled	False	Enable adaptive limiting
adaptive_scale_factor	0.5	Max scale-down factor (0-1)
adaptive_cpu_threshold	0.8	CPU threshold to trigger scaling
adaptive_memory_threshold	0.8	Memory threshold to trigger scaling
adaptive_check_interval	5.0	Metrics check interval (seconds)

Standalone usage

from drogue.protection.adaptive import AdaptiveRateLimiter

limiter = AdaptiveRateLimiter(scale_factor=0.5, check_interval=5.0)

# Get current metrics
metrics = limiter.get_metrics()
# {"cpu_percent": 65.2, "memory_percent": 72.1, "event_loop_latency": 0.012}

# Get adaptive limit
limit = limiter.get_adaptive_limit(base_limit=1000)
# 850 (if load is moderate)

# Check if system is loaded
if limiter.is_system_loaded():
    print("System under load")

Scaling behavior

CPU/Memory	Scale factor	Effective limit (base=1000)
0-80%	1.0	1000
80-90%	0.75	750
90-95%	0.5	500
95%+	0.25	250