34cf361b2b
Implement comprehensive metrics collection for the daemon with zero-overhead design: Features: - Request metrics: counts, latency percentiles (p50, p95, p99), error rates - Cache metrics: hit/miss ratios, eviction counts, database connections - Connection metrics: total, active, rejected connections - System metrics: memory usage, goroutine count, uptime Implementation: - New internal/rpc/metrics.go with Metrics collector - OpMetrics RPC operation for programmatic access - 'bd daemon --metrics' command (human-readable and JSON output) - Lock-free atomic operations for cache/connection metrics - Copy-and-compute pattern in Snapshot to minimize lock contention - Deferred metrics recording ensures all requests are tracked Improvements from code review: - JSON types use float64 for ms/seconds (not time.Duration) - Snapshot copies data under short lock, computes outside - Union of operations from counts and errors maps - Defensive clamping in percentile calculation - Defer pattern ensures metrics recorded even on early returns Documentation updated in README.md with usage examples. Closes bd-153 Amp-Thread-ID: https://ampcode.com/threads/T-20213187-65c7-47f7-ba21-5234c9e52e26 Co-authored-by: Amp <amp@ampcode.com>
26 KiB
26 KiB