Prometheus Go Code Review

Review Checklist

• Metric types match measurement semantics (Counter/Gauge/Histogram)
• Labels have low cardinality (no user IDs, timestamps, paths)
• Metric names follow conventions (snake_case, unit suffix)
• Histograms use appropriate bucket boundaries
• Metrics registered once, not per-request
• Collectors don't panic on race conditions
• /metrics endpoint exposed and accessible

Metric Type Selection