NOTE
Designing Logging
Structured logs, severity, correlation, context, sampling, retention, privacy, and operational querying.
This is a historical learning note and may contain outdated or incomplete understanding.
Logs should record discrete events with enough structured context to diagnose behavior: timestamp, service/version, operation, severity, stable request/trace identifiers, outcome/error category, and relevant resource IDs.
Do not log secrets, tokens, passwords, or unnecessary personal data. Control volume through levels/sampling/retention rather than dropping all detail during an incident.
Logs complement metrics and traces: use metrics to detect, traces to locate a distributed path, and logs for detailed event context.