tracing best practices

Use when instrumenting or reviewing Rust observability with tracing.

Mental model

• tracing is for structured, contextual observability, not just string logging.
• Think in spans and events: spans describe work over time, events describe points in time.
• Instrumentation should explain system behavior without forcing readers to reconstruct call flow from unstructured messages.

Spans and events

• Use spans for requests, jobs, command execution, database calls, and other scoped units of work.
• Use events for discrete facts: retries, state transitions, failures, external calls, and important decisions.
• Keep span boundaries meaningful; one giant span for the whole process usually hides more than it helps.

Fields and structure