Spring Boot Logging and Log Structure

Own what the process writes, in what shape, with what context, and at what volume. Logback is already configured sensibly by default; the work here is deciding what to override, what to never print, and how to follow one request through the whole system without generating a million lines to do it.

When to use

• Adding or restructuring logback-spring.xml, appenders, encoders, or rolling policies.
• Switching to JSON output for a log collector, or deciding not to.
• Putting a correlation id, trace id, or tenant into MDC and clearing it correctly.
• Debugging one specific request end to end, or a loop or batch job flooding the collector.
• Deciding what must be redacted, and enforcing it rather than trusting reviewers.

When not to use

• Meter, observation, and span design belong to spring-boot-observability.
• Which actuator endpoints are exposed and on which port belong to spring-boot-actuator.
• Creating the request context and the observation belong to spring-boot-mvc.
• Log shipping, retention, and index limits belong to the platform, not to the application.
• Traces and metrics that the log lines reference belong to spring-boot-observability.