Pipeline

Logger facade -> CoreLogger severity filter -> Processor -> Transport -> Formatter/output

Parts

• Logger wraps any logger with convenience methods like info() and warn().
• CoreLogger creates LogRecord objects and applies the severity filter.
• Processor optionally transforms a LogRecord before it reaches a transport.
• Transport captures the record and writes or stores it.
• Formatter converts a record to text when a transport needs formatted output.

Processors only run for records that pass minSeverity.

Failure Behavior

Logging is best-effort. If a processor throws, CoreLogger sends the original record to the transport. If a formatter or transport throws, the exception is contained and does not fail the request, job, or other application operation that produced the log.

CompositeTransport isolates each destination. A failure in one child does not prevent later children from receiving the record.

Because failures are intentionally contained, transports that need operational visibility should implement their own health reporting or metrics.

Convenience API

CoreLogger exposes the low-level log(severity, message, meta) method. Logger wraps any logger with convenience methods similar to console, including info(), warn(), and error().

createLogger builds a CoreLogger and returns it wrapped in Logger. createNamedLogger does the same and adds a logger metadata field. createLoggerFacade wraps an existing logger.