golem-logging-moonbit

Use the @logging module from golemcloud/golem_sdk/logging, which is pre-imported in the template moon.pkg. Call module-level functions like @logging.info("message") or @logging.error("message") directly with no initialization required.

Create a named logger with @logging.with_name("order-service"), which returns an immutable Logger value. Chaining with_name appends /-separated segments to the context string passed to the WASI logging interface.

Yes, println output is captured as stdout and appears in golem agent stream output. However, it lacks log levels and context, so @logging is preferred for structured, filterable logging.

Set a global minimum level with @logging.set_min_level(INFO) to suppress trace and debug output. Individual loggers can override this with logger.with_min_level(TRACE); otherwise they inherit the global minimum, which defaults to TRACE.

Logging is a side effect, so during replay after a crash, log calls from replayed operations are skipped. Logs are recorded in the oplog and remain visible via golem agent stream and golem agent invoke.