Application logging

Import the log functions from std.logging. The host sets the default minimum severity with NORM_LOG_LEVEL, accepting debug, info, warn, error or off. The default is info.

Console timestamps use the machine’s local time zone by default. Use currentSystem().setTimeZone("Asia/Singapore") from std.system to set the zone for the current execution. For example, a console timestamp in Singapore reads 2026-10-31T19:34:52+08:00.

NORM_LOG_OUTPUTS accepts a JSON array. Each entry names the fully qualified implementation in name. Optional level overrides the default threshold, source selects a package and its descendants, and options supplies string configuration to the implementation.

norm run --debug applies the debug threshold to the command, application, Norm packages and Java dependencies using SLF4J for that invocation. This explicit host option overrides NORM_LOG_LEVEL and every output entry's level, including off. Output destinations and source filters still select where events go. A --debug argument after -- is passed to the application.

An application can implement std.logging.LogDefaults to select its default destinations. NORM_LOG_OUTPUTS takes precedence.

[
  {"name": "std.logging.ConsoleLogOutputer", "level": "warn"},
  {"name": "std.logging.FileLogOutputer", "source": "shop", "options": {"directory": "log"}}
]

Log functions and routing · File output options · Provider discovery