logger

Package fakelib demonstrates how a library should do logging and in logger_test.go, this is controlled library will be on error level by default, but test/program can control its levels.

careful with this - will also set for all named loggers used in libraries rather create your own logger and set its level, or set level on Named(...).SetLevel(...) still: setting level like this will only affect loggers that did not set their own levels libraries should just create logger that defaults to level error, and then will be changed by this or Named(...).SetLevel() If a library did New().WithLevel(), it will not be affected by any of this..

SetGlobalWriter sets the writer on top and all existing and default for all new loggers.

use parent's level.

Logger does logging it can only be created from a INamedLogger which gives the structure to control log levels by name during run-time but that actually only control the writer's level, which is used by all loggers with the same name after creating a logger, the logger level can be changed in code, e.g.