env_logger

This is a super simple project which aims to help out with setting up logging correctly in your project. It is a true drop in replacement for logrus logger atm.

Usage

The entire logging framework is configured via a single environment variable LOG. The variable is a comma delimited list of packages and their respective log-levels. (falling back to InfoLevel if not configured).

Windows support

This logger should be fully able to work colored on windows! TTY detection may fail though, so to ensure that it does not set the environment variable CLICOLOR_FORCE=1 in your shell.

Bonus tricks

Some bonus modifiers exist for the log config:

ln enables printing of line numbers
gr adds number of goroutines to each log statement
grl adds number of goroutines to each log statement and starts a loop printing the number of routines every second
pp enables pprof and dynamic log config via http requests on 11111, port can be changed with ppport= (all of this requires the package to be built with -tags logpprof). The endpoint for the logconfig is POST /logstring. Send the new logstring as body
mut=10 allows to set runtime.SetMutexProfileFraction(val)
blk=10 allows to set runtime.SetBlockProfileFraction(val)

Bonus functions

log.Must, log.MustFatal if the passed error is not nil log it and throw a panic or end the program
log.Should, log.ShouldWarn if the passed error is not nul just log it, returns true if error has been printed
log.Wrap can be used with Should and must functions to provide additional error information (eg: log.Should(log.Wrap(err, "on testing %s", somedata)))
log.ShouldWrap convenience for the above
log.Indent can be used to prety print the public fields of a structure (eg: log.Info(log.Indent(myStructure)))
log.Timer and log.TimerEnd can be used to quickly measure the time between 2 places with a key, similar to js. this does not log on its own, use with one of the standard log functions (just like .Indent above)

Dynamic log config

If pp is active and tags logpprof have been set use this command to change the logconfig dynamically

curl -X POST -d 'grl' http://localhost:11111/logstring

Examples

LOG=foo=debug,bar=warn go run

This configures the foo package at loglevel Debug, the bar package at loglevel Warn and the default/fallback logger at Info.

LOG=foo=info,debug,bar=warn go run

This is the same as the previous example, except foo is now at loglevel Info, and the default loglevel is Debug.

LOG=debug go run

This example sets everything to Debug.

s00500 / env_logger