golog
Features
- Unstructured
- Leveled
- With caller (file path / name and line number)
- Customizable output format
- Rotating by size, date or hour
- Cross platform, tested on Linux, macOS and Windows
- No 3rd party dependance
- Fast
Installation
go get -u github.com/keakon/golog
Examples
Logging to console
package main
import (
"github.com/keakon/golog"
"github.com/keakon/golog/log"
)
func main() {
l := golog.NewStdoutLogger()
defer l.Close()
l.Infof("hello %d", 1)
log.SetDefaultLogger(l)
test()
}
func test() {
log.Infof("hello %d", 2)
}Logging to file
func main() {
w, _ := golog.NewBufferedFileWriter("test.log")
l := golog.NewLoggerWithWriter(w)
defer l.Close()
l.Infof("hello world")
}Rotating
func main() {
w, _ := golog.NewTimedRotatingFileWriter("test", golog.RotateByDate, 30)
l := golog.NewLoggerWithWriter(w)
defer l.Close()
l.Infof("hello world")
}Formatting
func main() {
w := golog.NewStdoutWriter()
f := golog.ParseFormat("[%l %D %T %S] %m")
h := golog.NewHandler(golog.InfoLevel, f)
h.AddWriter(w)
l := golog.NewLogger(golog.InfoLevel)
l.AddHandler(h)
defer l.Close()
l.Infof("hello world")
}Check document for more format directives.
Fast timer
func main() {
golog.StartFastTimer()
defer golog.StopFastTimer()
l := golog.NewStdoutLogger()
defer l.Close()
l.Infof("hello world")
}The fast timer is about 30% faster than calling time.Time() for each logging record. But it's not thread-safe which may cause some problems (I think those are neglectable in most cases):
- The timer updates every 1 second, so the logging time can be at most 1 second behind the real time.
- Each thread will notice the changes of timer in a few milliseconds, so the concurrent logging messages may get different logging time (less than 2% probability). eg:
[I 2021-09-13 14:31:25 log_test:206] test
[I 2021-09-13 14:31:24 log_test:206] test
[I 2021-09-13 14:31:25 log_test:206] test
- When the day changing, the logging date and time might from different day. eg:
[I 2021-09-12 23:59:59 log_test:206] test
[I 2021-09-13 23:59:59 log_test:206] test
[I 2021-09-12 00:00:00 log_test:206] test
Benchmarks
go1.17 darwin/amd64
cpu: Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
BenchmarkDiscardLogger-12 13788436 77.83 ns/op 0 B/op 0 allocs/op
BenchmarkDiscardLoggerWithoutTimer-12 10472464 112.1 ns/op 0 B/op 0 allocs/op
BenchmarkNopLog-12 1000000000 0.1918 ns/op 0 B/op 0 allocs/op
BenchmarkMultiLevels-12 3922504 304.8 ns/op 0 B/op 0 allocs/op
BenchmarkBufferedFileLogger-12 4937521 251.7 ns/op 0 B/op 0 allocs/op
BenchmarkDiscardZerolog-12 4074019 289.8 ns/op 280 B/op 3 allocs/op
BenchmarkDiscardZap-12 2908678 409.8 ns/op 321 B/op 7 allocs/op
Example output of the benchmarks:
[I 2018-11-20 17:05:37 log_test:118] test