Essential logger that avoids memory allocation (zero alloc). Intended for a high performance systems. That's why a stack trace is not printed and you must always put a method name or error code to find the place in source code. It prints in syslog format so later it can be easily be processed by journald from systemd. For example:
olog.Printf(olog.INFO + "Executing something\n")So info record will be printed as <6>Executing something and the <6> here is a syslog prefix for INFO level.
go get -u github.com/stokito/go-logger-noalloc
package main
import (
"github.com/stokito/go-logger-noalloc"
"os"
)
// Log Prints everything to STDOUT but only if log level higher than INFO
var Log = &olog.Logger{Out: os.Stdout, LogLevel: olog.LOG_INFO}
func main() {
// globally write to STDOUT
olog.Printf(olog.DEBUG + "Debug message to STDOUT\n")
// Log level must be concatenated as a prefix. The \n is required at end.
Log.Printf(olog.DEBUG+"Trace logging of vars like arg[0]: %s\n", os.Args[0])
// Try to avoid unnecessary calculations if the DEBUG is anyway disabled
if Log.IsLoggable(olog.LOG_DEBUG) {
// some heavy calculations
pwd, _ := os.Getwd()
Log.Printf("Started in %s\n", pwd)
Log.Printf(olog.DEBUG+"Started in %s\n", pwd)
}
Log.Printf(olog.INFO + "Describe execution step or the app sends/received a request from external system, minor error occurred like a timeout\n")
Log.Printf(olog.WARN + "Something suspicious happened, used deprecated API or an error occurred because a request is invalid\n")
Log.Printf(olog.NOTICE + "Application did something important: processed a request, finished processing\n")
Log.Printf(olog.ERR + "Unexpected internal error occurred: invalid request format\n")
Log.Printf(olog.CRIT + "App can't do something: a port is already taken, missing config etc, fatal panic\n")
// you can't log EMERG: leave it for OS
// Now try to disable logs...
Log.LogLevel = olog.LOG_EMERG
Log.Printf(olog.ERR + "...and any error will be anyway printed\n")
Log.Printf(olog.INFO + "But INFO now won't be printed\n")
}See example
0BSD (similar to Public Domain)