logutils is a Go package that augments the standard library "log" package to make logging a bit more modern, without fragmenting the Go ecosystem with new logging packages.
Presumably your application already uses the default log package. To switch, you'll want your code to look like the following:
package main
import (
"log"
"os"
"github.com/hashicorp/logutils"
)
func main() {
filter := &logutils.LevelFilter{
Levels: []logutils.LogLevel{"DEBUG", "WARN", "ERROR"},
MinLevel: logutils.LogLevel("WARN"),
Writer: os.Stderr,
}
log.SetOutput(filter)
log.Print("[DEBUG] Debugging") // this will not print
log.Print("[WARN] Warning") // this will
log.Print("[ERROR] Erring") // and so will this
log.Print("Message I haven't updated") // and so will this
}This logs to standard error exactly like go's standard logger. Any log messages you haven't converted to have a level will continue to print as before.