Add custom logger

logger.go

@@ -0,0 +1,35 @@
+package asynq
+
+import (
+	"io"
+	"log"
+	"os"
+)
+
+// global logger used in asynq package.
+var logger = newLogger(os.Stderr)
+
+func newLogger(out io.Writer) *asynqLogger {
+	return &asynqLogger{
+		log.New(out, "", log.Ldate|log.Ltime|log.Lmicroseconds|log.LUTC),
+	}
+}
+
+type asynqLogger struct {
+	*log.Logger
+}
+
+func (l *asynqLogger) info(format string, args ...interface{}) {
+	format = "INFO: " + format
+	l.Printf(format, args...)
+}
+
+func (l *asynqLogger) warn(format string, args ...interface{}) {
+	format = "WARN: " + format
+	l.Printf(format, args...)
+}
+
+func (l *asynqLogger) error(format string, args ...interface{}) {
+	format = "ERROR: " + format
+	l.Printf(format, args...)
+}