TUN-3470: Replace in-house logger calls with zerolog

vendor/github.com/rs/zerolog/syslog.go

@@ -0,0 +1,58 @@
+// +build !windows
+// +build !binary_log
+
+package zerolog
+
+import (
+	"io"
+)
+
+// SyslogWriter is an interface matching a syslog.Writer struct.
+type SyslogWriter interface {
+	io.Writer
+	Debug(m string) error
+	Info(m string) error
+	Warning(m string) error
+	Err(m string) error
+	Emerg(m string) error
+	Crit(m string) error
+}
+
+type syslogWriter struct {
+	w SyslogWriter
+}
+
+// SyslogLevelWriter wraps a SyslogWriter and call the right syslog level
+// method matching the zerolog level.
+func SyslogLevelWriter(w SyslogWriter) LevelWriter {
+	return syslogWriter{w}
+}
+
+func (sw syslogWriter) Write(p []byte) (n int, err error) {
+	return sw.w.Write(p)
+}
+
+// WriteLevel implements LevelWriter interface.
+func (sw syslogWriter) WriteLevel(level Level, p []byte) (n int, err error) {
+	switch level {
+	case TraceLevel:
+	case DebugLevel:
+		err = sw.w.Debug(string(p))
+	case InfoLevel:
+		err = sw.w.Info(string(p))
+	case WarnLevel:
+		err = sw.w.Warning(string(p))
+	case ErrorLevel:
+		err = sw.w.Err(string(p))
+	case FatalLevel:
+		err = sw.w.Emerg(string(p))
+	case PanicLevel:
+		err = sw.w.Crit(string(p))
+	case NoLevel:
+		err = sw.w.Info(string(p))
+	default:
+		panic("invalid level")
+	}
+	n = len(p)
+	return
+}