Add logger interface and stop relying on Logrus directly

pkg/log/logger.go

@@ -0,0 +1,17 @@
+// Package log provides a logger interface for logger libraries
+// so that dex does not depend on any of them directly.
+// It also includes a default implementation using Logrus (used by dex previously).
+package log
+
+// Logger serves as an adapter interface for logger libraries
+// so that dex does not depend on any of them directly.
+type Logger interface {
+	WithField(key string, value interface{}) Logger
+
+	Info(msg string)
+	Warn(msg string)
+
+	Debugf(format string, args ...interface{})
+	Infof(format string, args ...interface{})
+	Errorf(format string, args ...interface{})
+}