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{})
+}

pkg/log/logrus.go

@@ -0,0 +1,45 @@
+package log
+
+import "github.com/sirupsen/logrus"
+
+// LogrusLogger is an adapter for Logrus implementing the Logger interface.
+type LogrusLogger struct {
+	logger logrus.FieldLogger
+}
+
+// NewLogrusLogger returns a new Logger wrapping Logrus.
+func NewLogrusLogger(logger logrus.FieldLogger) *LogrusLogger {
+	return &LogrusLogger{
+		logger: logger,
+	}
+}
+
+// WithField adds a field to the log entry.
+func (l *LogrusLogger) WithField(key string, value interface{}) Logger {
+	return NewLogrusLogger(l.logger.WithField(key, value))
+}
+
+// Info logs an Info level event.
+func (l *LogrusLogger) Info(msg string) {
+	l.logger.Info(msg)
+}
+
+// Warn logs a Warn level event.
+func (l *LogrusLogger) Warn(msg string) {
+	l.logger.Warn(msg)
+}
+
+// Debugf formats and logs a Debug level event.
+func (l *LogrusLogger) Debugf(format string, args ...interface{}) {
+	l.logger.Debugf(format, args...)
+}
+
+// Infof formats and logs an Info level event.
+func (l *LogrusLogger) Infof(format string, args ...interface{}) {
+	l.logger.Infof(format, args...)
+}
+
+// Errorf formats and logs n Error level event.
+func (l *LogrusLogger) Errorf(format string, args ...interface{}) {
+	l.logger.Errorf(format, args...)
+}

pkg/log/logrus_test.go

@@ -0,0 +1,10 @@
+package log
+
+import "testing"
+
+func TestLogrusLoggerImplementsLoggerInterface(t *testing.T) {
+	var i interface{} = new(LogrusLogger)
+	if _, ok := i.(Logger); !ok {
+		t.Errorf("expected %T to implement Logger interface", i)
+	}
+}