chore: import upstream snapshot with attribution

logger/logger.go

@@ -0,0 +1,53 @@
+// Package log provides a log interface
+package logger
+
+var (
+	// Default logger.
+	DefaultLogger Logger = NewLogger()
+
+	// Default logger helper.
+	DefaultHelper *Helper = NewHelper(DefaultLogger)
+)
+
+// Logger is a generic logging interface.
+type Logger interface {
+	// Init initializes options
+	Init(options ...Option) error
+	// The Logger options
+	Options() Options
+	// Fields set fields to always be logged
+	Fields(fields map[string]interface{}) Logger
+	// Log writes a log entry
+	Log(level Level, v ...interface{})
+	// Logf writes a formatted log entry
+	Logf(level Level, format string, v ...interface{})
+	// String returns the name of logger
+	String() string
+}
+
+func Init(opts ...Option) error {
+	return DefaultLogger.Init(opts...)
+}
+
+func Fields(fields map[string]interface{}) Logger {
+	return DefaultLogger.Fields(fields)
+}
+
+func Log(level Level, v ...interface{}) {
+	DefaultLogger.Log(level, v...)
+}
+
+func Logf(level Level, format string, v ...interface{}) {
+	DefaultLogger.Logf(level, format, v...)
+}
+
+func String() string {
+	return DefaultLogger.String()
+}
+
+func LoggerOrDefault(l Logger) Logger {
+	if l == nil {
+		return DefaultLogger
+	}
+	return l
+}