[WIP] logger first (#1161)

* logger first

* log->logger

* update comment

* add context in Options

* add Fields

* remove logfi

* add field encode

* add common Field Types

* update logger field

logger/logger.go

@@ -0,0 +1,48 @@
+// Package log provides a log interface
+package logger
+
+import (
+	"fmt"
+	"sync"
+)
+
+// Logger is a generic logging interface
+type Logger interface {
+	Init(options ...Option) error
+	// String returns the name of logger
+	String() string
+	// SetLevel updates the logging level.
+	SetLevel(Level)
+	// Level returns the logging level
+	Level() Level
+	// Log inserts a log entry.  Arguments may be handled in the manner
+	// of fmt.Print, but the underlying logger may also decide to handle
+	// them differently.
+	Log(level Level, v ...interface{})
+	// Logf insets a log entry.  Arguments are handled in the manner of
+	// fmt.Printf.
+	Logf(level Level, format string, v ...interface{})
+	// Fields set fields to always be logged
+	Fields(fields ...Field) Logger
+}
+
+var (
+	mux       sync.Mutex
+	loggerMap = map[string]Logger{}
+)
+
+func Register(logger Logger) {
+	mux.Lock()
+	defer mux.Unlock()
+
+	loggerMap[logger.String()] = logger
+}
+
+func GetLogger(name string) (Logger, error) {
+	l := loggerMap[name]
+	if l == nil {
+		return nil, fmt.Errorf("no such name logger found %s", name)
+	}
+
+	return l, nil
+}