logger with helper methods (#1216)

* support unix daemon socket

* refactor(logger): logger fields changed to map[string]interface{}

* improvement(logger): adding string to Level Parser

* improvement(logger): rename ParseLevel to GetLevel

* refactor(logger): adding basic logger

adding micro default logger, and refactor logger interface

* refactor(logger): moved basic logger to top level package

* refactor(logger): adding default logger

logger/options.go

@@ -2,30 +2,48 @@ package logger
 
 import (
 	"context"
+	"io"
 )
 
-// Option for load profiles maybe
-// eg. yml
-// micro:
-//   logger:
-//     name:
-//     dialect: zap/default/logrus
-//     zap:
-//       xxx:
-//     logrus:
-//       xxx:
 type Option func(*Options)
 
 type Options struct {
-	// The Log Level
+	// The logging level the logger should log at. default is `InfoLevel`
 	Level Level
-	// Other opts
+	// fields to always be logged
+	Fields map[string]interface{}
+	// It's common to set this to a file, or leave it default which is `os.Stderr`
+	Out io.Writer
+	// Alternative options
 	Context context.Context
 }
 
-// WithLevel sets the log level
-func WithLevel(l Level) Option {
-	return func(o *Options) {
-		o.Level = l
+// WithFields set default fields for the logger
+func WithFields(fields map[string]interface{}) Option {
+	return func(args *Options) {
+		args.Fields = fields
+	}
+}
+
+// WithLevel set default level for the logger
+func WithLevel(level Level) Option {
+	return func(args *Options) {
+		args.Level = level
+	}
+}
+
+// WithOutput set default output writer for the logger
+func WithOutput(out io.Writer) Option {
+	return func(args *Options) {
+		args.Out = out
+	}
+}
+
+func SetOption(k, v interface{}) Option {
+	return func(o *Options) {
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, k, v)
 	}
 }