Add traffic stat of every request in access log (#642)

* Add traffic stat of every request in access log

* Fix: record pointer may be null

* Clarify the data unit in access log

app/dispatcher/default.go

@@ -154,12 +154,15 @@ func (d *DefaultDispatcher) getLink(ctx context.Context) (*transport.Link, *tran
 
 	if user != nil && len(user.Email) > 0 {
 		p := d.policy.ForLevel(user.Level)
+		accessMessage := log.AccessMessageFromContext(ctx)
+
 		if p.Stats.UserUplink {
 			name := "user>>>" + user.Email + ">>>traffic>>>uplink"
 			if c, _ := stats.GetOrRegisterCounter(d.stats, name); c != nil {
 				inboundLink.Writer = &SizeStatWriter{
 					Counter: c,
 					Writer:  inboundLink.Writer,
+					Record:  &accessMessage.BytesSent,
 				}
 			}
 		}
@@ -169,6 +172,7 @@ func (d *DefaultDispatcher) getLink(ctx context.Context) (*transport.Link, *tran
 				outboundLink.Writer = &SizeStatWriter{
 					Counter: c,
 					Writer:  outboundLink.Writer,
+					Record:  &accessMessage.BytesReceived,
 				}
 			}
 		}
@@ -285,12 +289,12 @@ func (d *DefaultDispatcher) routedDispatch(ctx context.Context, link *transport.
 		return
 	}
 
+	handler.Dispatch(ctx, link)
+
 	if accessMessage := log.AccessMessageFromContext(ctx); accessMessage != nil {
 		if tag := handler.Tag(); tag != "" {
 			accessMessage.Detour = tag
 		}
 		log.Record(accessMessage)
 	}
-
-	handler.Dispatch(ctx, link)
 }

app/dispatcher/stats.go

@@ -11,10 +11,15 @@ import (
 type SizeStatWriter struct {
 	Counter stats.Counter
 	Writer  buf.Writer
+	Record  *int64
 }
 
 func (w *SizeStatWriter) WriteMultiBuffer(mb buf.MultiBuffer) error {
-	w.Counter.Add(int64(mb.Len()))
+	bufLen := int64(mb.Len())
+	if w.Record != nil {
+		*w.Record += bufLen
+	}
+	w.Counter.Add(bufLen)
 	return w.Writer.WriteMultiBuffer(mb)
 }
 

common/log/access.go

@@ -2,6 +2,7 @@ package log
 
 import (
 	"context"
+	"fmt"
 	"strings"
 
 	"v2ray.com/core/common/serial"
@@ -21,12 +22,14 @@ const (
 )
 
 type AccessMessage struct {
-	From   interface{}
-	To     interface{}
-	Status AccessStatus
-	Reason interface{}
-	Email  string
-	Detour string
+	From          interface{}
+	To            interface{}
+	Status        AccessStatus
+	Reason        interface{}
+	Email         string
+	Detour        string
+	BytesSent     int64
+	BytesReceived int64
 }
 
 func (m *AccessMessage) String() string {
@@ -53,6 +56,8 @@ func (m *AccessMessage) String() string {
 		builder.WriteString(m.Email)
 	}
 
+	builder.WriteString(fmt.Sprintf(" bytes_sent: %d bytes_received: %d", m.BytesSent, m.BytesReceived))
+
 	return builder.String()
 }