metrics: add chain error counter

chain/chain.go

@@ -5,9 +5,17 @@ type Chainer interface {
 }
 
 type Chain struct {
+	name   string
 	groups []*NodeGroup
 }
 
+func NewChain(name string, groups ...*NodeGroup) *Chain {
+	return &Chain{
+		name:   name,
+		groups: groups,
+	}
+}
+
 func (c *Chain) AddNodeGroup(group *NodeGroup) {
 	c.groups = append(c.groups, group)
 }
@@ -17,7 +25,9 @@ func (c *Chain) Route(network, address string) (r *Route) {
 		return
 	}
 
-	r = &Route{}
+	r = &Route{
+		chain: c,
+	}
 	for _, group := range c.groups {
 		node := group.Next()
 		if node == nil {

chain/route.go

@@ -11,6 +11,7 @@ import (
 	"github.com/go-gost/core/common/util/udp"
 	"github.com/go-gost/core/connector"
 	"github.com/go-gost/core/logger"
+	"github.com/go-gost/core/metrics"
 )
 
 var (
@@ -18,8 +19,9 @@ var (
 )
 
 type Route struct {
-	nodes    []*Node
+	chain    *Chain
 	ifceName string
+	nodes    []*Node
 	logger   logger.Logger
 }
 
@@ -75,6 +77,12 @@ func (r *Route) connect(ctx context.Context) (conn net.Conn, err error) {
 		return nil, ErrEmptyRoute
 	}
 
+	defer func() {
+		if err != nil && r.chain != nil {
+			metrics.ChainErrors(r.chain.name).Inc()
+		}
+	}()
+
 	network := "ip"
 	node := r.nodes[0]