feat: add peer for selector (#2088)

* add peer for selector

selector/default_selector.go

@@ -53,6 +53,10 @@ func (d *Default) Select(ctx context.Context, opts ...SelectOption) (selected No
 	if err != nil {
 		return nil, nil, err
 	}
+	p, ok := FromPeerContext(ctx)
+	if ok {
+		p.Node = wn.Raw()
+	}
 	return wn.Raw(), done, nil
 }
 

selector/peer.go

@@ -0,0 +1,25 @@
+package selector
+
+import (
+	"context"
+)
+
+type peerKey struct{}
+
+// Peer contains the information of the peer for an RPC, such as the address
+// and authentication information.
+type Peer struct {
+	// node is the peer node.
+	Node Node
+}
+
+// NewPeerContext creates a new context with peer information attached.
+func NewPeerContext(ctx context.Context, p *Peer) context.Context {
+	return context.WithValue(ctx, peerKey{}, p)
+}
+
+// FromPeerContext returns the peer information in ctx if it exists.
+func FromPeerContext(ctx context.Context) (p *Peer, ok bool) {
+	p, ok = ctx.Value(peerKey{}).(*Peer)
+	return
+}

selector/peer_test.go

@@ -0,0 +1,24 @@
+package selector
+
+import (
+	"context"
+	"testing"
+)
+
+func TestPeer(t *testing.T) {
+	p := Peer{
+		Node: mockWeightedNode{},
+	}
+	ctx := NewPeerContext(context.Background(), &p)
+	p2, ok := FromPeerContext(ctx)
+	if !ok || p2.Node == nil {
+		t.Fatalf(" no peer found!")
+	}
+}
+
+func TestNotPeer(t *testing.T) {
+	_, ok := FromPeerContext(context.Background())
+	if ok {
+		t.Fatalf("test no peer found peer!")
+	}
+}

transport/grpc/client.go

@@ -184,6 +184,8 @@ func unaryClientInterceptor(ms []middleware.Middleware, timeout time.Duration, f
 		if len(ms) > 0 {
 			h = middleware.Chain(ms...)(h)
 		}
+		var p selector.Peer
+		ctx = selector.NewPeerContext(ctx, &p)
 		_, err := h(ctx, req)
 		return err
 	}

transport/http/client.go

@@ -247,6 +247,8 @@ func (client *Client) invoke(ctx context.Context, req *http.Request, args interf
 		}
 		return reply, nil
 	}
+	var p selector.Peer
+	ctx = selector.NewPeerContext(ctx, &p)
 	if len(client.opts.middleware) > 0 {
 		h = middleware.Chain(client.opts.middleware...)(h)
 	}