1 files changed, 28 insertions, 27 deletions

diff --git a/vendor/google.golang.org/grpc/naming/dns_resolver.go b/vendor/google.golang.org/grpc/naming/dns_resolver.go
index efd37e3..fd8cd3b 100644
--- a/vendor/google.golang.org/grpc/naming/dns_resolver.go
+++ b/vendor/google.golang.org/grpc/naming/dns_resolver.go
@@ -19,13 +19,13 @@
 package naming
 
 import (
+        "context"
         "errors"
         "fmt"
         "net"
         "strconv"
         "time"
 
-        "golang.org/x/net/context"
         "google.golang.org/grpc/grpclog"
 )
 
@@ -37,6 +37,9 @@ const (
 var (
         errMissingAddr  = errors.New("missing address")
         errWatcherClose = errors.New("watcher has been closed")
+
+        lookupHost = net.DefaultResolver.LookupHost
+        lookupSRV  = net.DefaultResolver.LookupSRV
 )
 
 // NewDNSResolverWithFreq creates a DNS Resolver that can resolve DNS names, and
@@ -141,8 +144,8 @@ type dnsWatcher struct {
         r    *dnsResolver
         host string
         port string
-        // The latest resolved address list
-        curAddrs []*Update
+        // The latest resolved address set
+        curAddrs map[string]*Update
         ctx      context.Context
         cancel   context.CancelFunc
         t        *time.Timer
@@ -153,10 +156,10 @@ type ipWatcher struct {
         updateChan chan *Update
 }
 
-// Next returns the adrress resolution Update for the target. For IP address,
-// the resolution is itself, thus polling name server is unncessary. Therefore,
+// Next returns the address resolution Update for the target. For IP address,
+// the resolution is itself, thus polling name server is unnecessary. Therefore,
 // Next() will return an Update the first time it is called, and will be blocked
-// for all following calls as no Update exisits until watcher is closed.
+// for all following calls as no Update exists until watcher is closed.
 func (i *ipWatcher) Next() ([]*Update, error) {
         u, ok := <-i.updateChan
         if !ok {
@@ -192,28 +195,24 @@ type AddrMetadataGRPCLB struct {
 
 // compileUpdate compares the old resolved addresses and newly resolved addresses,
 // and generates an update list
-func (w *dnsWatcher) compileUpdate(newAddrs []*Update) []*Update {
-        update := make(map[Update]bool)
-        for _, u := range newAddrs {
-                update[*u] = true
-        }
-        for _, u := range w.curAddrs {
-                if _, ok := update[*u]; ok {
-                        delete(update, *u)
-                        continue
+func (w *dnsWatcher) compileUpdate(newAddrs map[string]*Update) []*Update {
+        var res []*Update
+        for a, u := range w.curAddrs {
+                if _, ok := newAddrs[a]; !ok {
+                        u.Op = Delete
+                        res = append(res, u)
                 }
-                update[Update{Addr: u.Addr, Op: Delete, Metadata: u.Metadata}] = true
         }
-        res := make([]*Update, 0, len(update))
-        for k := range update {
-                tmp := k
-                res = append(res, &tmp)
+        for a, u := range newAddrs {
+                if _, ok := w.curAddrs[a]; !ok {
+                        res = append(res, u)
+                }
         }
         return res
 }
 
-func (w *dnsWatcher) lookupSRV() []*Update {
-        var newAddrs []*Update
+func (w *dnsWatcher) lookupSRV() map[string]*Update {
+        newAddrs := make(map[string]*Update)
         _, srvs, err := lookupSRV(w.ctx, "grpclb", "tcp", w.host)
         if err != nil {
                 grpclog.Infof("grpc: failed dns SRV record lookup due to %v.\n", err)
@@ -231,15 +230,16 @@ func (w *dnsWatcher) lookupSRV() []*Update {
                                 grpclog.Errorf("grpc: failed IP parsing due to %v.\n", err)
                                 continue
                         }
-                        newAddrs = append(newAddrs, &Update{Addr: a + ":" + strconv.Itoa(int(s.Port)),
-                                Metadata: AddrMetadataGRPCLB{AddrType: GRPCLB, ServerName: s.Target}})
+                        addr := a + ":" + strconv.Itoa(int(s.Port))
+                        newAddrs[addr] = &Update{Addr: addr,
+                                Metadata: AddrMetadataGRPCLB{AddrType: GRPCLB, ServerName: s.Target}}
                 }
         }
         return newAddrs
 }
 
-func (w *dnsWatcher) lookupHost() []*Update {
-        var newAddrs []*Update
+func (w *dnsWatcher) lookupHost() map[string]*Update {
+        newAddrs := make(map[string]*Update)
         addrs, err := lookupHost(w.ctx, w.host)
         if err != nil {
                 grpclog.Warningf("grpc: failed dns A record lookup due to %v.\n", err)
@@ -251,7 +251,8 @@ func (w *dnsWatcher) lookupHost() []*Update {
                         grpclog.Errorf("grpc: failed IP parsing due to %v.\n", err)
                         continue
                 }
-                newAddrs = append(newAddrs, &Update{Addr: a + ":" + w.port})
+                addr := a + ":" + w.port
+                newAddrs[addr] = &Update{Addr: addr}
         }
         return newAddrs
 }