VOL-1967 move api-server to separate repository
Change-Id: I21b85be74205805be15f8a85e53a903d16785671
diff --git a/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go b/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go
index 2d8da33..297492e 100644
--- a/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go
+++ b/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go
@@ -47,6 +47,8 @@
defaultFreq = time.Minute * 30
defaultDNSSvrPort = "53"
golang = "GO"
+ // txtPrefix is the prefix string to be prepended to the host name for txt record lookup.
+ txtPrefix = "_grpc_config."
// In DNS, service config is encoded in a TXT record via the mechanism
// described in RFC-1464 using the attribute name grpc_config.
txtAttribute = "grpc_config="
@@ -64,6 +66,9 @@
var (
defaultResolver netResolver = net.DefaultResolver
+ // To prevent excessive re-resolution, we enforce a rate limit on DNS
+ // resolution requests.
+ minDNSResRate = 30 * time.Second
)
var customAuthorityDialler = func(authority string) func(ctx context.Context, network, address string) (net.Conn, error) {
@@ -239,7 +244,13 @@
return
case <-d.t.C:
case <-d.rn:
+ if !d.t.Stop() {
+ // Before resetting a timer, it should be stopped to prevent racing with
+ // reads on it's channel.
+ <-d.t.C
+ }
}
+
result, sc := d.lookup()
// Next lookup should happen within an interval defined by d.freq. It may be
// more often due to exponential retry on empty address list.
@@ -252,6 +263,16 @@
}
d.cc.NewServiceConfig(sc)
d.cc.NewAddress(result)
+
+ // Sleep to prevent excessive re-resolutions. Incoming resolution requests
+ // will be queued in d.rn.
+ t := time.NewTimer(minDNSResRate)
+ select {
+ case <-t.C:
+ case <-d.ctx.Done():
+ t.Stop()
+ return
+ }
}
}
@@ -282,7 +303,7 @@
}
func (d *dnsResolver) lookupTXT() string {
- ss, err := d.resolver.LookupTXT(d.ctx, d.host)
+ ss, err := d.resolver.LookupTXT(d.ctx, txtPrefix+d.host)
if err != nil {
grpclog.Infof("grpc: failed dns TXT record lookup due to %v.\n", err)
return ""