rebase: use latest google.golang.org/grpc version

google.golang.org/grpc was listed in go.mod:replace and updating the
dependency was not possible. There should not be a reason to prevent
updating, commit 5aca04d540 added it but without explanation.

Signed-off-by: Niels de Vos <ndevos@redhat.com>

vendor/google.golang.org/grpc/internal/resolver/config_selector.go

@@ -24,6 +24,7 @@ import (
 	"sync"
 
 	"google.golang.org/grpc/internal/serviceconfig"
+	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/resolver"
 )
 
@@ -51,6 +52,74 @@ type RPCConfig struct {
 	Context      context.Context
 	MethodConfig serviceconfig.MethodConfig // configuration to use for this RPC
 	OnCommitted  func()                     // Called when the RPC has been committed (retries no longer possible)
+	Interceptor  ClientInterceptor
+}
+
+// ClientStream is the same as grpc.ClientStream, but defined here for circular
+// dependency reasons.
+type ClientStream interface {
+	// Header returns the header metadata received from the server if there
+	// is any. It blocks if the metadata is not ready to read.
+	Header() (metadata.MD, error)
+	// Trailer returns the trailer metadata from the server, if there is any.
+	// It must only be called after stream.CloseAndRecv has returned, or
+	// stream.Recv has returned a non-nil error (including io.EOF).
+	Trailer() metadata.MD
+	// CloseSend closes the send direction of the stream. It closes the stream
+	// when non-nil error is met. It is also not safe to call CloseSend
+	// concurrently with SendMsg.
+	CloseSend() error
+	// Context returns the context for this stream.
+	//
+	// It should not be called until after Header or RecvMsg has returned. Once
+	// called, subsequent client-side retries are disabled.
+	Context() context.Context
+	// SendMsg is generally called by generated code. On error, SendMsg aborts
+	// the stream. If the error was generated by the client, the status is
+	// returned directly; otherwise, io.EOF is returned and the status of
+	// the stream may be discovered using RecvMsg.
+	//
+	// SendMsg blocks until:
+	//   - There is sufficient flow control to schedule m with the transport, or
+	//   - The stream is done, or
+	//   - The stream breaks.
+	//
+	// SendMsg does not wait until the message is received by the server. An
+	// untimely stream closure may result in lost messages. To ensure delivery,
+	// users should ensure the RPC completed successfully using RecvMsg.
+	//
+	// It is safe to have a goroutine calling SendMsg and another goroutine
+	// calling RecvMsg on the same stream at the same time, but it is not safe
+	// to call SendMsg on the same stream in different goroutines. It is also
+	// not safe to call CloseSend concurrently with SendMsg.
+	SendMsg(m interface{}) error
+	// RecvMsg blocks until it receives a message into m or the stream is
+	// done. It returns io.EOF when the stream completes successfully. On
+	// any other error, the stream is aborted and the error contains the RPC
+	// status.
+	//
+	// It is safe to have a goroutine calling SendMsg and another goroutine
+	// calling RecvMsg on the same stream at the same time, but it is not
+	// safe to call RecvMsg on the same stream in different goroutines.
+	RecvMsg(m interface{}) error
+}
+
+// ClientInterceptor is an interceptor for gRPC client streams.
+type ClientInterceptor interface {
+	// NewStream produces a ClientStream for an RPC which may optionally use
+	// the provided function to produce a stream for delegation.  Note:
+	// RPCInfo.Context should not be used (will be nil).
+	//
+	// done is invoked when the RPC is finished using its connection, or could
+	// not be assigned a connection.  RPC operations may still occur on
+	// ClientStream after done is called, since the interceptor is invoked by
+	// application-layer operations.  done must never be nil when called.
+	NewStream(ctx context.Context, ri RPCInfo, done func(), newStream func(ctx context.Context, done func()) (ClientStream, error)) (ClientStream, error)
+}
+
+// ServerInterceptor is unimplementable; do not use.
+type ServerInterceptor interface {
+	notDefined()
 }
 
 type csKeyType string

vendor/google.golang.org/grpc/internal/resolver/dns/dns_resolver.go

@@ -34,6 +34,7 @@ import (
 
 	grpclbstate "google.golang.org/grpc/balancer/grpclb/state"
 	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/internal/backoff"
 	"google.golang.org/grpc/internal/envconfig"
 	"google.golang.org/grpc/internal/grpcrand"
 	"google.golang.org/grpc/resolver"
@@ -46,6 +47,13 @@ var EnableSRVLookups = false
 
 var logger = grpclog.Component("dns")
 
+// Globals to stub out in tests. TODO: Perhaps these two can be combined into a
+// single variable for testing the resolver?
+var (
+	newTimer           = time.NewTimer
+	newTimerDNSResRate = time.NewTimer
+)
+
 func init() {
 	resolver.Register(NewBuilder())
 }
@@ -143,7 +151,6 @@ func (b *dnsBuilder) Build(target resolver.Target, cc resolver.ClientConn, opts
 
 	d.wg.Add(1)
 	go d.watcher()
-	d.ResolveNow(resolver.ResolveNowOptions{})
 	return d, nil
 }
 
@@ -201,28 +208,38 @@ func (d *dnsResolver) Close() {
 
 func (d *dnsResolver) watcher() {
 	defer d.wg.Done()
+	backoffIndex := 1
 	for {
-		select {
-		case <-d.ctx.Done():
-			return
-		case <-d.rn:
-		}
-
 		state, err := d.lookup()
 		if err != nil {
+			// Report error to the underlying grpc.ClientConn.
 			d.cc.ReportError(err)
 		} else {
-			d.cc.UpdateState(*state)
+			err = d.cc.UpdateState(*state)
 		}
 
-		// Sleep to prevent excessive re-resolutions. Incoming resolution requests
-		// will be queued in d.rn.
-		t := time.NewTimer(minDNSResRate)
+		var timer *time.Timer
+		if err == nil {
+			// Success resolving, wait for the next ResolveNow. However, also wait 30 seconds at the very least
+			// to prevent constantly re-resolving.
+			backoffIndex = 1
+			timer = newTimerDNSResRate(minDNSResRate)
+			select {
+			case <-d.ctx.Done():
+				timer.Stop()
+				return
+			case <-d.rn:
+			}
+		} else {
+			// Poll on an error found in DNS Resolver or an error received from ClientConn.
+			timer = newTimer(backoff.DefaultExponential.Backoff(backoffIndex))
+			backoffIndex++
+		}
 		select {
-		case <-t.C:
 		case <-d.ctx.Done():
-			t.Stop()
+			timer.Stop()
 			return
+		case <-timer.C:
 		}
 	}
 }