rebase: bump google.golang.org/grpc from 1.45.0 to 1.46.0

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.45.0 to 1.46.0.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](https://github.com/grpc/grpc-go/compare/v1.45.0...v1.46.0)

---
updated-dependencies:
- dependency-name: google.golang.org/grpc
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

go.mod

@@ -26,7 +26,7 @@ require (
 	github.com/stretchr/testify v1.7.1
 	golang.org/x/crypto v0.0.0-20210817164053-32db794688a5
 	golang.org/x/sys v0.0.0-20220114195835-da31bd327af9
-	google.golang.org/grpc v1.45.0
+	google.golang.org/grpc v1.46.0
 	google.golang.org/protobuf v1.28.0
 	k8s.io/api v0.23.5
 	k8s.io/apimachinery v0.23.5

go.sum

@@ -210,6 +210,7 @@ github.com/cncf/udpa/go v0.0.0-20210930031921-04548b0d99d4/go.mod h1:6pvJx4me5XP
 github.com/cncf/xds/go v0.0.0-20210312221358-fbca930ec8ed/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/cncf/xds/go v0.0.0-20210805033703-aa0b78936158/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/cncf/xds/go v0.0.0-20210922020428-25de7278fc84/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
+github.com/cncf/xds/go v0.0.0-20211001041855-01bcc9b48dfe/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/cncf/xds/go v0.0.0-20211011173535-cb28da3451f1/go.mod h1:eXthEFrGJvWHgFFCl3hGmgk+/aYT6PnTQLykKQRLhEs=
 github.com/cockroachdb/apd v1.1.0/go.mod h1:8Sl8LxpKi29FqWXR16WEFZRNSz3SoPzUzeMeY4+DwBQ=
 github.com/cockroachdb/cockroach-go v0.0.0-20181001143604-e0a95dfd547c/go.mod h1:XGLbWH/ujMcbPbhZq52Nv6UrCghb1yGn//133kEsvDk=
@@ -308,6 +309,7 @@ github.com/envoyproxy/go-control-plane v0.9.9-0.20201210154907-fd9021fe5dad/go.m
 github.com/envoyproxy/go-control-plane v0.9.9-0.20210217033140-668b12f5399d/go.mod h1:cXg6YxExXjJnVBQHBLXeUAgxn2UodCpnH306RInaBQk=
 github.com/envoyproxy/go-control-plane v0.9.9-0.20210512163311-63b5d3c536b0/go.mod h1:hliV/p42l8fGbc6Y9bQ70uLwIvmJyVE5k4iMKlh8wCQ=
 github.com/envoyproxy/go-control-plane v0.9.10-0.20210907150352-cf90f659a021/go.mod h1:AFq3mo9L8Lqqiid3OhADV3RfLJnjiw63cSpi+fDTRC0=
+github.com/envoyproxy/go-control-plane v0.10.2-0.20220325020618-49ff273808a1/go.mod h1:KJwIaB5Mv44NWtYuAOFCVOjcI94vtpEz2JU/D2v6IjE=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
 github.com/euank/go-kmsg-parser v2.0.0+incompatible/go.mod h1:MhmAMZ8V4CYH4ybgdRwPr2TU5ThnS43puaKEMpja1uw=
 github.com/evanphx/json-patch v0.5.2/go.mod h1:ZWS5hhDbVDyob71nXKNL0+PWn6ToqBHMikGIFbs31qQ=
@@ -451,6 +453,7 @@ github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/google/go-cmp v0.5.3/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-cmp v0.5.7 h1:81/ik6ipDQS2aGcBfIN5dHDB36BwrStyeAQquSYCV4o=
 github.com/google/go-cmp v0.5.7/go.mod h1:n+brtR0CgQNWTVd5ZUFpTBC8YFBDLK/h/bpaJ8/DtOE=
 github.com/google/go-github v17.0.0+incompatible/go.mod h1:zLgOLi98H3fifZn+44m+umXrS52loVEgC2AApnigrVQ=
@@ -1635,8 +1638,8 @@ google.golang.org/grpc v1.37.0/go.mod h1:NREThFqKR1f3iQ6oBuvc5LadQuXVGo9rkm5ZGrQ
 google.golang.org/grpc v1.38.0/go.mod h1:NREThFqKR1f3iQ6oBuvc5LadQuXVGo9rkm5ZGrQdJfM=
 google.golang.org/grpc v1.40.0/go.mod h1:ogyxbiOoUXAkP+4+xa6PZSE9DZgIHtSpzjDTB9KAK34=
 google.golang.org/grpc v1.41.0/go.mod h1:U3l9uK9J0sini8mHphKoXyaqDA/8VyGnDee1zzIUK6k=
-google.golang.org/grpc v1.45.0 h1:NEpgUqV3Z+ZjkqMsxMg11IaDrXY4RY6CQukSGK0uI1M=
+google.golang.org/grpc v1.46.0 h1:oCjezcn6g6A75TGoKYBPgKmVBLexhYLM6MebdrPApP8=
-google.golang.org/grpc v1.45.0/go.mod h1:lN7owxKUQEqMfSyQikvvk5tf/6zMPsrK+ONuO11+0rQ=
+google.golang.org/grpc v1.46.0/go.mod h1:vN9eftEi1UMyUsIF80+uQXhHjbXYbm0uXoFCACuMGWk=
 google.golang.org/protobuf v1.22.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
 google.golang.org/protobuf v1.23.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
 google.golang.org/protobuf v1.23.1-0.20200526195155-81db48ad09cc/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=

vendor/google.golang.org/grpc/balancer/balancer.go

@@ -27,6 +27,7 @@ import (
 	"net"
 	"strings"
 
+	"google.golang.org/grpc/channelz"
 	"google.golang.org/grpc/connectivity"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/internal"
@@ -192,7 +193,7 @@ type BuildOptions struct {
 	// server can ignore this field.
 	Authority string
 	// ChannelzParentID is the parent ClientConn's channelz ID.
-	ChannelzParentID int64
+	ChannelzParentID *channelz.Identifier
 	// CustomUserAgent is the custom user agent set on the parent ClientConn.
 	// The balancer should set the same custom user agent if it creates a
 	// ClientConn.

vendor/google.golang.org/grpc/balancer_conn_wrappers.go

@@ -20,130 +20,178 @@ package grpc
 
 import (
 	"fmt"
+	"strings"
 	"sync"
 
 	"google.golang.org/grpc/balancer"
 	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/internal/balancer/gracefulswitch"
 	"google.golang.org/grpc/internal/buffer"
 	"google.golang.org/grpc/internal/channelz"
 	"google.golang.org/grpc/internal/grpcsync"
 	"google.golang.org/grpc/resolver"
 )
 
-// scStateUpdate contains the subConn and the new state it changed to.
+// ccBalancerWrapper sits between the ClientConn and the Balancer.
+//
+// ccBalancerWrapper implements methods corresponding to the ones on the
+// balancer.Balancer interface. The ClientConn is free to call these methods
+// concurrently and the ccBalancerWrapper ensures that calls from the ClientConn
+// to the Balancer happen synchronously and in order.
+//
+// ccBalancerWrapper also implements the balancer.ClientConn interface and is
+// passed to the Balancer implementations. It invokes unexported methods on the
+// ClientConn to handle these calls from the Balancer.
+//
+// It uses the gracefulswitch.Balancer internally to ensure that balancer
+// switches happen in a graceful manner.
+type ccBalancerWrapper struct {
+	cc *ClientConn
+
+	// Since these fields are accessed only from handleXxx() methods which are
+	// synchronized by the watcher goroutine, we do not need a mutex to protect
+	// these fields.
+	balancer        *gracefulswitch.Balancer
+	curBalancerName string
+
+	updateCh *buffer.Unbounded // Updates written on this channel are processed by watcher().
+	resultCh *buffer.Unbounded // Results of calls to UpdateClientConnState() are pushed here.
+	closed   *grpcsync.Event   // Indicates if close has been called.
+	done     *grpcsync.Event   // Indicates if close has completed its work.
+}
+
+// newCCBalancerWrapper creates a new balancer wrapper. The underlying balancer
+// is not created until the switchTo() method is invoked.
+func newCCBalancerWrapper(cc *ClientConn, bopts balancer.BuildOptions) *ccBalancerWrapper {
+	ccb := &ccBalancerWrapper{
+		cc:       cc,
+		updateCh: buffer.NewUnbounded(),
+		resultCh: buffer.NewUnbounded(),
+		closed:   grpcsync.NewEvent(),
+		done:     grpcsync.NewEvent(),
+	}
+	go ccb.watcher()
+	ccb.balancer = gracefulswitch.NewBalancer(ccb, bopts)
+	return ccb
+}
+
+// The following xxxUpdate structs wrap the arguments received as part of the
+// corresponding update. The watcher goroutine uses the 'type' of the update to
+// invoke the appropriate handler routine to handle the update.
+
+type ccStateUpdate struct {
+	ccs *balancer.ClientConnState
+}
+
 type scStateUpdate struct {
 	sc    balancer.SubConn
 	state connectivity.State
 	err   error
 }
 
-// exitIdle contains no data and is just a signal sent on the updateCh in
+type exitIdleUpdate struct{}
-// ccBalancerWrapper to instruct the balancer to exit idle.
-type exitIdle struct{}
 
-// ccBalancerWrapper is a wrapper on top of cc for balancers.
+type resolverErrorUpdate struct {
-// It implements balancer.ClientConn interface.
+	err error
-type ccBalancerWrapper struct {
-	cc          *ClientConn
-	balancerMu  sync.Mutex // synchronizes calls to the balancer
-	balancer    balancer.Balancer
-	hasExitIdle bool
-	updateCh    *buffer.Unbounded
-	closed      *grpcsync.Event
-	done        *grpcsync.Event
-
-	mu       sync.Mutex
-	subConns map[*acBalancerWrapper]struct{}
 }
 
-func newCCBalancerWrapper(cc *ClientConn, b balancer.Builder, bopts balancer.BuildOptions) *ccBalancerWrapper {
+type switchToUpdate struct {
-	ccb := &ccBalancerWrapper{
+	name string
-		cc:       cc,
-		updateCh: buffer.NewUnbounded(),
-		closed:   grpcsync.NewEvent(),
-		done:     grpcsync.NewEvent(),
-		subConns: make(map[*acBalancerWrapper]struct{}),
-	}
-	go ccb.watcher()
-	ccb.balancer = b.Build(ccb, bopts)
-	_, ccb.hasExitIdle = ccb.balancer.(balancer.ExitIdler)
-	return ccb
 }
 
-// watcher balancer functions sequentially, so the balancer can be implemented
+type subConnUpdate struct {
-// lock-free.
+	acbw *acBalancerWrapper
+}
+
+// watcher is a long-running goroutine which reads updates from a channel and
+// invokes corresponding methods on the underlying balancer. It ensures that
+// these methods are invoked in a synchronous fashion. It also ensures that
+// these methods are invoked in the order in which the updates were received.
 func (ccb *ccBalancerWrapper) watcher() {
 	for {
 		select {
-		case t := <-ccb.updateCh.Get():
+		case u := <-ccb.updateCh.Get():
 			ccb.updateCh.Load()
 			if ccb.closed.HasFired() {
 				break
 			}
-			switch u := t.(type) {
+			switch update := u.(type) {
+			case *ccStateUpdate:
+				ccb.handleClientConnStateChange(update.ccs)
 			case *scStateUpdate:
-				ccb.balancerMu.Lock()
+				ccb.handleSubConnStateChange(update)
-				ccb.balancer.UpdateSubConnState(u.sc, balancer.SubConnState{ConnectivityState: u.state, ConnectionError: u.err})
+			case *exitIdleUpdate:
-				ccb.balancerMu.Unlock()
+				ccb.handleExitIdle()
-			case *acBalancerWrapper:
+			case *resolverErrorUpdate:
-				ccb.mu.Lock()
+				ccb.handleResolverError(update.err)
-				if ccb.subConns != nil {
+			case *switchToUpdate:
-					delete(ccb.subConns, u)
+				ccb.handleSwitchTo(update.name)
-					ccb.cc.removeAddrConn(u.getAddrConn(), errConnDrain)
+			case *subConnUpdate:
-				}
+				ccb.handleRemoveSubConn(update.acbw)
-				ccb.mu.Unlock()
-			case exitIdle:
-				if ccb.cc.GetState() == connectivity.Idle {
-					if ei, ok := ccb.balancer.(balancer.ExitIdler); ok {
-						// We already checked that the balancer implements
-						// ExitIdle before pushing the event to updateCh, but
-						// check conditionally again as defensive programming.
-						ccb.balancerMu.Lock()
-						ei.ExitIdle()
-						ccb.balancerMu.Unlock()
-					}
-				}
 			default:
-				logger.Errorf("ccBalancerWrapper.watcher: unknown update %+v, type %T", t, t)
+				logger.Errorf("ccBalancerWrapper.watcher: unknown update %+v, type %T", update, update)
 			}
 		case <-ccb.closed.Done():
 		}
 
 		if ccb.closed.HasFired() {
-			ccb.balancerMu.Lock()
+			ccb.handleClose()
-			ccb.balancer.Close()
-			ccb.balancerMu.Unlock()
-			ccb.mu.Lock()
-			scs := ccb.subConns
-			ccb.subConns = nil
-			ccb.mu.Unlock()
-			ccb.UpdateState(balancer.State{ConnectivityState: connectivity.Connecting, Picker: nil})
-			ccb.done.Fire()
-			// Fire done before removing the addr conns.  We can safely unblock
-			// ccb.close and allow the removeAddrConns to happen
-			// asynchronously.
-			for acbw := range scs {
-				ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain)
-			}
 			return
 		}
 	}
 }
 
-func (ccb *ccBalancerWrapper) close() {
+// updateClientConnState is invoked by grpc to push a ClientConnState update to
-	ccb.closed.Fire()
+// the underlying balancer.
-	<-ccb.done.Done()
+//
+// Unlike other methods invoked by grpc to push updates to the underlying
+// balancer, this method cannot simply push the update onto the update channel
+// and return. It needs to return the error returned by the underlying balancer
+// back to grpc which propagates that to the resolver.
+func (ccb *ccBalancerWrapper) updateClientConnState(ccs *balancer.ClientConnState) error {
+	ccb.updateCh.Put(&ccStateUpdate{ccs: ccs})
+
+	var res interface{}
+	select {
+	case res = <-ccb.resultCh.Get():
+		ccb.resultCh.Load()
+	case <-ccb.closed.Done():
+		// Return early if the balancer wrapper is closed while we are waiting for
+		// the underlying balancer to process a ClientConnState update.
+		return nil
+	}
+	// If the returned error is nil, attempting to type assert to error leads to
+	// panic. So, this needs to handled separately.
+	if res == nil {
+		return nil
+	}
+	return res.(error)
 }
 
-func (ccb *ccBalancerWrapper) exitIdle() bool {
+// handleClientConnStateChange handles a ClientConnState update from the update
-	if !ccb.hasExitIdle {
+// channel and invokes the appropriate method on the underlying balancer.
-		return false
+//
+// If the addresses specified in the update contain addresses of type "grpclb"
+// and the selected LB policy is not "grpclb", these addresses will be filtered
+// out and ccs will be modified with the updated address list.
+func (ccb *ccBalancerWrapper) handleClientConnStateChange(ccs *balancer.ClientConnState) {
+	if ccb.curBalancerName != grpclbName {
+		// Filter any grpclb addresses since we don't have the grpclb balancer.
+		var addrs []resolver.Address
+		for _, addr := range ccs.ResolverState.Addresses {
+			if addr.Type == resolver.GRPCLB {
+				continue
 			}
-	ccb.updateCh.Put(exitIdle{})
+			addrs = append(addrs, addr)
-	return true
+		}
+		ccs.ResolverState.Addresses = addrs
+	}
+	ccb.resultCh.Put(ccb.balancer.UpdateClientConnState(*ccs))
 }
 
-func (ccb *ccBalancerWrapper) handleSubConnStateChange(sc balancer.SubConn, s connectivity.State, err error) {
+// updateSubConnState is invoked by grpc to push a subConn state update to the
+// underlying balancer.
+func (ccb *ccBalancerWrapper) updateSubConnState(sc balancer.SubConn, s connectivity.State, err error) {
 	// When updating addresses for a SubConn, if the address in use is not in
 	// the new addresses, the old ac will be tearDown() and a new ac will be
 	// created. tearDown() generates a state change with Shutdown state, we
@@ -161,44 +209,125 @@ func (ccb *ccBalancerWrapper) handleSubConnStateChange(sc balancer.SubConn, s co
 	})
 }
 
-func (ccb *ccBalancerWrapper) updateClientConnState(ccs *balancer.ClientConnState) error {
+// handleSubConnStateChange handles a SubConnState update from the update
-	ccb.balancerMu.Lock()
+// channel and invokes the appropriate method on the underlying balancer.
-	defer ccb.balancerMu.Unlock()
+func (ccb *ccBalancerWrapper) handleSubConnStateChange(update *scStateUpdate) {
-	return ccb.balancer.UpdateClientConnState(*ccs)
+	ccb.balancer.UpdateSubConnState(update.sc, balancer.SubConnState{ConnectivityState: update.state, ConnectionError: update.err})
+}
+
+func (ccb *ccBalancerWrapper) exitIdle() {
+	ccb.updateCh.Put(&exitIdleUpdate{})
+}
+
+func (ccb *ccBalancerWrapper) handleExitIdle() {
+	if ccb.cc.GetState() != connectivity.Idle {
+		return
+	}
+	ccb.balancer.ExitIdle()
 }
 
 func (ccb *ccBalancerWrapper) resolverError(err error) {
-	ccb.balancerMu.Lock()
+	ccb.updateCh.Put(&resolverErrorUpdate{err: err})
-	defer ccb.balancerMu.Unlock()
+}
+
+func (ccb *ccBalancerWrapper) handleResolverError(err error) {
 	ccb.balancer.ResolverError(err)
 }
 
+// switchTo is invoked by grpc to instruct the balancer wrapper to switch to the
+// LB policy identified by name.
+//
+// ClientConn calls newCCBalancerWrapper() at creation time. Upon receipt of the
+// first good update from the name resolver, it determines the LB policy to use
+// and invokes the switchTo() method. Upon receipt of every subsequent update
+// from the name resolver, it invokes this method.
+//
+// the ccBalancerWrapper keeps track of the current LB policy name, and skips
+// the graceful balancer switching process if the name does not change.
+func (ccb *ccBalancerWrapper) switchTo(name string) {
+	ccb.updateCh.Put(&switchToUpdate{name: name})
+}
+
+// handleSwitchTo handles a balancer switch update from the update channel. It
+// calls the SwitchTo() method on the gracefulswitch.Balancer with a
+// balancer.Builder corresponding to name. If no balancer.Builder is registered
+// for the given name, it uses the default LB policy which is "pick_first".
+func (ccb *ccBalancerWrapper) handleSwitchTo(name string) {
+	// TODO: Other languages use case-insensitive balancer registries. We should
+	// switch as well. See: https://github.com/grpc/grpc-go/issues/5288.
+	if strings.EqualFold(ccb.curBalancerName, name) {
+		return
+	}
+
+	// TODO: Ensure that name is a registered LB policy when we get here.
+	// We currently only validate the `loadBalancingConfig` field. We need to do
+	// the same for the `loadBalancingPolicy` field and reject the service config
+	// if the specified policy is not registered.
+	builder := balancer.Get(name)
+	if builder == nil {
+		channelz.Warningf(logger, ccb.cc.channelzID, "Channel switches to new LB policy %q, since the specified LB policy %q was not registered", PickFirstBalancerName, name)
+		builder = newPickfirstBuilder()
+	} else {
+		channelz.Infof(logger, ccb.cc.channelzID, "Channel switches to new LB policy %q", name)
+	}
+
+	if err := ccb.balancer.SwitchTo(builder); err != nil {
+		channelz.Errorf(logger, ccb.cc.channelzID, "Channel failed to build new LB policy %q: %v", name, err)
+		return
+	}
+	ccb.curBalancerName = builder.Name()
+}
+
+// handleRemoveSucConn handles a request from the underlying balancer to remove
+// a subConn.
+//
+// See comments in RemoveSubConn() for more details.
+func (ccb *ccBalancerWrapper) handleRemoveSubConn(acbw *acBalancerWrapper) {
+	ccb.cc.removeAddrConn(acbw.getAddrConn(), errConnDrain)
+}
+
+func (ccb *ccBalancerWrapper) close() {
+	ccb.closed.Fire()
+	<-ccb.done.Done()
+}
+
+func (ccb *ccBalancerWrapper) handleClose() {
+	ccb.balancer.Close()
+	ccb.done.Fire()
+}
+
 func (ccb *ccBalancerWrapper) NewSubConn(addrs []resolver.Address, opts balancer.NewSubConnOptions) (balancer.SubConn, error) {
 	if len(addrs) <= 0 {
 		return nil, fmt.Errorf("grpc: cannot create SubConn with empty address list")
 	}
-	ccb.mu.Lock()
-	defer ccb.mu.Unlock()
-	if ccb.subConns == nil {
-		return nil, fmt.Errorf("grpc: ClientConn balancer wrapper was closed")
-	}
 	ac, err := ccb.cc.newAddrConn(addrs, opts)
 	if err != nil {
+		channelz.Warningf(logger, ccb.cc.channelzID, "acBalancerWrapper: NewSubConn: failed to newAddrConn: %v", err)
 		return nil, err
 	}
 	acbw := &acBalancerWrapper{ac: ac}
 	acbw.ac.mu.Lock()
 	ac.acbw = acbw
 	acbw.ac.mu.Unlock()
-	ccb.subConns[acbw] = struct{}{}
 	return acbw, nil
 }
 
 func (ccb *ccBalancerWrapper) RemoveSubConn(sc balancer.SubConn) {
-	// The RemoveSubConn() is handled in the run() goroutine, to avoid deadlock
+	// Before we switched the ccBalancerWrapper to use gracefulswitch.Balancer, it
-	// during switchBalancer() if the old balancer calls RemoveSubConn() in its
+	// was required to handle the RemoveSubConn() method asynchronously by pushing
-	// Close().
+	// the update onto the update channel. This was done to avoid a deadlock as
-	ccb.updateCh.Put(sc)
+	// switchBalancer() was holding cc.mu when calling Close() on the old
+	// balancer, which would in turn call RemoveSubConn().
+	//
+	// With the use of gracefulswitch.Balancer in ccBalancerWrapper, handling this
+	// asynchronously is probably not required anymore since the switchTo() method
+	// handles the balancer switch by pushing the update onto the channel.
+	// TODO(easwars): Handle this inline.
+	acbw, ok := sc.(*acBalancerWrapper)
+	if !ok {
+		return
+	}
+	ccb.updateCh.Put(&subConnUpdate{acbw: acbw})
 }
 
 func (ccb *ccBalancerWrapper) UpdateAddresses(sc balancer.SubConn, addrs []resolver.Address) {
@@ -210,11 +339,6 @@ func (ccb *ccBalancerWrapper) UpdateAddresses(sc balancer.SubConn, addrs []resol
 }
 
 func (ccb *ccBalancerWrapper) UpdateState(s balancer.State) {
-	ccb.mu.Lock()
-	defer ccb.mu.Unlock()
-	if ccb.subConns == nil {
-		return
-	}
 	// Update picker before updating state.  Even though the ordering here does
 	// not matter, it can lead to multiple calls of Pick in the common start-up
 	// case where we wait for ready and then perform an RPC.  If the picker is

vendor/google.golang.org/grpc/channelz/channelz.go

@@ -0,0 +1,36 @@
+/*
+ *
+ * Copyright 2020 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package channelz exports internals of the channelz implementation as required
+// by other gRPC packages.
+//
+// The implementation of the channelz spec as defined in
+// https://github.com/grpc/proposal/blob/master/A14-channelz.md, is provided by
+// the `internal/channelz` package.
+//
+// Experimental
+//
+// Notice: All APIs in this package are experimental and may be removed in a
+// later release.
+package channelz
+
+import "google.golang.org/grpc/internal/channelz"
+
+// Identifier is an opaque identifier which uniquely identifies an entity in the
+// channelz database.
+type Identifier = channelz.Identifier

vendor/google.golang.org/grpc/clientconn.go

@@ -159,23 +159,20 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 		}
 	}()
 
-	if channelz.IsOn() {
+	pid := cc.dopts.channelzParentID
-		if cc.dopts.channelzParentID != 0 {
+	cc.channelzID = channelz.RegisterChannel(&channelzChannel{cc}, pid, target)
-			cc.channelzID = channelz.RegisterChannel(&channelzChannel{cc}, cc.dopts.channelzParentID, target)
+	ted := &channelz.TraceEventDesc{
-			channelz.AddTraceEvent(logger, cc.channelzID, 0, &channelz.TraceEventDesc{
+		Desc:     "Channel created",
-				Desc:     "Channel Created",
 		Severity: channelz.CtInfo,
-				Parent: &channelz.TraceEventDesc{
-					Desc:     fmt.Sprintf("Nested Channel(id:%d) created", cc.channelzID),
-					Severity: channelz.CtInfo,
-				},
-			})
-		} else {
-			cc.channelzID = channelz.RegisterChannel(&channelzChannel{cc}, 0, target)
-			channelz.Info(logger, cc.channelzID, "Channel Created")
 	}
+	if cc.dopts.channelzParentID != nil {
+		ted.Parent = &channelz.TraceEventDesc{
+			Desc:     fmt.Sprintf("Nested Channel(id:%d) created", cc.channelzID.Int()),
+			Severity: channelz.CtInfo,
+		}
+	}
+	channelz.AddTraceEvent(logger, cc.channelzID, 1, ted)
 	cc.csMgr.channelzID = cc.channelzID
-	}
 
 	if cc.dopts.copts.TransportCredentials == nil && cc.dopts.copts.CredsBundle == nil {
 		return nil, errNoTransportSecurity
@@ -281,7 +278,7 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 	if creds := cc.dopts.copts.TransportCredentials; creds != nil {
 		credsClone = creds.Clone()
 	}
-	cc.balancerBuildOpts = balancer.BuildOptions{
+	cc.balancerWrapper = newCCBalancerWrapper(cc, balancer.BuildOptions{
 		DialCreds:        credsClone,
 		CredsBundle:      cc.dopts.copts.CredsBundle,
 		Dialer:           cc.dopts.copts.Dialer,
@@ -289,7 +286,7 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 		CustomUserAgent:  cc.dopts.copts.UserAgent,
 		ChannelzParentID: cc.channelzID,
 		Target:           cc.parsedTarget,
-	}
+	})
 
 	// Build the resolver.
 	rWrapper, err := newCCResolverWrapper(cc, resolverBuilder)
@@ -398,7 +395,7 @@ type connectivityStateManager struct {
 	mu         sync.Mutex
 	state      connectivity.State
 	notifyChan chan struct{}
-	channelzID int64
+	channelzID *channelz.Identifier
 }
 
 // updateState updates the connectivity.State of ClientConn.
@@ -464,34 +461,36 @@ var _ ClientConnInterface = (*ClientConn)(nil)
 // handshakes. It also handles errors on established connections by
 // re-resolving the name and reconnecting.
 type ClientConn struct {
-	ctx    context.Context
+	ctx    context.Context    // Initialized using the background context at dial time.
-	cancel context.CancelFunc
+	cancel context.CancelFunc // Cancelled on close.
 
-	target       string
+	// The following are initialized at dial time, and are read-only after that.
-	parsedTarget resolver.Target
+	target          string               // User's dial target.
-	authority    string
+	parsedTarget    resolver.Target      // See parseTargetAndFindResolver().
-	dopts        dialOptions
+	authority       string               // See determineAuthority().
+	dopts           dialOptions          // Default and user specified dial options.
+	channelzID      *channelz.Identifier // Channelz identifier for the channel.
+	balancerWrapper *ccBalancerWrapper   // Uses gracefulswitch.balancer underneath.
+
+	// The following provide their own synchronization, and therefore don't
+	// require cc.mu to be held to access them.
 	csMgr              *connectivityStateManager
-
-	balancerBuildOpts balancer.BuildOptions
 	blockingpicker     *pickerWrapper
-
 	safeConfigSelector iresolver.SafeConfigSelector
+	czData             *channelzData
+	retryThrottler     atomic.Value // Updated from service config.
 
-	mu              sync.RWMutex
+	// firstResolveEvent is used to track whether the name resolver sent us at
-	resolverWrapper *ccResolverWrapper
+	// least one update. RPCs block on this event.
-	sc              *ServiceConfig
-	conns           map[*addrConn]struct{}
-	// Keepalive parameter can be updated if a GoAway is received.
-	mkp             keepalive.ClientParameters
-	curBalancerName string
-	balancerWrapper *ccBalancerWrapper
-	retryThrottler  atomic.Value
-
 	firstResolveEvent *grpcsync.Event
 
-	channelzID int64 // channelz unique identification number
+	// mu protects the following fields.
-	czData     *channelzData
+	// TODO: split mu so the same mutex isn't used for everything.
+	mu              sync.RWMutex
+	resolverWrapper *ccResolverWrapper         // Initialized in Dial; cleared in Close.
+	sc              *ServiceConfig             // Latest service config received from the resolver.
+	conns           map[*addrConn]struct{}     // Set to nil on close.
+	mkp             keepalive.ClientParameters // May be updated upon receipt of a GoAway.
 
 	lceMu               sync.Mutex // protects lastConnectionError
 	lastConnectionError error
@@ -536,14 +535,7 @@ func (cc *ClientConn) GetState() connectivity.State {
 // Notice: This API is EXPERIMENTAL and may be changed or removed in a later
 // release.
 func (cc *ClientConn) Connect() {
-	cc.mu.Lock()
+	cc.balancerWrapper.exitIdle()
-	defer cc.mu.Unlock()
-	if cc.balancerWrapper != nil && cc.balancerWrapper.exitIdle() {
-		return
-	}
-	for ac := range cc.conns {
-		go ac.connect()
-	}
 }
 
 func (cc *ClientConn) scWatcher() {
@@ -623,9 +615,7 @@ func (cc *ClientConn) updateResolverState(s resolver.State, err error) error {
 		// with the new addresses.
 		cc.maybeApplyDefaultServiceConfig(nil)
 
-		if cc.balancerWrapper != nil {
 		cc.balancerWrapper.resolverError(err)
-		}
 
 		// No addresses are valid with err set; return early.
 		cc.mu.Unlock()
@@ -653,16 +643,10 @@ func (cc *ClientConn) updateResolverState(s resolver.State, err error) error {
 			cc.applyServiceConfigAndBalancer(sc, configSelector, s.Addresses)
 		} else {
 			ret = balancer.ErrBadResolverState
-			if cc.balancerWrapper == nil {
+			if cc.sc == nil {
-				var err error
+				// Apply the failing LB only if we haven't received valid service config
-				if s.ServiceConfig.Err != nil {
+				// from the name resolver in the past.
-					err = status.Errorf(codes.Unavailable, "error parsing service config: %v", s.ServiceConfig.Err)
+				cc.applyFailingLB(s.ServiceConfig)
-				} else {
-					err = status.Errorf(codes.Unavailable, "illegal service config type: %T", s.ServiceConfig.Config)
-				}
-				cc.safeConfigSelector.UpdateConfigSelector(&defaultConfigSelector{cc.sc})
-				cc.blockingpicker.updatePicker(base.NewErrPicker(err))
-				cc.csMgr.updateState(connectivity.TransientFailure)
 				cc.mu.Unlock()
 				return ret
 			}
@@ -670,24 +654,12 @@ func (cc *ClientConn) updateResolverState(s resolver.State, err error) error {
 	}
 
 	var balCfg serviceconfig.LoadBalancingConfig
-	if cc.dopts.balancerBuilder == nil && cc.sc != nil && cc.sc.lbConfig != nil {
+	if cc.sc != nil && cc.sc.lbConfig != nil {
 		balCfg = cc.sc.lbConfig.cfg
 	}
-
-	cbn := cc.curBalancerName
 	bw := cc.balancerWrapper
 	cc.mu.Unlock()
-	if cbn != grpclbName {
+
-		// Filter any grpclb addresses since we don't have the grpclb balancer.
-		for i := 0; i < len(s.Addresses); {
-			if s.Addresses[i].Type == resolver.GRPCLB {
-				copy(s.Addresses[i:], s.Addresses[i+1:])
-				s.Addresses = s.Addresses[:len(s.Addresses)-1]
-				continue
-			}
-			i++
-		}
-	}
 	uccsErr := bw.updateClientConnState(&balancer.ClientConnState{ResolverState: s, BalancerConfig: balCfg})
 	if ret == nil {
 		ret = uccsErr // prefer ErrBadResolver state since any other error is
@@ -696,56 +668,28 @@ func (cc *ClientConn) updateResolverState(s resolver.State, err error) error {
 	return ret
 }
 
-// switchBalancer starts the switching from current balancer to the balancer
+// applyFailingLB is akin to configuring an LB policy on the channel which
-// with the given name.
+// always fails RPCs. Here, an actual LB policy is not configured, but an always
-//
+// erroring picker is configured, which returns errors with information about
-// It will NOT send the current address list to the new balancer. If needed,
+// what was invalid in the received service config. A config selector with no
-// caller of this function should send address list to the new balancer after
+// service config is configured, and the connectivity state of the channel is
-// this function returns.
+// set to TransientFailure.
 //
 // Caller must hold cc.mu.
-func (cc *ClientConn) switchBalancer(name string) {
+func (cc *ClientConn) applyFailingLB(sc *serviceconfig.ParseResult) {
-	if strings.EqualFold(cc.curBalancerName, name) {
+	var err error
-		return
+	if sc.Err != nil {
-	}
+		err = status.Errorf(codes.Unavailable, "error parsing service config: %v", sc.Err)
-
-	channelz.Infof(logger, cc.channelzID, "ClientConn switching balancer to %q", name)
-	if cc.dopts.balancerBuilder != nil {
-		channelz.Info(logger, cc.channelzID, "ignoring balancer switching: Balancer DialOption used instead")
-		return
-	}
-	if cc.balancerWrapper != nil {
-		// Don't hold cc.mu while closing the balancers. The balancers may call
-		// methods that require cc.mu (e.g. cc.NewSubConn()). Holding the mutex
-		// would cause a deadlock in that case.
-		cc.mu.Unlock()
-		cc.balancerWrapper.close()
-		cc.mu.Lock()
-	}
-
-	builder := balancer.Get(name)
-	if builder == nil {
-		channelz.Warningf(logger, cc.channelzID, "Channel switches to new LB policy %q due to fallback from invalid balancer name", PickFirstBalancerName)
-		channelz.Infof(logger, cc.channelzID, "failed to get balancer builder for: %v, using pick_first instead", name)
-		builder = newPickfirstBuilder()
 	} else {
-		channelz.Infof(logger, cc.channelzID, "Channel switches to new LB policy %q", name)
+		err = status.Errorf(codes.Unavailable, "illegal service config type: %T", sc.Config)
 	}
-
+	cc.safeConfigSelector.UpdateConfigSelector(&defaultConfigSelector{nil})
-	cc.curBalancerName = builder.Name()
+	cc.blockingpicker.updatePicker(base.NewErrPicker(err))
-	cc.balancerWrapper = newCCBalancerWrapper(cc, builder, cc.balancerBuildOpts)
+	cc.csMgr.updateState(connectivity.TransientFailure)
 }
 
 func (cc *ClientConn) handleSubConnStateChange(sc balancer.SubConn, s connectivity.State, err error) {
-	cc.mu.Lock()
+	cc.balancerWrapper.updateSubConnState(sc, s, err)
-	if cc.conns == nil {
-		cc.mu.Unlock()
-		return
-	}
-	// TODO(bar switching) send updates to all balancer wrappers when balancer
-	// gracefully switching is supported.
-	cc.balancerWrapper.handleSubConnStateChange(sc, s, err)
-	cc.mu.Unlock()
 }
 
 // newAddrConn creates an addrConn for addrs and adds it to cc.conns.
@@ -768,17 +712,21 @@ func (cc *ClientConn) newAddrConn(addrs []resolver.Address, opts balancer.NewSub
 		cc.mu.Unlock()
 		return nil, ErrClientConnClosing
 	}
-	if channelz.IsOn() {
+
-		ac.channelzID = channelz.RegisterSubChannel(ac, cc.channelzID, "")
+	var err error
+	ac.channelzID, err = channelz.RegisterSubChannel(ac, cc.channelzID, "")
+	if err != nil {
+		return nil, err
+	}
 	channelz.AddTraceEvent(logger, ac.channelzID, 0, &channelz.TraceEventDesc{
-			Desc:     "Subchannel Created",
+		Desc:     "Subchannel created",
 		Severity: channelz.CtInfo,
 		Parent: &channelz.TraceEventDesc{
-				Desc:     fmt.Sprintf("Subchannel(id:%d) created", ac.channelzID),
+			Desc:     fmt.Sprintf("Subchannel(id:%d) created", ac.channelzID.Int()),
 			Severity: channelz.CtInfo,
 		},
 	})
-	}
+
 	cc.conns[ac] = struct{}{}
 	cc.mu.Unlock()
 	return ac, nil
@@ -991,9 +939,6 @@ func (cc *ClientConn) applyServiceConfigAndBalancer(sc *ServiceConfig, configSel
 		cc.retryThrottler.Store((*retryThrottler)(nil))
 	}
 
-	if cc.dopts.balancerBuilder == nil {
-		// Only look at balancer types and switch balancer if balancer dial
-		// option is not set.
 	var newBalancerName string
 	if cc.sc != nil && cc.sc.lbConfig != nil {
 		newBalancerName = cc.sc.lbConfig.name
@@ -1013,13 +958,7 @@ func (cc *ClientConn) applyServiceConfigAndBalancer(sc *ServiceConfig, configSel
 			newBalancerName = PickFirstBalancerName
 		}
 	}
-		cc.switchBalancer(newBalancerName)
+	cc.balancerWrapper.switchTo(newBalancerName)
-	} else if cc.balancerWrapper == nil {
-		// Balancer dial option was set, and this is the first time handling
-		// resolved addresses. Build a balancer with dopts.balancerBuilder.
-		cc.curBalancerName = cc.dopts.balancerBuilder.Name()
-		cc.balancerWrapper = newCCBalancerWrapper(cc, cc.dopts.balancerBuilder, cc.balancerBuildOpts)
-	}
 }
 
 func (cc *ClientConn) resolveNow(o resolver.ResolveNowOptions) {
@@ -1070,11 +1009,11 @@ func (cc *ClientConn) Close() error {
 	rWrapper := cc.resolverWrapper
 	cc.resolverWrapper = nil
 	bWrapper := cc.balancerWrapper
-	cc.balancerWrapper = nil
 	cc.mu.Unlock()
 
+	// The order of closing matters here since the balancer wrapper assumes the
+	// picker is closed before it is closed.
 	cc.blockingpicker.close()
-
 	if bWrapper != nil {
 		bWrapper.close()
 	}
@@ -1085,22 +1024,22 @@ func (cc *ClientConn) Close() error {
 	for ac := range conns {
 		ac.tearDown(ErrClientConnClosing)
 	}
-	if channelz.IsOn() {
 	ted := &channelz.TraceEventDesc{
-			Desc:     "Channel Deleted",
+		Desc:     "Channel deleted",
 		Severity: channelz.CtInfo,
 	}
-		if cc.dopts.channelzParentID != 0 {
+	if cc.dopts.channelzParentID != nil {
 		ted.Parent = &channelz.TraceEventDesc{
-				Desc:     fmt.Sprintf("Nested channel(id:%d) deleted", cc.channelzID),
+			Desc:     fmt.Sprintf("Nested channel(id:%d) deleted", cc.channelzID.Int()),
 			Severity: channelz.CtInfo,
 		}
 	}
 	channelz.AddTraceEvent(logger, cc.channelzID, 0, ted)
-		// TraceEvent needs to be called before RemoveEntry, as TraceEvent may add trace reference to
+	// TraceEvent needs to be called before RemoveEntry, as TraceEvent may add
-		// the entity being deleted, and thus prevent it from being deleted right away.
+	// trace reference to the entity being deleted, and thus prevent it from being
+	// deleted right away.
 	channelz.RemoveEntry(cc.channelzID)
-	}
+
 	return nil
 }
 
@@ -1130,7 +1069,7 @@ type addrConn struct {
 	backoffIdx   int // Needs to be stateful for resetConnectBackoff.
 	resetBackoff chan struct{}
 
-	channelzID int64 // channelz unique identification number.
+	channelzID *channelz.Identifier
 	czData     *channelzData
 }
 
@@ -1312,14 +1251,12 @@ func (ac *addrConn) createTransport(addr resolver.Address, copts transport.Conne
 
 	connectCtx, cancel := context.WithDeadline(ac.ctx, connectDeadline)
 	defer cancel()
-	if channelz.IsOn() {
 	copts.ChannelzParentID = ac.channelzID
-	}
 
 	newTr, err := transport.NewClientTransport(connectCtx, ac.cc.ctx, addr, copts, func() { prefaceReceived.Fire() }, onGoAway, onClose)
 	if err != nil {
 		// newTr is either nil, or closed.
-		channelz.Warningf(logger, ac.channelzID, "grpc: addrConn.createTransport failed to connect to %v. Err: %v", addr, err)
+		channelz.Warningf(logger, ac.channelzID, "grpc: addrConn.createTransport failed to connect to %s. Err: %v", addr, err)
 		return err
 	}
 
@@ -1332,7 +1269,7 @@ func (ac *addrConn) createTransport(addr resolver.Address, copts transport.Conne
 		newTr.Close(transport.ErrConnClosing)
 		if connectCtx.Err() == context.DeadlineExceeded {
 			err := errors.New("failed to receive server preface within timeout")
-			channelz.Warningf(logger, ac.channelzID, "grpc: addrConn.createTransport failed to connect to %v: %v", addr, err)
+			channelz.Warningf(logger, ac.channelzID, "grpc: addrConn.createTransport failed to connect to %s: %v", addr, err)
 			return err
 		}
 		return nil
@@ -1497,19 +1434,18 @@ func (ac *addrConn) tearDown(err error) {
 		curTr.GracefulClose()
 		ac.mu.Lock()
 	}
-	if channelz.IsOn() {
 	channelz.AddTraceEvent(logger, ac.channelzID, 0, &channelz.TraceEventDesc{
-			Desc:     "Subchannel Deleted",
+		Desc:     "Subchannel deleted",
 		Severity: channelz.CtInfo,
 		Parent: &channelz.TraceEventDesc{
-				Desc:     fmt.Sprintf("Subchanel(id:%d) deleted", ac.channelzID),
+			Desc:     fmt.Sprintf("Subchannel(id:%d) deleted", ac.channelzID.Int()),
 			Severity: channelz.CtInfo,
 		},
 	})
-		// TraceEvent needs to be called before RemoveEntry, as TraceEvent may add trace reference to
+	// TraceEvent needs to be called before RemoveEntry, as TraceEvent may add
-		// the entity being deleted, and thus prevent it from being deleted right away.
+	// trace reference to the entity being deleted, and thus prevent it from
+	// being deleted right away.
 	channelz.RemoveEntry(ac.channelzID)
-	}
 	ac.mu.Unlock()
 }
 

vendor/google.golang.org/grpc/dialoptions.go

@@ -20,12 +20,11 @@ package grpc
 
 import (
 	"context"
-	"fmt"
 	"net"
 	"time"
 
 	"google.golang.org/grpc/backoff"
-	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/channelz"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/credentials/insecure"
 	"google.golang.org/grpc/internal"
@@ -55,9 +54,7 @@ type dialOptions struct {
 	authority                   string
 	copts                       transport.ConnectOptions
 	callOptions                 []CallOption
-	// This is used by WithBalancerName dial option.
+	channelzParentID            *channelz.Identifier
-	balancerBuilder             balancer.Builder
-	channelzParentID            int64
 	disableServiceConfig        bool
 	disableRetry                bool
 	disableHealthCheck          bool
@@ -195,25 +192,6 @@ func WithDecompressor(dc Decompressor) DialOption {
 	})
 }
 
-// WithBalancerName sets the balancer that the ClientConn will be initialized
-// with. Balancer registered with balancerName will be used. This function
-// panics if no balancer was registered by balancerName.
-//
-// The balancer cannot be overridden by balancer option specified by service
-// config.
-//
-// Deprecated: use WithDefaultServiceConfig and WithDisableServiceConfig
-// instead.  Will be removed in a future 1.x release.
-func WithBalancerName(balancerName string) DialOption {
-	builder := balancer.Get(balancerName)
-	if builder == nil {
-		panic(fmt.Sprintf("grpc.WithBalancerName: no balancer is registered for name %v", balancerName))
-	}
-	return newFuncDialOption(func(o *dialOptions) {
-		o.balancerBuilder = builder
-	})
-}
-
 // WithServiceConfig returns a DialOption which has a channel to read the
 // service configuration.
 //
@@ -304,8 +282,8 @@ func WithReturnConnectionError() DialOption {
 // WithCredentialsBundle or WithPerRPCCredentials) which require transport
 // security is incompatible and will cause grpc.Dial() to fail.
 //
-// Deprecated: use WithTransportCredentials and insecure.NewCredentials() instead.
+// Deprecated: use WithTransportCredentials and insecure.NewCredentials()
-// Will be supported throughout 1.x.
+// instead. Will be supported throughout 1.x.
 func WithInsecure() DialOption {
 	return newFuncDialOption(func(o *dialOptions) {
 		o.copts.TransportCredentials = insecure.NewCredentials()
@@ -498,7 +476,7 @@ func WithAuthority(a string) DialOption {
 //
 // Notice: This API is EXPERIMENTAL and may be changed or removed in a
 // later release.
-func WithChannelzParentID(id int64) DialOption {
+func WithChannelzParentID(id *channelz.Identifier) DialOption {
 	return newFuncDialOption(func(o *dialOptions) {
 		o.channelzParentID = id
 	})

vendor/google.golang.org/grpc/internal/balancer/gracefulswitch/gracefulswitch.go

@@ -0,0 +1,382 @@
+/*
+ *
+ * Copyright 2022 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package gracefulswitch implements a graceful switch load balancer.
+package gracefulswitch
+
+import (
+	"errors"
+	"fmt"
+	"sync"
+
+	"google.golang.org/grpc/balancer"
+	"google.golang.org/grpc/balancer/base"
+	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/resolver"
+)
+
+var errBalancerClosed = errors.New("gracefulSwitchBalancer is closed")
+var _ balancer.Balancer = (*Balancer)(nil)
+
+// NewBalancer returns a graceful switch Balancer.
+func NewBalancer(cc balancer.ClientConn, opts balancer.BuildOptions) *Balancer {
+	return &Balancer{
+		cc:    cc,
+		bOpts: opts,
+	}
+}
+
+// Balancer is a utility to gracefully switch from one balancer to
+// a new balancer. It implements the balancer.Balancer interface.
+type Balancer struct {
+	bOpts balancer.BuildOptions
+	cc    balancer.ClientConn
+
+	// mu protects the following fields and all fields within balancerCurrent
+	// and balancerPending. mu does not need to be held when calling into the
+	// child balancers, as all calls into these children happen only as a direct
+	// result of a call into the gracefulSwitchBalancer, which are also
+	// guaranteed to be synchronous. There is one exception: an UpdateState call
+	// from a child balancer when current and pending are populated can lead to
+	// calling Close() on the current. To prevent that racing with an
+	// UpdateSubConnState from the channel, we hold currentMu during Close and
+	// UpdateSubConnState calls.
+	mu              sync.Mutex
+	balancerCurrent *balancerWrapper
+	balancerPending *balancerWrapper
+	closed          bool // set to true when this balancer is closed
+
+	// currentMu must be locked before mu. This mutex guards against this
+	// sequence of events: UpdateSubConnState() called, finds the
+	// balancerCurrent, gives up lock, updateState comes in, causes Close() on
+	// balancerCurrent before the UpdateSubConnState is called on the
+	// balancerCurrent.
+	currentMu sync.Mutex
+}
+
+// swap swaps out the current lb with the pending lb and updates the ClientConn.
+// The caller must hold gsb.mu.
+func (gsb *Balancer) swap() {
+	gsb.cc.UpdateState(gsb.balancerPending.lastState)
+	cur := gsb.balancerCurrent
+	gsb.balancerCurrent = gsb.balancerPending
+	gsb.balancerPending = nil
+	go func() {
+		gsb.currentMu.Lock()
+		defer gsb.currentMu.Unlock()
+		cur.Close()
+	}()
+}
+
+// Helper function that checks if the balancer passed in is current or pending.
+// The caller must hold gsb.mu.
+func (gsb *Balancer) balancerCurrentOrPending(bw *balancerWrapper) bool {
+	return bw == gsb.balancerCurrent || bw == gsb.balancerPending
+}
+
+// SwitchTo initializes the graceful switch process, which completes based on
+// connectivity state changes on the current/pending balancer. Thus, the switch
+// process is not complete when this method returns. This method must be called
+// synchronously alongside the rest of the balancer.Balancer methods this
+// Graceful Switch Balancer implements.
+func (gsb *Balancer) SwitchTo(builder balancer.Builder) error {
+	gsb.mu.Lock()
+	if gsb.closed {
+		gsb.mu.Unlock()
+		return errBalancerClosed
+	}
+	bw := &balancerWrapper{
+		gsb: gsb,
+		lastState: balancer.State{
+			ConnectivityState: connectivity.Connecting,
+			Picker:            base.NewErrPicker(balancer.ErrNoSubConnAvailable),
+		},
+		subconns: make(map[balancer.SubConn]bool),
+	}
+	balToClose := gsb.balancerPending // nil if there is no pending balancer
+	if gsb.balancerCurrent == nil {
+		gsb.balancerCurrent = bw
+	} else {
+		gsb.balancerPending = bw
+	}
+	gsb.mu.Unlock()
+	balToClose.Close()
+	// This function takes a builder instead of a balancer because builder.Build
+	// can call back inline, and this utility needs to handle the callbacks.
+	newBalancer := builder.Build(bw, gsb.bOpts)
+	if newBalancer == nil {
+		// This is illegal and should never happen; we clear the balancerWrapper
+		// we were constructing if it happens to avoid a potential panic.
+		gsb.mu.Lock()
+		if gsb.balancerPending != nil {
+			gsb.balancerPending = nil
+		} else {
+			gsb.balancerCurrent = nil
+		}
+		gsb.mu.Unlock()
+		return balancer.ErrBadResolverState
+	}
+
+	// This write doesn't need to take gsb.mu because this field never gets read
+	// or written to on any calls from the current or pending. Calls from grpc
+	// to this balancer are guaranteed to be called synchronously, so this
+	// bw.Balancer field will never be forwarded to until this SwitchTo()
+	// function returns.
+	bw.Balancer = newBalancer
+	return nil
+}
+
+// Returns nil if the graceful switch balancer is closed.
+func (gsb *Balancer) latestBalancer() *balancerWrapper {
+	gsb.mu.Lock()
+	defer gsb.mu.Unlock()
+	if gsb.balancerPending != nil {
+		return gsb.balancerPending
+	}
+	return gsb.balancerCurrent
+}
+
+// UpdateClientConnState forwards the update to the latest balancer created.
+func (gsb *Balancer) UpdateClientConnState(state balancer.ClientConnState) error {
+	// The resolver data is only relevant to the most recent LB Policy.
+	balToUpdate := gsb.latestBalancer()
+	if balToUpdate == nil {
+		return errBalancerClosed
+	}
+	// Perform this call without gsb.mu to prevent deadlocks if the child calls
+	// back into the channel. The latest balancer can never be closed during a
+	// call from the channel, even without gsb.mu held.
+	return balToUpdate.UpdateClientConnState(state)
+}
+
+// ResolverError forwards the error to the latest balancer created.
+func (gsb *Balancer) ResolverError(err error) {
+	// The resolver data is only relevant to the most recent LB Policy.
+	balToUpdate := gsb.latestBalancer()
+	if balToUpdate == nil {
+		return
+	}
+	// Perform this call without gsb.mu to prevent deadlocks if the child calls
+	// back into the channel. The latest balancer can never be closed during a
+	// call from the channel, even without gsb.mu held.
+	balToUpdate.ResolverError(err)
+}
+
+// ExitIdle forwards the call to the latest balancer created.
+//
+// If the latest balancer does not support ExitIdle, the subConns are
+// re-connected to manually.
+func (gsb *Balancer) ExitIdle() {
+	balToUpdate := gsb.latestBalancer()
+	if balToUpdate == nil {
+		return
+	}
+	// There is no need to protect this read with a mutex, as the write to the
+	// Balancer field happens in SwitchTo, which completes before this can be
+	// called.
+	if ei, ok := balToUpdate.Balancer.(balancer.ExitIdler); ok {
+		ei.ExitIdle()
+		return
+	}
+	for sc := range balToUpdate.subconns {
+		sc.Connect()
+	}
+}
+
+// UpdateSubConnState forwards the update to the appropriate child.
+func (gsb *Balancer) UpdateSubConnState(sc balancer.SubConn, state balancer.SubConnState) {
+	gsb.currentMu.Lock()
+	defer gsb.currentMu.Unlock()
+	gsb.mu.Lock()
+	// Forward update to the appropriate child.  Even if there is a pending
+	// balancer, the current balancer should continue to get SubConn updates to
+	// maintain the proper state while the pending is still connecting.
+	var balToUpdate *balancerWrapper
+	if gsb.balancerCurrent != nil && gsb.balancerCurrent.subconns[sc] {
+		balToUpdate = gsb.balancerCurrent
+	} else if gsb.balancerPending != nil && gsb.balancerPending.subconns[sc] {
+		balToUpdate = gsb.balancerPending
+	}
+	gsb.mu.Unlock()
+	if balToUpdate == nil {
+		// SubConn belonged to a stale lb policy that has not yet fully closed,
+		// or the balancer was already closed.
+		return
+	}
+	balToUpdate.UpdateSubConnState(sc, state)
+}
+
+// Close closes any active child balancers.
+func (gsb *Balancer) Close() {
+	gsb.mu.Lock()
+	gsb.closed = true
+	currentBalancerToClose := gsb.balancerCurrent
+	gsb.balancerCurrent = nil
+	pendingBalancerToClose := gsb.balancerPending
+	gsb.balancerPending = nil
+	gsb.mu.Unlock()
+
+	currentBalancerToClose.Close()
+	pendingBalancerToClose.Close()
+}
+
+// balancerWrapper wraps a balancer.Balancer, and overrides some Balancer
+// methods to help cleanup SubConns created by the wrapped balancer.
+//
+// It implements the balancer.ClientConn interface and is passed down in that
+// capacity to the wrapped balancer. It maintains a set of subConns created by
+// the wrapped balancer and calls from the latter to create/update/remove
+// SubConns update this set before being forwarded to the parent ClientConn.
+// State updates from the wrapped balancer can result in invocation of the
+// graceful switch logic.
+type balancerWrapper struct {
+	balancer.Balancer
+	gsb *Balancer
+
+	lastState balancer.State
+	subconns  map[balancer.SubConn]bool // subconns created by this balancer
+}
+
+func (bw *balancerWrapper) UpdateSubConnState(sc balancer.SubConn, state balancer.SubConnState) {
+	if state.ConnectivityState == connectivity.Shutdown {
+		bw.gsb.mu.Lock()
+		delete(bw.subconns, sc)
+		bw.gsb.mu.Unlock()
+	}
+	// There is no need to protect this read with a mutex, as the write to the
+	// Balancer field happens in SwitchTo, which completes before this can be
+	// called.
+	bw.Balancer.UpdateSubConnState(sc, state)
+}
+
+// Close closes the underlying LB policy and removes the subconns it created. bw
+// must not be referenced via balancerCurrent or balancerPending in gsb when
+// called. gsb.mu must not be held.  Does not panic with a nil receiver.
+func (bw *balancerWrapper) Close() {
+	// before Close is called.
+	if bw == nil {
+		return
+	}
+	// There is no need to protect this read with a mutex, as Close() is
+	// impossible to be called concurrently with the write in SwitchTo(). The
+	// callsites of Close() for this balancer in Graceful Switch Balancer will
+	// never be called until SwitchTo() returns.
+	bw.Balancer.Close()
+	bw.gsb.mu.Lock()
+	for sc := range bw.subconns {
+		bw.gsb.cc.RemoveSubConn(sc)
+	}
+	bw.gsb.mu.Unlock()
+}
+
+func (bw *balancerWrapper) UpdateState(state balancer.State) {
+	// Hold the mutex for this entire call to ensure it cannot occur
+	// concurrently with other updateState() calls. This causes updates to
+	// lastState and calls to cc.UpdateState to happen atomically.
+	bw.gsb.mu.Lock()
+	defer bw.gsb.mu.Unlock()
+	bw.lastState = state
+
+	if !bw.gsb.balancerCurrentOrPending(bw) {
+		return
+	}
+
+	if bw == bw.gsb.balancerCurrent {
+		// In the case that the current balancer exits READY, and there is a pending
+		// balancer, you can forward the pending balancer's cached State up to
+		// ClientConn and swap the pending into the current. This is because there
+		// is no reason to gracefully switch from and keep using the old policy as
+		// the ClientConn is not connected to any backends.
+		if state.ConnectivityState != connectivity.Ready && bw.gsb.balancerPending != nil {
+			bw.gsb.swap()
+			return
+		}
+		// Even if there is a pending balancer waiting to be gracefully switched to,
+		// continue to forward current balancer updates to the Client Conn. Ignoring
+		// state + picker from the current would cause undefined behavior/cause the
+		// system to behave incorrectly from the current LB policies perspective.
+		// Also, the current LB is still being used by grpc to choose SubConns per
+		// RPC, and thus should use the most updated form of the current balancer.
+		bw.gsb.cc.UpdateState(state)
+		return
+	}
+	// This method is now dealing with a state update from the pending balancer.
+	// If the current balancer is currently in a state other than READY, the new
+	// policy can be swapped into place immediately. This is because there is no
+	// reason to gracefully switch from and keep using the old policy as the
+	// ClientConn is not connected to any backends.
+	if state.ConnectivityState != connectivity.Connecting || bw.gsb.balancerCurrent.lastState.ConnectivityState != connectivity.Ready {
+		bw.gsb.swap()
+	}
+}
+
+func (bw *balancerWrapper) NewSubConn(addrs []resolver.Address, opts balancer.NewSubConnOptions) (balancer.SubConn, error) {
+	bw.gsb.mu.Lock()
+	if !bw.gsb.balancerCurrentOrPending(bw) {
+		bw.gsb.mu.Unlock()
+		return nil, fmt.Errorf("%T at address %p that called NewSubConn is deleted", bw, bw)
+	}
+	bw.gsb.mu.Unlock()
+
+	sc, err := bw.gsb.cc.NewSubConn(addrs, opts)
+	if err != nil {
+		return nil, err
+	}
+	bw.gsb.mu.Lock()
+	if !bw.gsb.balancerCurrentOrPending(bw) { // balancer was closed during this call
+		bw.gsb.cc.RemoveSubConn(sc)
+		bw.gsb.mu.Unlock()
+		return nil, fmt.Errorf("%T at address %p that called NewSubConn is deleted", bw, bw)
+	}
+	bw.subconns[sc] = true
+	bw.gsb.mu.Unlock()
+	return sc, nil
+}
+
+func (bw *balancerWrapper) ResolveNow(opts resolver.ResolveNowOptions) {
+	// Ignore ResolveNow requests from anything other than the most recent
+	// balancer, because older balancers were already removed from the config.
+	if bw != bw.gsb.latestBalancer() {
+		return
+	}
+	bw.gsb.cc.ResolveNow(opts)
+}
+
+func (bw *balancerWrapper) RemoveSubConn(sc balancer.SubConn) {
+	bw.gsb.mu.Lock()
+	if !bw.gsb.balancerCurrentOrPending(bw) {
+		bw.gsb.mu.Unlock()
+		return
+	}
+	bw.gsb.mu.Unlock()
+	bw.gsb.cc.RemoveSubConn(sc)
+}
+
+func (bw *balancerWrapper) UpdateAddresses(sc balancer.SubConn, addrs []resolver.Address) {
+	bw.gsb.mu.Lock()
+	if !bw.gsb.balancerCurrentOrPending(bw) {
+		bw.gsb.mu.Unlock()
+		return
+	}
+	bw.gsb.mu.Unlock()
+	bw.gsb.cc.UpdateAddresses(sc, addrs)
+}
+
+func (bw *balancerWrapper) Target() string {
+	return bw.gsb.cc.Target()
+}

vendor/google.golang.org/grpc/internal/binarylog/binarylog.go

@@ -31,7 +31,7 @@ import (
 // Logger is the global binary logger. It can be used to get binary logger for
 // each method.
 type Logger interface {
-	getMethodLogger(methodName string) *MethodLogger
+	GetMethodLogger(methodName string) MethodLogger
 }
 
 // binLogger is the global binary logger for the binary. One of this should be
@@ -49,17 +49,24 @@ func SetLogger(l Logger) {
 	binLogger = l
 }
 
+// GetLogger gets the binarg logger.
+//
+// Only call this at init time.
+func GetLogger() Logger {
+	return binLogger
+}
+
 // GetMethodLogger returns the methodLogger for the given methodName.
 //
 // methodName should be in the format of "/service/method".
 //
 // Each methodLogger returned by this method is a new instance. This is to
 // generate sequence id within the call.
-func GetMethodLogger(methodName string) *MethodLogger {
+func GetMethodLogger(methodName string) MethodLogger {
 	if binLogger == nil {
 		return nil
 	}
-	return binLogger.getMethodLogger(methodName)
+	return binLogger.GetMethodLogger(methodName)
 }
 
 func init() {
@@ -68,17 +75,29 @@ func init() {
 	binLogger = NewLoggerFromConfigString(configStr)
 }
 
-type methodLoggerConfig struct {
+// MethodLoggerConfig contains the setting for logging behavior of a method
+// logger. Currently, it contains the max length of header and message.
+type MethodLoggerConfig struct {
 	// Max length of header and message.
-	hdr, msg uint64
+	Header, Message uint64
+}
+
+// LoggerConfig contains the config for loggers to create method loggers.
+type LoggerConfig struct {
+	All      *MethodLoggerConfig
+	Services map[string]*MethodLoggerConfig
+	Methods  map[string]*MethodLoggerConfig
+
+	Blacklist map[string]struct{}
 }
 
 type logger struct {
-	all      *methodLoggerConfig
+	config LoggerConfig
-	services map[string]*methodLoggerConfig
+}
-	methods  map[string]*methodLoggerConfig
 
-	blacklist map[string]struct{}
+// NewLoggerFromConfig builds a logger with the given LoggerConfig.
+func NewLoggerFromConfig(config LoggerConfig) Logger {
+	return &logger{config: config}
 }
 
 // newEmptyLogger creates an empty logger. The map fields need to be filled in
@@ -88,57 +107,57 @@ func newEmptyLogger() *logger {
 }
 
 // Set method logger for "*".
-func (l *logger) setDefaultMethodLogger(ml *methodLoggerConfig) error {
+func (l *logger) setDefaultMethodLogger(ml *MethodLoggerConfig) error {
-	if l.all != nil {
+	if l.config.All != nil {
 		return fmt.Errorf("conflicting global rules found")
 	}
-	l.all = ml
+	l.config.All = ml
 	return nil
 }
 
 // Set method logger for "service/*".
 //
 // New methodLogger with same service overrides the old one.
-func (l *logger) setServiceMethodLogger(service string, ml *methodLoggerConfig) error {
+func (l *logger) setServiceMethodLogger(service string, ml *MethodLoggerConfig) error {
-	if _, ok := l.services[service]; ok {
+	if _, ok := l.config.Services[service]; ok {
 		return fmt.Errorf("conflicting service rules for service %v found", service)
 	}
-	if l.services == nil {
+	if l.config.Services == nil {
-		l.services = make(map[string]*methodLoggerConfig)
+		l.config.Services = make(map[string]*MethodLoggerConfig)
 	}
-	l.services[service] = ml
+	l.config.Services[service] = ml
 	return nil
 }
 
 // Set method logger for "service/method".
 //
 // New methodLogger with same method overrides the old one.
-func (l *logger) setMethodMethodLogger(method string, ml *methodLoggerConfig) error {
+func (l *logger) setMethodMethodLogger(method string, ml *MethodLoggerConfig) error {
-	if _, ok := l.blacklist[method]; ok {
+	if _, ok := l.config.Blacklist[method]; ok {
 		return fmt.Errorf("conflicting blacklist rules for method %v found", method)
 	}
-	if _, ok := l.methods[method]; ok {
+	if _, ok := l.config.Methods[method]; ok {
 		return fmt.Errorf("conflicting method rules for method %v found", method)
 	}
-	if l.methods == nil {
+	if l.config.Methods == nil {
-		l.methods = make(map[string]*methodLoggerConfig)
+		l.config.Methods = make(map[string]*MethodLoggerConfig)
 	}
-	l.methods[method] = ml
+	l.config.Methods[method] = ml
 	return nil
 }
 
 // Set blacklist method for "-service/method".
 func (l *logger) setBlacklist(method string) error {
-	if _, ok := l.blacklist[method]; ok {
+	if _, ok := l.config.Blacklist[method]; ok {
 		return fmt.Errorf("conflicting blacklist rules for method %v found", method)
 	}
-	if _, ok := l.methods[method]; ok {
+	if _, ok := l.config.Methods[method]; ok {
 		return fmt.Errorf("conflicting method rules for method %v found", method)
 	}
-	if l.blacklist == nil {
+	if l.config.Blacklist == nil {
-		l.blacklist = make(map[string]struct{})
+		l.config.Blacklist = make(map[string]struct{})
 	}
-	l.blacklist[method] = struct{}{}
+	l.config.Blacklist[method] = struct{}{}
 	return nil
 }
 
@@ -148,23 +167,23 @@ func (l *logger) setBlacklist(method string) error {
 //
 // Each methodLogger returned by this method is a new instance. This is to
 // generate sequence id within the call.
-func (l *logger) getMethodLogger(methodName string) *MethodLogger {
+func (l *logger) GetMethodLogger(methodName string) MethodLogger {
 	s, m, err := grpcutil.ParseMethod(methodName)
 	if err != nil {
 		grpclogLogger.Infof("binarylogging: failed to parse %q: %v", methodName, err)
 		return nil
 	}
-	if ml, ok := l.methods[s+"/"+m]; ok {
+	if ml, ok := l.config.Methods[s+"/"+m]; ok {
-		return newMethodLogger(ml.hdr, ml.msg)
+		return newMethodLogger(ml.Header, ml.Message)
 	}
-	if _, ok := l.blacklist[s+"/"+m]; ok {
+	if _, ok := l.config.Blacklist[s+"/"+m]; ok {
 		return nil
 	}
-	if ml, ok := l.services[s]; ok {
+	if ml, ok := l.config.Services[s]; ok {
-		return newMethodLogger(ml.hdr, ml.msg)
+		return newMethodLogger(ml.Header, ml.Message)
 	}
-	if l.all == nil {
+	if l.config.All == nil {
 		return nil
 	}
-	return newMethodLogger(l.all.hdr, l.all.msg)
+	return newMethodLogger(l.config.All.Header, l.config.All.Message)
 }

vendor/google.golang.org/grpc/internal/binarylog/env_config.go

@@ -89,7 +89,7 @@ func (l *logger) fillMethodLoggerWithConfigString(config string) error {
 		if err != nil {
 			return fmt.Errorf("invalid config: %q, %v", config, err)
 		}
-		if err := l.setDefaultMethodLogger(&methodLoggerConfig{hdr: hdr, msg: msg}); err != nil {
+		if err := l.setDefaultMethodLogger(&MethodLoggerConfig{Header: hdr, Message: msg}); err != nil {
 			return fmt.Errorf("invalid config: %v", err)
 		}
 		return nil
@@ -104,11 +104,11 @@ func (l *logger) fillMethodLoggerWithConfigString(config string) error {
 		return fmt.Errorf("invalid header/message length config: %q, %v", suffix, err)
 	}
 	if m == "*" {
-		if err := l.setServiceMethodLogger(s, &methodLoggerConfig{hdr: hdr, msg: msg}); err != nil {
+		if err := l.setServiceMethodLogger(s, &MethodLoggerConfig{Header: hdr, Message: msg}); err != nil {
 			return fmt.Errorf("invalid config: %v", err)
 		}
 	} else {
-		if err := l.setMethodMethodLogger(s+"/"+m, &methodLoggerConfig{hdr: hdr, msg: msg}); err != nil {
+		if err := l.setMethodMethodLogger(s+"/"+m, &MethodLoggerConfig{Header: hdr, Message: msg}); err != nil {
 			return fmt.Errorf("invalid config: %v", err)
 		}
 	}

vendor/google.golang.org/grpc/internal/binarylog/method_logger.go

@@ -48,7 +48,11 @@ func (g *callIDGenerator) reset() {
 var idGen callIDGenerator
 
 // MethodLogger is the sub-logger for each method.
-type MethodLogger struct {
+type MethodLogger interface {
+	Log(LogEntryConfig)
+}
+
+type methodLogger struct {
 	headerMaxLen, messageMaxLen uint64
 
 	callID          uint64
@@ -57,8 +61,8 @@ type MethodLogger struct {
 	sink Sink // TODO(blog): make this plugable.
 }
 
-func newMethodLogger(h, m uint64) *MethodLogger {
+func newMethodLogger(h, m uint64) *methodLogger {
-	return &MethodLogger{
+	return &methodLogger{
 		headerMaxLen:  h,
 		messageMaxLen: m,
 
@@ -69,8 +73,10 @@ func newMethodLogger(h, m uint64) *MethodLogger {
 	}
 }
 
-// Log creates a proto binary log entry, and logs it to the sink.
+// Build is an internal only method for building the proto message out of the
-func (ml *MethodLogger) Log(c LogEntryConfig) {
+// input event. It's made public to enable other library to reuse as much logic
+// in methodLogger as possible.
+func (ml *methodLogger) Build(c LogEntryConfig) *pb.GrpcLogEntry {
 	m := c.toProto()
 	timestamp, _ := ptypes.TimestampProto(time.Now())
 	m.Timestamp = timestamp
@@ -85,11 +91,15 @@ func (ml *MethodLogger) Log(c LogEntryConfig) {
 	case *pb.GrpcLogEntry_Message:
 		m.PayloadTruncated = ml.truncateMessage(pay.Message)
 	}
-
+	return m
-	ml.sink.Write(m)
 }
 
-func (ml *MethodLogger) truncateMetadata(mdPb *pb.Metadata) (truncated bool) {
+// Log creates a proto binary log entry, and logs it to the sink.
+func (ml *methodLogger) Log(c LogEntryConfig) {
+	ml.sink.Write(ml.Build(c))
+}
+
+func (ml *methodLogger) truncateMetadata(mdPb *pb.Metadata) (truncated bool) {
 	if ml.headerMaxLen == maxUInt {
 		return false
 	}
@@ -119,7 +129,7 @@ func (ml *MethodLogger) truncateMetadata(mdPb *pb.Metadata) (truncated bool) {
 	return truncated
 }
 
-func (ml *MethodLogger) truncateMessage(msgPb *pb.Message) (truncated bool) {
+func (ml *methodLogger) truncateMessage(msgPb *pb.Message) (truncated bool) {
 	if ml.messageMaxLen == maxUInt {
 		return false
 	}

vendor/google.golang.org/grpc/internal/channelz/funcs.go

@@ -25,6 +25,7 @@ package channelz
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"sort"
 	"sync"
@@ -184,54 +185,77 @@ func GetServer(id int64) *ServerMetric {
 	return db.get().GetServer(id)
 }
 
-// RegisterChannel registers the given channel c in channelz database with ref
+// RegisterChannel registers the given channel c in the channelz database with
-// as its reference name, and add it to the child list of its parent (identified
+// ref as its reference name, and adds it to the child list of its parent
-// by pid). pid = 0 means no parent. It returns the unique channelz tracking id
+// (identified by pid). pid == nil means no parent.
-// assigned to this channel.
+//
-func RegisterChannel(c Channel, pid int64, ref string) int64 {
+// Returns a unique channelz identifier assigned to this channel.
+//
+// If channelz is not turned ON, the channelz database is not mutated.
+func RegisterChannel(c Channel, pid *Identifier, ref string) *Identifier {
 	id := idGen.genID()
+	var parent int64
+	isTopChannel := true
+	if pid != nil {
+		isTopChannel = false
+		parent = pid.Int()
+	}
+
+	if !IsOn() {
+		return newIdentifer(RefChannel, id, pid)
+	}
+
 	cn := &channel{
 		refName:     ref,
 		c:           c,
 		subChans:    make(map[int64]string),
 		nestedChans: make(map[int64]string),
 		id:          id,
-		pid:         pid,
+		pid:         parent,
 		trace:       &channelTrace{createdTime: time.Now(), events: make([]*TraceEvent, 0, getMaxTraceEntry())},
 	}
-	if pid == 0 {
+	db.get().addChannel(id, cn, isTopChannel, parent)
-		db.get().addChannel(id, cn, true, pid)
+	return newIdentifer(RefChannel, id, pid)
-	} else {
-		db.get().addChannel(id, cn, false, pid)
-	}
-	return id
 }
 
-// RegisterSubChannel registers the given channel c in channelz database with ref
+// RegisterSubChannel registers the given subChannel c in the channelz database
-// as its reference name, and add it to the child list of its parent (identified
+// with ref as its reference name, and adds it to the child list of its parent
-// by pid). It returns the unique channelz tracking id assigned to this subchannel.
+// (identified by pid).
-func RegisterSubChannel(c Channel, pid int64, ref string) int64 {
+//
-	if pid == 0 {
+// Returns a unique channelz identifier assigned to this subChannel.
-		logger.Error("a SubChannel's parent id cannot be 0")
+//
-		return 0
+// If channelz is not turned ON, the channelz database is not mutated.
+func RegisterSubChannel(c Channel, pid *Identifier, ref string) (*Identifier, error) {
+	if pid == nil {
+		return nil, errors.New("a SubChannel's parent id cannot be nil")
 	}
 	id := idGen.genID()
+	if !IsOn() {
+		return newIdentifer(RefSubChannel, id, pid), nil
+	}
+
 	sc := &subChannel{
 		refName: ref,
 		c:       c,
 		sockets: make(map[int64]string),
 		id:      id,
-		pid:     pid,
+		pid:     pid.Int(),
 		trace:   &channelTrace{createdTime: time.Now(), events: make([]*TraceEvent, 0, getMaxTraceEntry())},
 	}
-	db.get().addSubChannel(id, sc, pid)
+	db.get().addSubChannel(id, sc, pid.Int())
-	return id
+	return newIdentifer(RefSubChannel, id, pid), nil
 }
 
 // RegisterServer registers the given server s in channelz database. It returns
 // the unique channelz tracking id assigned to this server.
-func RegisterServer(s Server, ref string) int64 {
+//
+// If channelz is not turned ON, the channelz database is not mutated.
+func RegisterServer(s Server, ref string) *Identifier {
 	id := idGen.genID()
+	if !IsOn() {
+		return newIdentifer(RefServer, id, nil)
+	}
+
 	svr := &server{
 		refName:       ref,
 		s:             s,
@@ -240,71 +264,92 @@ func RegisterServer(s Server, ref string) int64 {
 		id:            id,
 	}
 	db.get().addServer(id, svr)
-	return id
+	return newIdentifer(RefServer, id, nil)
 }
 
 // RegisterListenSocket registers the given listen socket s in channelz database
 // with ref as its reference name, and add it to the child list of its parent
 // (identified by pid). It returns the unique channelz tracking id assigned to
 // this listen socket.
-func RegisterListenSocket(s Socket, pid int64, ref string) int64 {
+//
-	if pid == 0 {
+// If channelz is not turned ON, the channelz database is not mutated.
-		logger.Error("a ListenSocket's parent id cannot be 0")
+func RegisterListenSocket(s Socket, pid *Identifier, ref string) (*Identifier, error) {
-		return 0
+	if pid == nil {
+		return nil, errors.New("a ListenSocket's parent id cannot be 0")
 	}
 	id := idGen.genID()
-	ls := &listenSocket{refName: ref, s: s, id: id, pid: pid}
+	if !IsOn() {
-	db.get().addListenSocket(id, ls, pid)
+		return newIdentifer(RefListenSocket, id, pid), nil
-	return id
+	}
+
+	ls := &listenSocket{refName: ref, s: s, id: id, pid: pid.Int()}
+	db.get().addListenSocket(id, ls, pid.Int())
+	return newIdentifer(RefListenSocket, id, pid), nil
 }
 
 // RegisterNormalSocket registers the given normal socket s in channelz database
-// with ref as its reference name, and add it to the child list of its parent
+// with ref as its reference name, and adds it to the child list of its parent
 // (identified by pid). It returns the unique channelz tracking id assigned to
 // this normal socket.
-func RegisterNormalSocket(s Socket, pid int64, ref string) int64 {
+//
-	if pid == 0 {
+// If channelz is not turned ON, the channelz database is not mutated.
-		logger.Error("a NormalSocket's parent id cannot be 0")
+func RegisterNormalSocket(s Socket, pid *Identifier, ref string) (*Identifier, error) {
-		return 0
+	if pid == nil {
+		return nil, errors.New("a NormalSocket's parent id cannot be 0")
 	}
 	id := idGen.genID()
-	ns := &normalSocket{refName: ref, s: s, id: id, pid: pid}
+	if !IsOn() {
-	db.get().addNormalSocket(id, ns, pid)
+		return newIdentifer(RefNormalSocket, id, pid), nil
-	return id
+	}
+
+	ns := &normalSocket{refName: ref, s: s, id: id, pid: pid.Int()}
+	db.get().addNormalSocket(id, ns, pid.Int())
+	return newIdentifer(RefNormalSocket, id, pid), nil
 }
 
 // RemoveEntry removes an entry with unique channelz tracking id to be id from
 // channelz database.
-func RemoveEntry(id int64) {
+//
-	db.get().removeEntry(id)
+// If channelz is not turned ON, this function is a no-op.
+func RemoveEntry(id *Identifier) {
+	if !IsOn() {
+		return
+	}
+	db.get().removeEntry(id.Int())
 }
 
-// TraceEventDesc is what the caller of AddTraceEvent should provide to describe the event to be added
+// TraceEventDesc is what the caller of AddTraceEvent should provide to describe
-// to the channel trace.
+// the event to be added to the channel trace.
-// The Parent field is optional. It is used for event that will be recorded in the entity's parent
+//
-// trace also.
+// The Parent field is optional. It is used for an event that will be recorded
+// in the entity's parent trace.
 type TraceEventDesc struct {
 	Desc     string
 	Severity Severity
 	Parent   *TraceEventDesc
 }
 
-// AddTraceEvent adds trace related to the entity with specified id, using the provided TraceEventDesc.
+// AddTraceEvent adds trace related to the entity with specified id, using the
-func AddTraceEvent(l grpclog.DepthLoggerV2, id int64, depth int, desc *TraceEventDesc) {
+// provided TraceEventDesc.
-	for d := desc; d != nil; d = d.Parent {
+//
-		switch d.Severity {
+// If channelz is not turned ON, this will simply log the event descriptions.
+func AddTraceEvent(l grpclog.DepthLoggerV2, id *Identifier, depth int, desc *TraceEventDesc) {
+	// Log only the trace description associated with the bottom most entity.
+	switch desc.Severity {
 	case CtUnknown, CtInfo:
-			l.InfoDepth(depth+1, d.Desc)
+		l.InfoDepth(depth+1, withParens(id)+desc.Desc)
 	case CtWarning:
-			l.WarningDepth(depth+1, d.Desc)
+		l.WarningDepth(depth+1, withParens(id)+desc.Desc)
 	case CtError:
-			l.ErrorDepth(depth+1, d.Desc)
+		l.ErrorDepth(depth+1, withParens(id)+desc.Desc)
-		}
 	}
+
 	if getMaxTraceEntry() == 0 {
 		return
 	}
-	db.get().traceEvent(id, desc)
+	if IsOn() {
+		db.get().traceEvent(id.Int(), desc)
+	}
 }
 
 // channelMap is the storage data structure for channelz.

vendor/google.golang.org/grpc/internal/channelz/id.go

@@ -0,0 +1,75 @@
+/*
+ *
+ * Copyright 2022 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package channelz
+
+import "fmt"
+
+// Identifier is an opaque identifier which uniquely identifies an entity in the
+// channelz database.
+type Identifier struct {
+	typ RefChannelType
+	id  int64
+	str string
+	pid *Identifier
+}
+
+// Type returns the entity type corresponding to id.
+func (id *Identifier) Type() RefChannelType {
+	return id.typ
+}
+
+// Int returns the integer identifier corresponding to id.
+func (id *Identifier) Int() int64 {
+	return id.id
+}
+
+// String returns a string representation of the entity corresponding to id.
+//
+// This includes some information about the parent as well. Examples:
+// Top-level channel: [Channel #channel-number]
+// Nested channel:    [Channel #parent-channel-number Channel #channel-number]
+// Sub channel:       [Channel #parent-channel SubChannel #subchannel-number]
+func (id *Identifier) String() string {
+	return id.str
+}
+
+// Equal returns true if other is the same as id.
+func (id *Identifier) Equal(other *Identifier) bool {
+	if (id != nil) != (other != nil) {
+		return false
+	}
+	if id == nil && other == nil {
+		return true
+	}
+	return id.typ == other.typ && id.id == other.id && id.pid == other.pid
+}
+
+// NewIdentifierForTesting returns a new opaque identifier to be used only for
+// testing purposes.
+func NewIdentifierForTesting(typ RefChannelType, id int64, pid *Identifier) *Identifier {
+	return newIdentifer(typ, id, pid)
+}
+
+func newIdentifer(typ RefChannelType, id int64, pid *Identifier) *Identifier {
+	str := fmt.Sprintf("%s #%d", typ, id)
+	if pid != nil {
+		str = fmt.Sprintf("%s %s", pid, str)
+	}
+	return &Identifier{typ: typ, id: id, str: str, pid: pid}
+}

vendor/google.golang.org/grpc/internal/channelz/logging.go

@@ -26,77 +26,54 @@ import (
 
 var logger = grpclog.Component("channelz")
 
+func withParens(id *Identifier) string {
+	return "[" + id.String() + "] "
+}
+
 // Info logs and adds a trace event if channelz is on.
-func Info(l grpclog.DepthLoggerV2, id int64, args ...interface{}) {
+func Info(l grpclog.DepthLoggerV2, id *Identifier, args ...interface{}) {
-	if IsOn() {
 	AddTraceEvent(l, id, 1, &TraceEventDesc{
 		Desc:     fmt.Sprint(args...),
 		Severity: CtInfo,
 	})
-	} else {
-		l.InfoDepth(1, args...)
-	}
 }
 
 // Infof logs and adds a trace event if channelz is on.
-func Infof(l grpclog.DepthLoggerV2, id int64, format string, args ...interface{}) {
+func Infof(l grpclog.DepthLoggerV2, id *Identifier, format string, args ...interface{}) {
-	msg := fmt.Sprintf(format, args...)
-	if IsOn() {
 	AddTraceEvent(l, id, 1, &TraceEventDesc{
-			Desc:     msg,
+		Desc:     fmt.Sprintf(format, args...),
 		Severity: CtInfo,
 	})
-	} else {
-		l.InfoDepth(1, msg)
-	}
 }
 
 // Warning logs and adds a trace event if channelz is on.
-func Warning(l grpclog.DepthLoggerV2, id int64, args ...interface{}) {
+func Warning(l grpclog.DepthLoggerV2, id *Identifier, args ...interface{}) {
-	if IsOn() {
 	AddTraceEvent(l, id, 1, &TraceEventDesc{
 		Desc:     fmt.Sprint(args...),
 		Severity: CtWarning,
 	})
-	} else {
-		l.WarningDepth(1, args...)
-	}
 }
 
 // Warningf logs and adds a trace event if channelz is on.
-func Warningf(l grpclog.DepthLoggerV2, id int64, format string, args ...interface{}) {
+func Warningf(l grpclog.DepthLoggerV2, id *Identifier, format string, args ...interface{}) {
-	msg := fmt.Sprintf(format, args...)
-	if IsOn() {
 	AddTraceEvent(l, id, 1, &TraceEventDesc{
-			Desc:     msg,
+		Desc:     fmt.Sprintf(format, args...),
 		Severity: CtWarning,
 	})
-	} else {
-		l.WarningDepth(1, msg)
-	}
 }
 
 // Error logs and adds a trace event if channelz is on.
-func Error(l grpclog.DepthLoggerV2, id int64, args ...interface{}) {
+func Error(l grpclog.DepthLoggerV2, id *Identifier, args ...interface{}) {
-	if IsOn() {
 	AddTraceEvent(l, id, 1, &TraceEventDesc{
 		Desc:     fmt.Sprint(args...),
 		Severity: CtError,
 	})
-	} else {
-		l.ErrorDepth(1, args...)
-	}
 }
 
 // Errorf logs and adds a trace event if channelz is on.
-func Errorf(l grpclog.DepthLoggerV2, id int64, format string, args ...interface{}) {
+func Errorf(l grpclog.DepthLoggerV2, id *Identifier, format string, args ...interface{}) {
-	msg := fmt.Sprintf(format, args...)
-	if IsOn() {
 	AddTraceEvent(l, id, 1, &TraceEventDesc{
-			Desc:     msg,
+		Desc:     fmt.Sprintf(format, args...),
 		Severity: CtError,
 	})
-	} else {
-		l.ErrorDepth(1, msg)
-	}
 }

vendor/google.golang.org/grpc/internal/channelz/types.go

@@ -686,12 +686,33 @@ const (
 type RefChannelType int
 
 const (
+	// RefUnknown indicates an unknown entity type, the zero value for this type.
+	RefUnknown RefChannelType = iota
 	// RefChannel indicates the referenced entity is a Channel.
-	RefChannel RefChannelType = iota
+	RefChannel
 	// RefSubChannel indicates the referenced entity is a SubChannel.
 	RefSubChannel
+	// RefServer indicates the referenced entity is a Server.
+	RefServer
+	// RefListenSocket indicates the referenced entity is a ListenSocket.
+	RefListenSocket
+	// RefNormalSocket indicates the referenced entity is a NormalSocket.
+	RefNormalSocket
 )
 
+var refChannelTypeToString = map[RefChannelType]string{
+	RefUnknown:      "Unknown",
+	RefChannel:      "Channel",
+	RefSubChannel:   "SubChannel",
+	RefServer:       "Server",
+	RefListenSocket: "ListenSocket",
+	RefNormalSocket: "NormalSocket",
+}
+
+func (r RefChannelType) String() string {
+	return refChannelTypeToString[r]
+}
+
 func (c *channelTrace) dumpData() *ChannelTrace {
 	c.mu.Lock()
 	ct := &ChannelTrace{EventNum: c.eventCount, CreationTime: c.createdTime}

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

@@ -85,3 +85,9 @@ const (
 	// that supports backend returned by grpclb balancer.
 	CredsBundleModeBackendFromBalancer = "backend-from-balancer"
 )
+
+// RLSLoadBalancingPolicyName is the name of the RLS LB policy.
+//
+// It currently has an experimental suffix which would be removed once
+// end-to-end testing of the policy is completed.
+const RLSLoadBalancingPolicyName = "rls_experimental"

vendor/google.golang.org/grpc/internal/metadata/metadata.go

@@ -22,6 +22,9 @@
 package metadata
 
 import (
+	"fmt"
+	"strings"
+
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/resolver"
 )
@@ -72,3 +75,46 @@ func Set(addr resolver.Address, md metadata.MD) resolver.Address {
 	addr.Attributes = addr.Attributes.WithValue(mdKey, mdValue(md))
 	return addr
 }
+
+// Validate returns an error if the input md contains invalid keys or values.
+//
+// If the header is not a pseudo-header, the following items are checked:
+// - header names must contain one or more characters from this set [0-9 a-z _ - .].
+// - if the header-name ends with a "-bin" suffix, no validation of the header value is performed.
+// - otherwise, the header value must contain one or more characters from the set [%x20-%x7E].
+func Validate(md metadata.MD) error {
+	for k, vals := range md {
+		// pseudo-header will be ignored
+		if k[0] == ':' {
+			continue
+		}
+		// check key, for i that saving a conversion if not using for range
+		for i := 0; i < len(k); i++ {
+			r := k[i]
+			if !(r >= 'a' && r <= 'z') && !(r >= '0' && r <= '9') && r != '.' && r != '-' && r != '_' {
+				return fmt.Errorf("header key %q contains illegal characters not in [0-9a-z-_.]", k)
+			}
+		}
+		if strings.HasSuffix(k, "-bin") {
+			continue
+		}
+		// check value
+		for _, val := range vals {
+			if hasNotPrintable(val) {
+				return fmt.Errorf("header key %q contains value with non-printable ASCII characters", k)
+			}
+		}
+	}
+	return nil
+}
+
+// hasNotPrintable return true if msg contains any characters which are not in %x20-%x7E
+func hasNotPrintable(msg string) bool {
+	// for i that saving a conversion if not using for range
+	for i := 0; i < len(msg); i++ {
+		if msg[i] < 0x20 || msg[i] > 0x7E {
+			return true
+		}
+	}
+	return false
+}

vendor/google.golang.org/grpc/internal/pretty/pretty.go

@@ -0,0 +1,82 @@
+/*
+ *
+ * Copyright 2021 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package pretty defines helper functions to pretty-print structs for logging.
+package pretty
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+
+	"github.com/golang/protobuf/jsonpb"
+	protov1 "github.com/golang/protobuf/proto"
+	"google.golang.org/protobuf/encoding/protojson"
+	protov2 "google.golang.org/protobuf/proto"
+)
+
+const jsonIndent = "  "
+
+// ToJSON marshals the input into a json string.
+//
+// If marshal fails, it falls back to fmt.Sprintf("%+v").
+func ToJSON(e interface{}) string {
+	switch ee := e.(type) {
+	case protov1.Message:
+		mm := jsonpb.Marshaler{Indent: jsonIndent}
+		ret, err := mm.MarshalToString(ee)
+		if err != nil {
+			// This may fail for proto.Anys, e.g. for xDS v2, LDS, the v2
+			// messages are not imported, and this will fail because the message
+			// is not found.
+			return fmt.Sprintf("%+v", ee)
+		}
+		return ret
+	case protov2.Message:
+		mm := protojson.MarshalOptions{
+			Multiline: true,
+			Indent:    jsonIndent,
+		}
+		ret, err := mm.Marshal(ee)
+		if err != nil {
+			// This may fail for proto.Anys, e.g. for xDS v2, LDS, the v2
+			// messages are not imported, and this will fail because the message
+			// is not found.
+			return fmt.Sprintf("%+v", ee)
+		}
+		return string(ret)
+	default:
+		ret, err := json.MarshalIndent(ee, "", jsonIndent)
+		if err != nil {
+			return fmt.Sprintf("%+v", ee)
+		}
+		return string(ret)
+	}
+}
+
+// FormatJSON formats the input json bytes with indentation.
+//
+// If Indent fails, it returns the unchanged input as string.
+func FormatJSON(b []byte) string {
+	var out bytes.Buffer
+	err := json.Indent(&out, b, "", jsonIndent)
+	if err != nil {
+		return string(b)
+	}
+	return out.String()
+}

vendor/google.golang.org/grpc/internal/transport/http2_client.go

@@ -132,7 +132,7 @@ type http2Client struct {
 	kpDormant bool
 
 	// Fields below are for channelz metric collection.
-	channelzID int64 // channelz unique identification number
+	channelzID *channelz.Identifier
 	czData     *channelzData
 
 	onGoAway func(GoAwayReason)
@@ -351,8 +351,9 @@ func newHTTP2Client(connectCtx, ctx context.Context, addr resolver.Address, opts
 		}
 		t.statsHandler.HandleConn(t.ctx, connBegin)
 	}
-	if channelz.IsOn() {
+	t.channelzID, err = channelz.RegisterNormalSocket(t, opts.ChannelzParentID, fmt.Sprintf("%s -> %s", t.localAddr, t.remoteAddr))
-		t.channelzID = channelz.RegisterNormalSocket(t, opts.ChannelzParentID, fmt.Sprintf("%s -> %s", t.localAddr, t.remoteAddr))
+	if err != nil {
+		return nil, err
 	}
 	if t.keepaliveEnabled {
 		t.kpDormancyCond = sync.NewCond(&t.mu)
@@ -898,9 +899,7 @@ func (t *http2Client) Close(err error) {
 	t.controlBuf.finish()
 	t.cancel()
 	t.conn.Close()
-	if channelz.IsOn() {
 	channelz.RemoveEntry(t.channelzID)
-	}
 	// Append info about previous goaways if there were any, since this may be important
 	// for understanding the root cause for this connection to be closed.
 	_, goAwayDebugMessage := t.GetGoAwayReason()

vendor/google.golang.org/grpc/internal/transport/http2_server.go

@@ -36,6 +36,7 @@ import (
 	"golang.org/x/net/http2"
 	"golang.org/x/net/http2/hpack"
 	"google.golang.org/grpc/internal/grpcutil"
+	"google.golang.org/grpc/internal/syscall"
 
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/credentials"
@@ -117,7 +118,7 @@ type http2Server struct {
 	idle time.Time
 
 	// Fields below are for channelz metric collection.
-	channelzID int64 // channelz unique identification number
+	channelzID *channelz.Identifier
 	czData     *channelzData
 	bufferPool *bufferPool
 
@@ -231,6 +232,11 @@ func NewServerTransport(conn net.Conn, config *ServerConfig) (_ ServerTransport,
 	if kp.Timeout == 0 {
 		kp.Timeout = defaultServerKeepaliveTimeout
 	}
+	if kp.Time != infinity {
+		if err = syscall.SetTCPUserTimeout(conn, kp.Timeout); err != nil {
+			return nil, connectionErrorf(false, err, "transport: failed to set TCP_USER_TIMEOUT: %v", err)
+		}
+	}
 	kep := config.KeepalivePolicy
 	if kep.MinTime == 0 {
 		kep.MinTime = defaultKeepalivePolicyMinTime
@@ -275,12 +281,12 @@ func NewServerTransport(conn net.Conn, config *ServerConfig) (_ ServerTransport,
 		connBegin := &stats.ConnBegin{}
 		t.stats.HandleConn(t.ctx, connBegin)
 	}
-	if channelz.IsOn() {
+	t.channelzID, err = channelz.RegisterNormalSocket(t, config.ChannelzParentID, fmt.Sprintf("%s -> %s", t.remoteAddr, t.localAddr))
-		t.channelzID = channelz.RegisterNormalSocket(t, config.ChannelzParentID, fmt.Sprintf("%s -> %s", t.remoteAddr, t.localAddr))
+	if err != nil {
+		return nil, err
 	}
 
 	t.connectionID = atomic.AddUint64(&serverConnectionCounter, 1)
-
 	t.framer.writer.Flush()
 
 	defer func() {
@@ -1210,9 +1216,7 @@ func (t *http2Server) Close() {
 	if err := t.conn.Close(); err != nil && logger.V(logLevel) {
 		logger.Infof("transport: error closing conn during Close: %v", err)
 	}
-	if channelz.IsOn() {
 	channelz.RemoveEntry(t.channelzID)
-	}
 	// Cancel all active streams.
 	for _, s := range streams {
 		s.cancel()

vendor/google.golang.org/grpc/internal/transport/transport.go

@@ -34,6 +34,7 @@ import (
 
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/internal/channelz"
 	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/resolver"
@@ -529,7 +530,7 @@ type ServerConfig struct {
 	InitialConnWindowSize int32
 	WriteBufferSize       int
 	ReadBufferSize        int
-	ChannelzParentID      int64
+	ChannelzParentID      *channelz.Identifier
 	MaxHeaderListSize     *uint32
 	HeaderTableSize       *uint32
 }
@@ -563,7 +564,7 @@ type ConnectOptions struct {
 	// ReadBufferSize sets the size of read buffer, which in turn determines how much data can be read at most for one read syscall.
 	ReadBufferSize int
 	// ChannelzParentID sets the addrConn id which initiate the creation of this client transport.
-	ChannelzParentID int64
+	ChannelzParentID *channelz.Identifier
 	// MaxHeaderListSize sets the max (uncompressed) size of header list that is prepared to be received.
 	MaxHeaderListSize *uint32
 	// UseProxy specifies if a proxy should be used.

vendor/google.golang.org/grpc/metadata/metadata.go

@@ -188,7 +188,9 @@ func FromIncomingContext(ctx context.Context) (MD, bool) {
 		// map, and there's no guarantee that the MD attached to the context is
 		// created using our helper functions.
 		key := strings.ToLower(k)
-		out[key] = v
+		s := make([]string, len(v))
+		copy(s, v)
+		out[key] = s
 	}
 	return out, true
 }
@@ -226,7 +228,9 @@ func FromOutgoingContext(ctx context.Context) (MD, bool) {
 		// map, and there's no guarantee that the MD attached to the context is
 		// created using our helper functions.
 		key := strings.ToLower(k)
-		out[key] = v
+		s := make([]string, len(v))
+		copy(s, v)
+		out[key] = s
 	}
 	for _, added := range raw.added {
 		if len(added)%2 == 1 {

vendor/google.golang.org/grpc/pickfirst.go

@@ -46,77 +46,105 @@ func (*pickfirstBuilder) Name() string {
 type pickfirstBalancer struct {
 	state   connectivity.State
 	cc      balancer.ClientConn
-	sc    balancer.SubConn
+	subConn balancer.SubConn
 }
 
 func (b *pickfirstBalancer) ResolverError(err error) {
-	switch b.state {
-	case connectivity.TransientFailure, connectivity.Idle, connectivity.Connecting:
-		// Set a failing picker if we don't have a good picker.
-		b.cc.UpdateState(balancer.State{ConnectivityState: connectivity.TransientFailure,
-			Picker: &picker{err: fmt.Errorf("name resolver error: %v", err)},
-		})
-	}
 	if logger.V(2) {
 		logger.Infof("pickfirstBalancer: ResolverError called with error %v", err)
 	}
+	if b.subConn == nil {
+		b.state = connectivity.TransientFailure
 	}
 
-func (b *pickfirstBalancer) UpdateClientConnState(cs balancer.ClientConnState) error {
+	if b.state != connectivity.TransientFailure {
-	if len(cs.ResolverState.Addresses) == 0 {
+		// The picker will not change since the balancer does not currently
+		// report an error.
+		return
+	}
+	b.cc.UpdateState(balancer.State{
+		ConnectivityState: connectivity.TransientFailure,
+		Picker:            &picker{err: fmt.Errorf("name resolver error: %v", err)},
+	})
+}
+
+func (b *pickfirstBalancer) UpdateClientConnState(state balancer.ClientConnState) error {
+	if len(state.ResolverState.Addresses) == 0 {
+		// The resolver reported an empty address list. Treat it like an error by
+		// calling b.ResolverError.
+		if b.subConn != nil {
+			// Remove the old subConn. All addresses were removed, so it is no longer
+			// valid.
+			b.cc.RemoveSubConn(b.subConn)
+			b.subConn = nil
+		}
 		b.ResolverError(errors.New("produced zero addresses"))
 		return balancer.ErrBadResolverState
 	}
-	if b.sc == nil {
+
-		var err error
+	if b.subConn != nil {
-		b.sc, err = b.cc.NewSubConn(cs.ResolverState.Addresses, balancer.NewSubConnOptions{})
+		b.cc.UpdateAddresses(b.subConn, state.ResolverState.Addresses)
+		return nil
+	}
+
+	subConn, err := b.cc.NewSubConn(state.ResolverState.Addresses, balancer.NewSubConnOptions{})
 	if err != nil {
 		if logger.V(2) {
 			logger.Errorf("pickfirstBalancer: failed to NewSubConn: %v", err)
 		}
 		b.state = connectivity.TransientFailure
-			b.cc.UpdateState(balancer.State{ConnectivityState: connectivity.TransientFailure,
+		b.cc.UpdateState(balancer.State{
+			ConnectivityState: connectivity.TransientFailure,
 			Picker:            &picker{err: fmt.Errorf("error creating connection: %v", err)},
 		})
 		return balancer.ErrBadResolverState
 	}
+	b.subConn = subConn
 	b.state = connectivity.Idle
-		b.cc.UpdateState(balancer.State{ConnectivityState: connectivity.Idle, Picker: &picker{result: balancer.PickResult{SubConn: b.sc}}})
+	b.cc.UpdateState(balancer.State{
-		b.sc.Connect()
+		ConnectivityState: connectivity.Idle,
-	} else {
+		Picker:            &picker{result: balancer.PickResult{SubConn: b.subConn}},
-		b.cc.UpdateAddresses(b.sc, cs.ResolverState.Addresses)
+	})
-		b.sc.Connect()
+	b.subConn.Connect()
-	}
 	return nil
 }
 
-func (b *pickfirstBalancer) UpdateSubConnState(sc balancer.SubConn, s balancer.SubConnState) {
+func (b *pickfirstBalancer) UpdateSubConnState(subConn balancer.SubConn, state balancer.SubConnState) {
 	if logger.V(2) {
-		logger.Infof("pickfirstBalancer: UpdateSubConnState: %p, %v", sc, s)
+		logger.Infof("pickfirstBalancer: UpdateSubConnState: %p, %v", subConn, state)
 	}
-	if b.sc != sc {
+	if b.subConn != subConn {
 		if logger.V(2) {
-			logger.Infof("pickfirstBalancer: ignored state change because sc is not recognized")
+			logger.Infof("pickfirstBalancer: ignored state change because subConn is not recognized")
 		}
 		return
 	}
-	b.state = s.ConnectivityState
+	b.state = state.ConnectivityState
-	if s.ConnectivityState == connectivity.Shutdown {
+	if state.ConnectivityState == connectivity.Shutdown {
-		b.sc = nil
+		b.subConn = nil
 		return
 	}
 
-	switch s.ConnectivityState {
+	switch state.ConnectivityState {
 	case connectivity.Ready:
-		b.cc.UpdateState(balancer.State{ConnectivityState: s.ConnectivityState, Picker: &picker{result: balancer.PickResult{SubConn: sc}}})
+		b.cc.UpdateState(balancer.State{
+			ConnectivityState: state.ConnectivityState,
+			Picker:            &picker{result: balancer.PickResult{SubConn: subConn}},
+		})
 	case connectivity.Connecting:
-		b.cc.UpdateState(balancer.State{ConnectivityState: s.ConnectivityState, Picker: &picker{err: balancer.ErrNoSubConnAvailable}})
+		b.cc.UpdateState(balancer.State{
+			ConnectivityState: state.ConnectivityState,
+			Picker:            &picker{err: balancer.ErrNoSubConnAvailable},
+		})
 	case connectivity.Idle:
-		b.cc.UpdateState(balancer.State{ConnectivityState: s.ConnectivityState, Picker: &idlePicker{sc: sc}})
+		b.cc.UpdateState(balancer.State{
+			ConnectivityState: state.ConnectivityState,
+			Picker:            &idlePicker{subConn: subConn},
+		})
 	case connectivity.TransientFailure:
 		b.cc.UpdateState(balancer.State{
-			ConnectivityState: s.ConnectivityState,
+			ConnectivityState: state.ConnectivityState,
-			Picker:            &picker{err: s.ConnectionError},
+			Picker:            &picker{err: state.ConnectionError},
 		})
 	}
 }
@@ -125,8 +153,8 @@ func (b *pickfirstBalancer) Close() {
 }
 
 func (b *pickfirstBalancer) ExitIdle() {
-	if b.sc != nil && b.state == connectivity.Idle {
+	if b.subConn != nil && b.state == connectivity.Idle {
-		b.sc.Connect()
+		b.subConn.Connect()
 	}
 }
 
@@ -135,18 +163,18 @@ type picker struct {
 	err    error
 }
 
-func (p *picker) Pick(info balancer.PickInfo) (balancer.PickResult, error) {
+func (p *picker) Pick(balancer.PickInfo) (balancer.PickResult, error) {
 	return p.result, p.err
 }
 
 // idlePicker is used when the SubConn is IDLE and kicks the SubConn into
 // CONNECTING when Pick is called.
 type idlePicker struct {
-	sc balancer.SubConn
+	subConn balancer.SubConn
 }
 
-func (i *idlePicker) Pick(info balancer.PickInfo) (balancer.PickResult, error) {
+func (i *idlePicker) Pick(balancer.PickInfo) (balancer.PickResult, error) {
-	i.sc.Connect()
+	i.subConn.Connect()
 	return balancer.PickResult{}, balancer.ErrNoSubConnAvailable
 }
 

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

@@ -27,6 +27,7 @@ import (
 
 	"google.golang.org/grpc/attributes"
 	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/internal/pretty"
 	"google.golang.org/grpc/serviceconfig"
 )
 
@@ -139,13 +140,18 @@ type Address struct {
 
 // Equal returns whether a and o are identical.  Metadata is compared directly,
 // not with any recursive introspection.
-func (a *Address) Equal(o Address) bool {
+func (a Address) Equal(o Address) bool {
 	return a.Addr == o.Addr && a.ServerName == o.ServerName &&
 		a.Attributes.Equal(o.Attributes) &&
 		a.BalancerAttributes.Equal(o.BalancerAttributes) &&
 		a.Type == o.Type && a.Metadata == o.Metadata
 }
 
+// String returns JSON formatted string representation of the address.
+func (a Address) String() string {
+	return pretty.ToJSON(a)
+}
+
 // BuildOptions includes additional information for the builder to create
 // the resolver.
 type BuildOptions struct {

vendor/google.golang.org/grpc/resolver_conn_wrapper.go

@@ -19,7 +19,6 @@
 package grpc
 
 import (
-	"fmt"
 	"strings"
 	"sync"
 
@@ -27,6 +26,7 @@ import (
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/internal/channelz"
 	"google.golang.org/grpc/internal/grpcsync"
+	"google.golang.org/grpc/internal/pretty"
 	"google.golang.org/grpc/resolver"
 	"google.golang.org/grpc/serviceconfig"
 )
@@ -97,10 +97,7 @@ func (ccr *ccResolverWrapper) UpdateState(s resolver.State) error {
 	if ccr.done.HasFired() {
 		return nil
 	}
-	channelz.Infof(logger, ccr.cc.channelzID, "ccResolverWrapper: sending update to cc: %v", s)
-	if channelz.IsOn() {
 	ccr.addChannelzTraceEvent(s)
-	}
 	ccr.curState = s
 	if err := ccr.cc.updateResolverState(ccr.curState, nil); err == balancer.ErrBadResolverState {
 		return balancer.ErrBadResolverState
@@ -125,10 +122,7 @@ func (ccr *ccResolverWrapper) NewAddress(addrs []resolver.Address) {
 	if ccr.done.HasFired() {
 		return
 	}
-	channelz.Infof(logger, ccr.cc.channelzID, "ccResolverWrapper: sending new addresses to cc: %v", addrs)
-	if channelz.IsOn() {
 	ccr.addChannelzTraceEvent(resolver.State{Addresses: addrs, ServiceConfig: ccr.curState.ServiceConfig})
-	}
 	ccr.curState.Addresses = addrs
 	ccr.cc.updateResolverState(ccr.curState, nil)
 }
@@ -141,7 +135,7 @@ func (ccr *ccResolverWrapper) NewServiceConfig(sc string) {
 	if ccr.done.HasFired() {
 		return
 	}
-	channelz.Infof(logger, ccr.cc.channelzID, "ccResolverWrapper: got new service config: %v", sc)
+	channelz.Infof(logger, ccr.cc.channelzID, "ccResolverWrapper: got new service config: %s", sc)
 	if ccr.cc.dopts.disableServiceConfig {
 		channelz.Info(logger, ccr.cc.channelzID, "Service config lookups disabled; ignoring config")
 		return
@@ -151,9 +145,7 @@ func (ccr *ccResolverWrapper) NewServiceConfig(sc string) {
 		channelz.Warningf(logger, ccr.cc.channelzID, "ccResolverWrapper: error parsing service config: %v", scpr.Err)
 		return
 	}
-	if channelz.IsOn() {
 	ccr.addChannelzTraceEvent(resolver.State{Addresses: ccr.curState.Addresses, ServiceConfig: scpr})
-	}
 	ccr.curState.ServiceConfig = scpr
 	ccr.cc.updateResolverState(ccr.curState, nil)
 }
@@ -180,8 +172,5 @@ func (ccr *ccResolverWrapper) addChannelzTraceEvent(s resolver.State) {
 	} else if len(ccr.curState.Addresses) == 0 && len(s.Addresses) > 0 {
 		updates = append(updates, "resolver returned new addresses")
 	}
-	channelz.AddTraceEvent(logger, ccr.cc.channelzID, 0, &channelz.TraceEventDesc{
+	channelz.Infof(logger, ccr.cc.channelzID, "Resolver state updated: %s (%v)", pretty.ToJSON(s), strings.Join(updates, "; "))
-		Desc:     fmt.Sprintf("Resolver state updated: %+v (%v)", s, strings.Join(updates, "; ")),
-		Severity: channelz.CtInfo,
-	})
 }

vendor/google.golang.org/grpc/server.go

@@ -134,7 +134,7 @@ type Server struct {
 	channelzRemoveOnce sync.Once
 	serveWG            sync.WaitGroup // counts active Serve goroutines for GracefulStop
 
-	channelzID int64 // channelz unique identification number
+	channelzID *channelz.Identifier
 	czData     *channelzData
 
 	serverWorkerChannels []chan *serverWorkerData
@@ -584,9 +584,8 @@ func NewServer(opt ...ServerOption) *Server {
 		s.initServerWorkers()
 	}
 
-	if channelz.IsOn() {
 	s.channelzID = channelz.RegisterServer(&channelzServer{s}, "")
-	}
+	channelz.Info(logger, s.channelzID, "Server created")
 	return s
 }
 
@@ -712,7 +711,7 @@ var ErrServerStopped = errors.New("grpc: the server has been stopped")
 
 type listenSocket struct {
 	net.Listener
-	channelzID int64
+	channelzID *channelz.Identifier
 }
 
 func (l *listenSocket) ChannelzMetric() *channelz.SocketInternalMetric {
@@ -724,9 +723,8 @@ func (l *listenSocket) ChannelzMetric() *channelz.SocketInternalMetric {
 
 func (l *listenSocket) Close() error {
 	err := l.Listener.Close()
-	if channelz.IsOn() {
 	channelz.RemoveEntry(l.channelzID)
-	}
+	channelz.Info(logger, l.channelzID, "ListenSocket deleted")
 	return err
 }
 
@@ -759,11 +757,6 @@ func (s *Server) Serve(lis net.Listener) error {
 	ls := &listenSocket{Listener: lis}
 	s.lis[ls] = true
 
-	if channelz.IsOn() {
-		ls.channelzID = channelz.RegisterListenSocket(ls, s.channelzID, lis.Addr().String())
-	}
-	s.mu.Unlock()
-
 	defer func() {
 		s.mu.Lock()
 		if s.lis != nil && s.lis[ls] {
@@ -773,8 +766,16 @@ func (s *Server) Serve(lis net.Listener) error {
 		s.mu.Unlock()
 	}()
 
-	var tempDelay time.Duration // how long to sleep on accept failure
+	var err error
+	ls.channelzID, err = channelz.RegisterListenSocket(ls, s.channelzID, lis.Addr().String())
+	if err != nil {
+		s.mu.Unlock()
+		return err
+	}
+	s.mu.Unlock()
+	channelz.Info(logger, ls.channelzID, "ListenSocket created")
 
+	var tempDelay time.Duration // how long to sleep on accept failure
 	for {
 		rawConn, err := lis.Accept()
 		if err != nil {
@@ -1709,11 +1710,7 @@ func (s *Server) Stop() {
 		s.done.Fire()
 	}()
 
-	s.channelzRemoveOnce.Do(func() {
+	s.channelzRemoveOnce.Do(func() { channelz.RemoveEntry(s.channelzID) })
-		if channelz.IsOn() {
-			channelz.RemoveEntry(s.channelzID)
-		}
-	})
 
 	s.mu.Lock()
 	listeners := s.lis
@@ -1751,11 +1748,7 @@ func (s *Server) GracefulStop() {
 	s.quit.Fire()
 	defer s.done.Fire()
 
-	s.channelzRemoveOnce.Do(func() {
+	s.channelzRemoveOnce.Do(func() { channelz.RemoveEntry(s.channelzID) })
-		if channelz.IsOn() {
-			channelz.RemoveEntry(s.channelzID)
-		}
-	})
 	s.mu.Lock()
 	if s.conns == nil {
 		s.mu.Unlock()

vendor/google.golang.org/grpc/service_config.go

@@ -381,6 +381,9 @@ func init() {
 //
 // If any of them is NOT *ServiceConfig, return false.
 func equalServiceConfig(a, b serviceconfig.Config) bool {
+	if a == nil && b == nil {
+		return true
+	}
 	aa, ok := a.(*ServiceConfig)
 	if !ok {
 		return false

vendor/google.golang.org/grpc/stream.go

@@ -36,6 +36,7 @@ import (
 	"google.golang.org/grpc/internal/channelz"
 	"google.golang.org/grpc/internal/grpcrand"
 	"google.golang.org/grpc/internal/grpcutil"
+	imetadata "google.golang.org/grpc/internal/metadata"
 	iresolver "google.golang.org/grpc/internal/resolver"
 	"google.golang.org/grpc/internal/serviceconfig"
 	"google.golang.org/grpc/internal/transport"
@@ -166,6 +167,11 @@ func NewClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 }
 
 func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (_ ClientStream, err error) {
+	if md, _, ok := metadata.FromOutgoingContextRaw(ctx); ok {
+		if err := imetadata.Validate(md); err != nil {
+			return nil, status.Error(codes.Internal, err.Error())
+		}
+	}
 	if channelz.IsOn() {
 		cc.incrCallsStarted()
 		defer func() {
@@ -456,7 +462,7 @@ type clientStream struct {
 
 	retryThrottler *retryThrottler // The throttler active when the RPC began.
 
-	binlog *binarylog.MethodLogger // Binary logger, can be nil.
+	binlog binarylog.MethodLogger // Binary logger, can be nil.
 	// serverHeaderBinlogged is a boolean for whether server header has been
 	// logged. Server header will be logged when the first time one of those
 	// happens: stream.Header(), stream.Recv().
@@ -1428,7 +1434,7 @@ type serverStream struct {
 
 	statsHandler stats.Handler
 
-	binlog *binarylog.MethodLogger
+	binlog binarylog.MethodLogger
 	// serverHeaderBinlogged indicates whether server header has been logged. It
 	// will happen when one of the following two happens: stream.SendHeader(),
 	// stream.Send().
@@ -1448,11 +1454,20 @@ func (ss *serverStream) SetHeader(md metadata.MD) error {
 	if md.Len() == 0 {
 		return nil
 	}
+	err := imetadata.Validate(md)
+	if err != nil {
+		return status.Error(codes.Internal, err.Error())
+	}
 	return ss.s.SetHeader(md)
 }
 
 func (ss *serverStream) SendHeader(md metadata.MD) error {
-	err := ss.t.WriteHeader(ss.s, md)
+	err := imetadata.Validate(md)
+	if err != nil {
+		return status.Error(codes.Internal, err.Error())
+	}
+
+	err = ss.t.WriteHeader(ss.s, md)
 	if ss.binlog != nil && !ss.serverHeaderBinlogged {
 		h, _ := ss.s.Header()
 		ss.binlog.Log(&binarylog.ServerHeader{
@@ -1467,6 +1482,9 @@ func (ss *serverStream) SetTrailer(md metadata.MD) {
 	if md.Len() == 0 {
 		return
 	}
+	if err := imetadata.Validate(md); err != nil {
+		logger.Errorf("stream: failed to validate md when setting trailer, err: %v", err)
+	}
 	ss.s.SetTrailer(md)
 }
 

vendor/google.golang.org/grpc/version.go

@@ -19,4 +19,4 @@
 package grpc
 
 // Version is the current grpc version.
-const Version = "1.45.0"
+const Version = "1.46.0"

vendor/modules.txt

@@ -639,7 +639,7 @@ google.golang.org/appengine/urlfetch
 google.golang.org/genproto/googleapis/api/httpbody
 google.golang.org/genproto/googleapis/rpc/status
 google.golang.org/genproto/protobuf/field_mask
-# google.golang.org/grpc v1.45.0
+# google.golang.org/grpc v1.46.0
 ## explicit; go 1.14
 google.golang.org/grpc
 google.golang.org/grpc/attributes
@@ -649,6 +649,7 @@ google.golang.org/grpc/balancer/base
 google.golang.org/grpc/balancer/grpclb/state
 google.golang.org/grpc/balancer/roundrobin
 google.golang.org/grpc/binarylog/grpc_binarylog_v1
+google.golang.org/grpc/channelz
 google.golang.org/grpc/codes
 google.golang.org/grpc/connectivity
 google.golang.org/grpc/credentials
@@ -661,6 +662,7 @@ google.golang.org/grpc/health
 google.golang.org/grpc/health/grpc_health_v1
 google.golang.org/grpc/internal
 google.golang.org/grpc/internal/backoff
+google.golang.org/grpc/internal/balancer/gracefulswitch
 google.golang.org/grpc/internal/balancerload
 google.golang.org/grpc/internal/binarylog
 google.golang.org/grpc/internal/buffer
@@ -672,6 +674,7 @@ google.golang.org/grpc/internal/grpcrand
 google.golang.org/grpc/internal/grpcsync
 google.golang.org/grpc/internal/grpcutil
 google.golang.org/grpc/internal/metadata
+google.golang.org/grpc/internal/pretty
 google.golang.org/grpc/internal/resolver
 google.golang.org/grpc/internal/resolver/dns
 google.golang.org/grpc/internal/resolver/passthrough