protobuf: remove gogoproto

Removes gogo/protobuf from buildx and updates to a version of
moby/buildkit where gogo is removed.

This also changes how the proto files are generated. This is because
newer versions of protobuf are more strict about name conflicts. If two
files have the same name (even if they are relative paths) and are used
in different protoc commands, they'll conflict in the registry.

Since protobuf file generation doesn't work very well with
`paths=source_relative`, this removes the `go:generate` expression and
just relies on the dockerfile to perform the generation.

Signed-off-by: Jonathan A. Sternberg <jonathan.sternberg@docker.com>

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

@@ -94,14 +94,23 @@ func (gsb *Balancer) balancerCurrentOrPending(bw *balancerWrapper) bool {
 // 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.
+//
+// Deprecated: use ParseConfig and pass a parsed config to UpdateClientConnState
+// to cause the Balancer to automatically change to the new child when necessary.
 func (gsb *Balancer) SwitchTo(builder balancer.Builder) error {
+	_, err := gsb.switchTo(builder)
+	return err
+}
+
+func (gsb *Balancer) switchTo(builder balancer.Builder) (*balancerWrapper, error) {
 	gsb.mu.Lock()
 	if gsb.closed {
 		gsb.mu.Unlock()
-		return errBalancerClosed
+		return nil, errBalancerClosed
 	}
 	bw := &balancerWrapper{
-		gsb: gsb,
+		builder: builder,
+		gsb:     gsb,
 		lastState: balancer.State{
 			ConnectivityState: connectivity.Connecting,
 			Picker:            base.NewErrPicker(balancer.ErrNoSubConnAvailable),
@@ -129,7 +138,7 @@ func (gsb *Balancer) SwitchTo(builder balancer.Builder) error {
 			gsb.balancerCurrent = nil
 		}
 		gsb.mu.Unlock()
-		return balancer.ErrBadResolverState
+		return nil, balancer.ErrBadResolverState
 	}
 
 	// This write doesn't need to take gsb.mu because this field never gets read
@@ -138,7 +147,7 @@ func (gsb *Balancer) SwitchTo(builder balancer.Builder) error {
 	// bw.Balancer field will never be forwarded to until this SwitchTo()
 	// function returns.
 	bw.Balancer = newBalancer
-	return nil
+	return bw, nil
 }
 
 // Returns nil if the graceful switch balancer is closed.
@@ -152,12 +161,32 @@ func (gsb *Balancer) latestBalancer() *balancerWrapper {
 }
 
 // UpdateClientConnState forwards the update to the latest balancer created.
+//
+// If the state's BalancerConfig is the config returned by a call to
+// gracefulswitch.ParseConfig, then this function will automatically SwitchTo
+// the balancer indicated by the config before forwarding its config to it, if
+// necessary.
 func (gsb *Balancer) UpdateClientConnState(state balancer.ClientConnState) error {
 	// The resolver data is only relevant to the most recent LB Policy.
 	balToUpdate := gsb.latestBalancer()
+	gsbCfg, ok := state.BalancerConfig.(*lbConfig)
+	if ok {
+		// Switch to the child in the config unless it is already active.
+		if balToUpdate == nil || gsbCfg.childBuilder.Name() != balToUpdate.builder.Name() {
+			var err error
+			balToUpdate, err = gsb.switchTo(gsbCfg.childBuilder)
+			if err != nil {
+				return fmt.Errorf("could not switch to new child balancer: %w", err)
+			}
+		}
+		// Unwrap the child balancer's config.
+		state.BalancerConfig = gsbCfg.childConfig
+	}
+
 	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.
@@ -169,6 +198,10 @@ func (gsb *Balancer) ResolverError(err error) {
 	// The resolver data is only relevant to the most recent LB Policy.
 	balToUpdate := gsb.latestBalancer()
 	if balToUpdate == nil {
+		gsb.cc.UpdateState(balancer.State{
+			ConnectivityState: connectivity.TransientFailure,
+			Picker:            base.NewErrPicker(err),
+		})
 		return
 	}
 	// Perform this call without gsb.mu to prevent deadlocks if the child calls
@@ -261,7 +294,8 @@ func (gsb *Balancer) Close() {
 // graceful switch logic.
 type balancerWrapper struct {
 	balancer.Balancer
-	gsb *Balancer
+	gsb     *Balancer
+	builder balancer.Builder
 
 	lastState balancer.State
 	subconns  map[balancer.SubConn]bool // subconns created by this balancer