1 files changed, 75 insertions, 11 deletions
diff --git a/vendor/google.golang.org/grpc/balancer/balancer.go b/vendor/google.golang.org/grpc/balancer/balancer.go
index 84e10b6..f9d83c2 100644
--- a/vendor/google.golang.org/grpc/balancer/balancer.go
+++ b/vendor/google.golang.org/grpc/balancer/balancer.go
@@ -23,6 +23,7 @@ package balancer
 import (
 	"errors"
 	"net"
+	"strings"
 
 	"golang.org/x/net/context"
 	"google.golang.org/grpc/connectivity"
@@ -33,24 +34,26 @@ import (
 var (
 	// m is a map from name to balancer builder.
 	m = make(map[string]Builder)
-	// defaultBuilder is the default balancer to use.
-	defaultBuilder Builder // TODO(bar) install pickfirst as default.
 )
 
-// Register registers the balancer builder to the balancer map.
-// b.Name will be used as the name registered with this builder.
+// Register registers the balancer builder to the balancer map. b.Name
+// (lowercased) will be used as the name registered with this builder.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe. If multiple Balancers are
+// registered with the same name, the one registered last will take effect.
 func Register(b Builder) {
-	m[b.Name()] = b
+	m[strings.ToLower(b.Name())] = b
 }
 
 // Get returns the resolver builder registered with the given name.
-// If no builder is register with the name, the default pickfirst will
-// be used.
+// Note that the compare is done in a case-insenstive fashion.
+// If no builder is register with the name, nil will be returned.
 func Get(name string) Builder {
-	if b, ok := m[name]; ok {
+	if b, ok := m[strings.ToLower(name)]; ok {
 		return b
 	}
-	return defaultBuilder
+	return nil
 }
 
 // SubConn represents a gRPC sub connection.
@@ -66,6 +69,11 @@ func Get(name string) Builder {
 // When the connection encounters an error, it will reconnect immediately.
 // When the connection becomes IDLE, it will not reconnect unless Connect is
 // called.
+//
+// This interface is to be implemented by gRPC. Users should not need a
+// brand new implementation of this interface. For the situations like
+// testing, the new implementation should embed this interface. This allows
+// gRPC to add new methods to this interface.
 type SubConn interface {
 	// UpdateAddresses updates the addresses used in this SubConn.
 	// gRPC checks if currently-connected address is still in the new list.
@@ -83,6 +91,11 @@ type SubConn interface {
 type NewSubConnOptions struct{}
 
 // ClientConn represents a gRPC ClientConn.
+//
+// This interface is to be implemented by gRPC. Users should not need a
+// brand new implementation of this interface. For the situations like
+// testing, the new implementation should embed this interface. This allows
+// gRPC to add new methods to this interface.
 type ClientConn interface {
 	// NewSubConn is called by balancer to create a new SubConn.
 	// It doesn't block and wait for the connections to be established.
@@ -99,6 +112,9 @@ type ClientConn interface {
 	// on the new picker to pick new SubConn.
 	UpdateBalancerState(s connectivity.State, p Picker)
 
+	// ResolveNow is called by balancer to notify gRPC to do a name resolving.
+	ResolveNow(resolver.ResolveNowOption)
+
 	// Target returns the dial target for this ClientConn.
 	Target() string
 }
@@ -113,6 +129,8 @@ type BuildOptions struct {
 	// to a remote load balancer server. The Balancer implementations
 	// can ignore this if it doesn't need to talk to remote balancer.
 	Dialer func(context.Context, string) (net.Conn, error)
+	// ChannelzParentID is the entity parent's channelz unique identification number.
+	ChannelzParentID int64
 }
 
 // Builder creates a balancer.
@@ -131,6 +149,10 @@ type PickOptions struct{}
 type DoneInfo struct {
 	// Err is the rpc error the RPC finished with. It could be nil.
 	Err error
+	// BytesSent indicates if any bytes have been sent to the server.
+	BytesSent bool
+	// BytesReceived indicates if any byte has been received from the server.
+	BytesReceived bool
 }
 
 var (
@@ -143,7 +165,7 @@ var (
 )
 
 // Picker is used by gRPC to pick a SubConn to send an RPC.
-// Balancer is expected to generate a new picker from its snapshot everytime its
+// Balancer is expected to generate a new picker from its snapshot every time its
 // internal state has changed.
 //
 // The pickers used by gRPC can be updated by ClientConn.UpdateBalancerState().
@@ -161,7 +183,7 @@ type Picker interface {
 	// If a SubConn is returned:
 	// - If it is READY, gRPC will send the RPC on it;
 	// - If it is not ready, or becomes not ready after it's returned, gRPC will block
-	//   this call until a new picker is updated and will call pick on the new picker.
+	//   until UpdateBalancerState() is called and will call pick on the new picker.
 	//
 	// If the returned error is not nil:
 	// - If the error is ErrNoSubConnAvailable, gRPC will block until UpdateBalancerState()
@@ -204,3 +226,45 @@ type Balancer interface {
 	// ClientConn.RemoveSubConn for its existing SubConns.
 	Close()
 }
+
+// ConnectivityStateEvaluator takes the connectivity states of multiple SubConns
+// and returns one aggregated connectivity state.
+//
+// It's not thread safe.
+type ConnectivityStateEvaluator struct {
+	numReady            uint64 // Number of addrConns in ready state.
+	numConnecting       uint64 // Number of addrConns in connecting state.
+	numTransientFailure uint64 // Number of addrConns in transientFailure.
+}
+
+// RecordTransition records state change happening in subConn and based on that
+// it evaluates what aggregated state should be.
+//
+//  - If at least one SubConn in Ready, the aggregated state is Ready;
+//  - Else if at least one SubConn in Connecting, the aggregated state is Connecting;
+//  - Else the aggregated state is TransientFailure.
+//
+// Idle and Shutdown are not considered.
+func (cse *ConnectivityStateEvaluator) RecordTransition(oldState, newState connectivity.State) connectivity.State {
+	// Update counters.
+	for idx, state := range []connectivity.State{oldState, newState} {
+		updateVal := 2*uint64(idx) - 1 // -1 for oldState and +1 for new.
+		switch state {
+		case connectivity.Ready:
+			cse.numReady += updateVal
+		case connectivity.Connecting:
+			cse.numConnecting += updateVal
+		case connectivity.TransientFailure:
+			cse.numTransientFailure += updateVal
+		}
+	}
+
+	// Evaluate.
+	if cse.numReady > 0 {
+		return connectivity.Ready
+	}
+	if cse.numConnecting > 0 {
+		return connectivity.Connecting
+	}
+	return connectivity.TransientFailure
+}