Update dependencies

18 files changed, 1077 insertions, 153 deletions

diff --git a/vendor/google.golang.org/grpc/README.md b/vendor/google.golang.org/grpc/README.md
index 110a8cf..39120c2 100644
--- a/vendor/google.golang.org/grpc/README.md
+++ b/vendor/google.golang.org/grpc/README.md
@@ -18,6 +18,22 @@ Prerequisites
 
 This requires Go 1.5 or later.
 
+A note on the version used: significant performance improvements in benchmarks
+of grpc-go have been seen by upgrading the go version from 1.5 to the latest
+1.7.1.
+
+From https://golang.org/doc/install, one way to install the latest version of go is:
+```
+$ GO_VERSION=1.7.1
+$ OS=linux
+$ ARCH=amd64
+$ curl -O https://storage.googleapis.com/golang/go${GO_VERSION}.${OS}-${ARCH}.tar.gz
+$ sudo tar -C /usr/local -xzf go$GO_VERSION.$OS-$ARCH.tar.gz
+$ # Put go on the PATH, keep the usual installation dir
+$ sudo ln -s /usr/local/go/bin/go /usr/bin/go
+$ rm go$GO_VERSION.$OS-$ARCH.tar.gz
+```
+
 Constraints
 -----------
 The grpc package should only depend on standard Go packages and a small number of exceptions. If your contribution introduces new dependencies which are NOT in the [list](http://godoc.org/google.golang.org/grpc?imports), you need a discussion with gRPC-Go authors and consultants.
@@ -30,3 +46,12 @@ Status
 ------
 GA
 
+FAQ
+---
+
+#### Compiling error, undefined: grpc.SupportPackageIsVersion
+
+Please update proto package, gRPC package and rebuild the proto files:
+ - `go get -u github.com/golang/protobuf/{proto,protoc-gen-go}`
+ - `go get -u google.golang.org/grpc`
+ - `protoc --go_out=plugins=grpc:. *.proto`
diff --git a/vendor/google.golang.org/grpc/call.go b/vendor/google.golang.org/grpc/call.go
index 772c817..4d8023d 100644
--- a/vendor/google.golang.org/grpc/call.go
+++ b/vendor/google.golang.org/grpc/call.go
@@ -42,6 +42,7 @@ import (
 	"golang.org/x/net/context"
 	"golang.org/x/net/trace"
 	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/stats"
 	"google.golang.org/grpc/transport"
 )
 
@@ -49,7 +50,8 @@ import (
 // On error, it returns the error and indicates whether the call should be retried.
 //
 // TODO(zhaoq): Check whether the received message sequence is valid.
-func recvResponse(dopts dialOptions, t transport.ClientTransport, c *callInfo, stream *transport.Stream, reply interface{}) (err error) {
+// TODO ctx is used for stats collection and processing. It is the context passed from the application.
+func recvResponse(ctx context.Context, dopts dialOptions, t transport.ClientTransport, c *callInfo, stream *transport.Stream, reply interface{}) (err error) {
 	// Try to acquire header metadata from the server if there is any.
 	defer func() {
 		if err != nil {
@@ -63,14 +65,25 @@ func recvResponse(dopts dialOptions, t transport.ClientTransport, c *callInfo, s
 		return
 	}
 	p := &parser{r: stream}
+	var inPayload *stats.InPayload
+	if stats.On() {
+		inPayload = &stats.InPayload{
+			Client: true,
+		}
+	}
 	for {
-		if err = recv(p, dopts.codec, stream, dopts.dc, reply, math.MaxInt32); err != nil {
+		if err = recv(p, dopts.codec, stream, dopts.dc, reply, math.MaxInt32, inPayload); err != nil {
 			if err == io.EOF {
 				break
 			}
 			return
 		}
 	}
+	if inPayload != nil && err == io.EOF && stream.StatusCode() == codes.OK {
+		// TODO in the current implementation, inTrailer may be handled before inPayload in some cases.
+		// Fix the order if necessary.
+		stats.HandleRPC(ctx, inPayload)
+	}
 	c.trailerMD = stream.Trailer()
 	return nil
 }
@@ -89,15 +102,27 @@ func sendRequest(ctx context.Context, codec Codec, compressor Compressor, callHd
 			}
 		}
 	}()
-	var cbuf *bytes.Buffer
+	var (
+		cbuf       *bytes.Buffer
+		outPayload *stats.OutPayload
+	)
 	if compressor != nil {
 		cbuf = new(bytes.Buffer)
 	}
-	outBuf, err := encode(codec, args, compressor, cbuf)
+	if stats.On() {
+		outPayload = &stats.OutPayload{
+			Client: true,
+		}
+	}
+	outBuf, err := encode(codec, args, compressor, cbuf, outPayload)
 	if err != nil {
 		return nil, Errorf(codes.Internal, "grpc: %v", err)
 	}
 	err = t.Write(stream, outBuf, opts)
+	if err == nil && outPayload != nil {
+		outPayload.SentTime = time.Now()
+		stats.HandleRPC(ctx, outPayload)
+	}
 	// t.NewStream(...) could lead to an early rejection of the RPC (e.g., the service/method
 	// does not exist.) so that t.Write could get io.EOF from wait(...). Leave the following
 	// recvResponse to get the final status.
@@ -118,8 +143,16 @@ func Invoke(ctx context.Context, method string, args, reply interface{}, cc *Cli
 	return invoke(ctx, method, args, reply, cc, opts...)
 }
 
-func invoke(ctx context.Context, method string, args, reply interface{}, cc *ClientConn, opts ...CallOption) (err error) {
+func invoke(ctx context.Context, method string, args, reply interface{}, cc *ClientConn, opts ...CallOption) (e error) {
 	c := defaultCallInfo
+	if mc, ok := cc.getMethodConfig(method); ok {
+		c.failFast = !mc.WaitForReady
+		if mc.Timeout > 0 {
+			var cancel context.CancelFunc
+			ctx, cancel = context.WithTimeout(ctx, mc.Timeout)
+			defer cancel()
+		}
+	}
 	for _, o := range opts {
 		if err := o.before(&c); err != nil {
 			return toRPCErr(err)
@@ -140,12 +173,31 @@ func invoke(ctx context.Context, method string, args, reply interface{}, cc *Cli
 		c.traceInfo.tr.LazyLog(&c.traceInfo.firstLine, false)
 		// TODO(dsymonds): Arrange for c.traceInfo.firstLine.remoteAddr to be set.
 		defer func() {
-			if err != nil {
-				c.traceInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
+			if e != nil {
+				c.traceInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{e}}, true)
 				c.traceInfo.tr.SetError()
 			}
 		}()
 	}
+	if stats.On() {
+		ctx = stats.TagRPC(ctx, &stats.RPCTagInfo{FullMethodName: method})
+		begin := &stats.Begin{
+			Client:    true,
+			BeginTime: time.Now(),
+			FailFast:  c.failFast,
+		}
+		stats.HandleRPC(ctx, begin)
+	}
+	defer func() {
+		if stats.On() {
+			end := &stats.End{
+				Client:  true,
+				EndTime: time.Now(),
+				Error:   e,
+			}
+			stats.HandleRPC(ctx, end)
+		}
+	}()
 	topts := &transport.Options{
 		Last:  true,
 		Delay: false,
@@ -167,6 +219,7 @@ func invoke(ctx context.Context, method string, args, reply interface{}, cc *Cli
 		if cc.dopts.cp != nil {
 			callHdr.SendCompress = cc.dopts.cp.Type()
 		}
+
 		gopts := BalancerGetOptions{
 			BlockingWait: !c.failFast,
 		}
@@ -205,7 +258,7 @@ func invoke(ctx context.Context, method string, args, reply interface{}, cc *Cli
 			}
 			return toRPCErr(err)
 		}
-		err = recvResponse(cc.dopts, t, &c, stream, reply)
+		err = recvResponse(ctx, cc.dopts, t, &c, stream, reply)
 		if err != nil {
 			if put != nil {
 				put()
diff --git a/vendor/google.golang.org/grpc/clientconn.go b/vendor/google.golang.org/grpc/clientconn.go
index 6167472..aa6b63d 100644
--- a/vendor/google.golang.org/grpc/clientconn.go
+++ b/vendor/google.golang.org/grpc/clientconn.go
@@ -54,6 +54,8 @@ var (
 	ErrClientConnClosing = errors.New("grpc: the client connection is closing")
 	// ErrClientConnTimeout indicates that the ClientConn cannot establish the
 	// underlying connections within the specified timeout.
+	// DEPRECATED: Please use context.DeadlineExceeded instead. This error will be
+	// removed in Q1 2017.
 	ErrClientConnTimeout = errors.New("grpc: timed out when dialing")
 
 	// errNoTransportSecurity indicates that there is no transport security
@@ -93,6 +95,7 @@ type dialOptions struct {
 	block     bool
 	insecure  bool
 	timeout   time.Duration
+	scChan    <-chan ServiceConfig
 	copts     transport.ConnectOptions
 }
 
@@ -129,6 +132,13 @@ func WithBalancer(b Balancer) DialOption {
 	}
 }
 
+// WithServiceConfig returns a DialOption which has a channel to read the service configuration.
+func WithServiceConfig(c <-chan ServiceConfig) DialOption {
+	return func(o *dialOptions) {
+		o.scChan = c
+	}
+}
+
 // WithBackoffMaxDelay configures the dialer to use the provided maximum delay
 // when backing off after failed connection attempts.
 func WithBackoffMaxDelay(md time.Duration) DialOption {
@@ -199,6 +209,8 @@ func WithTimeout(d time.Duration) DialOption {
 }
 
 // WithDialer returns a DialOption that specifies a function to use for dialing network addresses.
+// If FailOnNonTempDialError() is set to true, and an error is returned by f, gRPC checks the error's
+// Temporary() method to decide if it should try to reconnect to the network address.
 func WithDialer(f func(string, time.Duration) (net.Conn, error)) DialOption {
 	return func(o *dialOptions) {
 		o.copts.Dialer = func(ctx context.Context, addr string) (net.Conn, error) {
@@ -210,6 +222,17 @@ func WithDialer(f func(string, time.Duration) (net.Conn, error)) DialOption {
 	}
 }
 
+// FailOnNonTempDialError returns a DialOption that specified if gRPC fails on non-temporary dial errors.
+// If f is true, and dialer returns a non-temporary error, gRPC will fail the connection to the network
+// address and won't try to reconnect.
+// The default value of FailOnNonTempDialError is false.
+// This is an EXPERIMENTAL API.
+func FailOnNonTempDialError(f bool) DialOption {
+	return func(o *dialOptions) {
+		o.copts.FailOnNonTempDialError = f
+	}
+}
+
 // WithUserAgent returns a DialOption that specifies a user agent string for all the RPCs.
 func WithUserAgent(s string) DialOption {
 	return func(o *dialOptions) {
@@ -247,6 +270,15 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 		conns:  make(map[Address]*addrConn),
 	}
 	cc.ctx, cc.cancel = context.WithCancel(context.Background())
+	for _, opt := range opts {
+		opt(&cc.dopts)
+	}
+	if cc.dopts.timeout > 0 {
+		var cancel context.CancelFunc
+		ctx, cancel = context.WithTimeout(ctx, cc.dopts.timeout)
+		defer cancel()
+	}
+
 	defer func() {
 		select {
 		case <-ctx.Done():
@@ -259,10 +291,17 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 		}
 	}()
 
-	for _, opt := range opts {
-		opt(&cc.dopts)
+	if cc.dopts.scChan != nil {
+		// Wait for the initial service config.
+		select {
+		case sc, ok := <-cc.dopts.scChan:
+			if ok {
+				cc.sc = sc
+			}
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		}
 	}
-
 	// Set defaults.
 	if cc.dopts.codec == nil {
 		cc.dopts.codec = protoCodec{}
@@ -284,6 +323,9 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 	waitC := make(chan error, 1)
 	go func() {
 		var addrs []Address
+		if cc.dopts.balancer == nil && cc.sc.LB != nil {
+			cc.dopts.balancer = cc.sc.LB
+		}
 		if cc.dopts.balancer == nil {
 			// Connect to target directly if balancer is nil.
 			addrs = append(addrs, Address{Addr: target})
@@ -319,10 +361,6 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 		}
 		close(waitC)
 	}()
-	var timeoutCh <-chan time.Time
-	if cc.dopts.timeout > 0 {
-		timeoutCh = time.After(cc.dopts.timeout)
-	}
 	select {
 	case <-ctx.Done():
 		return nil, ctx.Err()
@@ -330,14 +368,17 @@ func DialContext(ctx context.Context, target string, opts ...DialOption) (conn *
 		if err != nil {
 			return nil, err
 		}
-	case <-timeoutCh:
-		return nil, ErrClientConnTimeout
 	}
+
 	// If balancer is nil or balancer.Notify() is nil, ok will be false here.
 	// The lbWatcher goroutine will not be created.
 	if ok {
 		go cc.lbWatcher()
 	}
+
+	if cc.dopts.scChan != nil {
+		go cc.scWatcher()
+	}
 	return cc, nil
 }
 
@@ -384,6 +425,7 @@ type ClientConn struct {
 	dopts     dialOptions
 
 	mu    sync.RWMutex
+	sc    ServiceConfig
 	conns map[Address]*addrConn
 }
 
@@ -422,6 +464,24 @@ func (cc *ClientConn) lbWatcher() {
 	}
 }
 
+func (cc *ClientConn) scWatcher() {
+	for {
+		select {
+		case sc, ok := <-cc.dopts.scChan:
+			if !ok {
+				return
+			}
+			cc.mu.Lock()
+			// TODO: load balance policy runtime change is ignored.
+			// We may revist this decision in the future.
+			cc.sc = sc
+			cc.mu.Unlock()
+		case <-cc.ctx.Done():
+			return
+		}
+	}
+}
+
 // resetAddrConn creates an addrConn for addr and adds it to cc.conns.
 // If there is an old addrConn for addr, it will be torn down, using tearDownErr as the reason.
 // If tearDownErr is nil, errConnDrain will be used instead.
@@ -509,6 +569,14 @@ func (cc *ClientConn) resetAddrConn(addr Address, skipWait bool, tearDownErr err
 	return nil
 }
 
+// TODO: Avoid the locking here.
+func (cc *ClientConn) getMethodConfig(method string) (m MethodConfig, ok bool) {
+	cc.mu.RLock()
+	defer cc.mu.RUnlock()
+	m, ok = cc.sc.Methods[method]
+	return
+}
+
 func (cc *ClientConn) getTransport(ctx context.Context, opts BalancerGetOptions) (transport.ClientTransport, func(), error) {
 	var (
 		ac  *addrConn
diff --git a/vendor/google.golang.org/grpc/codegen.sh b/vendor/google.golang.org/grpc/codegen.sh
index b009488..4cdc6ba 100755
--- a/vendor/google.golang.org/grpc/codegen.sh
+++ b/vendor/google.golang.org/grpc/codegen.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # This script serves as an example to demonstrate how to generate the gRPC-Go
 # interface and the related messages from .proto file.
diff --git a/vendor/google.golang.org/grpc/coverage.sh b/vendor/google.golang.org/grpc/coverage.sh
index 1202353..b85f918 100755
--- a/vendor/google.golang.org/grpc/coverage.sh
+++ b/vendor/google.golang.org/grpc/coverage.sh
@@ -1,4 +1,5 @@
-#!/bin/bash
+#!/usr/bin/env bash
+
 
 set -e
 
diff --git a/vendor/google.golang.org/grpc/credentials/oauth/oauth.go b/vendor/google.golang.org/grpc/credentials/oauth/oauth.go
index 8e68c4d..25393cc 100644
--- a/vendor/google.golang.org/grpc/credentials/oauth/oauth.go
+++ b/vendor/google.golang.org/grpc/credentials/oauth/oauth.go
@@ -61,7 +61,7 @@ func (ts TokenSource) GetRequestMetadata(ctx context.Context, uri ...string) (ma
 	}, nil
 }
 
-// RequireTransportSecurity indicates whether the credentails requires transport security.
+// RequireTransportSecurity indicates whether the credentials requires transport security.
 func (ts TokenSource) RequireTransportSecurity() bool {
 	return true
 }
diff --git a/vendor/google.golang.org/grpc/metadata/metadata.go b/vendor/google.golang.org/grpc/metadata/metadata.go
index 3c0ca7a..65dc5af 100644
--- a/vendor/google.golang.org/grpc/metadata/metadata.go
+++ b/vendor/google.golang.org/grpc/metadata/metadata.go
@@ -141,6 +141,8 @@ func NewContext(ctx context.Context, md MD) context.Context {
 }
 
 // FromContext returns the MD in ctx if it exists.
+// The returned md should be immutable, writing to it may cause races.
+// Modification should be made to the copies of the returned md.
 func FromContext(ctx context.Context) (md MD, ok bool) {
 	md, ok = ctx.Value(mdKey{}).(MD)
 	return
diff --git a/vendor/google.golang.org/grpc/rpc_util.go b/vendor/google.golang.org/grpc/rpc_util.go
index 6b60095..2619d39 100644
--- a/vendor/google.golang.org/grpc/rpc_util.go
+++ b/vendor/google.golang.org/grpc/rpc_util.go
@@ -42,11 +42,13 @@ import (
 	"io/ioutil"
 	"math"
 	"os"
+	"time"
 
 	"github.com/golang/protobuf/proto"
 	"golang.org/x/net/context"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/stats"
 	"google.golang.org/grpc/transport"
 )
 
@@ -255,9 +257,11 @@ func (p *parser) recvMsg(maxMsgSize int) (pf payloadFormat, msg []byte, err erro
 
 // encode serializes msg and prepends the message header. If msg is nil, it
 // generates the message header of 0 message length.
-func encode(c Codec, msg interface{}, cp Compressor, cbuf *bytes.Buffer) ([]byte, error) {
-	var b []byte
-	var length uint
+func encode(c Codec, msg interface{}, cp Compressor, cbuf *bytes.Buffer, outPayload *stats.OutPayload) ([]byte, error) {
+	var (
+		b      []byte
+		length uint
+	)
 	if msg != nil {
 		var err error
 		// TODO(zhaoq): optimize to reduce memory alloc and copying.
@@ -265,6 +269,12 @@ func encode(c Codec, msg interface{}, cp Compressor, cbuf *bytes.Buffer) ([]byte
 		if err != nil {
 			return nil, err
 		}
+		if outPayload != nil {
+			outPayload.Payload = msg
+			// TODO truncate large payload.
+			outPayload.Data = b
+			outPayload.Length = len(b)
+		}
 		if cp != nil {
 			if err := cp.Do(cbuf, b); err != nil {
 				return nil, err
@@ -295,6 +305,10 @@ func encode(c Codec, msg interface{}, cp Compressor, cbuf *bytes.Buffer) ([]byte
 	// Copy encoded msg to buf
 	copy(buf[5:], b)
 
+	if outPayload != nil {
+		outPayload.WireLength = len(buf)
+	}
+
 	return buf, nil
 }
 
@@ -311,11 +325,14 @@ func checkRecvPayload(pf payloadFormat, recvCompress string, dc Decompressor) er
 	return nil
 }
 
-func recv(p *parser, c Codec, s *transport.Stream, dc Decompressor, m interface{}, maxMsgSize int) error {
+func recv(p *parser, c Codec, s *transport.Stream, dc Decompressor, m interface{}, maxMsgSize int, inPayload *stats.InPayload) error {
 	pf, d, err := p.recvMsg(maxMsgSize)
 	if err != nil {
 		return err
 	}
+	if inPayload != nil {
+		inPayload.WireLength = len(d)
+	}
 	if err := checkRecvPayload(pf, s.RecvCompress(), dc); err != nil {
 		return err
 	}
@@ -333,6 +350,13 @@ func recv(p *parser, c Codec, s *transport.Stream, dc Decompressor, m interface{
 	if err := c.Unmarshal(d, m); err != nil {
 		return Errorf(codes.Internal, "grpc: failed to unmarshal the received message %v", err)
 	}
+	if inPayload != nil {
+		inPayload.RecvTime = time.Now()
+		inPayload.Payload = m
+		// TODO truncate large payload.
+		inPayload.Data = d
+		inPayload.Length = len(d)
+	}
 	return nil
 }
 
@@ -448,10 +472,48 @@ func convertCode(err error) codes.Code {
 	return codes.Unknown
 }
 
-// SupportPackageIsVersion3 is referenced from generated protocol buffer files
+// MethodConfig defines the configuration recommended by the service providers for a
+// particular method.
+// This is EXPERIMENTAL and subject to change.
+type MethodConfig struct {
+	// WaitForReady indicates whether RPCs sent to this method should wait until
+	// the connection is ready by default (!failfast). The value specified via the
+	// gRPC client API will override the value set here.
+	WaitForReady bool
+	// Timeout is the default timeout for RPCs sent to this method. The actual
+	// deadline used will be the minimum of the value specified here and the value
+	// set by the application via the gRPC client API.  If either one is not set,
+	// then the other will be used.  If neither is set, then the RPC has no deadline.
+	Timeout time.Duration
+	// MaxReqSize is the maximum allowed payload size for an individual request in a
+	// stream (client->server) in bytes. The size which is measured is the serialized,
+	// uncompressed payload in bytes. The actual value used is the minumum of the value
+	// specified here and the value set by the application via the gRPC client API. If
+	// either one is not set, then the other will be used.  If neither is set, then the
+	// built-in default is used.
+	// TODO: support this.
+	MaxReqSize uint64
+	// MaxRespSize is the maximum allowed payload size for an individual response in a
+	// stream (server->client) in bytes.
+	// TODO: support this.
+	MaxRespSize uint64
+}
+
+// ServiceConfig is provided by the service provider and contains parameters for how
+// clients that connect to the service should behave.
+// This is EXPERIMENTAL and subject to change.
+type ServiceConfig struct {
+	// LB is the load balancer the service providers recommends. The balancer specified
+	// via grpc.WithBalancer will override this.
+	LB Balancer
+	// Methods contains a map for the methods in this service.
+	Methods map[string]MethodConfig
+}
+
+// SupportPackageIsVersion4 is referenced from generated protocol buffer files
 // to assert that that code is compatible with this version of the grpc package.
 //
 // This constant may be renamed in the future if a change in the generated code
 // requires a synchronised update of grpc-go and protoc-gen-go. This constant
 // should not be referenced from any other code.
-const SupportPackageIsVersion3 = true
+const SupportPackageIsVersion4 = true
diff --git a/vendor/google.golang.org/grpc/server.go b/vendor/google.golang.org/grpc/server.go
index e0bb187..b52a563 100644
--- a/vendor/google.golang.org/grpc/server.go
+++ b/vendor/google.golang.org/grpc/server.go
@@ -54,6 +54,8 @@ import (
 	"google.golang.org/grpc/grpclog"
 	"google.golang.org/grpc/internal"
 	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/stats"
+	"google.golang.org/grpc/tap"
 	"google.golang.org/grpc/transport"
 )
 
@@ -110,6 +112,7 @@ type options struct {
 	maxMsgSize           int
 	unaryInt             UnaryServerInterceptor
 	streamInt            StreamServerInterceptor
+	inTapHandle          tap.ServerInHandle
 	maxConcurrentStreams uint32
 	useHandlerImpl       bool // use http.Handler-based server
 }
@@ -186,6 +189,17 @@ func StreamInterceptor(i StreamServerInterceptor) ServerOption {
 	}
 }
 
+// InTapHandle returns a ServerOption that sets the tap handle for all the server
+// transport to be created. Only one can be installed.
+func InTapHandle(h tap.ServerInHandle) ServerOption {
+	return func(o *options) {
+		if o.inTapHandle != nil {
+			panic("The tap handle has been set.")
+		}
+		o.inTapHandle = h
+	}
+}
+
 // NewServer creates a gRPC server which has no service registered and has not
 // started to accept requests yet.
 func NewServer(opt ...ServerOption) *Server {
@@ -329,6 +343,7 @@ func (s *Server) useTransportAuthenticator(rawConn net.Conn) (net.Conn, credenti
 // read gRPC requests and then call the registered handlers to reply to them.
 // Serve returns when lis.Accept fails with fatal errors.  lis will be closed when
 // this method returns.
+// Serve always returns non-nil error.
 func (s *Server) Serve(lis net.Listener) error {
 	s.mu.Lock()
 	s.printf("serving")
@@ -412,17 +427,22 @@ func (s *Server) handleRawConn(rawConn net.Conn) {
 	if s.opts.useHandlerImpl {
 		s.serveUsingHandler(conn)
 	} else {
-		s.serveNewHTTP2Transport(conn, authInfo)
+		s.serveHTTP2Transport(conn, authInfo)
 	}
 }
 
-// serveNewHTTP2Transport sets up a new http/2 transport (using the
+// serveHTTP2Transport sets up a http/2 transport (using the
 // gRPC http2 server transport in transport/http2_server.go) and
 // serves streams on it.
 // This is run in its own goroutine (it does network I/O in
 // transport.NewServerTransport).
-func (s *Server) serveNewHTTP2Transport(c net.Conn, authInfo credentials.AuthInfo) {
-	st, err := transport.NewServerTransport("http2", c, s.opts.maxConcurrentStreams, authInfo)
+func (s *Server) serveHTTP2Transport(c net.Conn, authInfo credentials.AuthInfo) {
+	config := &transport.ServerConfig{
+		MaxStreams:  s.opts.maxConcurrentStreams,
+		AuthInfo:    authInfo,
+		InTapHandle: s.opts.inTapHandle,
+	}
+	st, err := transport.NewServerTransport("http2", c, config)
 	if err != nil {
 		s.mu.Lock()
 		s.errorf("NewServerTransport(%q) failed: %v", c.RemoteAddr(), err)
@@ -448,6 +468,12 @@ func (s *Server) serveStreams(st transport.ServerTransport) {
 			defer wg.Done()
 			s.handleStream(st, stream, s.traceInfo(st, stream))
 		}()
+	}, func(ctx context.Context, method string) context.Context {
+		if !EnableTracing {
+			return ctx
+		}
+		tr := trace.New("grpc.Recv."+methodFamily(method), method)
+		return trace.NewContext(ctx, tr)
 	})
 	wg.Wait()
 }
@@ -497,15 +523,17 @@ func (s *Server) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 // traceInfo returns a traceInfo and associates it with stream, if tracing is enabled.
 // If tracing is not enabled, it returns nil.
 func (s *Server) traceInfo(st transport.ServerTransport, stream *transport.Stream) (trInfo *traceInfo) {
-	if !EnableTracing {
+	tr, ok := trace.FromContext(stream.Context())
+	if !ok {
 		return nil
 	}
+
 	trInfo = &traceInfo{
-		tr: trace.New("grpc.Recv."+methodFamily(stream.Method()), stream.Method()),
+		tr: tr,
 	}
 	trInfo.firstLine.client = false
 	trInfo.firstLine.remoteAddr = st.RemoteAddr()
-	stream.TraceContext(trInfo.tr)
+
 	if dl, ok := stream.Context().Deadline(); ok {
 		trInfo.firstLine.deadline = dl.Sub(time.Now())
 	}
@@ -532,11 +560,17 @@ func (s *Server) removeConn(c io.Closer) {
 }
 
 func (s *Server) sendResponse(t transport.ServerTransport, stream *transport.Stream, msg interface{}, cp Compressor, opts *transport.Options) error {
-	var cbuf *bytes.Buffer
+	var (
+		cbuf       *bytes.Buffer
+		outPayload *stats.OutPayload
+	)
 	if cp != nil {
 		cbuf = new(bytes.Buffer)
 	}
-	p, err := encode(s.opts.codec, msg, cp, cbuf)
+	if stats.On() {
+		outPayload = &stats.OutPayload{}
+	}
+	p, err := encode(s.opts.codec, msg, cp, cbuf, outPayload)
 	if err != nil {
 		// This typically indicates a fatal issue (e.g., memory
 		// corruption or hardware faults) the application program
@@ -547,10 +581,32 @@ func (s *Server) sendResponse(t transport.ServerTransport, stream *transport.Str
 		// the optimal option.
 		grpclog.Fatalf("grpc: Server failed to encode response %v", err)
 	}
-	return t.Write(stream, p, opts)
+	err = t.Write(stream, p, opts)
+	if err == nil && outPayload != nil {
+		outPayload.SentTime = time.Now()
+		stats.HandleRPC(stream.Context(), outPayload)
+	}
+	return err
 }
 
 func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.Stream, srv *service, md *MethodDesc, trInfo *traceInfo) (err error) {
+	if stats.On() {
+		begin := &stats.Begin{
+			BeginTime: time.Now(),
+		}
+		stats.HandleRPC(stream.Context(), begin)
+	}
+	defer func() {
+		if stats.On() {
+			end := &stats.End{
+				EndTime: time.Now(),
+			}
+			if err != nil && err != io.EOF {
+				end.Error = toRPCErr(err)
+			}
+			stats.HandleRPC(stream.Context(), end)
+		}
+	}()
 	if trInfo != nil {
 		defer trInfo.tr.Finish()
 		trInfo.firstLine.client = false
@@ -579,14 +635,14 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 		if err != nil {
 			switch err := err.(type) {
 			case *rpcError:
-				if err := t.WriteStatus(stream, err.code, err.desc); err != nil {
-					grpclog.Printf("grpc: Server.processUnaryRPC failed to write status %v", err)
+				if e := t.WriteStatus(stream, err.code, err.desc); e != nil {
+					grpclog.Printf("grpc: Server.processUnaryRPC failed to write status %v", e)
 				}
 			case transport.ConnectionError:
 				// Nothing to do here.
 			case transport.StreamError:
-				if err := t.WriteStatus(stream, err.Code, err.Desc); err != nil {
-					grpclog.Printf("grpc: Server.processUnaryRPC failed to write status %v", err)
+				if e := t.WriteStatus(stream, err.Code, err.Desc); e != nil {
+					grpclog.Printf("grpc: Server.processUnaryRPC failed to write status %v", e)
 				}
 			default:
 				panic(fmt.Sprintf("grpc: Unexpected error (%T) from recvMsg: %v", err, err))
@@ -597,20 +653,29 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 		if err := checkRecvPayload(pf, stream.RecvCompress(), s.opts.dc); err != nil {
 			switch err := err.(type) {
 			case *rpcError:
-				if err := t.WriteStatus(stream, err.code, err.desc); err != nil {
-					grpclog.Printf("grpc: Server.processUnaryRPC failed to write status %v", err)
+				if e := t.WriteStatus(stream, err.code, err.desc); e != nil {
+					grpclog.Printf("grpc: Server.processUnaryRPC failed to write status %v", e)
 				}
+				return err
 			default:
-				if err := t.WriteStatus(stream, codes.Internal, err.Error()); err != nil {
-					grpclog.Printf("grpc: Server.processUnaryRPC failed to write status %v", err)
+				if e := t.WriteStatus(stream, codes.Internal, err.Error()); e != nil {
+					grpclog.Printf("grpc: Server.processUnaryRPC failed to write status %v", e)
 				}
-
+				// TODO checkRecvPayload always return RPC error. Add a return here if necessary.
+			}
+		}
+		var inPayload *stats.InPayload
+		if stats.On() {
+			inPayload = &stats.InPayload{
+				RecvTime: time.Now(),
 			}
-			return err
 		}
 		statusCode := codes.OK
 		statusDesc := ""
 		df := func(v interface{}) error {
+			if inPayload != nil {
+				inPayload.WireLength = len(req)
+			}
 			if pf == compressionMade {
 				var err error
 				req, err = s.opts.dc.Do(bytes.NewReader(req))
@@ -618,7 +683,7 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 					if err := t.WriteStatus(stream, codes.Internal, err.Error()); err != nil {
 						grpclog.Printf("grpc: Server.processUnaryRPC failed to write status %v", err)
 					}
-					return err
+					return Errorf(codes.Internal, err.Error())
 				}
 			}
 			if len(req) > s.opts.maxMsgSize {
@@ -630,6 +695,12 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 			if err := s.opts.codec.Unmarshal(req, v); err != nil {
 				return err
 			}
+			if inPayload != nil {
+				inPayload.Payload = v
+				inPayload.Data = req
+				inPayload.Length = len(req)
+				stats.HandleRPC(stream.Context(), inPayload)
+			}
 			if trInfo != nil {
 				trInfo.tr.LazyLog(&payload{sent: false, msg: v}, true)
 			}
@@ -650,9 +721,8 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 			}
 			if err := t.WriteStatus(stream, statusCode, statusDesc); err != nil {
 				grpclog.Printf("grpc: Server.processUnaryRPC failed to write status: %v", err)
-				return err
 			}
-			return nil
+			return Errorf(statusCode, statusDesc)
 		}
 		if trInfo != nil {
 			trInfo.tr.LazyLog(stringer("OK"), false)
@@ -677,11 +747,32 @@ func (s *Server) processUnaryRPC(t transport.ServerTransport, stream *transport.
 		if trInfo != nil {
 			trInfo.tr.LazyLog(&payload{sent: true, msg: reply}, true)
 		}
-		return t.WriteStatus(stream, statusCode, statusDesc)
+		errWrite := t.WriteStatus(stream, statusCode, statusDesc)
+		if statusCode != codes.OK {
+			return Errorf(statusCode, statusDesc)
+		}
+		return errWrite
 	}
 }
 
 func (s *Server) processStreamingRPC(t transport.ServerTransport, stream *transport.Stream, srv *service, sd *StreamDesc, trInfo *traceInfo) (err error) {
+	if stats.On() {
+		begin := &stats.Begin{
+			BeginTime: time.Now(),
+		}
+		stats.HandleRPC(stream.Context(), begin)
+	}
+	defer func() {
+		if stats.On() {
+			end := &stats.End{
+				EndTime: time.Now(),
+			}
+			if err != nil && err != io.EOF {
+				end.Error = toRPCErr(err)
+			}
+			stats.HandleRPC(stream.Context(), end)
+		}
+	}()
 	if s.opts.cp != nil {
 		stream.SetSendCompress(s.opts.cp.Type())
 	}
@@ -744,7 +835,11 @@ func (s *Server) processStreamingRPC(t transport.ServerTransport, stream *transp
 		}
 		ss.mu.Unlock()
 	}
-	return t.WriteStatus(ss.s, ss.statusCode, ss.statusDesc)
+	errWrite := t.WriteStatus(ss.s, ss.statusCode, ss.statusDesc)
+	if ss.statusCode != codes.OK {
+		return Errorf(ss.statusCode, ss.statusDesc)
+	}
+	return errWrite
 
 }
 
@@ -759,7 +854,8 @@ func (s *Server) handleStream(t transport.ServerTransport, stream *transport.Str
 			trInfo.tr.LazyLog(&fmtStringer{"Malformed method name %q", []interface{}{sm}}, true)
 			trInfo.tr.SetError()
 		}
-		if err := t.WriteStatus(stream, codes.InvalidArgument, fmt.Sprintf("malformed method name: %q", stream.Method())); err != nil {
+		errDesc := fmt.Sprintf("malformed method name: %q", stream.Method())
+		if err := t.WriteStatus(stream, codes.InvalidArgument, errDesc); err != nil {
 			if trInfo != nil {
 				trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
 				trInfo.tr.SetError()
@@ -779,7 +875,8 @@ func (s *Server) handleStream(t transport.ServerTransport, stream *transport.Str
 			trInfo.tr.LazyLog(&fmtStringer{"Unknown service %v", []interface{}{service}}, true)
 			trInfo.tr.SetError()
 		}
-		if err := t.WriteStatus(stream, codes.Unimplemented, fmt.Sprintf("unknown service %v", service)); err != nil {
+		errDesc := fmt.Sprintf("unknown service %v", service)
+		if err := t.WriteStatus(stream, codes.Unimplemented, errDesc); err != nil {
 			if trInfo != nil {
 				trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
 				trInfo.tr.SetError()
@@ -804,7 +901,8 @@ func (s *Server) handleStream(t transport.ServerTransport, stream *transport.Str
 		trInfo.tr.LazyLog(&fmtStringer{"Unknown method %v", []interface{}{method}}, true)
 		trInfo.tr.SetError()
 	}
-	if err := t.WriteStatus(stream, codes.Unimplemented, fmt.Sprintf("unknown method %v", method)); err != nil {
+	errDesc := fmt.Sprintf("unknown method %v", method)
+	if err := t.WriteStatus(stream, codes.Unimplemented, errDesc); err != nil {
 		if trInfo != nil {
 			trInfo.tr.LazyLog(&fmtStringer{"%v", []interface{}{err}}, true)
 			trInfo.tr.SetError()
diff --git a/vendor/google.golang.org/grpc/stats/handlers.go b/vendor/google.golang.org/grpc/stats/handlers.go
new file mode 100644
index 0000000..ce47786
--- /dev/null
+++ b/vendor/google.golang.org/grpc/stats/handlers.go
@@ -0,0 +1,146 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+package stats
+
+import (
+	"net"
+	"sync/atomic"
+
+	"golang.org/x/net/context"
+	"google.golang.org/grpc/grpclog"
+)
+
+// ConnTagInfo defines the relevant information needed by connection context tagger.
+type ConnTagInfo struct {
+	// RemoteAddr is the remote address of the corresponding connection.
+	RemoteAddr net.Addr
+	// LocalAddr is the local address of the corresponding connection.
+	LocalAddr net.Addr
+	// TODO add QOS related fields.
+}
+
+// RPCTagInfo defines the relevant information needed by RPC context tagger.
+type RPCTagInfo struct {
+	// FullMethodName is the RPC method in the format of /package.service/method.
+	FullMethodName string
+}
+
+var (
+	on          = new(int32)
+	rpcHandler  func(context.Context, RPCStats)
+	connHandler func(context.Context, ConnStats)
+	connTagger  func(context.Context, *ConnTagInfo) context.Context
+	rpcTagger   func(context.Context, *RPCTagInfo) context.Context
+)
+
+// HandleRPC processes the RPC stats using the rpc handler registered by the user.
+func HandleRPC(ctx context.Context, s RPCStats) {
+	if rpcHandler == nil {
+		return
+	}
+	rpcHandler(ctx, s)
+}
+
+// RegisterRPCHandler registers the user handler function for RPC stats processing.
+// It should be called only once. The later call will overwrite the former value if it is called multiple times.
+// This handler function will be called to process the rpc stats.
+func RegisterRPCHandler(f func(context.Context, RPCStats)) {
+	rpcHandler = f
+}
+
+// HandleConn processes the stats using the call back function registered by user.
+func HandleConn(ctx context.Context, s ConnStats) {
+	if connHandler == nil {
+		return
+	}
+	connHandler(ctx, s)
+}
+
+// RegisterConnHandler registers the user handler function for conn stats.
+// It should be called only once. The later call will overwrite the former value if it is called multiple times.
+// This handler function will be called to process the conn stats.
+func RegisterConnHandler(f func(context.Context, ConnStats)) {
+	connHandler = f
+}
+
+// TagConn calls user registered connection context tagger.
+func TagConn(ctx context.Context, info *ConnTagInfo) context.Context {
+	if connTagger == nil {
+		return ctx
+	}
+	return connTagger(ctx, info)
+}
+
+// RegisterConnTagger registers the user connection context tagger function.
+// The connection context tagger can attach some information to the given context.
+// The returned context will be used for stats handling.
+// For conn stats handling, the context used in connHandler for this
+// connection will be derived from the context returned.
+// For RPC stats handling,
+//  - On server side, the context used in rpcHandler for all RPCs on this
+// connection will be derived from the context returned.
+//  - On client side, the context is not derived from the context returned.
+func RegisterConnTagger(t func(context.Context, *ConnTagInfo) context.Context) {
+	connTagger = t
+}
+
+// TagRPC calls the user registered RPC context tagger.
+func TagRPC(ctx context.Context, info *RPCTagInfo) context.Context {
+	if rpcTagger == nil {
+		return ctx
+	}
+	return rpcTagger(ctx, info)
+}
+
+// RegisterRPCTagger registers the user RPC context tagger function.
+// The RPC context tagger can attach some information to the given context.
+// The context used in stats rpcHandler for this RPC will be derived from the
+// context returned.
+func RegisterRPCTagger(t func(context.Context, *RPCTagInfo) context.Context) {
+	rpcTagger = t
+}
+
+// Start starts the stats collection and processing if there is a registered stats handle.
+func Start() {
+	if rpcHandler == nil && connHandler == nil {
+		grpclog.Println("rpcHandler and connHandler are both nil when starting stats. Stats is not started")
+		return
+	}
+	atomic.StoreInt32(on, 1)
+}
+
+// On indicates whether the stats collection and processing is on.
+func On() bool {
+	return atomic.CompareAndSwapInt32(on, 1, 1)
+}
diff --git a/vendor/google.golang.org/grpc/stats/stats.go b/vendor/google.golang.org/grpc/stats/stats.go
new file mode 100644
index 0000000..a82448a
--- /dev/null
+++ b/vendor/google.golang.org/grpc/stats/stats.go
@@ -0,0 +1,223 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+// Package stats is for collecting and reporting various network and RPC stats.
+// This package is for monitoring purpose only. All fields are read-only.
+// All APIs are experimental.
+package stats // import "google.golang.org/grpc/stats"
+
+import (
+	"net"
+	"time"
+)
+
+// RPCStats contains stats information about RPCs.
+type RPCStats interface {
+	isRPCStats()
+	// IsClient returns true if this RPCStats is from client side.
+	IsClient() bool
+}
+
+// Begin contains stats when an RPC begins.
+// FailFast are only valid if Client is true.
+type Begin struct {
+	// Client is true if this Begin is from client side.
+	Client bool
+	// BeginTime is the time when the RPC begins.
+	BeginTime time.Time
+	// FailFast indicates if this RPC is failfast.
+	FailFast bool
+}
+
+// IsClient indicates if this is from client side.
+func (s *Begin) IsClient() bool { return s.Client }
+
+func (s *Begin) isRPCStats() {}
+
+// InPayload contains the information for an incoming payload.
+type InPayload struct {
+	// Client is true if this InPayload is from client side.
+	Client bool
+	// Payload is the payload with original type.
+	Payload interface{}
+	// Data is the serialized message payload.
+	Data []byte
+	// Length is the length of uncompressed data.
+	Length int
+	// WireLength is the length of data on wire (compressed, signed, encrypted).
+	WireLength int
+	// RecvTime is the time when the payload is received.
+	RecvTime time.Time
+}
+
+// IsClient indicates if this is from client side.
+func (s *InPayload) IsClient() bool { return s.Client }
+
+func (s *InPayload) isRPCStats() {}
+
+// InHeader contains stats when a header is received.
+// FullMethod, addresses and Compression are only valid if Client is false.
+type InHeader struct {
+	// Client is true if this InHeader is from client side.
+	Client bool
+	// WireLength is the wire length of header.
+	WireLength int
+
+	// FullMethod is the full RPC method string, i.e., /package.service/method.
+	FullMethod string
+	// RemoteAddr is the remote address of the corresponding connection.
+	RemoteAddr net.Addr
+	// LocalAddr is the local address of the corresponding connection.
+	LocalAddr net.Addr
+	// Compression is the compression algorithm used for the RPC.
+	Compression string
+}
+
+// IsClient indicates if this is from client side.
+func (s *InHeader) IsClient() bool { return s.Client }
+
+func (s *InHeader) isRPCStats() {}
+
+// InTrailer contains stats when a trailer is received.
+type InTrailer struct {
+	// Client is true if this InTrailer is from client side.
+	Client bool
+	// WireLength is the wire length of trailer.
+	WireLength int
+}
+
+// IsClient indicates if this is from client side.
+func (s *InTrailer) IsClient() bool { return s.Client }
+
+func (s *InTrailer) isRPCStats() {}
+
+// OutPayload contains the information for an outgoing payload.
+type OutPayload struct {
+	// Client is true if this OutPayload is from client side.
+	Client bool
+	// Payload is the payload with original type.
+	Payload interface{}
+	// Data is the serialized message payload.
+	Data []byte
+	// Length is the length of uncompressed data.
+	Length int
+	// WireLength is the length of data on wire (compressed, signed, encrypted).
+	WireLength int
+	// SentTime is the time when the payload is sent.
+	SentTime time.Time
+}
+
+// IsClient indicates if this is from client side.
+func (s *OutPayload) IsClient() bool { return s.Client }
+
+func (s *OutPayload) isRPCStats() {}
+
+// OutHeader contains stats when a header is sent.
+// FullMethod, addresses and Compression are only valid if Client is true.
+type OutHeader struct {
+	// Client is true if this OutHeader is from client side.
+	Client bool
+	// WireLength is the wire length of header.
+	WireLength int
+
+	// FullMethod is the full RPC method string, i.e., /package.service/method.
+	FullMethod string
+	// RemoteAddr is the remote address of the corresponding connection.
+	RemoteAddr net.Addr
+	// LocalAddr is the local address of the corresponding connection.
+	LocalAddr net.Addr
+	// Compression is the compression algorithm used for the RPC.
+	Compression string
+}
+
+// IsClient indicates if this is from client side.
+func (s *OutHeader) IsClient() bool { return s.Client }
+
+func (s *OutHeader) isRPCStats() {}
+
+// OutTrailer contains stats when a trailer is sent.
+type OutTrailer struct {
+	// Client is true if this OutTrailer is from client side.
+	Client bool
+	// WireLength is the wire length of trailer.
+	WireLength int
+}
+
+// IsClient indicates if this is from client side.
+func (s *OutTrailer) IsClient() bool { return s.Client }
+
+func (s *OutTrailer) isRPCStats() {}
+
+// End contains stats when an RPC ends.
+type End struct {
+	// Client is true if this End is from client side.
+	Client bool
+	// EndTime is the time when the RPC ends.
+	EndTime time.Time
+	// Error is the error just happened. Its type is gRPC error.
+	Error error
+}
+
+// IsClient indicates if this is from client side.
+func (s *End) IsClient() bool { return s.Client }
+
+func (s *End) isRPCStats() {}
+
+// ConnStats contains stats information about connections.
+type ConnStats interface {
+	isConnStats()
+	// IsClient returns true if this ConnStats is from client side.
+	IsClient() bool
+}
+
+// ConnBegin contains the stats of a connection when it is established.
+type ConnBegin struct {
+	// Client is true if this ConnBegin is from client side.
+	Client bool
+}
+
+// IsClient indicates if this is from client side.
+func (s *ConnBegin) IsClient() bool { return s.Client }
+
+func (s *ConnBegin) isConnStats() {}
+
+// ConnEnd contains the stats of a connection when it ends.
+type ConnEnd struct {
+	// Client is true if this ConnEnd is from client side.
+	Client bool
+}
+
+// IsClient indicates if this is from client side.
+func (s *ConnEnd) IsClient() bool { return s.Client }
+
+func (s *ConnEnd) isConnStats() {}
diff --git a/vendor/google.golang.org/grpc/stream.go b/vendor/google.golang.org/grpc/stream.go
index 4681054..d3a4deb 100644
--- a/vendor/google.golang.org/grpc/stream.go
+++ b/vendor/google.golang.org/grpc/stream.go
@@ -45,6 +45,7 @@ import (
 	"golang.org/x/net/trace"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/stats"
 	"google.golang.org/grpc/transport"
 )
 
@@ -97,7 +98,7 @@ type ClientStream interface {
 
 // NewClientStream creates a new Stream for the client side. This is called
 // by generated code.
-func NewClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (ClientStream, error) {
+func NewClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, method string, opts ...CallOption) (_ ClientStream, err error) {
 	if cc.dopts.streamInt != nil {
 		return cc.dopts.streamInt(ctx, desc, cc, method, newClientStream, opts...)
 	}
@@ -106,11 +107,18 @@ 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) {
 	var (
-		t   transport.ClientTransport
-		s   *transport.Stream
-		put func()
+		t      transport.ClientTransport
+		s      *transport.Stream
+		put    func()
+		cancel context.CancelFunc
 	)
 	c := defaultCallInfo
+	if mc, ok := cc.getMethodConfig(method); ok {
+		c.failFast = !mc.WaitForReady
+		if mc.Timeout > 0 {
+			ctx, cancel = context.WithTimeout(ctx, mc.Timeout)
+		}
+	}
 	for _, o := range opts {
 		if err := o.before(&c); err != nil {
 			return nil, toRPCErr(err)
@@ -143,6 +151,25 @@ func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 			}
 		}()
 	}
+	if stats.On() {
+		ctx = stats.TagRPC(ctx, &stats.RPCTagInfo{FullMethodName: method})
+		begin := &stats.Begin{
+			Client:    true,
+			BeginTime: time.Now(),
+			FailFast:  c.failFast,
+		}
+		stats.HandleRPC(ctx, begin)
+	}
+	defer func() {
+		if err != nil && stats.On() {
+			// Only handle end stats if err != nil.
+			end := &stats.End{
+				Client: true,
+				Error:  err,
+			}
+			stats.HandleRPC(ctx, end)
+		}
+	}()
 	gopts := BalancerGetOptions{
 		BlockingWait: !c.failFast,
 	}
@@ -180,12 +207,13 @@ func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 		break
 	}
 	cs := &clientStream{
-		opts:  opts,
-		c:     c,
-		desc:  desc,
-		codec: cc.dopts.codec,
-		cp:    cc.dopts.cp,
-		dc:    cc.dopts.dc,
+		opts:   opts,
+		c:      c,
+		desc:   desc,
+		codec:  cc.dopts.codec,
+		cp:     cc.dopts.cp,
+		dc:     cc.dopts.dc,
+		cancel: cancel,
 
 		put: put,
 		t:   t,
@@ -194,6 +222,8 @@ func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 
 		tracing: EnableTracing,
 		trInfo:  trInfo,
+
+		statsCtx: ctx,
 	}
 	if cc.dopts.cp != nil {
 		cs.cbuf = new(bytes.Buffer)
@@ -227,16 +257,17 @@ func newClientStream(ctx context.Context, desc *StreamDesc, cc *ClientConn, meth
 
 // clientStream implements a client side Stream.
 type clientStream struct {
-	opts  []CallOption
-	c     callInfo
-	t     transport.ClientTransport
-	s     *transport.Stream
-	p     *parser
-	desc  *StreamDesc
-	codec Codec
-	cp    Compressor
-	cbuf  *bytes.Buffer
-	dc    Decompressor
+	opts   []CallOption
+	c      callInfo
+	t      transport.ClientTransport
+	s      *transport.Stream
+	p      *parser
+	desc   *StreamDesc
+	codec  Codec
+	cp     Compressor
+	cbuf   *bytes.Buffer
+	dc     Decompressor
+	cancel context.CancelFunc
 
 	tracing bool // set to EnableTracing when the clientStream is created.
 
@@ -246,6 +277,11 @@ type clientStream struct {
 	// trInfo.tr is set when the clientStream is created (if EnableTracing is true),
 	// and is set to nil when the clientStream's finish method is called.
 	trInfo traceInfo
+
+	// statsCtx keeps the user context for stats handling.
+	// All stats collection should use the statsCtx (instead of the stream context)
+	// so that all the generated stats for a particular RPC can be associated in the processing phase.
+	statsCtx context.Context
 }
 
 func (cs *clientStream) Context() context.Context {
@@ -274,6 +310,8 @@ func (cs *clientStream) SendMsg(m interface{}) (err error) {
 		}
 		cs.mu.Unlock()
 	}
+	// TODO Investigate how to signal the stats handling party.
+	// generate error stats if err != nil && err != io.EOF?
 	defer func() {
 		if err != nil {
 			cs.finish(err)
@@ -296,7 +334,13 @@ func (cs *clientStream) SendMsg(m interface{}) (err error) {
 		}
 		err = toRPCErr(err)
 	}()
-	out, err := encode(cs.codec, m, cs.cp, cs.cbuf)
+	var outPayload *stats.OutPayload
+	if stats.On() {
+		outPayload = &stats.OutPayload{
+			Client: true,
+		}
+	}
+	out, err := encode(cs.codec, m, cs.cp, cs.cbuf, outPayload)
 	defer func() {
 		if cs.cbuf != nil {
 			cs.cbuf.Reset()
@@ -305,11 +349,37 @@ func (cs *clientStream) SendMsg(m interface{}) (err error) {
 	if err != nil {
 		return Errorf(codes.Internal, "grpc: %v", err)
 	}
-	return cs.t.Write(cs.s, out, &transport.Options{Last: false})
+	err = cs.t.Write(cs.s, out, &transport.Options{Last: false})
+	if err == nil && outPayload != nil {
+		outPayload.SentTime = time.Now()
+		stats.HandleRPC(cs.statsCtx, outPayload)
+	}
+	return err
 }
 
 func (cs *clientStream) RecvMsg(m interface{}) (err error) {
-	err = recv(cs.p, cs.codec, cs.s, cs.dc, m, math.MaxInt32)
+	defer func() {
+		if err != nil && stats.On() {
+			// Only generate End if err != nil.
+			// If err == nil, it's not the last RecvMsg.
+			// The last RecvMsg gets either an RPC error or io.EOF.
+			end := &stats.End{
+				Client:  true,
+				EndTime: time.Now(),
+			}
+			if err != io.EOF {
+				end.Error = toRPCErr(err)
+			}
+			stats.HandleRPC(cs.statsCtx, end)
+		}
+	}()
+	var inPayload *stats.InPayload
+	if stats.On() {
+		inPayload = &stats.InPayload{
+			Client: true,
+		}
+	}
+	err = recv(cs.p, cs.codec, cs.s, cs.dc, m, math.MaxInt32, inPayload)
 	defer func() {
 		// err != nil indicates the termination of the stream.
 		if err != nil {
@@ -324,11 +394,15 @@ func (cs *clientStream) RecvMsg(m interface{}) (err error) {
 			}
 			cs.mu.Unlock()
 		}
+		if inPayload != nil {
+			stats.HandleRPC(cs.statsCtx, inPayload)
+		}
 		if !cs.desc.ClientStreams || cs.desc.ServerStreams {
 			return
 		}
 		// Special handling for client streaming rpc.
-		err = recv(cs.p, cs.codec, cs.s, cs.dc, m, math.MaxInt32)
+		// This recv expects EOF or errors, so we don't collect inPayload.
+		err = recv(cs.p, cs.codec, cs.s, cs.dc, m, math.MaxInt32, nil)
 		cs.closeTransportStream(err)
 		if err == nil {
 			return toRPCErr(errors.New("grpc: client streaming protocol violation: get <nil>, want <EOF>"))
@@ -384,6 +458,11 @@ func (cs *clientStream) closeTransportStream(err error) {
 }
 
 func (cs *clientStream) finish(err error) {
+	defer func() {
+		if cs.cancel != nil {
+			cs.cancel()
+		}
+	}()
 	cs.mu.Lock()
 	defer cs.mu.Unlock()
 	for _, o := range cs.opts {
@@ -482,7 +561,11 @@ func (ss *serverStream) SendMsg(m interface{}) (err error) {
 			ss.mu.Unlock()
 		}
 	}()
-	out, err := encode(ss.codec, m, ss.cp, ss.cbuf)
+	var outPayload *stats.OutPayload
+	if stats.On() {
+		outPayload = &stats.OutPayload{}
+	}
+	out, err := encode(ss.codec, m, ss.cp, ss.cbuf, outPayload)
 	defer func() {
 		if ss.cbuf != nil {
 			ss.cbuf.Reset()
@@ -495,6 +578,10 @@ func (ss *serverStream) SendMsg(m interface{}) (err error) {
 	if err := ss.t.Write(ss.s, out, &transport.Options{Last: false}); err != nil {
 		return toRPCErr(err)
 	}
+	if outPayload != nil {
+		outPayload.SentTime = time.Now()
+		stats.HandleRPC(ss.s.Context(), outPayload)
+	}
 	return nil
 }
 
@@ -513,7 +600,11 @@ func (ss *serverStream) RecvMsg(m interface{}) (err error) {
 			ss.mu.Unlock()
 		}
 	}()
-	if err := recv(ss.p, ss.codec, ss.s, ss.dc, m, ss.maxMsgSize); err != nil {
+	var inPayload *stats.InPayload
+	if stats.On() {
+		inPayload = &stats.InPayload{}
+	}
+	if err := recv(ss.p, ss.codec, ss.s, ss.dc, m, ss.maxMsgSize, inPayload); err != nil {
 		if err == io.EOF {
 			return err
 		}
@@ -522,5 +613,8 @@ func (ss *serverStream) RecvMsg(m interface{}) (err error) {
 		}
 		return toRPCErr(err)
 	}
+	if inPayload != nil {
+		stats.HandleRPC(ss.s.Context(), inPayload)
+	}
 	return nil
 }
diff --git a/vendor/google.golang.org/grpc/tap/tap.go b/vendor/google.golang.org/grpc/tap/tap.go
new file mode 100644
index 0000000..0f36647
--- /dev/null
+++ b/vendor/google.golang.org/grpc/tap/tap.go
@@ -0,0 +1,54 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+// Package tap defines the function handles which are executed on the transport
+// layer of gRPC-Go and related information. Everything here is EXPERIMENTAL.
+package tap
+
+import (
+	"golang.org/x/net/context"
+)
+
+// Info defines the relevant information needed by the handles.
+type Info struct {
+	// FullMethodName is the string of grpc method (in the format of
+	// /package.service/method).
+	FullMethodName string
+	// TODO: More to be added.
+}
+
+// ServerInHandle defines the function which runs when a new stream is created
+// on the server side. Note that it is executed in the per-connection I/O goroutine(s) instead
+// of per-RPC goroutine. Therefore, users should NOT have any blocking/time-consuming
+// work in this handle. Otherwise all the RPCs would slow down.
+type ServerInHandle func(ctx context.Context, info *Info) (context.Context, error)
diff --git a/vendor/google.golang.org/grpc/transport/control.go b/vendor/google.golang.org/grpc/transport/control.go
index 4ef0830..2586cba 100644
--- a/vendor/google.golang.org/grpc/transport/control.go
+++ b/vendor/google.golang.org/grpc/transport/control.go
@@ -111,35 +111,9 @@ func newQuotaPool(q int) *quotaPool {
 	return qb
 }
 
-// add adds n to the available quota and tries to send it on acquire.
-func (qb *quotaPool) add(n int) {
-	qb.mu.Lock()
-	defer qb.mu.Unlock()
-	qb.quota += n
-	if qb.quota <= 0 {
-		return
-	}
-	select {
-	case qb.c <- qb.quota:
-		qb.quota = 0
-	default:
-	}
-}
-
-// cancel cancels the pending quota sent on acquire, if any.
-func (qb *quotaPool) cancel() {
-	qb.mu.Lock()
-	defer qb.mu.Unlock()
-	select {
-	case n := <-qb.c:
-		qb.quota += n
-	default:
-	}
-}
-
-// reset cancels the pending quota sent on acquired, incremented by v and sends
+// add cancels the pending quota sent on acquired, incremented by v and sends
 // it back on acquire.
-func (qb *quotaPool) reset(v int) {
+func (qb *quotaPool) add(v int) {
 	qb.mu.Lock()
 	defer qb.mu.Unlock()
 	select {
@@ -151,6 +125,10 @@ func (qb *quotaPool) reset(v int) {
 	if qb.quota <= 0 {
 		return
 	}
+	// After the pool has been created, this is the only place that sends on
+	// the channel. Since mu is held at this point and any quota that was sent
+	// on the channel has been retrieved, we know that this code will always
+	// place any positive quota value on the channel.
 	select {
 	case qb.c <- qb.quota:
 		qb.quota = 0
diff --git a/vendor/google.golang.org/grpc/transport/handler_server.go b/vendor/google.golang.org/grpc/transport/handler_server.go
index 114e349..10b6dc0 100644
--- a/vendor/google.golang.org/grpc/transport/handler_server.go
+++ b/vendor/google.golang.org/grpc/transport/handler_server.go
@@ -268,7 +268,7 @@ func (ht *serverHandlerTransport) WriteHeader(s *Stream, md metadata.MD) error {
 	})
 }
 
-func (ht *serverHandlerTransport) HandleStreams(startStream func(*Stream)) {
+func (ht *serverHandlerTransport) HandleStreams(startStream func(*Stream), traceCtx func(context.Context, string) context.Context) {
 	// With this transport type there will be exactly 1 stream: this HTTP request.
 
 	var ctx context.Context
diff --git a/vendor/google.golang.org/grpc/transport/http2_client.go b/vendor/google.golang.org/grpc/transport/http2_client.go
index 2b0f680..605b1e5 100644
--- a/vendor/google.golang.org/grpc/transport/http2_client.go
+++ b/vendor/google.golang.org/grpc/transport/http2_client.go
@@ -51,16 +51,20 @@ import (
 	"google.golang.org/grpc/grpclog"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/peer"
+	"google.golang.org/grpc/stats"
 )
 
 // http2Client implements the ClientTransport interface with HTTP2.
 type http2Client struct {
-	target    string // server name/addr
-	userAgent string
-	md        interface{}
-	conn      net.Conn             // underlying communication channel
-	authInfo  credentials.AuthInfo // auth info about the connection
-	nextID    uint32               // the next stream ID to be used
+	ctx        context.Context
+	target     string // server name/addr
+	userAgent  string
+	md         interface{}
+	conn       net.Conn // underlying communication channel
+	remoteAddr net.Addr
+	localAddr  net.Addr
+	authInfo   credentials.AuthInfo // auth info about the connection
+	nextID     uint32               // the next stream ID to be used
 
 	// writableChan synchronizes write access to the transport.
 	// A writer acquires the write lock by sending a value on writableChan
@@ -150,6 +154,9 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (
 	scheme := "http"
 	conn, err := dial(ctx, opts.Dialer, addr.Addr)
 	if err != nil {
+		if opts.FailOnNonTempDialError {
+			return nil, connectionErrorf(isTemporary(err), err, "transport: %v", err)
+		}
 		return nil, connectionErrorf(true, err, "transport: %v", err)
 	}
 	// Any further errors will close the underlying connection
@@ -175,11 +182,14 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (
 	}
 	var buf bytes.Buffer
 	t := &http2Client{
-		target:    addr.Addr,
-		userAgent: ua,
-		md:        addr.Metadata,
-		conn:      conn,
-		authInfo:  authInfo,
+		ctx:        ctx,
+		target:     addr.Addr,
+		userAgent:  ua,
+		md:         addr.Metadata,
+		conn:       conn,
+		remoteAddr: conn.RemoteAddr(),
+		localAddr:  conn.LocalAddr(),
+		authInfo:   authInfo,
 		// The client initiated stream id is odd starting from 1.
 		nextID:          1,
 		writableChan:    make(chan int, 1),
@@ -199,6 +209,16 @@ func newHTTP2Client(ctx context.Context, addr TargetInfo, opts ConnectOptions) (
 		maxStreams:      math.MaxInt32,
 		streamSendQuota: defaultWindowSize,
 	}
+	if stats.On() {
+		t.ctx = stats.TagConn(t.ctx, &stats.ConnTagInfo{
+			RemoteAddr: t.remoteAddr,
+			LocalAddr:  t.localAddr,
+		})
+		connBegin := &stats.ConnBegin{
+			Client: true,
+		}
+		stats.HandleConn(t.ctx, connBegin)
+	}
 	// Start the reader goroutine for incoming message. Each transport has
 	// a dedicated goroutine which reads HTTP2 frame from network. Then it
 	// dispatches the frame to the corresponding stream entity.
@@ -270,12 +290,13 @@ func (t *http2Client) newStream(ctx context.Context, callHdr *CallHdr) *Stream {
 // streams.
 func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Stream, err error) {
 	pr := &peer.Peer{
-		Addr: t.conn.RemoteAddr(),
+		Addr: t.remoteAddr,
 	}
 	// Attach Auth info if there is any.
 	if t.authInfo != nil {
 		pr.AuthInfo = t.authInfo
 	}
+	userCtx := ctx
 	ctx = peer.NewContext(ctx, pr)
 	authData := make(map[string]string)
 	for _, c := range t.creds {
@@ -347,6 +368,7 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 		return nil, ErrConnClosing
 	}
 	s := t.newStream(ctx, callHdr)
+	s.clientStatsCtx = userCtx
 	t.activeStreams[s.id] = s
 
 	// This stream is not counted when applySetings(...) initialize t.streamsQuota.
@@ -357,7 +379,7 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 	}
 	t.mu.Unlock()
 	if reset {
-		t.streamsQuota.reset(-1)
+		t.streamsQuota.add(-1)
 	}
 
 	// HPACK encodes various headers. Note that once WriteField(...) is
@@ -413,6 +435,7 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 		}
 	}
 	first := true
+	bufLen := t.hBuf.Len()
 	// Sends the headers in a single batch even when they span multiple frames.
 	for !endHeaders {
 		size := t.hBuf.Len()
@@ -447,6 +470,17 @@ func (t *http2Client) NewStream(ctx context.Context, callHdr *CallHdr) (_ *Strea
 			return nil, connectionErrorf(true, err, "transport: %v", err)
 		}
 	}
+	if stats.On() {
+		outHeader := &stats.OutHeader{
+			Client:      true,
+			WireLength:  bufLen,
+			FullMethod:  callHdr.Method,
+			RemoteAddr:  t.remoteAddr,
+			LocalAddr:   t.localAddr,
+			Compression: callHdr.SendCompress,
+		}
+		stats.HandleRPC(s.clientStatsCtx, outHeader)
+	}
 	t.writableChan <- 0
 	return s, nil
 }
@@ -525,6 +559,12 @@ func (t *http2Client) Close() (err error) {
 		s.mu.Unlock()
 		s.write(recvMsg{err: ErrConnClosing})
 	}
+	if stats.On() {
+		connEnd := &stats.ConnEnd{
+			Client: true,
+		}
+		stats.HandleConn(t.ctx, connEnd)
+	}
 	return
 }
 
@@ -582,19 +622,14 @@ func (t *http2Client) Write(s *Stream, data []byte, opts *Options) error {
 		var p []byte
 		if r.Len() > 0 {
 			size := http2MaxFrameLen
-			s.sendQuotaPool.add(0)
 			// Wait until the stream has some quota to send the data.
 			sq, err := wait(s.ctx, s.done, s.goAway, t.shutdownChan, s.sendQuotaPool.acquire())
 			if err != nil {
 				return err
 			}
-			t.sendQuotaPool.add(0)
 			// Wait until the transport has some quota to send the data.
 			tq, err := wait(s.ctx, s.done, s.goAway, t.shutdownChan, t.sendQuotaPool.acquire())
 			if err != nil {
-				if _, ok := err.(StreamError); ok || err == io.EOF {
-					t.sendQuotaPool.cancel()
-				}
 				return err
 			}
 			if sq < size {
@@ -874,6 +909,24 @@ func (t *http2Client) operateHeaders(frame *http2.MetaHeadersFrame) {
 	}
 
 	endStream := frame.StreamEnded()
+	var isHeader bool
+	defer func() {
+		if stats.On() {
+			if isHeader {
+				inHeader := &stats.InHeader{
+					Client:     true,
+					WireLength: int(frame.Header().Length),
+				}
+				stats.HandleRPC(s.clientStatsCtx, inHeader)
+			} else {
+				inTrailer := &stats.InTrailer{
+					Client:     true,
+					WireLength: int(frame.Header().Length),
+				}
+				stats.HandleRPC(s.clientStatsCtx, inTrailer)
+			}
+		}
+	}()
 
 	s.mu.Lock()
 	if !endStream {
@@ -885,6 +938,7 @@ func (t *http2Client) operateHeaders(frame *http2.MetaHeadersFrame) {
 		}
 		close(s.headerChan)
 		s.headerDone = true
+		isHeader = true
 	}
 	if !endStream || s.state == streamDone {
 		s.mu.Unlock()
@@ -994,13 +1048,13 @@ func (t *http2Client) applySettings(ss []http2.Setting) {
 			t.maxStreams = int(s.Val)
 			t.mu.Unlock()
 			if reset {
-				t.streamsQuota.reset(int(s.Val) - ms)
+				t.streamsQuota.add(int(s.Val) - ms)
 			}
 		case http2.SettingInitialWindowSize:
 			t.mu.Lock()
 			for _, stream := range t.activeStreams {
 				// Adjust the sending quota for each stream.
-				stream.sendQuotaPool.reset(int(s.Val - t.streamSendQuota))
+				stream.sendQuotaPool.add(int(s.Val - t.streamSendQuota))
 			}
 			t.streamSendQuota = s.Val
 			t.mu.Unlock()
diff --git a/vendor/google.golang.org/grpc/transport/http2_server.go b/vendor/google.golang.org/grpc/transport/http2_server.go
index a62fb7c..316188e 100644
--- a/vendor/google.golang.org/grpc/transport/http2_server.go
+++ b/vendor/google.golang.org/grpc/transport/http2_server.go
@@ -50,6 +50,8 @@ import (
 	"google.golang.org/grpc/grpclog"
 	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/peer"
+	"google.golang.org/grpc/stats"
+	"google.golang.org/grpc/tap"
 )
 
 // ErrIllegalHeaderWrite indicates that setting header is illegal because of
@@ -58,9 +60,13 @@ var ErrIllegalHeaderWrite = errors.New("transport: the stream is done or WriteHe
 
 // http2Server implements the ServerTransport interface with HTTP2.
 type http2Server struct {
+	ctx         context.Context
 	conn        net.Conn
+	remoteAddr  net.Addr
+	localAddr   net.Addr
 	maxStreamID uint32               // max stream ID ever seen
 	authInfo    credentials.AuthInfo // auth info about the connection
+	inTapHandle tap.ServerInHandle
 	// writableChan synchronizes write access to the transport.
 	// A writer acquires the write lock by receiving a value on writableChan
 	// and releases it by sending on writableChan.
@@ -91,12 +97,13 @@ type http2Server struct {
 
 // newHTTP2Server constructs a ServerTransport based on HTTP2. ConnectionError is
 // returned if something goes wrong.
-func newHTTP2Server(conn net.Conn, maxStreams uint32, authInfo credentials.AuthInfo) (_ ServerTransport, err error) {
+func newHTTP2Server(conn net.Conn, config *ServerConfig) (_ ServerTransport, err error) {
 	framer := newFramer(conn)
 	// Send initial settings as connection preface to client.
 	var settings []http2.Setting
 	// TODO(zhaoq): Have a better way to signal "no limit" because 0 is
 	// permitted in the HTTP2 spec.
+	maxStreams := config.MaxStreams
 	if maxStreams == 0 {
 		maxStreams = math.MaxUint32
 	} else {
@@ -121,12 +128,16 @@ func newHTTP2Server(conn net.Conn, maxStreams uint32, authInfo credentials.AuthI
 	}
 	var buf bytes.Buffer
 	t := &http2Server{
+		ctx:             context.Background(),
 		conn:            conn,
-		authInfo:        authInfo,
+		remoteAddr:      conn.RemoteAddr(),
+		localAddr:       conn.LocalAddr(),
+		authInfo:        config.AuthInfo,
 		framer:          framer,
 		hBuf:            &buf,
 		hEnc:            hpack.NewEncoder(&buf),
 		maxStreams:      maxStreams,
+		inTapHandle:     config.InTapHandle,
 		controlBuf:      newRecvBuffer(),
 		fc:              &inFlow{limit: initialConnWindowSize},
 		sendQuotaPool:   newQuotaPool(defaultWindowSize),
@@ -136,13 +147,21 @@ func newHTTP2Server(conn net.Conn, maxStreams uint32, authInfo credentials.AuthI
 		activeStreams:   make(map[uint32]*Stream),
 		streamSendQuota: defaultWindowSize,
 	}
+	if stats.On() {
+		t.ctx = stats.TagConn(t.ctx, &stats.ConnTagInfo{
+			RemoteAddr: t.remoteAddr,
+			LocalAddr:  t.localAddr,
+		})
+		connBegin := &stats.ConnBegin{}
+		stats.HandleConn(t.ctx, connBegin)
+	}
 	go t.controller()
 	t.writableChan <- 0
 	return t, nil
 }
 
 // operateHeader takes action on the decoded headers.
-func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(*Stream)) (close bool) {
+func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(*Stream), traceCtx func(context.Context, string) context.Context) (close bool) {
 	buf := newRecvBuffer()
 	s := &Stream{
 		id:  frame.Header().StreamID,
@@ -168,12 +187,12 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 	}
 	s.recvCompress = state.encoding
 	if state.timeoutSet {
-		s.ctx, s.cancel = context.WithTimeout(context.TODO(), state.timeout)
+		s.ctx, s.cancel = context.WithTimeout(t.ctx, state.timeout)
 	} else {
-		s.ctx, s.cancel = context.WithCancel(context.TODO())
+		s.ctx, s.cancel = context.WithCancel(t.ctx)
 	}
 	pr := &peer.Peer{
-		Addr: t.conn.RemoteAddr(),
+		Addr: t.remoteAddr,
 	}
 	// Attach Auth info if there is any.
 	if t.authInfo != nil {
@@ -195,6 +214,18 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 	}
 	s.recvCompress = state.encoding
 	s.method = state.method
+	if t.inTapHandle != nil {
+		var err error
+		info := &tap.Info{
+			FullMethodName: state.method,
+		}
+		s.ctx, err = t.inTapHandle(s.ctx, info)
+		if err != nil {
+			// TODO: Log the real error.
+			t.controlBuf.put(&resetStream{s.id, http2.ErrCodeRefusedStream})
+			return
+		}
+	}
 	t.mu.Lock()
 	if t.state != reachable {
 		t.mu.Unlock()
@@ -218,13 +249,26 @@ func (t *http2Server) operateHeaders(frame *http2.MetaHeadersFrame, handle func(
 	s.windowHandler = func(n int) {
 		t.updateWindow(s, uint32(n))
 	}
+	s.ctx = traceCtx(s.ctx, s.method)
+	if stats.On() {
+		s.ctx = stats.TagRPC(s.ctx, &stats.RPCTagInfo{FullMethodName: s.method})
+		inHeader := &stats.InHeader{
+			FullMethod:  s.method,
+			RemoteAddr:  t.remoteAddr,
+			LocalAddr:   t.localAddr,
+			Compression: s.recvCompress,
+			WireLength:  int(frame.Header().Length),
+		}
+		stats.HandleRPC(s.ctx, inHeader)
+	}
 	handle(s)
 	return
 }
 
 // HandleStreams receives incoming streams using the given handler. This is
 // typically run in a separate goroutine.
-func (t *http2Server) HandleStreams(handle func(*Stream)) {
+// traceCtx attaches trace to ctx and returns the new context.
+func (t *http2Server) HandleStreams(handle func(*Stream), traceCtx func(context.Context, string) context.Context) {
 	// Check the validity of client preface.
 	preface := make([]byte, len(clientPreface))
 	if _, err := io.ReadFull(t.conn, preface); err != nil {
@@ -279,7 +323,7 @@ func (t *http2Server) HandleStreams(handle func(*Stream)) {
 		}
 		switch frame := frame.(type) {
 		case *http2.MetaHeadersFrame:
-			if t.operateHeaders(frame, handle) {
+			if t.operateHeaders(frame, handle, traceCtx) {
 				t.Close()
 				break
 			}
@@ -492,9 +536,16 @@ func (t *http2Server) WriteHeader(s *Stream, md metadata.MD) error {
 			t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: entry})
 		}
 	}
+	bufLen := t.hBuf.Len()
 	if err := t.writeHeaders(s, t.hBuf, false); err != nil {
 		return err
 	}
+	if stats.On() {
+		outHeader := &stats.OutHeader{
+			WireLength: bufLen,
+		}
+		stats.HandleRPC(s.Context(), outHeader)
+	}
 	t.writableChan <- 0
 	return nil
 }
@@ -547,10 +598,17 @@ func (t *http2Server) WriteStatus(s *Stream, statusCode codes.Code, statusDesc s
 			t.hEnc.WriteField(hpack.HeaderField{Name: k, Value: entry})
 		}
 	}
+	bufLen := t.hBuf.Len()
 	if err := t.writeHeaders(s, t.hBuf, true); err != nil {
 		t.Close()
 		return err
 	}
+	if stats.On() {
+		outTrailer := &stats.OutTrailer{
+			WireLength: bufLen,
+		}
+		stats.HandleRPC(s.Context(), outTrailer)
+	}
 	t.closeStream(s)
 	t.writableChan <- 0
 	return nil
@@ -579,19 +637,14 @@ func (t *http2Server) Write(s *Stream, data []byte, opts *Options) error {
 			return nil
 		}
 		size := http2MaxFrameLen
-		s.sendQuotaPool.add(0)
 		// Wait until the stream has some quota to send the data.
 		sq, err := wait(s.ctx, nil, nil, t.shutdownChan, s.sendQuotaPool.acquire())
 		if err != nil {
 			return err
 		}
-		t.sendQuotaPool.add(0)
 		// Wait until the transport has some quota to send the data.
 		tq, err := wait(s.ctx, nil, nil, t.shutdownChan, t.sendQuotaPool.acquire())
 		if err != nil {
-			if _, ok := err.(StreamError); ok {
-				t.sendQuotaPool.cancel()
-			}
 			return err
 		}
 		if sq < size {
@@ -659,7 +712,7 @@ func (t *http2Server) applySettings(ss []http2.Setting) {
 			t.mu.Lock()
 			defer t.mu.Unlock()
 			for _, stream := range t.activeStreams {
-				stream.sendQuotaPool.reset(int(s.Val - t.streamSendQuota))
+				stream.sendQuotaPool.add(int(s.Val - t.streamSendQuota))
 			}
 			t.streamSendQuota = s.Val
 		}
@@ -736,6 +789,10 @@ func (t *http2Server) Close() (err error) {
 	for _, s := range streams {
 		s.cancel()
 	}
+	if stats.On() {
+		connEnd := &stats.ConnEnd{}
+		stats.HandleConn(t.ctx, connEnd)
+	}
 	return
 }
 
@@ -767,7 +824,7 @@ func (t *http2Server) closeStream(s *Stream) {
 }
 
 func (t *http2Server) RemoteAddr() net.Addr {
-	return t.conn.RemoteAddr()
+	return t.remoteAddr
 }
 
 func (t *http2Server) Drain() {
diff --git a/vendor/google.golang.org/grpc/transport/transport.go b/vendor/google.golang.org/grpc/transport/transport.go
index 413f749..4726bb2 100644
--- a/vendor/google.golang.org/grpc/transport/transport.go
+++ b/vendor/google.golang.org/grpc/transport/transport.go
@@ -45,10 +45,10 @@ import (
 	"sync"
 
 	"golang.org/x/net/context"
-	"golang.org/x/net/trace"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/tap"
 )
 
 // recvMsg represents the received msg from the transport. All transport
@@ -167,6 +167,11 @@ type Stream struct {
 	id uint32
 	// nil for client side Stream.
 	st ServerTransport
+	// clientStatsCtx keeps the user context for stats handling.
+	// It's only valid on client side. Server side stats context is same as s.ctx.
+	// All client side stats collection should use the clientStatsCtx (instead of the stream context)
+	// so that all the generated stats for a particular RPC can be associated in the processing phase.
+	clientStatsCtx context.Context
 	// ctx is the associated context of the stream.
 	ctx context.Context
 	// cancel is always nil for client side Stream.
@@ -266,11 +271,6 @@ func (s *Stream) Context() context.Context {
 	return s.ctx
 }
 
-// TraceContext recreates the context of s with a trace.Trace.
-func (s *Stream) TraceContext(tr trace.Trace) {
-	s.ctx = trace.NewContext(s.ctx, tr)
-}
-
 // Method returns the method for the stream.
 func (s *Stream) Method() string {
 	return s.method
@@ -355,10 +355,17 @@ const (
 	draining
 )
 
+// ServerConfig consists of all the configurations to establish a server transport.
+type ServerConfig struct {
+	MaxStreams  uint32
+	AuthInfo    credentials.AuthInfo
+	InTapHandle tap.ServerInHandle
+}
+
 // NewServerTransport creates a ServerTransport with conn or non-nil error
 // if it fails.
-func NewServerTransport(protocol string, conn net.Conn, maxStreams uint32, authInfo credentials.AuthInfo) (ServerTransport, error) {
-	return newHTTP2Server(conn, maxStreams, authInfo)
+func NewServerTransport(protocol string, conn net.Conn, config *ServerConfig) (ServerTransport, error) {
+	return newHTTP2Server(conn, config)
 }
 
 // ConnectOptions covers all relevant options for communicating with the server.
@@ -367,6 +374,8 @@ type ConnectOptions struct {
 	UserAgent string
 	// Dialer specifies how to dial a network address.
 	Dialer func(context.Context, string) (net.Conn, error)
+	// FailOnNonTempDialError specifies if gRPC fails on non-temporary dial errors.
+	FailOnNonTempDialError bool
 	// PerRPCCredentials stores the PerRPCCredentials required to issue RPCs.
 	PerRPCCredentials []credentials.PerRPCCredentials
 	// TransportCredentials stores the Authenticator required to setup a client connection.
@@ -466,7 +475,7 @@ type ClientTransport interface {
 // Write methods for a given Stream will be called serially.
 type ServerTransport interface {
 	// HandleStreams receives incoming streams using the given handler.
-	HandleStreams(func(*Stream))
+	HandleStreams(func(*Stream), func(context.Context, string) context.Context)
 
 	// WriteHeader sends the header metadata for the given stream.
 	// WriteHeader may not be called on all streams.