clientv3: fix "hasleader" metadata key, embed client version

.words

@@ -30,6 +30,7 @@ etcd
 gRPC
 goroutine
 goroutines
+hasleader
 healthcheck
 hostname
 iff

clientv3/client.go

@@ -37,7 +37,6 @@ import (
 	"google.golang.org/grpc/codes"
 	grpccredentials "google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/keepalive"
-	"google.golang.org/grpc/metadata"
 	"google.golang.org/grpc/status"
 )
 
@@ -393,13 +392,6 @@ func (c *Client) dialWithBalancerCreds(ep string) grpccredentials.TransportCrede
 	return creds
 }
 
-// WithRequireLeader requires client requests to only succeed
-// when the cluster has a leader.
-func WithRequireLeader(ctx context.Context) context.Context {
-	md := metadata.Pairs(rpctypes.MetadataRequireLeaderKey, rpctypes.MetadataHasLeader)
-	return metadata.NewOutgoingContext(ctx, md)
-}
-
 func newClient(cfg *Config) (*Client, error) {
 	if cfg == nil {
 		cfg = &Config{}

clientv3/ctx.go

@@ -0,0 +1,48 @@
+// Copyright 2020 The etcd 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 clientv3
+
+import (
+	"context"
+
+	"go.etcd.io/etcd/etcdserver/api/v3rpc/rpctypes"
+	"go.etcd.io/etcd/version"
+	"google.golang.org/grpc/metadata"
+)
+
+// WithRequireLeader requires client requests to only succeed
+// when the cluster has a leader.
+func WithRequireLeader(ctx context.Context) context.Context {
+	md, ok := metadata.FromOutgoingContext(ctx)
+	if !ok { // no outgoing metadata ctx key, create one
+		md = metadata.Pairs(rpctypes.MetadataRequireLeaderKey, rpctypes.MetadataHasLeader)
+		return metadata.NewOutgoingContext(ctx, md)
+	}
+	// overwrite/add 'hasleader' key/value
+	md.Set(rpctypes.MetadataRequireLeaderKey, rpctypes.MetadataHasLeader)
+	return metadata.NewOutgoingContext(ctx, md)
+}
+
+// embeds client version
+func withVersion(ctx context.Context) context.Context {
+	md, ok := metadata.FromOutgoingContext(ctx)
+	if !ok { // no outgoing metadata ctx key, create one
+		md = metadata.Pairs(rpctypes.MetadataClientAPIVersionKey, version.APIVersion)
+		return metadata.NewOutgoingContext(ctx, md)
+	}
+	// overwrite/add version key/value
+	md.Set(rpctypes.MetadataClientAPIVersionKey, version.APIVersion)
+	return metadata.NewOutgoingContext(ctx, md)
+}

clientv3/ctx_test.go

@@ -0,0 +1,67 @@
+// Copyright 2020 The etcd 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 clientv3
+
+import (
+	"context"
+	"reflect"
+	"testing"
+
+	"go.etcd.io/etcd/etcdserver/api/v3rpc/rpctypes"
+	"go.etcd.io/etcd/version"
+	"google.golang.org/grpc/metadata"
+)
+
+func TestMetadataWithRequireLeader(t *testing.T) {
+	ctx := context.TODO()
+	md, ok := metadata.FromOutgoingContext(ctx)
+	if ok {
+		t.Fatal("expected no outgoing metadata ctx key")
+	}
+
+	// add a conflicting key with some other value
+	md = metadata.Pairs(rpctypes.MetadataRequireLeaderKey, "invalid")
+	// add a key, and expect not be overwritten
+	md.Set("hello", "1", "2")
+	ctx = metadata.NewOutgoingContext(ctx, md)
+
+	// expect overwrites but still keep other keys
+	ctx = WithRequireLeader(ctx)
+	md, ok = metadata.FromOutgoingContext(ctx)
+	if !ok {
+		t.Fatal("expected outgoing metadata ctx key")
+	}
+	if ss := md.Get(rpctypes.MetadataRequireLeaderKey); !reflect.DeepEqual(ss, []string{rpctypes.MetadataHasLeader}) {
+		t.Fatalf("unexpected metadata for %q %v", rpctypes.MetadataRequireLeaderKey, ss)
+	}
+	if ss := md.Get("hello"); !reflect.DeepEqual(ss, []string{"1", "2"}) {
+		t.Fatalf("unexpected metadata for 'hello' %v", ss)
+	}
+}
+
+func TestMetadataWithClientAPIVersion(t *testing.T) {
+	ctx := withVersion(WithRequireLeader(context.TODO()))
+
+	md, ok := metadata.FromOutgoingContext(ctx)
+	if !ok {
+		t.Fatal("expected outgoing metadata ctx key")
+	}
+	if ss := md.Get(rpctypes.MetadataRequireLeaderKey); !reflect.DeepEqual(ss, []string{rpctypes.MetadataHasLeader}) {
+		t.Fatalf("unexpected metadata for %q %v", rpctypes.MetadataRequireLeaderKey, ss)
+	}
+	if ss := md.Get(rpctypes.MetadataClientAPIVersionKey); !reflect.DeepEqual(ss, []string{version.APIVersion}) {
+		t.Fatalf("unexpected metadata for %q %v", rpctypes.MetadataClientAPIVersionKey, ss)
+	}
+}

clientv3/integration/kv_test.go

@@ -17,8 +17,10 @@ package integration
 import (
 	"bytes"
 	"context"
+	"fmt"
 	"os"
 	"reflect"
+	"strconv"
 	"strings"
 	"testing"
 	"time"
@@ -28,6 +30,7 @@ import (
 	"go.etcd.io/etcd/integration"
 	"go.etcd.io/etcd/mvcc/mvccpb"
 	"go.etcd.io/etcd/pkg/testutil"
+	"go.etcd.io/etcd/version"
 
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
@@ -208,6 +211,22 @@ func TestKVPutWithRequireLeader(t *testing.T) {
 		t.Fatal(err)
 	}
 
+	cnt, err := clus.Members[0].Metric(
+		"etcd_server_client_requests_total",
+		`type="unary"`,
+		fmt.Sprintf(`client_api_version="%v"`, version.APIVersion),
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+	cv, err := strconv.ParseInt(cnt, 10, 32)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if cv < 1 { // >1 when retried
+		t.Fatalf("expected at least 1, got %q", cnt)
+	}
+
 	// clients may give timeout errors since the members are stopped; take
 	// the clients so that terminating the cluster won't complain
 	clus.Client(1).Close()

clientv3/integration/watch_test.go

@@ -20,6 +20,7 @@ import (
 	"math/rand"
 	"reflect"
 	"sort"
+	"strconv"
 	"testing"
 	"time"
 
@@ -29,6 +30,7 @@ import (
 	"go.etcd.io/etcd/integration"
 	mvccpb "go.etcd.io/etcd/mvcc/mvccpb"
 	"go.etcd.io/etcd/pkg/testutil"
+	"go.etcd.io/etcd/version"
 
 	"google.golang.org/grpc/metadata"
 )
@@ -839,6 +841,22 @@ func TestWatchWithRequireLeader(t *testing.T) {
 	if _, ok := <-chNoLeader; !ok {
 		t.Fatalf("expected response, got closed channel")
 	}
+
+	cnt, err := clus.Members[0].Metric(
+		"etcd_server_client_requests_total",
+		`type="stream"`,
+		fmt.Sprintf(`client_api_version="%v"`, version.APIVersion),
+	)
+	if err != nil {
+		t.Fatal(err)
+	}
+	cv, err := strconv.ParseInt(cnt, 10, 32)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if cv < 2 { // >2 when retried
+		t.Fatalf("expected at least 2, got %q", cnt)
+	}
 }
 
 // TestWatchWithFilter checks that watch filtering works.

clientv3/retry_interceptor.go

@@ -38,6 +38,7 @@ import (
 func (c *Client) unaryClientInterceptor(logger *zap.Logger, optFuncs ...retryOption) grpc.UnaryClientInterceptor {
 	intOpts := reuseOrNewWithCallOptions(defaultOptions, optFuncs)
 	return func(ctx context.Context, method string, req, reply interface{}, cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
+		ctx = withVersion(ctx)
 		grpcOpts, retryOpts := filterCallOptions(opts)
 		callOpts := reuseOrNewWithCallOptions(intOpts, retryOpts)
 		// short circuit for simplicity, and avoiding allocations.
@@ -103,6 +104,7 @@ func (c *Client) unaryClientInterceptor(logger *zap.Logger, optFuncs ...retryOpt
 func (c *Client) streamClientInterceptor(logger *zap.Logger, optFuncs ...retryOption) grpc.StreamClientInterceptor {
 	intOpts := reuseOrNewWithCallOptions(defaultOptions, optFuncs)
 	return func(ctx context.Context, desc *grpc.StreamDesc, cc *grpc.ClientConn, method string, streamer grpc.Streamer, opts ...grpc.CallOption) (grpc.ClientStream, error) {
+		ctx = withVersion(ctx)
 		grpcOpts, retryOpts := filterCallOptions(opts)
 		callOpts := reuseOrNewWithCallOptions(intOpts, retryOpts)
 		// short circuit for simplicity, and avoiding allocations.

etcdserver/api/v3rpc/interceptor.go

@@ -53,6 +53,12 @@ func newUnaryInterceptor(s *etcdserver.EtcdServer) grpc.UnaryServerInterceptor {
 
 		md, ok := metadata.FromIncomingContext(ctx)
 		if ok {
+			ver, vs := "unknown", md.Get(rpctypes.MetadataClientAPIVersionKey)
+			if len(vs) > 0 {
+				ver = vs[0]
+			}
+			clientRequests.WithLabelValues("unary", ver).Inc()
+
 			if ks := md[rpctypes.MetadataRequireLeaderKey]; len(ks) > 0 && ks[0] == rpctypes.MetadataHasLeader {
 				if s.Leader() == types.ID(raft.None) {
 					return nil, rpctypes.ErrGRPCNoLeader
@@ -184,6 +190,12 @@ func newStreamInterceptor(s *etcdserver.EtcdServer) grpc.StreamServerInterceptor
 
 		md, ok := metadata.FromIncomingContext(ss.Context())
 		if ok {
+			ver, vs := "unknown", md.Get(rpctypes.MetadataClientAPIVersionKey)
+			if len(vs) > 0 {
+				ver = vs[0]
+			}
+			clientRequests.WithLabelValues("stream", ver).Inc()
+
 			if ks := md[rpctypes.MetadataRequireLeaderKey]; len(ks) > 0 && ks[0] == rpctypes.MetadataHasLeader {
 				if s.Leader() == types.ID(raft.None) {
 					return rpctypes.ErrGRPCNoLeader
@@ -202,7 +214,6 @@ func newStreamInterceptor(s *etcdserver.EtcdServer) grpc.StreamServerInterceptor
 					smap.mu.Unlock()
 					cancel()
 				}()
-
 			}
 		}
 

etcdserver/api/v3rpc/metrics.go

@@ -39,10 +39,20 @@ var (
 	},
 		[]string{"Type", "API"},
 	)
+
+	clientRequests = prometheus.NewCounterVec(prometheus.CounterOpts{
+		Namespace: "etcd",
+		Subsystem: "server",
+		Name:      "client_requests_total",
+		Help:      "The total number of client requests per client version.",
+	},
+		[]string{"type", "client_api_version"},
+	)
 )
 
 func init() {
 	prometheus.MustRegister(sentBytes)
 	prometheus.MustRegister(receivedBytes)
 	prometheus.MustRegister(streamFailures)
+	prometheus.MustRegister(clientRequests)
 }

etcdserver/api/v3rpc/rpctypes/md.go

@@ -17,4 +17,6 @@ package rpctypes
 var (
 	MetadataRequireLeaderKey = "hasleader"
 	MetadataHasLeader        = "true"
+
+	MetadataClientAPIVersionKey = "client-api-version"
 )

integration/cluster.go

@@ -1143,7 +1143,7 @@ func (m *member) Terminate(t testing.TB) {
 }
 
 // Metric gets the metric value for a member
-func (m *member) Metric(metricName string) (string, error) {
+func (m *member) Metric(metricName string, expectLabels ...string) (string, error) {
 	cfgtls := transport.TLSInfo{}
 	tr, err := transport.NewTimeoutTransport(cfgtls, time.Second, time.Second, time.Second)
 	if err != nil {
@@ -1161,9 +1161,20 @@ func (m *member) Metric(metricName string) (string, error) {
 	}
 	lines := strings.Split(string(b), "\n")
 	for _, l := range lines {
-		if strings.HasPrefix(l, metricName) {
-			return strings.Split(l, " ")[1], nil
+		if !strings.HasPrefix(l, metricName) {
+			continue
+		}
+		ok := true
+		for _, lv := range expectLabels {
+			if !strings.Contains(l, lv) {
+				ok = false
+				break
+			}
+		}
+		if !ok {
+			continue
 		}
+		return strings.Split(l, " ")[1], nil
 	}
 	return "", nil
 }