add failover test cases

tests/framework/integration/cluster.go

@@ -1372,6 +1372,14 @@ func (c *Cluster) Client(i int) *clientv3.Client {
 	return c.Members[i].Client
 }
 
+func (c *Cluster) Endpoints() []string {
+	var endpoints []string
+	for _, m := range c.Members {
+		endpoints = append(endpoints, m.GrpcURL)
+	}
+	return endpoints
+}
+
 func (c *Cluster) ClusterClient() (client *clientv3.Client, err error) {
 	if c.clusterClient == nil {
 		endpoints := []string{}

tests/integration/v3_failover_test.go

@@ -0,0 +1,173 @@
+// Copyright 2022 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 integration
+
+import (
+	"bytes"
+	"context"
+	"crypto/tls"
+	"go.etcd.io/etcd/api/v3/v3rpc/rpctypes"
+	clientv3test "go.etcd.io/etcd/tests/v3/integration/clientv3"
+	"testing"
+	"time"
+
+	"go.etcd.io/etcd/client/v3"
+	integration2 "go.etcd.io/etcd/tests/v3/framework/integration"
+	"google.golang.org/grpc"
+)
+
+func TestFailover(t *testing.T) {
+	cases := []struct {
+		name     string
+		testFunc func(*testing.T, *tls.Config, *integration2.Cluster) (*clientv3.Client, error)
+	}{
+		{
+			name:     "create client before the first server down",
+			testFunc: createClientBeforeServerDown,
+		},
+		{
+			name:     "create client after the first server down",
+			testFunc: createClientAfterServerDown,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Logf("Starting test [%s]", tc.name)
+			integration2.BeforeTest(t)
+
+			// Launch an etcd cluster with 3 members
+			t.Logf("Launching an etcd cluster with 3 members [%s]", tc.name)
+			clus := integration2.NewCluster(t, &integration2.ClusterConfig{Size: 3, ClientTLS: &integration2.TestTLSInfo})
+			defer clus.Terminate(t)
+
+			cc, err := integration2.TestTLSInfo.ClientConfig()
+			if err != nil {
+				t.Fatal(err)
+			}
+			// Create an etcd client before or after first server down
+			t.Logf("Creating an etcd client [%s]", tc.name)
+			cli, err := tc.testFunc(t, cc, clus)
+			if err != nil {
+				t.Fatalf("Failed to create client: %v", err)
+			}
+			defer cli.Close()
+
+			// Sanity test
+			t.Logf("Running sanity test [%s]", tc.name)
+			key, val := "key1", "val1"
+			putWithRetries(t, cli, key, val, 10)
+			getWithRetries(t, cli, key, val, 10)
+
+			t.Logf("Test done [%s]", tc.name)
+		})
+	}
+}
+
+func createClientBeforeServerDown(t *testing.T, cc *tls.Config, clus *integration2.Cluster) (*clientv3.Client, error) {
+	cli, err := createClient(t, cc, clus)
+	if err != nil {
+		return nil, err
+	}
+	clus.Members[0].Close()
+	return cli, nil
+}
+
+func createClientAfterServerDown(t *testing.T, cc *tls.Config, clus *integration2.Cluster) (*clientv3.Client, error) {
+	clus.Members[0].Close()
+	return createClient(t, cc, clus)
+}
+
+func createClient(t *testing.T, cc *tls.Config, clus *integration2.Cluster) (*clientv3.Client, error) {
+	cli, err := integration2.NewClient(t, clientv3.Config{
+		Endpoints:   clus.Endpoints(),
+		DialTimeout: 5 * time.Second,
+		DialOptions: []grpc.DialOption{grpc.WithBlock()},
+		TLS:         cc,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return cli, nil
+}
+
+func putWithRetries(t *testing.T, cli *clientv3.Client, key, val string, retryCount int) {
+	for retryCount > 0 {
+		// put data test
+		err := func() error {
+			t.Log("Sanity test, putting data")
+			ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+			defer cancel()
+
+			if _, putErr := cli.Put(ctx, key, val); putErr != nil {
+				t.Logf("Failed to put data (%v)", putErr)
+				return putErr
+			}
+			return nil
+		}()
+
+		if err != nil {
+			retryCount--
+			if shouldRetry(err) {
+				continue
+			} else {
+				t.Fatal(err)
+			}
+		}
+		break
+	}
+}
+
+func getWithRetries(t *testing.T, cli *clientv3.Client, key, val string, retryCount int) {
+	for retryCount > 0 {
+		// get data test
+		err := func() error {
+			t.Log("Sanity test, getting data")
+			ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+			defer cancel()
+			resp, getErr := cli.Get(ctx, key)
+			if getErr != nil {
+				t.Logf("Failed to get key (%v)", getErr)
+				return getErr
+			}
+			if len(resp.Kvs) != 1 {
+				t.Fatalf("Expected 1 key, got %d", len(resp.Kvs))
+			}
+			if !bytes.Equal([]byte(val), resp.Kvs[0].Value) {
+				t.Fatalf("Unexpected value, expected: %s, got: %s", val, string(resp.Kvs[0].Value))
+			}
+			return nil
+		}()
+
+		if err != nil {
+			retryCount--
+			if shouldRetry(err) {
+				continue
+			} else {
+				t.Fatal(err)
+			}
+		}
+		break
+	}
+}
+
+func shouldRetry(err error) bool {
+	if clientv3test.IsClientTimeout(err) || clientv3test.IsServerCtxTimeout(err) ||
+		err == rpctypes.ErrTimeout || err == rpctypes.ErrTimeoutDueToLeaderFail {
+		return true
+	}
+	return false
+}

tests/integration/v3_kv_test.go

@@ -1,3 +1,17 @@
+// Copyright 2022 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 integration
 
 import (