From 8795633f3db61df38dccdcba0400296a38dca25b Mon Sep 17 00:00:00 2001
From: Gyuho Lee <gyuhox@gmail.com>
Date: Thu, 8 Feb 2018 07:03:12 -0800
Subject: [PATCH] clientv3/integration: test watch response fragmentation

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>
---
 clientv3/integration/watch_fragment_test.go | 123 ++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 clientv3/integration/watch_fragment_test.go

diff --git a/clientv3/integration/watch_fragment_test.go b/clientv3/integration/watch_fragment_test.go
new file mode 100644
index 000000000000..9f321bcd94fb
--- /dev/null
+++ b/clientv3/integration/watch_fragment_test.go
@@ -0,0 +1,123 @@
+// Copyright 2018 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 (
+	"context"
+	"fmt"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/coreos/etcd/clientv3"
+	"github.com/coreos/etcd/integration"
+	"github.com/coreos/etcd/pkg/testutil"
+)
+
+// TestWatchFragmentEnable ensures that large watch
+// response exceeding server-side request limit arrive
+// with watch response fragmentation.
+func TestWatchFragmentEnable(t *testing.T) {
+	testWatchFragment(t, true, false)
+}
+
+// TestWatchFragmentDisable ensures that large watch
+// response exceeding server-side request limit can
+// arrive even without watch response fragmentation.
+func TestWatchFragmentDisable(t *testing.T) {
+	testWatchFragment(t, false, false)
+}
+
+// TestWatchFragmentEnableWithGRPCLimit verifies
+// large watch response exceeding server-side request
+// limit and client-side gRPC response receive limit
+// can arrive only when watch events are fragmented.
+func TestWatchFragmentEnableWithGRPCLimit(t *testing.T) {
+	testWatchFragment(t, true, true)
+}
+
+// TestWatchFragmentDisableWithGRPCLimit verifies
+// large watch response exceeding server-side request
+// limit and client-side gRPC response receive limit
+// cannot arrive without watch events fragmentation,
+// because multiple events exceed client-side gRPC
+// response receive limit.
+func TestWatchFragmentDisableWithGRPCLimit(t *testing.T) {
+	testWatchFragment(t, false, true)
+}
+
+// testWatchFragment triggers watch response that spans over multiple
+// revisions exceeding server request limits when combined.
+func testWatchFragment(t *testing.T, fragment, overGRPCLimit bool) {
+	cfg := &integration.ClusterConfig{
+		Size:            1,
+		MaxRequestBytes: 1.5 * 1024 * 1024,
+	}
+	if overGRPCLimit {
+		cfg.ClientMaxCallRecvMsgSize = 1.5 * 1024 * 1024
+	}
+	clus := integration.NewClusterV3(t, cfg)
+	defer clus.Terminate(t)
+
+	cli := clus.Client(0)
+	errc := make(chan error)
+	for i := 0; i < 10; i++ {
+		go func(i int) {
+			_, err := cli.Put(context.TODO(),
+				fmt.Sprint("foo", i),
+				strings.Repeat("a", 1024*1024),
+			)
+			errc <- err
+		}(i)
+	}
+	for i := 0; i < 10; i++ {
+		if err := <-errc; err != nil {
+			t.Errorf("failed to put: %v", err)
+		}
+	}
+
+	opts := []clientv3.OpOption{
+		clientv3.WithPrefix(),
+		clientv3.WithRev(1),
+	}
+	if !fragment {
+		opts = append(opts, clientv3.WithNoFragment())
+	}
+	wch := cli.Watch(context.TODO(), "foo", opts...)
+
+	// expect 10 MiB watch response
+	select {
+	case ws := <-wch:
+		// without fragment, should exceed gRPC client receive limit
+		if !fragment && overGRPCLimit {
+			if len(ws.Events) != 0 {
+				t.Errorf("expected 0 events with watch fragmentation, got %d", len(ws.Events))
+			}
+			exp := "code = ResourceExhausted desc = grpc: received message larger than max ("
+			if !strings.Contains(ws.Err().Error(), exp) {
+				t.Errorf("expected 'ResourceExhausted' error, got %v", ws.Err())
+			}
+		} else {
+			if len(ws.Events) != 10 {
+				t.Errorf("expected 10 events with watch fragmentation, got %d", len(ws.Events))
+			}
+			if ws.Err() != nil {
+				t.Errorf("unexpected error %v", ws.Err())
+			}
+		}
+	case <-time.After(testutil.RequestTimeout):
+		t.Fatalf("took too long to receive events")
+	}
+}