From 467de8cb4fc60977123f570eafd4a6185ab96801 Mon Sep 17 00:00:00 2001
From: Anthony Romano <anthony.romano@coreos.com>
Date: Mon, 9 May 2016 21:31:16 -0700
Subject: [PATCH] benchmark: watch-get for testing unsynced watcher/get
 contention

---
 tools/benchmark/cmd/watch_get.go | 123 +++++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 tools/benchmark/cmd/watch_get.go

diff --git a/tools/benchmark/cmd/watch_get.go b/tools/benchmark/cmd/watch_get.go
new file mode 100644
index 000000000..b7b99b702
--- /dev/null
+++ b/tools/benchmark/cmd/watch_get.go
@@ -0,0 +1,123 @@
+// Copyright 2016 CoreOS, Inc.
+//
+// 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 cmd
+
+import (
+	"fmt"
+	"sync"
+	"time"
+
+	v3 "github.com/coreos/etcd/clientv3"
+
+	"github.com/spf13/cobra"
+	"golang.org/x/net/context"
+	"gopkg.in/cheggaaa/pb.v1"
+)
+
+// watchGetCmd represents the watch command
+var watchGetCmd = &cobra.Command{
+	Use:   "watch-get",
+	Short: "Benchmark watch with get",
+	Long:  `Benchmark for serialized key gets with many unsynced watchers`,
+	Run:   watchGetFunc,
+}
+
+var (
+	watchGetTotalStreams int
+	watchEvents          int
+	firstWatch           sync.Once
+)
+
+func init() {
+	RootCmd.AddCommand(watchGetCmd)
+	watchGetCmd.Flags().IntVar(&watchGetTotalStreams, "watchers", 10000, "Total number of watchers")
+	watchGetCmd.Flags().IntVar(&watchEvents, "events", 8, "Number of events per watcher")
+}
+
+func watchGetFunc(cmd *cobra.Command, args []string) {
+	clients := mustCreateClients(totalClients, totalConns)
+
+	// setup keys for watchers
+	watchRev := int64(0)
+	for i := 0; i < watchEvents; i++ {
+		v := fmt.Sprintf("%d", i)
+		resp, err := clients[0].Put(context.TODO(), "watchkey", v)
+		if err != nil {
+			panic(err)
+		}
+		if i == 0 {
+			watchRev = resp.Header.Revision
+		}
+	}
+
+	streams := make([]v3.Watcher, watchGetTotalStreams)
+	for i := range streams {
+		streams[i] = v3.NewWatcher(clients[i%len(clients)])
+	}
+
+	// results from trying to do serialized gets with concurrent watchers
+	results = make(chan result)
+
+	bar = pb.New(watchGetTotalStreams * watchEvents)
+	bar.Format("Bom !")
+	bar.Start()
+
+	pdoneC := printReport(results)
+	wg.Add(len(streams))
+	ctx, cancel := context.WithCancel(context.TODO())
+	f := func() {
+		doSerializedGet(ctx, clients[0], results)
+	}
+	for i := range streams {
+		go doUnsyncWatch(streams[i], watchRev, f)
+	}
+	wg.Wait()
+	cancel()
+	bar.Finish()
+	fmt.Printf("Get during watch summary:\n")
+	<-pdoneC
+}
+
+func doSerializedGet(ctx context.Context, client *v3.Client, results chan result) {
+	for {
+		st := time.Now()
+		_, err := client.Get(ctx, "abc", v3.WithSerializable())
+		if ctx.Err() != nil {
+			break
+		}
+		var errStr string
+		if err != nil {
+			errStr = err.Error()
+		}
+		res := result{errStr: errStr, duration: time.Since(st), happened: time.Now()}
+		results <- res
+	}
+	close(results)
+}
+
+func doUnsyncWatch(stream v3.Watcher, rev int64, f func()) {
+	wch := stream.Watch(context.TODO(), "watchkey", v3.WithRev(rev))
+	if wch == nil {
+		panic("could not open watch channel")
+	}
+	firstWatch.Do(func() { go f() })
+	i := 0
+	for i < watchEvents {
+		wev := <-wch
+		i += len(wev.Events)
+		bar.Add(len(wev.Events))
+	}
+	wg.Done()
+}