feat(store/store_bench_test.go) add a benchmark for set operation of store pkg

We randomly generage N 3 level keys. We benchmark the speed of setting each key into etcd store.

store/store_bench_test.go

@@ -0,0 +1,50 @@
+/*
+Copyright 2014 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 store
+
+import (
+	"fmt"
+	"math/rand"
+	"testing"
+)
+
+func BenchmarkStoreSet(b *testing.B) {
+	s := newStore()
+	b.StopTimer()
+	kvs := generateNRandomKV(b.N)
+	b.StartTimer()
+
+	for i := 0; i < b.N; i++ {
+		_, err := s.Set(kvs[i][0], false, kvs[i][1], Permanent)
+		if err != nil {
+			panic(err)
+		}
+	}
+}
+
+func generateNRandomKV(n int) [][]string {
+	kvs := make([][]string, n)
+
+	for i := 0; i < n; i++ {
+		kvs[i] = make([]string, 2)
+		kvs[i][0] = fmt.Sprintf("/%d/%d/%d",
+			rand.Int()%100, rand.Int()%100, rand.Int()%100)
+		kvs[i][1] = fmt.Sprint(i)
+	}
+
+	return kvs
+}