mirror of
https://github.com/etcd-io/etcd.git
synced 2024-09-27 06:25:44 +00:00
123 lines
3.0 KiB
Go
123 lines
3.0 KiB
Go
// Copyright 2019 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 quorum
|
|
|
|
import (
|
|
"math"
|
|
"math/rand"
|
|
"reflect"
|
|
"testing"
|
|
"testing/quick"
|
|
)
|
|
|
|
// TestQuick uses quickcheck to heuristically assert that the main
|
|
// implementation of (MajorityConfig).CommittedIndex agrees with a "dumb"
|
|
// alternative version.
|
|
func TestQuick(t *testing.T) {
|
|
cfg := &quick.Config{
|
|
MaxCount: 50000,
|
|
}
|
|
|
|
t.Run("majority_commit", func(t *testing.T) {
|
|
fn1 := func(c memberMap, l idxMap) uint64 {
|
|
return uint64(MajorityConfig(c).CommittedIndex(mapAckIndexer(l)))
|
|
}
|
|
fn2 := func(c memberMap, l idxMap) uint64 {
|
|
return uint64(alternativeMajorityCommittedIndex(MajorityConfig(c), mapAckIndexer(l)))
|
|
}
|
|
if err := quick.CheckEqual(fn1, fn2, cfg); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
})
|
|
}
|
|
|
|
// smallRandIdxMap returns a reasonably sized map of ids to commit indexes.
|
|
func smallRandIdxMap(rand *rand.Rand, _ int) map[uint64]Index {
|
|
// Hard-code a reasonably small size here (quick will hard-code 50, which
|
|
// is not useful here).
|
|
size := 10
|
|
|
|
n := rand.Intn(size)
|
|
ids := rand.Perm(2 * n)[:n]
|
|
idxs := make([]int, len(ids))
|
|
for i := range idxs {
|
|
idxs[i] = rand.Intn(n)
|
|
}
|
|
|
|
m := map[uint64]Index{}
|
|
for i := range ids {
|
|
m[uint64(ids[i])] = Index(idxs[i])
|
|
}
|
|
return m
|
|
}
|
|
|
|
type idxMap map[uint64]Index
|
|
|
|
func (idxMap) Generate(rand *rand.Rand, size int) reflect.Value {
|
|
m := smallRandIdxMap(rand, size)
|
|
return reflect.ValueOf(m)
|
|
}
|
|
|
|
type memberMap map[uint64]struct{}
|
|
|
|
func (memberMap) Generate(rand *rand.Rand, size int) reflect.Value {
|
|
m := smallRandIdxMap(rand, size)
|
|
mm := map[uint64]struct{}{}
|
|
for id := range m {
|
|
mm[id] = struct{}{}
|
|
}
|
|
return reflect.ValueOf(mm)
|
|
}
|
|
|
|
// This is an alternative implementation of (MajorityConfig).CommittedIndex(l).
|
|
func alternativeMajorityCommittedIndex(c MajorityConfig, l AckedIndexer) Index {
|
|
if len(c) == 0 {
|
|
return math.MaxUint64
|
|
}
|
|
|
|
idToIdx := map[uint64]Index{}
|
|
for id := range c {
|
|
if idx, ok := l.AckedIndex(id); ok {
|
|
idToIdx[id] = idx
|
|
}
|
|
}
|
|
|
|
// Build a map from index to voters who have acked that or any higher index.
|
|
idxToVotes := map[Index]int{}
|
|
for _, idx := range idToIdx {
|
|
idxToVotes[idx] = 0
|
|
}
|
|
|
|
for _, idx := range idToIdx {
|
|
for idy := range idxToVotes {
|
|
if idy > idx {
|
|
continue
|
|
}
|
|
idxToVotes[idy]++
|
|
}
|
|
}
|
|
|
|
// Find the maximum index that has achieved quorum.
|
|
q := len(c)/2 + 1
|
|
var maxQuorumIdx Index
|
|
for idx, n := range idxToVotes {
|
|
if n >= q && idx > maxQuorumIdx {
|
|
maxQuorumIdx = idx
|
|
}
|
|
}
|
|
|
|
return maxQuorumIdx
|
|
}
|