func TestWeightedAlgorithms(t *testing.T) {
t.Parallel()
wg := sync.WaitGroup{}
testAlgorithmForWeight := func(id string, inst types.UpstreamBalancingAlgorithm) {
isWeighted := !strings.HasPrefix(id, unweightedPrefix)
upstreams := testutils.GetRandomUpstreams(5, 20)
inst.Set(upstreams)
var totalWeight uint32
weights := map[string]uint32{}
for _, u := range upstreams {
weights[u.Host] = u.Weight
totalWeight += u.Weight
}
mapping := map[string]uint32{}
urlsToTest := uint32(25000)
for i := uint32(0); i < urlsToTest; i++ {
url := testutils.GenerateMeAString(rand.Int63(), 5+rand.Int63n(100))
if res, err := inst.Get(url); err != nil {
t.Errorf("Unexpected error when getting url %s from algorithm %s: %s", url, id, err)
} else {
mapping[res.Host]++
}
}
var deviation float64
expectedPercent := 100.0 / float64(len(upstreams))
for host, count := range mapping {
if isWeighted {
expectedPercent = float64(weights[host]) * 100.0 / float64(totalWeight)
}
actualPercent := float64(count) * 100 / float64(urlsToTest)
deviation += math.Abs(actualPercent - expectedPercent)
t.Logf("Algorithm %s, host %s: expected percent %f (weight %d out of %d) but got %f (%d out of %d); deviation %f%%\n",
id, host, expectedPercent, weights[host], totalWeight, actualPercent, count, urlsToTest, math.Abs(actualPercent-expectedPercent))
}
threshold := 3.0
avgDeviation := deviation / float64(len(upstreams))
if avgDeviation > threshold {
t.Errorf("The average deviation for algorithm %s is above the threshold of %f%%: %f",
id, threshold, avgDeviation)
}
wg.Done()
}
for id, constructor := range allAlgorithms {
wg.Add(1)
go testAlgorithmForWeight(id, constructor())
}
wg.Wait()
}
func consistenHashAlgorithmTest(t *testing.T, wg *sync.WaitGroup, id string) {
inst := allAlgorithms[id]()
upstreams := testutils.GetRandomUpstreams(10, 100)
inst.Set(upstreams)
urlsToTest := 3000 + rand.Intn(1000)
mapping := map[string]string{}
for i := 0; i < urlsToTest; i++ {
url := testutils.GenerateMeAString(rand.Int63(), 5+rand.Int63n(100))
if res1, err := inst.Get(url); err != nil {
t.Errorf("Unexpected error when getting url %s from algorithm %s: %s", url, id, err)
} else if res2, err := inst.Get(url); err != nil {
t.Errorf("Unexpected error when getting url %s from algorithm %s for the second time: %s", url, id, err)
} else if !reflect.DeepEqual(res1, res2) {
t.Errorf("The two results for url %s by algorithm %s are different: %#v and %#v", url, id, res1, res2)
} else {
mapping[url] = res1.Host
}
}
oldWeght := getTotalWeight(upstreams)
checkDeviation := func(newUpstreams []*types.UpstreamAddress) {
inst.Set(newUpstreams)
var sameCount float64
for url, oldHost := range mapping {
if res, err := inst.Get(url); err != nil {
t.Errorf("Unexpected error when getting url %s from algorithm %s: %s", url, id, err)
} else if res.Host == oldHost {
sameCount++
}
}
total := float64(len(mapping))
newWeght := getTotalWeight(newUpstreams)
weightDiff := math.Abs(oldWeght - newWeght)
if math.Abs(weightDiff/oldWeght-(total-sameCount)/total) > 0.25 {
t.Errorf("[%s] Same count is %f of %f (count diff %f%%); upstreams are %d out of %d (weight diff %f-%f=%f or %f%%); deviation from expected: %f\n\n",
id, sameCount, total, (total-sameCount)*100/total,
len(newUpstreams), len(upstreams), oldWeght, newWeght, oldWeght-newWeght, weightDiff*100/oldWeght,
math.Abs(weightDiff/oldWeght-(total-sameCount)/total)*100)
}
}
// Add an extra server at the start
newUpstream := testutils.GetUpstream(len(upstreams))
checkDeviation(append([]*types.UpstreamAddress{newUpstream}, upstreams...))
// Remove a random server
randomServer := rand.Intn(len(upstreams))
checkDeviation(append(upstreams[:randomServer], upstreams[randomServer+1:]...))
// Add an extra server at that point
checkDeviation(append(upstreams[:randomServer], append([]*types.UpstreamAddress{newUpstream}, upstreams[randomServer:]...)...))
// Add an extra server at the end
checkDeviation(append(upstreams, newUpstream))
wg.Done()
}
func TestPercentageCalculations(t *testing.T) {
t.Parallel()
r := New()
r.Set(testutils.GetRandomUpstreams(1, 200))
var totalPercent float64
for _, b := range r.buckets {
totalPercent += b.weightPercent
}
if math.Abs(totalPercent-1.0) > 0.000001 {
t.Errorf("Bucket percentages do not combine to 1: %f", totalPercent)
}
}
// This test will probably only be useful if `go test -race` is used
func TestRandomConcurrentUsage(t *testing.T) {
t.Parallel()
wg := sync.WaitGroup{}
randomlyTestAlgorithm := func(id string, inst types.UpstreamBalancingAlgorithm) {
inst.Set([]*types.UpstreamAddress{testutils.GetUpstream(rand.Int())}) // Prevent expected errors
setters := 50 + rand.Intn(200)
wg.Add(setters)
for i := 0; i < setters; i++ {
go func() {
time.Sleep(time.Duration(rand.Intn(100)) * time.Millisecond)
inst.Set(testutils.GetRandomUpstreams(1, 100))
wg.Done()
}()
}
getters := 100 + rand.Intn(500)
wg.Add(getters)
for i := 0; i < getters; i++ {
go func() {
time.Sleep(time.Duration(rand.Intn(100)) * time.Millisecond)
path := fmt.Sprintf("some/path/%d.jpn", rand.Int())
if _, err := inst.Get(path); err != nil {
t.Errorf("Unexpected algorithm %s error for path %s: %s", id, path, err)
}
wg.Done()
}()
}
}
for id, constructor := range allAlgorithms {
randomlyTestAlgorithm(id, constructor())
}
wg.Wait()
}