grpc-go/balancer/ringhash/ring_test.go

113 lines
3.3 KiB
Go

/*
*
* Copyright 2021 gRPC 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 ringhash
import (
"fmt"
"math"
"testing"
xxhash "github.com/cespare/xxhash/v2"
"google.golang.org/grpc/internal/balancer/weight"
"google.golang.org/grpc/resolver"
)
var testEndpoints []resolver.Endpoint
var testEndpointStateMap *resolver.EndpointMap[*endpointState]
func init() {
testEndpoints = []resolver.Endpoint{
testEndpoint("a", 3),
testEndpoint("b", 3),
testEndpoint("c", 4),
}
testEndpointStateMap = resolver.NewEndpointMap[*endpointState]()
testEndpointStateMap.Set(testEndpoints[0], &endpointState{hashKey: "a", weight: 3})
testEndpointStateMap.Set(testEndpoints[1], &endpointState{hashKey: "b", weight: 3})
testEndpointStateMap.Set(testEndpoints[2], &endpointState{hashKey: "c", weight: 4})
}
func testEndpoint(addr string, endpointWeight uint32) resolver.Endpoint {
ep := resolver.Endpoint{Addresses: []resolver.Address{{Addr: addr}}}
return weight.Set(ep, weight.EndpointInfo{Weight: endpointWeight})
}
func (s) TestRingNew(t *testing.T) {
var totalWeight float64 = 10
for _, min := range []uint64{3, 4, 6, 8} {
for _, max := range []uint64{20, 8} {
t.Run(fmt.Sprintf("size-min-%v-max-%v", min, max), func(t *testing.T) {
r := newRing(testEndpointStateMap, min, max, nil)
totalCount := len(r.items)
if totalCount < int(min) || totalCount > int(max) {
t.Fatalf("unexpected size %v, want min %v, max %v", totalCount, min, max)
}
for _, e := range testEndpoints {
var count int
for _, ii := range r.items {
if ii.hashKey == hashKey(e) {
count++
}
}
got := float64(count) / float64(totalCount)
want := float64(getWeightAttribute(e)) / totalWeight
if !equalApproximately(got, want) {
t.Fatalf("unexpected item weight in ring: %v != %v", got, want)
}
}
})
}
}
}
func equalApproximately(x, y float64) bool {
delta := math.Abs(x - y)
mean := math.Abs(x+y) / 2.0
return delta/mean < 0.25
}
func (s) TestRingPick(t *testing.T) {
r := newRing(testEndpointStateMap, 10, 20, nil)
for _, h := range []uint64{xxhash.Sum64String("1"), xxhash.Sum64String("2"), xxhash.Sum64String("3"), xxhash.Sum64String("4")} {
t.Run(fmt.Sprintf("picking-hash-%v", h), func(t *testing.T) {
e := r.pick(h)
var low uint64
if e.idx > 0 {
low = r.items[e.idx-1].hash
}
high := e.hash
// h should be in [low, high).
if h < low || h >= high {
t.Fatalf("unexpected item picked, hash: %v, low: %v, high: %v", h, low, high)
}
})
}
}
func (s) TestRingNext(t *testing.T) {
r := newRing(testEndpointStateMap, 10, 20, nil)
for _, e := range r.items {
ne := r.next(e)
if ne.idx != (e.idx+1)%len(r.items) {
t.Fatalf("next(%+v) returned unexpected %+v", e, ne)
}
}
}