Switch to xxhash, drop vendored siphash, modernize CI

.github/workflows/go.yml

@@ -4,19 +4,18 @@ on:
   push:
     branches: [ master ]
   pull_request:
-    branches: [ master ]
 
 jobs:
 
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
 
     - name: Set up Go
-      uses: actions/setup-go@v2
+      uses: actions/setup-go@v5
       with:
-        go-version: 1.15
+        go-version: '1.21'
 
     - name: Build
       run: go build -v ./...

README.md

@@ -1,7 +1,7 @@
 Maglev: A Google Maglev Hashing Algorithm implement in Golang
 ==============
 
-[![GoDoc](https://godoc.org/github.com/kkdai/maglev?status.svg)](https://godoc.org/github.com/kkdai/maglev)  [![Build Status](https://travis-ci.org/kkdai/maglev.svg?branch=master)](https://travis-ci.org/kkdai/maglev) [![](https://goreportcard.com/badge/github.com/kkdai/maglev)](https://goreportcard.com/badge/github.com/kkdai/maglev) ![Go](https://github.com/kkdai/maglev/workflows/Go/badge.svg)
+[![GoDoc](https://godoc.org/github.com/kkdai/maglev?status.svg)](https://godoc.org/github.com/kkdai/maglev) [![](https://goreportcard.com/badge/github.com/kkdai/maglev)](https://goreportcard.com/badge/github.com/kkdai/maglev) ![Go](https://github.com/kkdai/maglev/workflows/Go/badge.svg)
 
 
 ![](http://www.evanlin.com/images/2016/maglev1.png)

go.mod

@@ -1,5 +1,5 @@
 module github.com/kkdai/maglev
 
-go 1.15
+go 1.21
 
-require github.com/dchest/siphash v1.2.2
+require github.com/cespare/xxhash/v2 v2.3.0

go.sum

@@ -1,2 +1,2 @@
-github.com/dchest/siphash v1.2.2 h1:9DFz8tQwl9pTVt5iok/9zKyzA1Q6bRGiF3HPiEEVr9I=
-github.com/dchest/siphash v1.2.2/go.mod h1:q+IRvb2gOSrUnYoPqHiyHXS0FOBBOdl6tONBlVnOnt4=
+github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
+github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=

maglev.go

@@ -6,14 +6,14 @@ import (
 	"sort"
 	"sync"
 
-	"github.com/dchest/siphash"
+	"github.com/cespare/xxhash/v2"
 )
 
 const (
 	bigM uint64 = 65537
 )
 
-//Maglev :
+// Maglev :
 type Maglev struct {
 	n           uint64 //size of VIP backends
 	m           uint64 //size of the lookup table
@@ -23,10 +23,10 @@ type Maglev struct {
 	lock        *sync.RWMutex
 }
 
-//NewMaglev :
+// NewMaglev :
 func NewMaglev(backends []string, m uint64) (*Maglev, error) {
 	if !big.NewInt(0).SetUint64(m).ProbablyPrime(1) {
-		return nil, errors.New("Lookup table size is not a prime number")
+		return nil, errors.New("lookup table size is not a prime number")
 	}
 	mag := &Maglev{m: m, lock: &sync.RWMutex{}}
 	if err := mag.Set(backends); err != nil {
@@ -35,19 +35,19 @@ func NewMaglev(backends []string, m uint64) (*Maglev, error) {
 	return mag, nil
 }
 
-//Add : Return nil if add success, otherwise return error
+// Add : Return nil if add success, otherwise return error
 func (m *Maglev) Add(backend string) error {
 	m.lock.Lock()
 	defer m.lock.Unlock()
 
 	// Use binary search since nodeList is always sorted after generatePopulation
 	index := sort.SearchStrings(m.nodeList, backend)
 	if index < len(m.nodeList) && m.nodeList[index] == backend {
-		return errors.New("Exist already")
+		return errors.New("backend already exists")
 	}
 
 	if m.m == m.n {
-		return errors.New("Number of backends would be greater than lookup table")
+		return errors.New("number of backends would be greater than lookup table")
 	}
 
 	m.nodeList = append(m.nodeList, backend)
@@ -57,14 +57,14 @@ func (m *Maglev) Add(backend string) error {
 	return nil
 }
 
-//Remove :
+// Remove :
 func (m *Maglev) Remove(backend string) error {
 	m.lock.Lock()
 	defer m.lock.Unlock()
 
 	index := sort.SearchStrings(m.nodeList, backend)
 	if index >= len(m.nodeList) || m.nodeList[index] != backend {
-		return errors.New("Not found")
+		return errors.New("backend not found")
 	}
 
 	m.nodeList = append(m.nodeList[:index], m.nodeList[index+1:]...)
@@ -81,7 +81,7 @@ func (m *Maglev) Set(backends []string) error {
 
 	n := uint64(len(backends))
 	if m.m < n {
-		return errors.New("Number of backends is greater than lookup table")
+		return errors.New("number of backends is greater than lookup table")
 	}
 	m.nodeList = make([]string, n)
 	copy(m.nodeList, backends) // Copy to avoid modifying original input afterwards
@@ -100,20 +100,31 @@ func (m *Maglev) Clear() {
 	m.lookup = nil
 }
 
-//Get :Get node name by object string.
+// Get :Get node name by object string.
 func (m *Maglev) Get(obj string) (string, error) {
 	m.lock.RLock()
 	defer m.lock.RUnlock()
 
 	if len(m.nodeList) == 0 {
-		return "", errors.New("Empty")
+		return "", errors.New("empty")
 	}
 	key := m.hashKey(obj)
 	return m.nodeList[m.lookup[key%m.m]], nil
 }
 
 func (m *Maglev) hashKey(obj string) uint64 {
-	return siphash.Hash(0xdeadbabe, 0, []byte(obj))
+	return xxhash.Sum64([]byte(obj))
+}
+
+// saltedHash mixes salt into the hash so that offset and skip below are
+// derived from independent hash values, mirroring the two distinct
+// SipHash keys used previously. Reusing a single unsalted hash for both
+// would correlate offset and skip and weaken the permutation.
+func saltedHash(salt byte, data []byte) uint64 {
+	d := xxhash.New()
+	d.Write([]byte{salt})
+	d.Write(data)
+	return d.Sum64()
 }
 
 func (m *Maglev) generatePopulation() {
@@ -130,8 +141,8 @@ func (m *Maglev) generatePopulation() {
 	for i := 0; i < len(m.nodeList); i++ {
 		bData := []byte(m.nodeList[i])
 
-		offset := siphash.Hash(0xdeadbabe, 0, bData) % m.m
-		skip := (siphash.Hash(0xdeadbeef, 0, bData) % (m.m - 1)) + 1
+		offset := saltedHash(0xba, bData) % m.m
+		skip := (saltedHash(0xbe, bData) % (m.m - 1)) + 1
 
 		iRow := make([]uint64, m.m)
 		var j uint64

maglev_test.go

@@ -33,6 +33,16 @@ import (
 const sizeN = 5
 const lookupSizeM = 13 //need prime and
 
+func TestRequiresPrime(t *testing.T) {
+	var names []string
+	names = append(names, "testing")
+
+	_, err := NewMaglev(names, 4)
+	if err == nil {
+		t.Error("Should disallow non-prime lookup table size")
+	}
+}
+
 func TestSimple(t *testing.T) {
 	var names []string
 	for i := 0; i < sizeN; i++ {