代碼記錄

程序結構目錄

--------程序包

balance.go

package balancetype Balancer interface {DoBalance([]*Instance, ...string) (*Instance, error) }

instance.go

package balanceimport ("strconv" )type Instance struct {host stringport int }func NewInstance(host string, port int) *Instance {return &Instance{host: host,port: port,} }//定義Instance結構體的方法GetHost() func (p *Instance) GetHost() string {return p.host }//定義方法GetPort() func (p *Instance) GetPort() int {return p.port } func (p *Instance) String() string {return p.host + ":" + strconv.Itoa(p.port) }

mgr.go

package balanceimport "fmt"type BalanceMgr struct {allBalancer map[string]Balancer }var mgr = BalanceMgr{allBalancer: make(map[string]Balancer), }func (p *BalanceMgr) registerBalancer(name string, b Balancer) {p.allBalancer[name] = b } func RegisterBalancer(name string, b Balancer) {mgr.registerBalancer(name, b) } func DoBalance(name string, insts []*Instance) (inst *Instance, err error) {balancer, ok := mgr.allBalancer[name]if !ok {err = fmt.Errorf("Not found %s balancer", name)return}fmt.Printf("use %s balancer\n", name)inst, err = balancer.DoBalance(insts)return }

random.go

package balanceimport ("errors""math/rand" )func init() {RegisterBalancer("random", &RandomBalance{}) }type RandomBalance struct { }func (p *RandomBalance) DoBalance(insts []*Instance, key ...string) (inst *Instance, err error) {if len(insts) == 0 {err = errors.New("No instance")return}lens := len(insts)index := rand.Intn(lens)inst = insts[index]return }

roundrobin.go

package balanceimport ("errors" )func init() {RegisterBalancer("roundrobin", &RoundRobinBalance{}) }type RoundRobinBalance struct {curIndex int }func (p *RoundRobinBalance) DoBalance(insts []*Instance, key ...string) (inst *Instance, err error) {if len(insts) == 0 {err = errors.New("No instance")return}lens := len(insts)if p.curIndex >= lens {p.curIndex = 0}inst = insts[p.curIndex]p.curIndex = (p.curIndex + 1) % lensreturn }

------入口

main.go

package mainimport ("fmt""../balance""math/rand""os""time" )func main() {var insts []*balance.Instancefor i := 0; i < 16; i++ {host := fmt.Sprintf("192.168.%d.%d", rand.Intn(255), rand.Intn(255))one := balance.NewInstance(host, 8080)insts = append(insts, one)}var balanceName = "random"if len(os.Args) > 1 {balanceName = os.Args[1]}for {inst, err := balance.DoBalance(balanceName, insts)if err != nil {fmt.Println("do balance err:", err)fmt.Fprintf(os.Stdout, "do balance err\n")continue}fmt.Println(inst)time.Sleep(time.Second)} }

hash.go

package mainimport ("fmt""../balance""hash/crc32""math/rand" )type HashBalance struct {Name stringAge int }func init() {balance.RegisterBalancer("hash", &HashBalance{}) } func (p *HashBalance) DoBalance(insts []*balance.Instance, key ...string) (inst *balance.Instance, err error) {var defKey string = fmt.Sprintf("%d", rand.Int())if len(key) > 0 {defKey = key[0]}lens := len(insts)if lens == 0 {err = fmt.Errorf("No backend instance")return}crcTable := crc32.MakeTable(crc32.IEEE)hashVal := crc32.Checksum([]byte(defKey), crcTable)index := int(hashVal) % lensinst = insts[index]return }

總結

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