游戏服务器开发实战笔记

// NextID generates a next unique ID.
func (sf *Idgenerator) NextID() (uint64, error) {
    const maskSequence = uint32(1<<BitLenSequence - 1)

    sf.mutex.Lock()
    defer sf.mutex.Unlock()

    current := currentElapsedTime(sf.startTime)
    if sf.elapsedTime < current {
        sf.elapsedTime = current
        sf.sequence = 0
    } else { // sf.elapsedTime >= current
        sf.sequence = (sf.sequence + 1) & maskSequence
        if sf.sequence == 0 {
            sf.elapsedTime++
            overtime := sf.elapsedTime - current
            time.Sleep(sleepTime(overtime))
        }
    }

    return sf.toID()
}

func (sf *Idgenerator) toID() (uint64, error) {
    if sf.elapsedTime >= 1<<BitLenTime {
        return 0, errors.New("over the time limit")
    }

    return uint64(sf.elapsedTime)<<(BitLenSequence+BitLenMachineID) |
        uint64(sf.sequence)<<BitLenMachineID |
        uint64(sf.machineID), nil
}

package main

func main() {}

func PluginAdd(a, b int) int {
    return a + b
}

func loadPlugin(pname string) {
    plug, err := plugin.Open(pname)
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
    addf, err := plug.Lookup("PluginAdd")
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
    sum := addf.(func(a, b int) int)(1, 2)
    fmt.Printf("plugin func a+b=%v \n", sum)
}

# Plugin 编译
go build -buildmode=plugin -o plugin.so

# 宿主程序编译
go build -o plugintest

plugin.Open("./plugin2/plugin2"): plugin was built with a different
version of package plugintest/common

service
├── lobby
│   └── plugin
│       ├── dbproc/hotswapbureau
│       ├── msgproc/hotswapbureau
│       ├── nsqproc/hotswapbureau
│       └── rpcproc/hotswapbureau
├── login
│   └── plugin
│       └── httpproc/hotswapbureau
└── scene
    └── plugin
        ├── msgproc/hotswapbureau
        └── rpcproc

密文 = MD5签名(24B) + Code(2B) + Version(4B) + IV(24B) + AES密文(nB)

// SafeCommEncode 将原文加密为密文
func SafeCommEncode(origin []byte) (ciphertext []byte, err error) {
    iv := randutil.RandBytes(16)
    aes := NewAESCrypto(&CryptoData{
        Mode:    &CBCMode{},
        Padding: &PKCS5Padding{},
        Format:  &HexFormat{},
    })
    cipher, err := aes.Encrypt(origin, aesKey, HamcMd5(iv, hamcMd5Key))
    if err != nil {
        return ciphertext, err
    }

    ciphertext = make([]byte, extLen+len(cipher))
    binary.LittleEndian.PutUint16(ciphertext[codeBytes[0]:codeBytes[1]], okCode)
    copy(ciphertext[vBytes[0]:vBytes[1]], version)

    base64Fmt := &Base64Format{}
    ivbase64 := base64Fmt.Encode(iv)
    copy(ciphertext[ivBytes[0]:ivBytes[1]], ivbase64)
    copy(ciphertext[extLen:], cipher)

    md5Sign := base64Fmt.Encode(HamcMd5(ciphertext[md5Bytes[1]:], hamcMd5Key))
    copy(ciphertext[md5Bytes[0]:md5Bytes[1]], md5Sign)

    return ciphertext, nil
}

// SafeCommDecode 将密文解密为原文，同时校验完整性
func SafeCommDecode(cipher []byte) ([]byte, error) {
    if len(cipher) < extLen {
        return nil, errors.New("input cipher text is invalid: length too short")
    }

    // 校验 Code 和 Version
    c := binary.LittleEndian.Uint16(cipher[codeBytes[0]:codeBytes[1]])
    if c != okCode {
        return nil, errors.New("input cipher text is invalid: code error")
    }

    // HMAC-MD5 完整性校验
    base64Fmt := &Base64Format{}
    recvMd5Sign := cipher[md5Bytes[0]:md5Bytes[1]]
    md5Code := base64Fmt.Encode(HamcMd5(cipher[md5Bytes[1]:], hamcMd5Key))
    if string(recvMd5Sign) != string(md5Code) {
        return nil, errors.New("data is modified")
    }

    // AES 解密
    aes := NewAESCrypto(&CryptoData{
        Mode:    &CBCMode{},
        Padding: &PKCS5Padding{},
        Format:  &HexFormat{},
    })
    iv, _ := base64Fmt.Decode(cipher[ivBytes[0]:ivBytes[1]])
    return aes.Decrypt(cipher[extLen:], aesKey, HamcMd5(iv, hamcMd5Key))
}

var bufpool = sync.Pool{
    New: func() interface{} {
        buf := make([]byte, 512)
        return &buf
    },
}

bp := bufpool.Get().(*[]byte)
b := *bp
defer func() {
    *bp = b
    bufpool.Put(bp)
}()

func (a *AuthenticationResponse) reset() {
    a.Token = ""
    a.UserID = ""
}

rsp := authPool.Get().(*AuthenticationResponse)
defer func() {
    rsp.reset()
    authPool.Put(rsp)
}()

map[string]int (1000万元素): gc took: ~100ms
map[int]int    (1000万元素): gc took: ~4ms

easyjson -all file.go
# 生成 file_json.go，自动实现 json.Marshaller 接口

BenchmarkStringBuildNaive-8      5000000    255 ns/op    216 B/op    8 allocs/op
BenchmarkStringBuildBuilder-8   20000000   54.9 ns/op     64 B/op    1 allocs/op

BenchmarkStrconv-8   30000000    39.5 ns/op    32 B/op    1 allocs/op
BenchmarkFmt-8       10000000     143 ns/op    72 B/op    3 allocs/op

// 差：从容量 0 开始，8 个元素会触发 5 次扩容
var userIDs []string
for _, bar := range rsp.Users {
    userIDs = append(userIDs, bar.ID)
}

// 好：预分配容量，0 次扩容
userIDs := make([]string, 0, len(rsp.Users))
for _, bar := range rsp.Users {
    userIDs = append(userIDs, bar.ID)
}