(TOC)

命令行参数

import "flag"
func main() {ports := flag.String("ports", "10086", "list the port ....")var version_check boolflag.BoolVar(&version_check, "v", false, "version")flag.Parse()if version_check {do()}portsList := strings.Split(*ports, ",")if len(portsList) > 5 {fmt.Println("no more than 5 ports")return}
}

配置文件

package main
import ("fmt""github.com/BurntSushi/toml"
)
type tomlConfig struct {Title   stringMysql mysqlInfo
}
type mysqlInfo struct {Host stringPort  intUser stringPasswd    stringDb    string
}
func main() {var config tomlConfigif _, err := toml.DecodeFile("config.toml", &config); err != nil {fmt.Println(err)return}fmt.Println(config.Title)fmt.Println(config.Mysql.Host)
}

配置文件如下，需要名称和tomlconfig中的相同，并且代码中首字母大写，配置中小写

Title = "test"
[mysql]
host = "11.22.33.44"
port = 3306
user = "smart"
passwd = "smart"
db = "smart"

MySQL

package main
import ("database/sql""fmt"_ "github.com/go-sql-driver/mysql"
)
func fetchdata() {db, err := sql.Open("mysql", "user:passwd@tcp(host:port)/database")if err != nil {fmt.Println(err)}err = db.Ping()if err != nil {fmt.Println(err)}rows, err := db.Query("select * from table")if err != nil {fmt.Println(err)}for rows.Next() {var counts stringvar indexs intif err := rows.Scan(&counts, &indexs); err != nil {fmt.Println(err)}fmt.Println(counts, indexs)}defer db.Close()
}
func main() {fetchdata()
}

Socket

func udpReceiver(port string) {defer workExitLock.Done()var addr *net.UDPAddrvar server *net.UDPConnvar err errorif addr, err = net.ResolveUDPAddr("udp", port); err != nil {Error.Printf("Udp listener error: %s", err)return}if server, err = net.ListenUDP("udp", addr); err != nil {Error.Printf("Udp listener error: %s", err)return}if err = server.SetReadBuffer(UDP_READ_BUFF); err != nil {Error.Printf("Udp listener error: %s", err)return}Info.Printf("Listen Udp Sucessfully, port: %s", port)var buf []bytefor {if len(buf) < UDP_PACK_SIZE {buf = make([]byte, PACK_BUF_SIZE, PACK_BUF_SIZE)}nbytes, addr, err := server.ReadFromUDP(buf)if err != nil {Error.Printf("Receive udp data error: %s", err)continue}msg := buf[:nbytes]buf = buf[nbytes:]udpChan <- UdpMessage{addr, msg}}
}// 可选udp或者tcp
func netSender(typename string, addr string, retry int) {for {conn, err := net.Dial(typename, addr)if err != nil {Error.Printf("make conn error: ", err)time.Sleep(time.Duration(retry) * time.Second)continue}for one := range resChan {_, err = conn.Write([]byte(one))if err != nil {Error.Printf("send data error: %s", err)conn.Close()break}}}
}

在实验环境中，如果对端没有处理指定端口的数据，会每隔一秒种返回一个ICMP包提示 udp port distinct unreachable 此时发送程序会有对应的发送失败提示，也是每秒钟一个

log

package main
import ("config""io""log""os"
)
var (Info    *log.LoggerError   *log.Logger
)
func Init(infoHandle io.Writer,errorHandle io.Writer) {Info = log.New(infoHandle,"INFO: ",log.Ldate|log.Ltime|log.Lshortfile)Error = log.New(errorHandle,"ERROR: ",log.Ldate|log.Ltime|log.Lshortfile)
}
func logInit(conf config.ProcessInfo) {pinfo := conf.Logdir + "/" + "log.info"perro := conf.Logdir + "/" + "log.err"finfo, err := os.OpenFile(pinfo, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)if err != nil {log.Fatalf("file open error : %v", err)}ferro, err := os.OpenFile(perro, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)if err != nil {log.Fatalf("file open error : %v", err)}Init(finfo, ferro)
}func main() {gomaxprocs := runtime.NumCPU() - 1runtime.GOMAXPROCS(gomaxprocs)Info.Printf("Program start. GOMAXPROCS: %d", gomaxprocs)
}

同步统计

使用sync/atomic，利用其实现的函数可以达到无冲突的统计

import "sync/atomic"
type count64 uint64
func (c *count64) increment(incr int) count64 {return count64(atomic.AddUint64((*uint64)(c), uint64(incr)))
}
func (c *count64) get() count64 {return count64(atomic.LoadUint64((*uint64)(c)))
}

其他

要注意golang特有的一些格式要求，比如：

1. 不能有没用的变量，没用到的import
2. 对外提供的函数，首字母必须大写，否则不能被其他package使用。同一个package不同文件的函数和全局变量直接使用
3. 尽量少使用异常，通过返回err进行判断和处理，panic在严重时才使用