Go 實戰(zhàn)：實現(xiàn)一個簡單的日志庫

前言

一個完整的日志庫不僅僅涵蓋日志記錄功能，還要包括日志 level、行號、文件切分，甚至包含統(tǒng)計與分析等，Go 語言中的日志庫也是很多，其中知名度比較高的有:

備注：star 數(shù)獲取時間為 2020-05-28 23:26:00

一千個人有一千個需求，不管是哪個開源日志庫，用著總有不順手的時候，沒關(guān)系，那就自己實現(xiàn)一個吧，相信自己，來，就讓咱們先從實現(xiàn)簡單的日志記錄功能開始吧～「手動狗頭」

思路

1. 功能設(shè)計

   根據(jù)自己的需求，我想要的日志記錄功能有：

• 按照 level 輸出日志
• 能夠同時輸出到文件和控制臺
• 控制臺能夠根據(jù) level 將內(nèi)容輸出為不同顏色
• 日志文件根據(jù)大小進行分割
• 輸出行號

2. API 設(shè)計

   一般來說，根據(jù) level 不同，設(shè)計有不同的 API，level 大概可以分為: trace、warn、error、fatal， 也就是說對外的 API 可以概括為: T(...inter), W(...), E(...), F(...)

type?logger?interface{
????T(format?string,?v?...interface{})
????W(format?string,?v?...interface{})
????E(format?string,?v?...interface{})
????F(format?string,?v?...interface{})
}

3. 結(jié)構(gòu)設(shè)計

   根據(jù)需求，日志記錄器 logger 的結(jié)構(gòu)需要包含 writers、文件名、文件保存路徑、文件分割大小 完整結(jié)構(gòu)設(shè)計如下：

type?myLog?struct?{
???sync.Once
???sync.Mutex?????????????????????//用于outs并發(fā)訪問
???outs?????map[logType]io.Writer?//writer集合
???file?????*os.File??????????????//文件句柄
???fileName?string????????????????//日志名
???dir??????string????????????????//日志存放路徑
???size?????int64?????????????????//單個日志文件的大小限制
}

4. 關(guān)鍵方法實現(xiàn)

• 日志文件大小檢測

func?(m?*myLog)?checkLogSize()?{
???if?m.file?==?nil?{
???????return
???}
???m.Lock()
???defer?m.Unlock()?//此處必須加鎖，否則會出現(xiàn)并發(fā)問題
???fileInfo,?err?:=?m.file.Stat()
???if?err?!=?nil?{
???????panic(err)
???}
???if?m.size?>?fileInfo.Size()?{
???????return
???}
???//需要分割,重新打開一個新的文件句柄替換老的，并關(guān)閉老的文件句柄，
???newName?:=?path.Join(m.dir,?time.Now().Format("2006_01_02_15:04:03")+".log")
???name?:=?path.Join(m.dir,?m.fileName)

???err?=?os.Rename(name,?newName)
???if?err?!=?nil?{
???????panic(err)
???}

???file,?err?:=?os.OpenFile(name,?os.O_CREATE|os.O_APPEND|os.O_WRONLY,?0755)
???if?err?!=?nil?{
???????panic(err)
???}

???m.file.Close()
???m.file?=?file
???m.outs[logTypeFile]?=?file
???return
}

• 控制臺帶顏色輸出內(nèi)容

func?setColor(msg?string,?text?int)?string?{
????return?fmt.Sprintf("%c[%dm%s%c[0m",?0x1B,?text,?msg,?0x1B)
}

• 獲取行號

func?shortFileName(file?string)?string?{
???short?:=?file
???for?i?:=?len(file)?-?1;?i?>?0;?i--?{
???????if?file[i]?==?'/'?{
???????????short?=?file[i+1:]
???????????break
???????}
???}
???return?short
}

完整代碼實現(xiàn)

package?logUtil

import?(
????"fmt"
????"io"
????"os"
????"path"
????"runtime"
????"strconv"
????"sync"
????"time"
)

const?(
????colorRed????=?31
????colorYellow?=?33
????colorBlue???=?34

????levelT?=?"[T]?"
????levelE?=?"[E]?"
????levelW?=?"[W]?"

????defaultFileSize?=?60?*?1024?*?1024
????minFileSize?????=?1?*?1024?*?1024
????defaultLogDir???=?"log"
????defaultLogName??=?"default.log"

????logTypeStd?logType?=?iota?+?1
????logTypeFile
)

type?(
????logType?int

????LogOption?func(log?*myLog)

????myLog?struct?{
????????sync.Once
????????sync.Mutex
????????outs?????map[logType]io.Writer?//writer集合
????????file?????*os.File??????????????//文件句柄
????????fileName?string????????????????//日志名
????????dir??????string????????????????//日志存放路徑
????????size?????int64?????????????????//單個日志文件的大小限制
????}
)

var?(
????defaultLogger?=?&myLog{}
)

func?(m?*myLog)?init()?{
????if?m.dir?==?""?{
????????m.dir?=?defaultLogDir
????}
????if?m.fileName?==?""?{
????????m.fileName?=?defaultLogName
????}
????if?m.size?==?0?{
????????m.size?=?defaultFileSize
????}?else?{
????????if?m.size?????????????panic(fmt.Sprintf("invalid?size:?%d",?m.size))
????????}
????}

????if?m.outs?==?nil?{
????????m.outs?=?make(map[logType]io.Writer)
????}
????if?!isExist(m.dir)?{
????????if?err?:=?os.Mkdir(m.dir,?0777);?err?!=?nil?{
????????????panic(err)
????????}
????}
????name?:=?path.Join(m.dir,?m.fileName)
????file,?err?:=?os.OpenFile(name,?os.O_CREATE|os.O_APPEND|os.O_WRONLY,?0755)
????if?err?!=?nil?{
????????panic(err)
????}

????m.file?=?file
????m.outs[logTypeStd]?=?os.Stdout
????m.outs[logTypeFile]?=?file
}

func?(m?*myLog)?checkLogSize()?{
????if?m.file?==?nil?{
????????return
????}
????m.Lock()
????defer?m.Unlock()
????fileInfo,?err?:=?m.file.Stat()
????if?err?!=?nil?{
????????panic(err)
????}
????if?m.size?>?fileInfo.Size()?{
????????return
????}
????//需要分割
????newName?:=?path.Join(m.dir,?time.Now().Format("2006_01_02_15:04:03")+".log")
????name?:=?path.Join(m.dir,?m.fileName)

????err?=?os.Rename(name,?newName)
????if?err?!=?nil?{
????????panic(err)
????}

????file,?err?:=?os.OpenFile(name,?os.O_CREATE|os.O_APPEND|os.O_WRONLY,?0755)
????if?err?!=?nil?{
????????panic(err)
????}

????m.file.Close()
????m.file?=?file
????m.outs[logTypeFile]?=?file
????return
}

func?(m?*myLog)?write(level?string,?content?string)?{
????m.checkLogSize()
????var?colorText?int
????switch?level?{
????case?levelT:
????????colorText?=?colorBlue
????case?levelW:
????????colorText?=?colorYellow
????case?levelE:
????????colorText?=?colorRed
????}

????for?k,?wr?:=?range?m.outs?{
????????if?k?==?logTypeStd?{
????????????fmt.Fprintf(wr,?setColor(content,?colorText))
????????}?else?{
????????????fmt.Fprintf(wr,?content)
????????}
????}
}

func?WithSize(size?int64)?LogOption?{
????return?func(log?*myLog)?{
????????log.size?=?size
????}
}

func?WithLogDir(dir?string)?LogOption?{
????return?func(log?*myLog)?{
????????log.dir?=?dir
????}
}

func?WithFileName(name?string)?LogOption?{
????return?func(log?*myLog)?{
????????log.fileName?=?name
????}
}

func?InitLogger(args?...LogOption)?{
????defaultLogger.Do(func()?{
????????for?_,?af?:=?range?args?{
????????????af(defaultLogger)
????????}
????????defaultLogger.init()
????})
}

//Info
func?T(format?string,?v?...interface{})?{
????_,?file,?line,?_?:=?runtime.Caller(1)
????timeStr?:=?time.Now().Format("2006-01-02?15:04:05.0000")?+?"?"
????codeLine?:=?"["?+?timeStr?+?shortFileName(file)?+?":"?+?strconv.Itoa(line)?+?"]"
????content?:=?levelT?+?codeLine?+?fmt.Sprintf(format,?v...)?+?"\n"
????defaultLogger.write(levelT,?content)
}

//Error
func?E(format?string,?v?...interface{})?{
????_,?file,?line,?_?:=?runtime.Caller(1)
????timeStr?:=?time.Now().Format("2006-01-02?15:04:05.0000")?+?"?"
????codeLine?:=?"["?+?timeStr?+?shortFileName(file)?+?":"?+?strconv.Itoa(line)?+?"]"
????content?:=?levelE?+?codeLine?+?fmt.Sprintf(format,?v...)?+?"\n"
????defaultLogger.write(levelE,?content)
}

//Warn
func?W(format?string,?v?...interface{})?{
????_,?file,?line,?_?:=?runtime.Caller(1)
????timeStr?:=?time.Now().Format("2006-01-02?15:04:05.0000")?+?"?"
????codeLine?:=?"["?+?timeStr?+?shortFileName(file)?+?":"?+?strconv.Itoa(line)?+?"]"
????content?:=?levelW?+?codeLine?+?fmt.Sprintf(format,?v...)?+?"\n"
????defaultLogger.write(levelW,?content)
}

func?isExist(path?string)?bool?{
????_,?err?:=?os.Stat(path)
????if?err?!=?nil?{
????????if?os.IsExist(err)?{
????????????return?true
????????}
????????return?false
????}
????return?true
}

func?shortFileName(file?string)?string?{
????short?:=?file
????for?i?:=?len(file)?-?1;?i?>?0;?i--?{
????????if?file[i]?==?'/'?{
????????????short?=?file[i+1:]
????????????break
????????}
????}
????return?short
}

func?setColor(msg?string,?text?int)?string?{
????return?fmt.Sprintf("%c[%dm%s%c[0m",?0x1B,?text,?msg,?0x1B)
}

最后

如有不足，還請不吝指教！

附上代碼地址：logUtil^[5]，歡迎指正！

參考資料