level.go

package blog4go

import (

"fmt"

"strings"

)

// LevelType type defined for logging level

// just use int

type LevelType int

const (

// level enum  日志枚举

// TRACE trace level

TRACE LevelType = iota

// DEBUG debug level

DEBUG

// INFO info level

INFO

// WARNING warn level

WARNING

// ERROR error level

ERROR

// CRITICAL critical level

CRITICAL

// UNKNOWN unknown level

UNKNOWN = "UNKNOWN"

// DefaultLevel default level for writers

DefaultLevel = TRACE

// PrefixFormat每个消息头前缀

PrefixFormat = " [%s] " //约定格式

// ColoredPrefixFormat 不同日志级别对应不同的颜色消息

ColoredPrefixFormat = " [\x1b[%dm%s\x1b[0m] " //格式化的颜色

// color enum used in formating color bytes

// NOCOLOR no color

NOCOLOR = 0

// RED red color

RED = 31

// GREEN green color

GREEN = 32

// YELLOW yellow color

YELLOW = 33

// BLUE blue color

BLUE = 34

// GRAY gray color

GRAY = 37

)

var (

// LevelStrings is string present for each level

LevelStrings = [...]string{"TRACE", "DEBUG", "INFO", "WARN", "ERROR", "CRITICAL"}

// StringLevels is map, level strings to levels

StringLevels = map[string]LevelType{"TRACE": TRACE, "DEBUG": DEBUG, "INFO": INFO, "WARN": WARNING, "ERROR": ERROR, "CRITICAL": CRITICAL}

// Levels is a slice consist of all levels

Levels = [...]LevelType{TRACE, DEBUG, INFO, WARNING, ERROR, CRITICAL}

// Prefix is preformatted level prefix string

// help reduce string formatted burden in realtime logging

Prefix = make(map[LevelType]string)

)

func init() {

initPrefix(false) // preformat level prefix string

}

// initPrefix is designed to preformat level prefix string for each level.

// colored decide whether preformat in colored format or not.

// if colored is true, preformat level prefix string in colored format

func initPrefix(colored bool) {

if colored {

Prefix[TRACE] = fmt.Sprintf(ColoredPrefixFormat, GRAY, TRACE.String())

Prefix[DEBUG] = fmt.Sprintf(ColoredPrefixFormat, GREEN, DEBUG.String())

Prefix[INFO] = fmt.Sprintf(ColoredPrefixFormat, BLUE, INFO.String())

Prefix[WARNING] = fmt.Sprintf(ColoredPrefixFormat, YELLOW, WARNING.String())

Prefix[ERROR] = fmt.Sprintf(ColoredPrefixFormat, RED, ERROR.String())

Prefix[CRITICAL] = fmt.Sprintf(ColoredPrefixFormat, RED, CRITICAL.String())

} else {

Prefix[TRACE] = fmt.Sprintf(PrefixFormat, TRACE.String())

Prefix[DEBUG] = fmt.Sprintf(PrefixFormat, DEBUG.String())

Prefix[INFO] = fmt.Sprintf(PrefixFormat, INFO.String())

Prefix[WARNING] = fmt.Sprintf(PrefixFormat, WARNING.String())

Prefix[ERROR] = fmt.Sprintf(PrefixFormat, ERROR.String())

Prefix[CRITICAL] = fmt.Sprintf(PrefixFormat, CRITICAL.String())

}

}

// valid determines whether a Level instance is valid or not

func (level LevelType) valid() bool {

if TRACE > level || CRITICAL < level {

return false

}

return true

}

// String return string format associate with a Level instance

func (level LevelType) String() string {

if !level.valid() {

return UNKNOWN

}

return LevelStrings[level]

}

// prefix return formatted prefix string associate with a Level instance

func (level LevelType) prefix() string {

return Prefix[level]

}

// LevelFromString return Level according to given string

func LevelFromString(str string) LevelType {

level, ok := StringLevels[strings.ToUpper(str)]

if !ok {

return LevelType(-1)

}

return level

}