logging.go

package main

import (
	log "github.com/cihub/seelog"
)

func setLogLevel(level string) (err error) {

	// https://en.wikipedia.org/wiki/ANSI_escape_code#3/4_bit
	// https://github.com/cihub/seelog/wiki/Log-levels
	appConfig := `
	<seelog minlevel="` + level + `">
	<outputs formatid="stdout">
	<filter levels="debug,trace">
		<console formatid="debug"/>
	</filter>
	<filter levels="info">
		<console formatid="info"/>
	</filter>
	<filter levels="critical,error">
		<console formatid="error"/>
	</filter>
	<filter levels="warn">
		<console formatid="warn"/>
	</filter>
	</outputs>
	<formats>
		<format id="stdout"   format="%Date %Time [%LEVEL] %File %FuncShort:%Line %Msg %n" />

		<format id="debug"   format="%Date %Time %EscM(37)[%LEVEL]%EscM(0) %File %FuncShort:%Line %Msg %n" />
		<format id="info"    format="%Date %Time %EscM(36)[%LEVEL]%EscM(0) %File %FuncShort:%Line %Msg %n" />
		<format id="warn"    format="%Date %Time %EscM(33)[%LEVEL]%EscM(0) %File %FuncShort:%Line %Msg %n" />
		<format id="error"   format="%Date %Time %EscM(31)[%LEVEL]%EscM(0) %File %FuncShort:%Line %Msg %n" />

	</formats>
	</seelog>
	`
	logger, err := log.LoggerFromConfigAsBytes([]byte(appConfig))
	if err != nil {
		return
	}
	log.ReplaceLogger(logger)
	return
}