log.sh

#!/bin/echo Warnning, this library must only be sourced!

# vim: set expandtab smarttab shiftwidth=4 tabstop=4:

#

# Author: tuantuan.lv <tuantuan.lv@alibaba-inc.com>

# Description: a simple log library for pet

#

# Create the log file if not exists

# $1: the log file name

function _create_logfile()

{

    # FIXME: change the permission of log file

    if [ ! -f "$1" ]; then

        mkdir -p `dirname $1`; touch $1; chmod 666 $1

    fi

}

#

# Prevent the pet log library to be sourced again, so we can protect

# the log file to be created only once.

#

function _prevent_sourced_again()

{

    _petlog_sourced_="__petlog_sourced_$$__"

    if [ -n "${!_petlog_sourced_}" ]; then

        return

    fi

    eval "$_petlog_sourced_=1"

    # Set the default log file path

    if [ -f "$0" ]; then # Use the script name (not including the extension)

        _petlog_filename="/tmp/$(basename $0 | awk -F. '{print $1}').log.`date +'%Y%m%d'`"

    else # Otherwise, just using the default name

        _petlog_filename="/tmp/petlog.log.`date +'%Y%m%d'`"

    fi

    _create_logfile "$_petlog_filename"

    # The log level, we only print logs whose level less than this

    _petlog_level=3                                      # DEBUG

    # The log data format

    _petlog_datefmt='%Y-%m-%d %H:%M:%S'                  # 2014-11-11 11:11:11

    # The log line format

    _petlog_fmt="[<levelname>] [<asctime>] <message>"    # [DEUBG] [2014-11-11 11:11:11] a simple log

}

# Print log messages

# $1: The log level number

# $2: C-style printf format string

# $3..$N: C-style printf arguments

function _print_log()

{

    local level=$1 msg="$2" fmt="${_petlog_fmt}"

    local levelnames=('ERROR' 'WARNING' 'INFO' 'DEBUG')

    local logcolors=('red' 'yellow' 'green' '')

    # Prepare the log format strings

    fmt="${fmt//<asctime>/$(date +"$_petlog_datefmt")}"

    fmt="${fmt//<message>/$msg}"

    fmt="${fmt//<levelname>/${levelnames[$level]}}"

    # We also decide to print all the log messages to the log file

    shift 2 && printf "$fmt" "$@" >> $_petlog_filename

    # Only print the log whose level less than the log level we set before

    if [ $level -le $_petlog_level ]; then

        ${logcolors[level]:-printf} "$fmt" "$@"

    fi

}

#

# Make the strings to be echoed as differnt colors

#

function red() { printf "\033[1;31m$(echo "$1" | sed -r 's/(\\n)?$/\\033[0m\1/')" "${@:2}"; }

function yellow() { printf "\033[1;33m$(echo "$1" | sed -r 's/(\\n)?$/\\033[0m\1/')" "${@:2}"; }

function green() { printf "\033[1;32m$(echo "$1" | sed -r 's/(\\n)?$/\\033[0m\1/')" "${@:2}"; }

function blue() { printf "\033[1;34m$(echo "$1" | sed -r 's/(\\n)?$/\\033[0m\1/')" "${@:2}"; }

function cyan() { printf "\033[1;36m$(echo "$1" | sed -r 's/(\\n)?$/\\033[0m\1/')" "${@:2}"; }

function purple() { printf "\033[1;35m$(echo "$1" | sed -r 's/(\\n)?$/\\033[0m\1/')" "${@:2}"; }

#

# Log print functions, such as debug_msg, info_msg... etc.

#

# Define the log level constants, just for convenience

LOG_QUIET=-1 LOG_ERROR=0 LOG_WARNING=1 LOG_INFO=2 LOG_DEBUG=3

function debug_msg() { _print_log $LOG_DEBUG "$1" "${@:2}"; }

function info_msg() { _print_log $LOG_INFO "$1" "${@:2}"; }

function warn_msg() { _print_log $LOG_WARNING "$1" "${@:2}"; }

function error_msg() { _print_log $LOG_ERROR "$1" "${@:2}"; return 1; }

function die_msg() { error_msg "$@"; exit 1; }

function exit_msg() { die_msg "$@"; } # should be deprecated, use die_msg instead

function warning_msg() { warn_msg "$@"; } # the same as warn_msg

#

# Customize the log functions

#

# Set the default log file

# $1: the log filename

function set_logfile()

{

    if [ -z "$1" ]; then

        die_msg "the log filename is empty\n"

    fi

    _petlog_filename="$1"

    _create_logfile "$_petlog_filename"

}

# Get the log filename

function get_logfile() { echo "$_petlog_filename"; }

# Set the default log level

# $1: level name or level number

function set_loglevel()

{

    if echo "$1" | grep -qE "^(-1|0|1|2|3)$"; then

        _petlog_level="$1"

    elif echo "$1" | grep -qE '^LOG_(QUIET|DEBUG|INFO|ERROR|WARNING)$'; then

        _petlog_level="${!1}"

    else

        die_msg "the log level is not valid, please check\n"

    fi

}

# Set log format

function set_logfmt()

{

    if [ -z "$1" ]; then

        die_msg "the log format is empty, please check\n"

    fi

    _petlog_fmt="$1"

}

# Set the log date format

# $1: the log date format, see `man data`

function set_logdatefmt()

{

    if [ -z "$1" ]; then

        die_msg "the log data format is empty, please check\n"

    fi

    _petlog_datefmt="$1"

}

_prevent_sourced_again # Yeah, prevent to be sourced again

#!/bin/bash

. ./log.sh

echo "1. use default log settings"

echo

debug_msg "hello,world\n"

info_msg 'hello,world\n'

warn_msg 'hello,world\n'

warning_msg 'hello,world\n'

error_msg 'hello,world\n'

g

echo

echo "2. set loglevel to $LOG_INFO"

echo

set_loglevel $LOG_INFO

debug_msg "hello,world\n"

info_msg 'hello,world\n'

warn_msg 'hello,world\n'

error_msg 'hello,world\n'

echo

echo "3. set log fmt to [<asctime> - <levelname>] <message>"

echo

set_logfmt "[<asctime> - <levelname>] <message>"

info_msg 'hello,%s\n' world

warn_msg 'hello,%s\n' pet

echo

echo "4. set date fmt to %Y/%m/%d %H:%M:%S"

echo

set_logdatefmt "%Y/%m/%d %H:%M:%S"

info_msg 'hello,world\n'

warn_msg 'hello,world\n'

echo

echo '5. use colorful print'

echo

red "hello,world\n"

green "hello,world\n"

yellow "hello,world\n"

cyan "hello,world\n"

purple "hello,world\n"

blue "hello,world\n"

echo

echo '6. exit script'

echo

die_msg "exit script\n"