.log.rc

#!/bin/sh


_LOG_DIR=`dirname "$(readlink -f "$0")"`

_LOG_INFO_FD=3
_VERBOSE_DEFAULT=3
_LOG_PREFIX_INDENT="  "

# Set defaults.
[[ "${_VERBOSE}" == "" ]] && _VERBOSE=${_VERBOSE_DEFAULT}

# Color definitions can be found in '.color.rc'.
# You can either place it to the same directory of this script and un-comment 
# the following line to source it, or you can source it before this script.
# Notes: Not sourcing the '.color.rc' will simply disable color.
# -----
# source "$(dirname "$(readlink -f "$0")")/.color.rc"

# Suppress ${_LOG_INFO_FD} file descriptor if _VERBOSE is lower than 4.
# Then, `echo "info" >&${_LOG_INFO_FD}` will be suppressed if _VERBOSE is lower than 4.
# Ref: https://stackoverflow.com/questions/8756535/conditional-redirection-in-bash
# Ref: https://stackoverflow.com/questions/26607577/how-to-write-to-a-named-file-descriptor-in-bash
if [[ ${_VERBOSE} -lt 4 ]]; then
    eval "exec ${_LOG_INFO_FD}>/dev/null"
else
    eval "exec ${_LOG_INFO_FD}>&1"
fi

_log_error() {
    [[ ${_VERBOSE} -lt 1 ]] && return
	[[ ${_NO_COLOR} ]] || echo -n -e ${_COLOR_BRed}
	echo "${_LOG_PREFIX}[ERR] $1"
	[[ ${_NO_COLOR} ]] || echo -n -e ${_COLOR_Off}
}

_log_warning() {
    [[ ${_VERBOSE} -lt 2 ]] && return
	[[ ${_NO_COLOR} ]] || echo -n -e ${_COLOR_BYellow}
	echo "${_LOG_PREFIX}[WRN] $1"
	[[ ${_NO_COLOR} ]] || echo -n -e ${_COLOR_Off}
}

_log_highlight() {
    [[ ${_VERBOSE} -lt 3 ]] && return
	[[ ${_NO_COLOR} ]] || echo -n -e ${_COLOR_BGreen}
	echo "${_LOG_PREFIX}$1"
	[[ ${_NO_COLOR} ]] || echo -n -e ${_COLOR_Off}
}

_log_info() {
    [[ ${_VERBOSE} -lt 4 ]] && return
    [[ ${_NO_COLOR} ]] || echo -n -e ${_COLOR_Off}
    echo "${_LOG_PREFIX}$1"
    [[ ${_NO_COLOR} ]] || echo -n -e ${_COLOR_Off}
}

_log_empty_line() {
    [[ ${_VERBOSE} -lt 4 ]] && return
    echo ""
}

_LOG_HELP=$(cat << _EOF_
    _VERBOSE=LEVEL  Set verbose LEVEL. Default is ${_VERBOSE_DEFAULT}.
                    LEVEL: 0 (none), 1 (error), 2 (warnning), 3 (important), 4 (info)
    _NO_COLOR=0     Disable color messages.
_EOF_
)