# socialnerds log engine for bash/shell scripts
#
# version: 0.1a
# author: david@socialnerds.org


#  ****  help  ****
# this is basically a collection of bash functions
# for making a decent logging in a bash script
# amazingly easy.
#
# in order to use this little logging script
# you need to have some global variables defined
#    loglevel=<0-4>
#        0  --  no logging
#        1  --  just errors
#        2  --  errors & warnings
#        3  --  even infos (something like "user was created")
#        4  --  debug (more than everything)
#
#    logfile="/path/to/logfile.log"
#        well.. should be understandable..
#
#    logwhat="kvm-tools"
#        tells the engine what is actually been logged (example: name of calling script)
#        just used for syslog
#
#    log2syslog="0|1"
#        (de)activates logging to the syslog deamen
#
#    log2stdout="0|1"
#        (de)activates logging to stdout
#        useful if you don't want to deal with output in your script
#
#    log2file="0|1"
#        (de)activates logging to logfile
#
#
# usage:
# log error|warning|info|debug "log message"

#  ****  log function  ****
log()
{
    # getting local hostname
    local hostname=$(cat /etc/hostname)

    # if no loglevel is defined the script will end
    if [ -z $loglevel ]; then
        echo "logengine[error]: no loglevel defined"
        exit 1

    # if loglevel is 0, skip logging
    elif [ $loglevel = "0" ]; then
        # logging is disabled
        return 0

    # loglevel has to be something between 0 and 5
    elif [ ! $loglevel -gt "0" -o ! $loglevel -lt "5" ]; then
        # loglevel unknown
        echo "logengine[error]: unknown loglevel"
        exit 1
    fi


    # stdout routine
    if [ -z $log2stdout ]; then
        log2stdout="0"
    elif [ $log2stdout = "0" ]; then
        # stdout is disabled
        :
    elif [ $log2stdout = "1" ]; then
        # here goes the actual logging process (stdout)
        if [ $1 = "error" -a $loglevel -gt "0" ]; then
            # errors
            echo "[$1]: $2"
        elif [ $1 = "warning" -a $loglevel -gt "1" ]; then
            # warnings
            echo "[$1]: $2"
        elif [ $1 = "info" -a $loglevel -gt "2" ]; then
            # informational
            echo "[$1]: $2"
        elif [ $1 = "debug" -a $loglevel -gt "3" ]; then
            # debug messages
            echo "[$1]: $2"
        fi
    fi

    # syslog routine
    if [ -z $log2syslog ]; then
        log2syslog="0"
    elif [ $log2syslog = "0" ]; then
        # syslog is disabled
        :
    elif [ -z $logwhat ]; then
        # for syslogging logwhat has to be defined
        echo "logengine[error]: logwhat not defined"
    elif [ $log2syslog = "1" ]; then
        # here goes the actual logging process (syslog)
        if [ $1 = "error" -a $loglevel -gt "0" ]; then
            # errors
            logger -t "$logwhat[$1]" "$2"
        elif [ $1 = "warning" -a $loglevel -gt "1" ]; then
            # warnings
            logger -t "$logwhat[$1]" "$2"
        elif [ $1 = "info" -a $loglevel -gt "2" ]; then
            # informational
            logger -t "$logwhat[$1]" "$2"
        elif [ $1 = "debug" -a $loglevel -gt "3" ]; then
            # debug messages
            logger -t "$logwhat[$1]" "$2"
        fi
    fi

    # logfile routine
    if [ -z $log2file ]; then
        log2file="0"
    elif [ $log2file = "0" ]; then
        # file is disabled
        :
    elif [ $log2file = "1" ]; then
        if [ -z $logfile ]; then
            # if no logfile is defined the script will end
            echo "logengine[error]: no logfile defined"
            exit 1
        elif ! [ -a $logfile ]; then
            echo "logengine[warning]: logfile not found"
            echo "logengine[info]: creating new logfile"
            touch $logfile
            if [ $? != 0 ]; then
                # probably a permission denied error
                echo "logengine[error]: could not create logfile."
                exit 1
            fi
        fi
        # here goes the actual logging process (logfile)
        if [ $1 = "error" -a $loglevel -gt "0" ]; then
            # errors
            echo "$(gettimestamp nice) [$1]: $2" >> $logfile
        elif [ $1 = "warning" -a $loglevel -gt "1" ]; then
            # warnings
            echo "$(gettimestamp nice) [$1]: $2" >> $logfile
        elif [ $1 = "info" -a $loglevel -gt "2" ]; then
            # informational
            echo "$(gettimestamp nice) [$1]: $2" >> $logfile
        elif [ $1 = "debug" -a $loglevel -gt "3" ]; then
            # debug messages
            echo "$(gettimestamp nice) [$1]: $2" >> $logfile
        fi
    fi

}

# end of file