# log something (basically echo it together with a timestamp)
#
# Set $PROGRAM to a string to have it added to the output.
function log () {
        if [ -z "${PROGRAM}" ]; then
                echo "$(date +"%b %d %H:%M:%S") $(hostname -s) [$$] $@"
        else
                echo "$(date +"%b %d %H:%M:%S") $(hostname -s) ${PROGRAM}[$$]: $@"
        fi
}

# log the message using log() but then also send a mail
# to the address configured in MAILTO (if non-empty)
function log_error () {
        log "$@"
        if [ -z "${MAILTO}" ]; then
                echo "$@" | mail -e -s "[$PROGRAM@$(hostname -s)] ERROR [$$]" ${MAILTO}
        fi
}

# debug log, only output when DEBUG=1
function debug () {
    if [ $DEBUG -eq 1 ]; then
        log "$*"
    fi
}