Skip to content

Instantly share code, notes, and snippets.

@JadedDragoon JadedDragoon/cronwrap.sh Secret
Last active Jan 22, 2018

Embed
What would you like to do?
Wrapper script to implement sane logging to journald for cron jobs. Also allows errors to "bubble up" to cron for email alerts. (not working)
#!/bin/bash
#===============================================================================
#
# Wrapper script to implement sane logging to journald for cron jobs. Also
# allows errors to "bubble up" to cron for email alerts.
#
# Exit Codes:
# 0 - success
# 1 - failure
#
#===============================================================================
# MIT License
#
# Copyright (c) 2017 Jeremy Cliff Armstrong
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
#===============================================================================
_opts=`getopt -o a:e:t:h --long arguments:,executable:,identifier:,help -- "$@"`
_sn=$(basename "$0")
_sn=${_sn%%.*}
if [ $? != 0 ] ; then echo "$_sn: Failed parsing options." >&2 ; exit 1 ; fi
eval set -- "$_opts"
_help=0
while true
do
case "$1" in
-a | --arguments ) _ARGS="$2"; shift 2 ;;
-e | --executable ) _EXEC="$2"; shift 2 ;;
-t | --identifier ) _IDENT="$2"; shift 2 ;;
-h | --help ) _help=1; shift ;;
-- ) shift; break ;;
* ) break ;;
esac
done
if [[ _help -gt 0 ]]; then
# 0 1 2 3 4 5 6 7 8
# |123456789|123456789|123456789|123456789|123456789|123456789|123456789|123456789|
echo "$_sn: Usage"
echo
echo " -a|--arguments Specify arguments for the executable to be wrapped. If"
echo " argument string contains spaces it must be enclosed in"
echo " quotes."
echo
echo " -e|--executable Specify path for the executable to be wrapped. If path"
echo " contains spaces it must be enclosed in quotes. REQUIRED."
echo
echo " -t|--identifier Specify a short string that is used to identify the cronjob"
echo " being logged. Will be prefixed with \"cronwrap-\". REQUIRED."
echo
echo " -h|--help Displays this help message."
echo
exit 0
fi
# set defaults for missing required arguments or error
if [ -z ${_EXEC:+x} ]; then echo "$_sn: -e|--executable is a required argument. Try with --help." >&2; exit 1; fi
if [ -z ${_IDENT:+x} ]; then echo "$_sn: -t|--identifier is a required argument. Try with --help." >&2; exit 1; fi
# ensure command exists and is executable for us
if [ ! -x $_EXEC ]; then echo "$_sn: Unable to locate executable $_EXEC. Check your path and permissions." >&2; exit 1; fi
# use a named pipe to get around race condition with journald.
_pipe=/tmp/$_IDENT.out
if [ -p $_pipe ]; then echo "$_sn: $_pipe Exisits! Either wrapper is being called too often for identifier $_IDENT or pipe is a zombie." >&2; exit 1; fi
# create pipe and hold it open with file handle
mkfifo $_pipe
systemd-cat --identifier=$_IDENT --priority="info" < $_pipe &
exec 3>$_pipe
# trap exit signal to ensure cleanup
function finish {
exec 3>&-
if [ -p $_pipe ]; then rm $_pipe; fi
}
trap finish EXIT
# log function to actualy write out results.
function journaldlog {
__tmplvl="$1"
#__msg="${@:2}"
__msg=$(cat; echo x)
__msg=${__msg%x}
#echo "DEBUG journaldlog: \$1 = $__tmplvl" #debugging - deleteme
#echo "DEBUG journaldlog: \$(cat) = $__msg" #debugging - deleteme
if [ -z ${__tmplvl:+x} ]; then __tmplvl=4; __msg='Empty log priority and message!'; fi
if [ -z ${__msg:+x} ]; then __tmplvl=4; __msg='Empty log message!'; fi
case "$__tmplvl" in
debug | 7 ) __level='7'; __lname='DEBUG' ;;
info | 6 ) __level='6'; __lname='INFO' ;;
notice | 5 ) __level='5'; __lname='NOTICE' ;;
warning | warn | 4 ) __level='4'; __lname='WARNING' ;;
error | 3 ) __level='3'; __lname='ERROR' ;;
critical | 2 ) __level='2'; __lname='CRITICAL' ;;
emergency | 1 ) __level='1'; __lname='EMERGENCY';;
* ) echo "$_sn: Unknown log priority $1. Exiting." >&2; exit 1;;
esac
# log the thing
echo "\<$__level\> $__lname: $__msg" >&3
#if [ "$__level" -le "4" ]; then echo "$_sn: $__lname - $__msg" >&2; fi
echo "$_sn - $__lname: $__msg"
}
# redirect all further stdout to the log function using "info" priority level (maybe some other day)
#exec 1>journaldlog info -
# redirect all further stderr to the log function with "error" priority level (maybe some other day)
#exec 2>journaldlog error -
#do the thing - triggers only for the error invocation, passes NULL for second parameter
#(
# exec 7>&1
# (
# stdbuf -oL -eL $_EXEC $_ARGS | journaldlog info
# ) 2>&7 1>/dev/null
#) | journaldlog error
#do the thing - triggers journaldlog only twice, not line by line.
{ $_EXEC $_ARGS 2>&1 1>&7 7>&- | journaldlog error; } 7>&1 1>&2 | journaldlog info
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.