#!/bin/bash
-# Copyright (C) 2016 Ian Kelling
+# I, Ian Kelling, follow the GNU license recommendations at
+# https://www.gnu.org/licenses/license-recommendations.en.html. They
+# recommend that small programs, < 300 lines, be licensed under the
+# Apache License 2.0. This file contains or is part of one or more small
+# programs. If a small program grows beyond 300 lines, I plan to switch
+# its license to GPL.
+
+# Copyright 2024 Ian Kelling
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# limitations under the License.
+
set -eE -o pipefail
trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" returned $?" >&2' ERR
errors=3
-cbase=$HOME/sysd-mail-once-state
+tmp=(~)
+cbase="${tmp[0]}/sysd-mail-once-state"
to=root
-case "$1" in
- -h|--help)
- cat <<EOF
+dryrun=false
+print_all=false
+while [[ $1 == -* ]]; do
+ case "$1" in
+ -h|--help)
+ cat <<EOF
Usage: sysd-mail-once [-t TO_ADDRESS] [-ERRORS] SERVICE COMMAND [COMMAND_ARGS...]
For use with systemd timers, to email (with exim) on repeated failure &
Stores error counts in $cbase
--ERRORS: ERRORS is the number of failurs to accumulate before mailing the error.
- Default is 3.
+-ERRORS ERRORS is the number of failurs to accumulate before mailing the error.
+ Default is 3.
--t TO_ADDRESS: Address to email about errors
+-a Email the logs of all errors intead of just the last one.
+-t TO_ADDRESS Address to email about errors
+-n Dry run. Execute command but only print out what we would do in response.
EOF
- exit 0
- ;;
- -[0-9]*)
- errors=${1#-}
- shift
- ;;
- -t)
- to="$2"
- shift 2
- ;;
-esac
-service=$1
+ exit 0
+ ;;
+ -[0-9]*)
+ errors=${1#-}
+ ;;
+ -a)
+ print_all=true
+ ;;
+ -t)
+ to="$2"
+ shift
+ ;;
+ -n)
+ dryrun=true
+ ;;
+ *)
+ echo "error: unexpected arg: $1"
+ exit 1
+ ;;
+ esac
+ shift
+done
+
+if (( $# < 2 )); then
+ echo "error: expected at least 2 args after options. args:"
+ exit 1
+fi
+
+service="$1"
shift
+
+# maybe run, depending on $dryrun
+m() {
+ if $dryrun; then
+ printf "%s\n" "$*"
+ else
+ "$@"
+ fi
+}
+# maybe run, with stdin
+mi() {
+ if $dryrun; then
+ printf "%s <<'EOF'\n" "$*"
+ cat
+ echo EOF
+ else
+ "$@"
+ fi
+}
+e() {
+ if $dryrun; then
+ printf "dryrun: %s\n" "$*"
+ fi
+}
+
c=$cbase/$service # c for command file path base
-glob="$c[0-9]*"
+e "c=$c"
+
+glob="${c}[0-9]*"
arr=($glob); file="${arr[0]}"; [[ $glob != "$file" ]] || file=
-[[ -d $cbase ]] || mkdir -p $cbase
+if [[ $file ]]; then
+ e "file=$file"
+fi
-if [[ ! $file ]]; then
- cursor=$(journalctl --show-cursor -qn0|sed 's/^\s*--\scursor:\s*//')
+if ! [[ -d $cbase ]]; then
+ mkdir -p $cbase
fi
+
code=0
"$@" || code=$?
if (( code )); then
send_mail=false
+ cursor=$(journalctl --show-cursor -qn0|sed 's/^\s*--\scursor:\s*//')
if [[ $file ]]; then
- i=${file#$c}
+ i=${file#"$c"}
if (( i < errors )); then
new_file=$c$((i+1))
- mv $file $new_file
+ m mv $file $new_file
file=$new_file
if [[ $file == $c$errors ]]; then
send_mail=true
+ else
+ if $dryrun; then
+ printf "dryrun: appending to file $file: %s\n" "$cursor"
+ else
+ printf "%s\n" "$cursor" >>$file
+ fi
fi
fi
else
file=${c}1
- printf "%s\n" "$cursor" >$file
+ if $dryrun; then
+ printf "dryrun: creating $file, contents: %s\n" "$cursor"
+ else
+ printf "%s\n" "$cursor" >$file
+ fi
if (( errors == 1 )); then
send_mail=true
fi
fi
if $send_mail; then
- exim -odf -t <<EOF
+ if $print_all; then
+ cursor=$(head -n1 $file)
+ else
+ cursor=$(tail -n1 $file)
+ fi
+ echo "sysd-mail-once: emailing on $errors errors. exit code: $code"
+ mi exim -odf -t <<EOF
To: $to
-From: $USER@$(hostname -f)
+From: $(id -u -n)@$(hostname -f)
Subject: $HOSTNAME: $service exit code: $code
-$(journalctl -u $service.service --after-cursor=$(<$file))
+$(journalctl -u $service.service --after-cursor="$cursor")
EOF
fi
else
if [[ $file ]]; then
- rm -f $file
+ m rm -f $file
if [[ $file == $c$errors ]]; then
- exim -odf -t <<EOF
+ echo "sysd-mail-once: emailing success after >= $errors errors."
+ mi exim -odf -t <<EOF
To: $to
-From: $USER@$(hostname -f)
+From: $(id -u -n)@$(hostname -f)
Subject: $HOSTNAME: $service success
EOF