iankelling.org Git - log-quiet/blob - sysd-mail-once

   1 #!/bin/bash
   2 # Copyright (C) 2016 Ian Kelling
   3
   4 # Licensed under the Apache License, Version 2.0 (the "License");
   5 # you may not use this file except in compliance with the License.
   6 # You may obtain a copy of the License at
   7
   8 #     http://www.apache.org/licenses/LICENSE-2.0
   9
  10 # Unless required by applicable law or agreed to in writing, software
  11 # distributed under the License is distributed on an "AS IS" BASIS,
  12 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13 # See the License for the specific language governing permissions and
  14 # limitations under the License.
  15
  16
  17 set -eE -o pipefail
  18 trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" returned $?" >&2' ERR
  19
  20 errors=3
  21 cbase=$HOME/sysd-mail-once-state
  22 case "$1" in
  23   -h|--help)
  24     cat <<EOF
  25 Usage: sysd-log-once [-ERRORS] SERVICE COMMAND [ARGS...]
  26 For systemd timers, email on repeated failure & success after failure.
  27
  28 In the service triggered by the timer, prepend this script to the ExecStart.
  29 The email will contain the service's logs for the last ERRORS runs.
  30
  31
  32 Stores error counts in $cbase
  33
  34 -ERRORS:  ERRORS is the number of failurs to accumulate before mailing the error.
  35           Default is 3.
  36 EOF
  37     exit 0
  38     ;;
  39   -[0-9]*)
  40     errors=${1#-}
  41     shift
  42     ;;
  43 esac
  44 service=$1
  45 shift
  46
  47 c=$cbase/$service # c for command file path base
  48
  49 glob="$c[0-9]*"
  50 arr=($glob); file="${arr[0]}"; [[ $glob != "$file" ]] || file=
  51 [[ -d $cbase ]] || mkdir -p $cbase
  52
  53 if [[ ! $file ]]; then
  54   cursor=$(journalctl --show-cursor -qn0|sed 's/^\s*--\scursor:\s*//')
  55 fi
  56
  57 code=0
  58 "$@" || code=$?
  59 if (( code )); then
  60   send_mail=false
  61   if [[ $file ]]; then
  62     i=${file#$c}
  63     if (( i < errors )); then
  64       new_file=$c$((i+1))
  65       mv $file $new_file
  66       file=$new_file
  67       if [[ $file == $c$errors ]]; then
  68         send_mail=true
  69       fi
  70     fi
  71   else
  72     file=${c}1
  73     printf "%s\n" "$cursor" >$file
  74     if (( errors == 1 )); then
  75       send_mail=true
  76     fi
  77   fi
  78   if $send_mail; then
  79     journalctl -u $service.service --after-cursor=$(<$file) | \
  80       mail -s "$HOSTNAME: $service exit code: $code" root
  81   fi
  82 else
  83   if [[ $file ]]; then
  84     rm -f $file
  85     if [[ $file == $c$errors ]]; then
  86       echo | mail -s "$HOSTNAME: $service success" root
  87     fi
  88   fi
  89 fi