backmeupscotty

   1 #!/bin/bash
   2
   3 REMOTE_HOST=localhost
   4 REMOTE_DIR=/tmp/backmeupscotty/test
   5 ARCHIVE_KEEPNBACKUPS=30
   6 ARCHIVE_KEEPNDAYS=30
   7 BACKUP_RUNEVERYNTHDAY=1
   8 BWLIMIT=500KiB
   9
  10 _ERROR_ENCOUNTERED=0
  11
  12 function timestamp {
  13     date +'[%y-%m-%d|%H:%M:%S]'
  14 }
  15
  16 function scottyline {
  17     echo $(timestamp) $@
  18 }
  19
  20 function scottyinfo {
  21     if [ $_ERROR_ENCOUNTERED -eq 0 ]; then
  22         scottyline $@
  23     else
  24             scottyline $@ >&2
  25     fi
  26 }
  27
  28 function scottyerror {
  29     scottyline $@ >&2
  30     if [ $_ERROR_ENCOUNTERED -eq 0 ]; then
  31             _ERROR_ENCOUNTERED=1
  32             scottyline "Going into verbose mode after error encounter." >&2
  33     fi
  34 }
  35
  36 function ssh255 {
  37     ssh $@
  38     sshret=$?
  39
  40     if [ $sshret -eq 255 ]; then
  41             scottyerror "SSH connection failed!"
  42             exit 1
  43     else
  44             return $sshret
  45     fi
  46 }
  47
  48 function grepbackups {
  49     ssh255 $REMOTE_HOST "ls $REMOTE_DIR" | grep -E '[0-9]+-[0-9]+'
  50 }
  51
  52 function isIncomplete {
  53     if ( ssh255 $REMOTE_HOST '[ -d '$REMOTE_DIR/incomplete' ]' ); then
  54             return 0
  55     else
  56             return 1
  57     fi
  58 }
  59
  60 function isNthDay {
  61     if [ $(( ( $(date +%s) / (60*60*24) ) % $BACKUP_RUNEVERYNTHDAY )) -eq 0 ];
  62     then
  63             return 0
  64     else
  65             return 1
  66     fi
  67 }
  68
  69 function latestTooOld {
  70     for oldbackup in $(grepbackups); do
  71             tstamp=$(echo $oldbackup | cut -d'-' -f1)
  72
  73             if [ $(( $(date +%s) - $tstamp )) -lt $(( ($BACKUP_RUNEVERYNTHDAY*24+12)*60*60 )) ]
  74             then
  75                 return 1
  76             fi
  77     done
  78
  79     return 0
  80 }
  81
  82 function scottysync {
  83     timestamp=$(date +%s)
  84
  85     scottyinfo "Syncing $SYNC_SRC to $REMOTE_HOST:$REMOTE_DIR @$timestamp."
  86
  87     if [ ! -d "$SYNC_SRC" ]; then
  88             scottyerror "Source dir $SYNC_SRC does not exist. Not syncing!"
  89             return 1
  90     fi
  91
  92     if [ $(ls -A "$SYNC_SRC" | wc -l) -eq 0 ]; then
  93             scottyerror "Source dir $SYNC_SRC is empty. Not syncing!"
  94             return 1
  95     fi
  96
  97     dir_current=$REMOTE_DIR/current
  98     dir_incomplete=$REMOTE_DIR/incomplete
  99     dir_timestamped=$REMOTE_DIR/$timestamp-$(date -d @$timestamp +%Y%m%d%H%M%S)
 100
 101     if [ -z $SYNC_EXC ]; then
 102             rsync_exclude=""
 103     else
 104             rsync_exclude=$(eval echo --exclude={$SYNC_EXC} | tr -d {})
 105     fi
 106
 107     if (ssh255 $REMOTE_HOST '[ ! -d '$REMOTE_DIR' ]'); then
 108             scottyinfo "Creating destination directory $REMOTE_HOST:$REMOTE_DIR."
 109             ssh255 $REMOTE_HOST "mkdir $REMOTE_DIR"
 110     fi
 111
 112     if isIncomplete; then
 113             scottyerror "Continuing old incomplete backup."
 114     fi
 115
 116     scottyinfo "Starting rsync."
 117     rsync -e ssh --bwlimit=$BWLIMIT \
 118           -v -aHAX --numeric-ids --delete --delete-excluded \
 119           --link-dest=$dir_current \
 120           $rsync_exclude \
 121           $SYNC_SRC/ $REMOTE_HOST:$dir_incomplete/
 122
 123     if [ $? -eq 0 ]; then
 124             scottyinfo "Timestamping completed backup and linking to current backup."
 125             ssh255 $REMOTE_HOST \
 126                    "mv $dir_incomplete $dir_timestamped && rm -f $dir_current && \
 127                ln -s $(basename $dir_timestamped) $dir_current"
 128     else
 129             scottyerror "Rsync failed."
 130     fi
 131
 132     while [ $(grepbackups | wc -l) -gt $ARCHIVE_KEEPNBACKUPS ]; do
 133             oldestbackup=$(grepbackups | head -1)
 134             oldestbackuptstamp=$(echo $oldestbackup | cut -d'-' -f1)
 135
 136             if [ $oldestbackuptstamp -lt $(( $(date +%s) - $ARCHIVE_KEEPNDAYS*60*60*24 )) ]; then
 137                 scottyinfo "Removing old backup $oldestbackup."
 138                 ssh255 $REMOTE_HOST rm -r "$REMOTE_DIR/$oldestbackup"
 139             else
 140                 break
 141             fi
 142     done
 143 }
 144
 145 function deleteLock {
 146     if ! rmdir /var/lock/$(basename $0); then
 147             scottyerror "Could not delete lockfile /tmp/$(basename $0).lock!"
 148     fi
 149 }
 150
 151 function cleanup_abort {
 152     scottyerror "Caught exit signal! Cleaning up."
 153
 154     cleanup ABORT
 155
 156     if [ $(jobs -p) ]; then
 157             scottyerror "TERMinating remaining child processes."
 158             kill $(jobs -p)
 159     fi
 160
 161     deleteLock
 162
 163     exit
 164 }
 165
 166 function cleanup {
 167     scottyinfo "No cleanup function was defined."
 168 }
 169
 170 function prepare {
 171     scottyinfo "No prepare function was defined."
 172 }
 173
 174 function cleanup_normal {
 175     cleanup
 176     deleteLock
 177 }
 178
 179 function printhelp {
 180     cat <<EOF
 181 Usage: $(basename $0) [OPTION]...
 182
 183 Recognized options:
 184   -q   Only output errors
 185   -n   Run only on nth day
 186   -h   Print out this help
 187 EOF
 188 }
 189
 190 function backmeupscotty {
 191     while getopts "qn:h" opt; do
 192             case $opt in
 193                 q)
 194                         exec > /dev/null
 195                         ;;
 196                 n)
 197                         BACKUP_RUNEVERYNTHDAY=$OPTARG
 198                         ;;
 199                 h)
 200                         printhelp
 201                 exit 0
 202                 ;;
 203             esac
 204     done
 205
 206     ssh255 $REMOTE_HOST exit
 207
 208     if latestTooOld; then
 209             scottyerror "The latest backup is too old."
 210     elif isNthDay; then
 211             scottyinfo "This is the nth day."
 212     else
 213             scottyinfo "No backup has to be done. Exiting."
 214             exit 0
 215     fi
 216
 217     scottyinfo "Performing backup."
 218
 219     trap cleanup_abort EXIT
 220
 221     prepare
 222     scottysync
 223
 224     trap cleanup_normal EXIT
 225
 226     exit 0
 227 }
 228
 229 if ! mkdir /var/lock/$(basename $0); then
 230     scottyerror "Another instance of $(basename $0) is still running!"
 231     exit 1
 232 else
 233     trap deleteLock EXIT
 234 fi