handlers/maildir

   1 # -*- mode: sh; sh-basic-offset: 3; indent-tabs-mode: nil; -*-
   2
   3 ###############################################################
   4 #
   5 #  This handler slowly creates a backup of each user's maildir
   6 #  to a remote server. It is designed to be run with low overhead
   7 #  in terms of cpu and bandwidth so it runs pretty slow.
   8 #
   9 #  if destdir is /backup/maildir/, then it will contain the files
  10 #    daily.1
  11 #    daily.2
  12 #    daily.3
  13 #    weekly.1
  14 #    weekly.2
  15 #    monthly.1
  16 #  if keepdaily is 3, keepweekly is 2, and keepmonthly is 1.
  17 #
  18 #  The basic algorithm is to rsync each maildir individually,
  19 #  and to use hard links for retaining historical data.
  20 #
  21 #  We rsync each maildir individually because it becomes very
  22 #  unweldy to start a single rsync of many hundreds of thousands
  23 #  of files.
  24 #
  25 #  For the backup rotation to work, destuser must be able to run
  26 #  arbitrary bash commands on the desthost.
  27 #
  28 ##############################################################
  29
  30 getconf rotate yes
  31 getconf remove yes
  32
  33 getconf loadlimit 5
  34 getconf speedlimit 0
  35 getconf keepdaily 5
  36 getconf keepweekly 3
  37 getconf keepmonthly 1
  38
  39 getconf srcdir /var/maildir
  40 getconf destdir
  41 getconf desthost
  42 getconf destport 22
  43 getconf destuser
  44
  45 failedcount=0
  46
  47 # strip trailing /
  48 destdir=${destdir%/}
  49 srcdir=${srcdir%/}
  50
  51 # used for testing
  52 #getconf letter
  53 #getconf testuser elijah
  54 getconf backup yes
  55 #letters=e
  56 letters="a b c d e f g h i j k l m n o p q r s t u v w x y z"
  57
  58 [ -d $srcdir ] || fatal "source directory $srcdir doesn't exist"
  59
  60 [ ! $test ] || testflags="--dry-run -v"
  61 rsyncflags="$testflags -e 'ssh -p $destport' -r -v --ignore-existing --delete --size-only --bwlimit=$speedlimit"
  62 excludes="--exclude '.Trash/\*' --exclude '.Mistakes/\*' --exclude '.Spam/\*'"
  63
  64 # see if we can login
  65 debug "ssh -o PasswordAuthentication=no $desthost -l $destuser 'echo -n 1'"
  66 if [ ! $test ]; then
  67         result=`ssh -o PasswordAuthentication=no $desthost -l $destuser 'echo -n 1' 2>&1`
  68         if [ "$result" != "1" ]; then
  69                 fatal "Can't connect to $desthost as $destuser."
  70         fi
  71 fi
  72
  73 ##################################################################
  74 ### FUNCTIONS
  75
  76 function do_user() {
  77         local user=$1
  78         local destdir=$2
  79         local letter=${user:0:1}
  80         local dir="$srcdir/$letter/$user"
  81         [ -d $dir ] || fatal "maildir $dir not found".
  82
  83 #       while true; do
  84 #               load=`uptime | sed 's/^.*load average: \\([^,]*\\).*$/\\1/'`
  85 #               over=`expr $load \> $loadlimit`
  86 #               if [ $over == 1 ]; then
  87 #                       info "load $load, sleeping..."
  88 #                       sleep 600
  89 #               else
  90 #                       break
  91 #               fi
  92 #       done
  93
  94         cmd="$RSYNC $rsyncflags $excludes $dir $destuser@$desthost:$destdir/$letter"
  95         ret=`rsync -e "ssh -p $destport" -r \
  96 --links --ignore-existing --delete --size-only --bwlimit=$speedlimit \
  97 --exclude '.Trash/*' --exclude '.Mistakes/*' --exclude '.Spam/*' \
  98 $dir $destuser@$desthost:$destdir/$letter \
  99 2>&1`
 100         ret=$?
 101         # ignore 0 (success) and 24 (file vanished before it could be copied)
 102         if [ $ret != 0 -a $ret != 24 ]; then
 103                 warning "rsync $user failed"
 104                 warning "  returned: $ret"
 105                 let "failedcount = failedcount + 1"
 106                 if [ $failedcount -gt 100 ]; then
 107                         fatal "100 rsync errors -- something is not working right. bailing out."
 108                 fi
 109         fi
 110 }
 111
 112 # remove any maildirs from backup which might have been deleted
 113 # and add new ones which have just been created.
 114
 115 function do_remove() {
 116         local tmp1=`maketemp maildir-tmp-file`
 117         local tmp2=`maketemp maildir-tmp-file`
 118
 119         for i in a b c d e f g h i j k l m n o p q r s t u v w x y z; do
 120                 ls -1 "$srcdir/$i" | sort > $tmp1
 121                 ssh -p $destport $desthost ls -1 '$destdir/maildir/$i' | sort > $tmp2
 122                 for deluser in `join -v 2 $tmp1 $tmp2`; do
 123                         cmd="ssh -p $destport $desthost rm -vr '$destdir/maildir/$i/$deluser/'"
 124                         debug $cmd
 125                 done
 126         done
 127         rm $tmp1
 128         rm $tmp2
 129 }
 130
 131 function do_rotate() {
 132         backuproot=$destdir
 133
 134 (
 135         debug Connecting to $desthost
 136         ssh -T -o PasswordAuthentication=no $desthost -l $destuser <<EOF
 137 ##### BEGIN REMOTE SCRIPT #####
 138         seconds_daily=86400
 139         seconds_weekly=604800
 140         seconds_monthly=2628000
 141         keepdaily=$keepdaily
 142         keepweekly=$keepweekly
 143         keepmonthly=$keepmonthly
 144         now=\`date +%s\`
 145
 146         for rottype in daily weekly monthly; do
 147                 seconds=\$((seconds_\${rottype}))
 148
 149                 dir="$backuproot/\$rottype"
 150                 if [ ! -d \$dir.1 ]; then
 151                         echo "Info: \$dir.1 does not exist. This backup is missing, so we are skipping the rotation."
 152                         continue 1
 153                 elif [ ! -f \$dir.1/created ]; then
 154                         echo "Warning: \$dir.1/created does not exist. This backup may be only partially completed. Skipping rotation."
 155                         continue 1
 156                 fi
 157
 158                 # Rotate the current list of backups, if we can.
 159                 oldest=\`find $backuproot -type d -maxdepth 1 -name \$rottype'.*' | sed 's/^.*\.//' | sort -n | tail -1\`
 160                 echo "Debug: oldest \$oldest"
 161                 [ "\$oldest" == "" ] && oldest=0
 162                 for (( i=\$oldest; i > 0; i-- )); do
 163                         if [ -d \$dir.\$i ]; then
 164                                 if [ -f \$dir.\$i/created ]; then
 165                                         created=\`tail -1 \$dir.\$i/created\`
 166                                 else
 167                                         created=0
 168                                 fi
 169                                 cutoff_time=\$(( now - (seconds*(i-1)) ))
 170                                 if [ ! \$created -gt \$cutoff_time ]; then
 171                                         next=\$(( i + 1 ))
 172                                         if [ ! -d \$dir.\$next ]; then
 173                                                 echo "Debug: mv \$dir.\$i \$dir.\$next"
 174                                                 mv \$dir.\$i \$dir.\$next
 175                                                 date +%c%n%s > \$dir.\$next/rotated
 176                                         else
 177                                                 echo "Info: skipping rotation of \$dir.\$i because \$dir.\$next already exists."
 178                                         fi
 179                                 else
 180                                         echo "Info: skipping rotation of \$dir.\$i because it was created" \$(( (now-created)/86400)) "days ago ("\$(( (now-cutoff_time)/86400))" needed)."
 181                                 fi
 182                         fi
 183                 done
 184         done
 185
 186         max=\$((keepdaily+1))
 187         if [ \( \$keepweekly -gt 0 -a -d $backuproot/daily.\$max \) -a ! -d $backuproot/weekly.1 ]; then
 188                 echo mv $backuproot/daily.\$max $backuproot/weekly.1
 189                 mv $backuproot/daily.\$max $backuproot/weekly.1
 190                 date +%c%n%s > $backuproot/weekly.1/rotated
 191         fi
 192
 193         max=\$((keepweekly+1))
 194         if [ \( \$keepmonthly -gt 0 -a -d $backuproot/weekly.\$max \) -a ! -d $backuproot/monthly.1 ]; then
 195                 echo mv $backuproot/weekly.\$max $backuproot/monthly.1
 196                 mv $backuproot/weekly.\$max $backuproot/monthly.1
 197                 date +%c%n%s > $backuproot/monthly.1/rotated
 198         fi
 199
 200         for rottype in daily weekly monthly; do
 201                 max=\$((keep\${rottype}+1))
 202                 dir="$backuproot/\$rottype"
 203                 oldest=\`find $backuproot -type d -maxdepth 1 -name \$rottype'.*' | sed 's/^.*\.//' | sort -n | tail -1\`
 204                 [ "\$oldest" == "" ] && oldest=0
 205                 # if we've rotated the last backup off the stack, remove it.
 206                 for (( i=\$oldest; i >= \$max; i-- )); do
 207                         if [ -d \$dir.\$i ]; then
 208                                 if [ -d $backuproot/rotate.tmp ]; then
 209                                         echo "Info: removing $backuproot/rotate.tmp"
 210                                         rm -rf $backuproot/rotate.tmp
 211                                 fi
 212                                 echo "Info: moving \$dir.\$i to $backuproot/rotate.tmp"
 213                                 mv \$dir.\$i $backuproot/rotate.tmp
 214                         fi
 215                 done
 216         done
 217 ####### END REMOTE SCRIPT #######
 218 EOF
 219 ) | (while read a; do passthru $a; done)
 220
 221 }
 222
 223
 224 function setup_remote_dirs() {
 225         local backuptype=$1
 226         local dir="$destdir/$backuptype"
 227
 228 (
 229         ssh -T -o PasswordAuthentication=no $desthost -l $destuser <<EOF
 230                 if [ ! -d $destdir ]; then
 231                         echo "Fatal: Destination directory $destdir does not exist on host $desthost."
 232                         exit 1
 233                 elif [ -d $dir.1 ]; then
 234                         if [ -f $dir.1/created ]; then
 235                                 echo "Warning: $dir.1 already exists. Overwriting contents."
 236                         else
 237                                 echo "Warning: we seem to be resuming a partially written $dir.1"
 238                         fi
 239                 else
 240                         if [ -d $destdir/rotate.tmp ]; then
 241                                 mv $destdir/rotate.tmp $dir.1
 242                                 if [ \$? == 1 ]; then
 243                                         echo "Fatal: could mv $destdir/rotate.tmp $dir.1 on host $desthost"
 244                                         exit 1
 245                                 fi
 246                         else
 247                                 mkdir $dir.1
 248                                 if [ \$? == 1 ]; then
 249                                         echo "Fatal: could not create directory $dir.1 on host $desthost"
 250                                         exit 1
 251                                 fi
 252                                 for i in a b c d e f g h i j k l m n o p q r s t u v w y x z; do
 253                                         mkdir $dir.1/\$i
 254                                 done
 255                         fi
 256                         if [ -d $destdir/$backuptype.2 ]; then
 257                                 echo "Info: updating hard links to $dir.1. This may take a while."
 258                                 cp -alf $destdir/$backuptype.2/. $dir.1
 259                                 #if [ \$? == 1 ]; then
 260                                 #       echo "Fatal: could not create hard links to $dir.1 on host $desthost"
 261                                 #       exit 1
 262                                 #fi
 263                         fi
 264                 fi
 265                 [ -f $dir.1/created ] && rm $dir.1/created
 266                 [ -f $dir.1/rotated ] && rm $dir.1/rotated
 267                 exit 0
 268 EOF
 269 ) | (while read a; do passthru $a; done)
 270
 271         if [ $? == 1 ]; then exit; fi
 272 }
 273
 274 ###
 275 ##################################################################
 276
 277 ### ROTATE BACKUPS ###
 278
 279 if [ "$rotate" == "yes" ]; then
 280         do_rotate
 281 fi
 282
 283 ### REMOVE OLD MAILDIRS ###
 284
 285 if [ "$remove" == "yes" ]; then
 286         debug remove
 287 fi
 288
 289 ### MAKE BACKUPS ###
 290
 291 if [ "$backup" == "yes" ]; then
 292         if [ $keepdaily -gt 0 ]; then btype=daily
 293         elif [ $keepweekly -gt 0 ]; then btype=weekly
 294         elif [ $keepmonthly -gt 0 ]; then btype=monthly
 295         else fatal "keeping no backups"; fi
 296
 297         setup_remote_dirs $btype
 298
 299         for i in $letters; do
 300                 [ -d "$srcdir/$i" ] || fatal "directory $srcdir/$i not found."
 301                 cd "$srcdir/$i"
 302                 debug $i
 303                 for user in `ls -1`; do
 304                         if [ "$testuser" != "" -a "$testuser" != "$user" ]; then continue; fi
 305                         do_user $user $destdir/$btype.1
 306                 done
 307         done
 308
 309         ssh -o PasswordAuthentication=no $desthost -l $destuser "date +%c%n%s > $destdir/$btype.1/created"
 310 fi