handlers/maildir

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