iankelling.org Git - distro-setup/blob - switch-mail-host

   1 #!/bin/bash
   2 set -x
   3 set -eE -o pipefail
   4 trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" returned $?" >&2' ERR
   5
   6 usage() {
   7     cat <<EOF
   8 Usage: ${0##*/} OLD_HOST NEW_HOST
   9
  10 Adjust home network dns so NEW_HOST resolves locally if it is on the
  11 local network.  Turn off mail receiving on OLD_HOST, run btrbk to move
  12 mail to NEW_HOST, turn on mail receiving on NEW_HOST.
  13
  14
  15 -h|--help  Print help and exit.
  16
  17 Note: Uses GNU getopt options parsing style
  18 EOF
  19     exit $1
  20 }
  21
  22 ##### begin command line parsing ########
  23
  24 if (( $# != 2 )) || [[ $1 == -* || $2 == -* ]]; then
  25     usage 1
  26 fi
  27
  28 old_host=$1
  29 new_host=$2
  30
  31 if [[ $old_host != $MAIL_HOST ]]; then
  32     read -p "warning: \$old_host != \$MAIL_HOST: $old_host != $MAIL_HOST, proceed? y/N "
  33     if [[ $REPLY != [yY] ]]; then
  34         exit 1
  35     fi
  36 fi
  37
  38 if [[ $new_host == "$HOSTNAME" ]]; then
  39     localhost_new=true
  40     new_shell="ssh $new_host"
  41 else
  42     localhost_new=false
  43     new_shell=
  44 fi
  45
  46 old_shell=
  47 if [[ $old_host == "$HOSTNAME" ]]; then
  48     old_shell="ssh $old_host"
  49 fi
  50
  51 if [[ ! $new_host || ! $old_host ]]; then
  52     echo "$0: bad args. see script"
  53     exit 1
  54 fi
  55
  56 at_home=false
  57 if [[ $HOSTNAME == treetowl ]] || [[ $HOSTNAME == frodo ]] || timeout -s 9 5 ssh wrt.lan :; then
  58     at_home=true
  59 fi
  60 echo "$0: at_home = $at_home"
  61
  62 source /a/bin/bash_unpublished/source-semi-priv
  63 #### begin convert private hostnames to public hostnames ####
  64 if ! $at_home; then
  65     for var in old_host new_host; do
  66         case ${!var} in
  67             treetowl)
  68                 eval $var=$HOME_DOMAIN
  69                 ;;
  70         esac
  71     done
  72 fi
  73 ####  end convert private hostnames to public hostnames ####
  74
  75
  76 # because our port forward is not robust enough, we can't use proxy command,
  77 # todo: just open an ssh port to the world on wrt.lan
  78 if ! $at_home; then
  79     wrt_shell="ssh $HOME_DOMAIN ssh wrt.lan"
  80 else
  81     wrt_shell="ssh wrt.lan"
  82 fi
  83
  84 btrbk_test="systemctl is-active btrbk.service"
  85 while ! $new_shell $btrbk_test || $old_shell $btrbk_test; do
  86     echo "$0: btrbk is running on new or old host. sleeping for 8 seconds"
  87     sleep 6
  88     echo "$0: testing for btrbk activity in 2 seconds"
  89     sleep 2
  90 done
  91
  92 ########### end initial processing, begin actually modifying things ##########
  93
  94 restore_new_btrbk=false
  95 if $new_shell systemctl is-active btrbk.timer; then
  96     $new_shell sudo systemctl stop btrbk.timer
  97     restore_new_btrbk=true
  98 fi
  99 restore_old_btrbk=false
 100 if $old_shell systemctl is-active btrbk.timer; then
 101     $old_shell sudo systemctl stop btrbk.timer
 102     restore_old_btrbk=true
 103 fi
 104
 105 $new_shell bash -s <<'EOF'
 106 set -eE
 107 if mountpoint /m; then sudo umount /m; fi
 108 if mountpoint /o; then sudo umount /o; fi
 109 EOF
 110
 111 # if new_host is not on home network, make mail.iankelling.org not resolve
 112 # on the home network.
 113 if [[ $new_host == $HOSTNAME ]] && ! $at_home; then
 114     echo | $wrt_shell cedit mail_host /etc/hosts || [[ $? == 1 ]] # 1 means file changed.
 115 else
 116     $wrt_shell bash -s <<EOFOUTER
 117     cedit mail_host /etc/hosts <<'EOF' || /etc/init.d/dnsmasq restart
 118 \$(grep "\b$new_host\b" /etc/hosts | awk '{print $1}') mail.iankelling.org
 119 EOF
 120 EOFOUTER
 121 fi
 122
 123 mail-setup() {
 124     shell="$1"
 125     $shell sed -ri "s/MAIL_HOST=.*/MAIL_HOST=$new_host/" /a/bin/bash_unpublished/source-semi-priv
 126     $shell /a/bin/distro-setup/mail-setup exim4
 127 }
 128
 129 mail-setup "$old_shell"
 130
 131 sudo dd of=/etc/btrbk.conf <<'EOF'
 132 ssh_identity /root/.ssh/id_rsa
 133 # Just a guess that local7 is a good facility to pick.
 134 # It's a bit odd that the transaction log has to be logged to
 135 # a file or syslog, while other output is sent to std out.
 136 # The man does not mention a way for them to be together, but
 137 # I dunno if setting a log level like warn might also output
 138 # transaction info.
 139 transaction_syslog local7
 140
 141 # so we only run one at a time
 142 lockfile                   /var/lock/btrbk.lock
 143
 144 # default format of short does not accomidate hourly preservation setting
 145 timestamp_format long-iso
 146
 147 # only make a snapshot if things have changed
 148 snapshot_create onchange
 149 # I could make this different from target_preserve,
 150 # if one disk had less space.
 151 # for now, keeping them equal.
 152 snapshot_preserve 36h 14d 8w 24m
 153 snapshot_preserve_min 4h
 154 snapshot_dir btrbk
 155
 156 # so, total backups = ~89
 157 target_preserve 36h 14d 8w 24m
 158 target_preserve_min 4h
 159
 160 # if something fails and it's not obvious, try doing
 161 # btrbk -l debug -v dryrun
 162
 163
 164 EOF
 165
 166
 167 if $localhost_new; then
 168     btrbk_src=ssh://$old_host/mnt/root
 169     btrbk_dst=/mnt/root/btrbk
 170 else
 171     btrbk_src=/mnt/root
 172     btrbk_dst=ssh://$old_host/mnt/root/btrbk
 173 fi
 174
 175 sudo tee -a /etc/btrbk.conf <<EOF
 176 volume $btrbk_src
 177 subvolume o
 178 target send-receive $btrbk_dst
 179 EOF
 180
 181
 182 sudo btrbk --progress run
 183 $new_shell mount-latest-subvol
 184
 185 mail-setup
 186
 187 if $restore_new_btrbk; then
 188     $new_shell sudo systemctl start btrbk.timer
 189 fi
 190 if $restore_old_btrbk; then
 191     $old_shell sudo systemctl start btrbk.timer
 192 fi