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     ssh_prefix=ssh
  41 else
  42     localhost_new=false
  43     ssh_prefix=
  44 fi
  45 if [[ ! $new_host || ! $old_host ]]; then
  46     echo "$0: bad args. see script"
  47     exit 1
  48 fi
  49
  50 at_home=false
  51 if timeout -s 9 10 ssh root@wrt.lan :; then
  52     at_home=true
  53 fi
  54
  55 source /a/bin/bash_unpublished/source-semi-priv
  56 #### begin convert private hostnames to public hostnames ####
  57 if ! $at_home; then
  58     for var in old_host new_host; do
  59         case ${!var} in
  60             treetowl)
  61                 eval $var=$HOME_DOMAIN
  62                 ;;
  63         esac
  64     done
  65 fi
  66 ####  end convert private hostnames to public hostnames ####
  67
  68
  69 # because our port forward is not robust enough, we can't use proxy command,
  70 # todo: just open an ssh port to the world on wrt
  71 if ! $at_home; then
  72     ssh_cmd="ssh $HOME_DOMAIN ssh wrt"
  73 else
  74     ssh_cmd="ssh wrt"
  75 fi
  76 # if new_host is not on home network, make mail.iankelling.org not resolve
  77 # on the home network.
  78 if [[ $new_host == $HOSTNAME ]] && ! $at_home; then
  79     echo | $ssh_cmd cedit mail_host /etc/hosts
  80 else
  81     $ssh_cmd bash -s <<EOFOUTER
  82     cedit mail_host /etc/hosts <<'EOF' || /etc/init.d/dnsmasq restart
  83 \$(grep "\b$new_host\b" /etc/hosts | awk '{print $1}') mail.iankelling.org
  84 EOF
  85 EOFOUTER
  86 fi
  87
  88 mail-setup() {
  89     shell="$1"
  90     $shell sed -ri "s/MAIL_HOST=.*/MAIL_HOST=$new_host/" /a/bin/bash_unpublished/source-semi-priv
  91     $shell /a/bin/distro-setup/mail-setup exim4
  92 }
  93
  94 mail-setup "ssh $old_host"
  95
  96 sudo dd of=/etc/btrbk.conf <<'EOF'
  97 ssh_identity /root/.ssh/id_rsa
  98 # Just a guess that local7 is a good facility to pick.
  99 # It's a bit odd that the transaction log has to be logged to
 100 # a file or syslog, while other output is sent to std out.
 101 # The man does not mention a way for them to be together, but
 102 # I dunno if setting a log level like warn might also output
 103 # transaction info.
 104 transaction_syslog local7
 105
 106 # so we only run one at a time
 107 lockfile                   /var/lock/btrbk.lock
 108
 109 # default format of short does not accomidate hourly preservation setting
 110 timestamp_format long-iso
 111
 112 # only make a snapshot if things have changed
 113 snapshot_create onchange
 114 # I could make this different from target_preserve,
 115 # if one disk had less space.
 116 # for now, keeping them equal.
 117 snapshot_preserve 36h 14d 8w 24m
 118 snapshot_preserve_min 4h
 119 snapshot_dir btrbk
 120
 121 # so, total backups = ~89
 122 target_preserve 36h 14d 8w 24m
 123 target_preserve_min 4h
 124
 125 # if something fails and it's not obvious, try doing
 126 # btrbk -l debug -v dryrun
 127
 128
 129 EOF
 130
 131
 132 if $localhost_new; then
 133     btrbk_src=ssh://$old_host/mnt/root
 134     btrbk_dst=/mnt/root/btrbk
 135 else
 136     btrbk_src=/mnt/root
 137     btrbk_dst=ssh://$old_host/mnt/root/btrbk
 138 fi
 139
 140 sudo tee -a /etc/btrbk.conf <<EOF
 141 volume $btrbk_src
 142 subvolume o
 143 target send-receive $btrbk_dst
 144 EOF
 145
 146
 147 sudo btrbk --progress run
 148 $ssh_prefix $new_host mount-latest-subvol
 149
 150 mail-setup