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

   1 #!/bin/bash
   2
   3 source /usr/local/lib/err
   4
   5 usage() {
   6   cat <<EOF
   7 Usage: ${0##*/} push|pull HOST
   8
   9 Turn off mail receiving on OLD_HOST, run btrbk to move mail to NEW_HOST,
  10 turn on mail receiving on NEW_HOST.  Assumes we want to move all
  11 filesystems unless passing -o.
  12
  13 -o         Only btrbk /o, instead of all filesystems.
  14 -h|--help  Print help and exit.
  15
  16 I used to adjust home network dns so NEW_HOST resolves locally if it is
  17 on the local network, but its simpler just not to and just rely
  18 on the internet. Email can wait.
  19
  20 Note: Uses GNU getopt options parsing style
  21 EOF
  22   exit $1
  23 }
  24
  25 restore_new_btrbk=false
  26 restore_old_btrbk=false
  27 err-cleanup() {
  28   if $restore_new_btrbk; then
  29     e WARNING: due to failure, btrbk.timer may need manual restoration:
  30     e $new_shell sudo systemctl start btrbk.timer
  31   fi
  32   if $restore_old_btrbk; then
  33     e WARNING: due to failure, btrbk.timer may need manual restoration:
  34     e $old_shell sudo systemctl start btrbk.timer
  35   fi
  36 }
  37
  38 pre="${0##*/}:"
  39 m() { printf "$pre %s\n"  "$*"; "$@"; }
  40 e() { printf "$pre %s\n"  "$*"; }
  41 err() { echo "$pre ERROR: $*" >&2; }
  42 mexit() { echo "$pre exiting with status $1"; exit $1; }
  43
  44 ##### begin command line parsing ########
  45
  46 force=false
  47 mp_args="-m /o,/q,/a"
  48 temp=$(getopt -l force,help owh "$@") || usage 1
  49 eval set -- "$temp"
  50 while true; do
  51   case $1 in
  52     --force) force=true ;;
  53     -o) mp_args="-m /o"; shift ;;
  54     -h|--help) usage ;;
  55     --) shift; break ;;
  56     *) echo "$0: Internal error! unexpected args: $*" ; mexit 1 ;;
  57   esac
  58 done
  59
  60
  61 (( $# == 2 )) || usage 1
  62
  63 if [[ ! $HOSTNAME ]]; then
  64   err '$HOSTNAME is unset'
  65   mexit 1
  66 fi
  67
  68 case $1 in
  69   push)
  70     old_host=$HOSTNAME
  71     old_hostname=$HOSTNAME
  72     new_host=$2
  73     bbk_args="-t $new_host"
  74     new_shell="ssh $new_host"
  75     new_hostname=$($new_shell hostname)
  76     ;;
  77   pull)
  78     old_host=$2
  79     new_host=$HOSTNAME
  80     new_hostname=$HOSTNAME
  81     bbk_args="-s $old_host"
  82     old_shell="ssh $old_host"
  83     # tests ssh connection
  84     old_hostname=$($old_shell hostname)
  85     ;;
  86   *)
  87     err invalid first argument
  88     mexit 1
  89     ;;
  90 esac
  91
  92 source /a/bin/bash_unpublished/source-state
  93
  94 if [[ $old_hostname != "$MAIL_HOST" ]] && ! $force; then
  95   err "\$old_hostname($old_hostname) != \$MAIL_HOST($MAIL_HOST). Rerun with --force if you really want this."
  96   mexit 1
  97 fi
  98
  99 if [[ ! $new_host || ! $old_host ]]; then
 100   echo "$0: bad args. see script"
 101   mexit 1
 102 fi
 103
 104
 105 ########### end initial processing, begin actually modifying things ##########
 106
 107 if $new_shell systemctl is-active btrbk.timer; then
 108   m $new_shell sudo systemctl stop btrbk.timer
 109   restore_new_btrbk=true
 110 fi
 111 if $old_shell systemctl is-active btrbk.timer; then
 112   m $old_shell sudo systemctl stop btrbk.timer
 113   restore_old_btrbk=true
 114 fi
 115
 116 btrbk_test="systemctl is-active btrbk.service"
 117 active=true
 118 while $active; do
 119   active=false
 120   for shell in "$new_shell" "$old_shell"; do
 121     e $shell $btrbk_test
 122     status=$($shell $btrbk_test) ||:
 123     case $status in
 124       inactive|failed) : ;;
 125       *)
 126         # This covers conditions like "activating", which still return 3 from
 127         # systemctl is-active.
 128         active=true
 129         e "btrbk active on shell:$shell, status:$status, sleeping 8 seconds"
 130         sleep 8
 131         break
 132         ;;
 133     esac
 134   done
 135 done
 136
 137 # ensure these are unused before doing anything
 138
 139 e "umounting /m and /o via $new_shell"
 140 $new_shell bash -xs <<'EOF'
 141 set -eE
 142 if mountpoint -q /m; then sudo umount /m; fi
 143 if mountpoint -q /o; then sudo umount /o; fi
 144 EOF
 145
 146 # previously, I was checking to see if the new mail host
 147 # is on my home network, then changing my home dns
 148 # to resolve on the local network, so that I didnt
 149 # have to send traffic out to the internet or rely
 150 # on that. However, that breaks for a laptop that roams.
 151 # So, we could have a cronjob that updates that dns,
 152 # however, another solution is to just use ipv6,
 153 # and I prefer that.
 154 #
 155 # TODO: enable ipv6 for email. exim config setting disables it.
 156 # need to add vpn support. need to add firewall / routing.
 157 # I think exim will try ipv6 first, so no need to disable
 158 # ipv6 i think.
 159
 160
 161 e Running initial btrbk
 162 if ! m btrbk-run -v $bbk_args $mp_args; then
 163   ret=$?
 164   err "failed initial btrbk"
 165   mexit $ret
 166 fi
 167
 168 m $old_shell /a/exe/primary-setup $new_hostname
 169
 170 e Running main btrbk
 171 m btrbk-run -v $bbk_args -m /o || ret=$?
 172 if (( ret )); then
 173   bang="$(printf "$(tput setaf 5)█$(tput sgr0)%.0s" 1 2 3 4 5 6 7)"
 174   e $bang failed btrbk of /o. restoring old host as primary
 175   m $old_shell /a/exe/primary-setup localhost
 176   mexit $ret
 177 fi
 178
 179 m $new_shell /a/exe/primary-setup localhost
 180
 181 mexit 0