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 $1; }
  43
  44 ##### begin command line parsing ########
  45
  46 temp=$(getopt -l help owh "$@") || usage 1
  47 mp_args="-m /o,/q,/a"
  48 eval set -- "$temp"
  49 while true; do
  50   case $1 in
  51     -o) mp_args="-m /o"; shift ;;
  52     -h|--help) usage ;;
  53     --) shift; break ;;
  54     *) echo "$0: Internal error! unexpected args: $*" ; mexit 1 ;;
  55   esac
  56 done
  57
  58
  59 (( $# == 2 )) || usage 1
  60
  61 if [[ ! $HOSTNAME ]]; then
  62   err '$HOSTNAME is unset'
  63   mexit 1
  64 fi
  65
  66 case $1 in
  67   push)
  68     old_host=$HOSTNAME
  69     new_host=$2
  70     bbk_args="-s $old_host"
  71     new_shell="ssh $new_host"
  72     new_hostname=$($new_shell hostname)
  73     ;;
  74   pull)
  75     old_host=$2
  76     new_host=$HOSTNAME
  77     new_hostname=$HOSTNAME
  78     bbk_args="-t $new_host"
  79     bbk_args="-s $old_host"
  80     old_shell="ssh $old_host"
  81     # test ssh connection
  82     $old_shell :
  83     ;;
  84   *)
  85     err invalid first argument
  86     mexit 1
  87     ;;
  88 esac
  89
  90 source /a/bin/bash_unpublished/source-state
  91
  92 if [[ $old_host != "$MAIL_HOST" ]]; then
  93   e "WARNING: \$old_host != \$MAIL_HOST. Sleeping for 5 seconds in case you want to reconsider"
  94   sleep 5
  95 fi
  96
  97 if [[ ! $new_host || ! $old_host ]]; then
  98   echo "$0: bad args. see script"
  99   mexit 1
 100 fi
 101
 102
 103 ########### end initial processing, begin actually modifying things ##########
 104
 105 if $new_shell systemctl is-active btrbk.timer; then
 106   m $new_shell sudo systemctl stop btrbk.timer
 107   restore_new_btrbk=true
 108 fi
 109 if $old_shell systemctl is-active btrbk.timer; then
 110   m $old_shell sudo systemctl stop btrbk.timer
 111   restore_old_btrbk=true
 112 fi
 113
 114 btrbk_test="systemctl is-active btrbk.service"
 115 while true; do
 116   for shell in "$new_shell" "$old_shell"; do
 117     e $shell $btrbk_test
 118     status=$($shell $btrbk_test) ||:
 119     case $status in
 120       inactive|failed) : ;;
 121       *)
 122         e "btrbk active on shell:$shell, status:$status, sleeping 8 seconds"
 123         sleep 8
 124         continue
 125         ;;
 126     esac
 127   done
 128   break
 129 done
 130
 131 # ensure these are unused before doing anything
 132
 133 e "umounting /m and /o via $new_shell"
 134 $new_shell bash -xs <<'EOF'
 135 set -eE
 136 if mountpoint -q /m; then sudo umount /m; fi
 137 if mountpoint -q /o; then sudo umount /o; fi
 138 EOF
 139
 140 # previously, I was checking to see if the new mail host
 141 # is on my home network, then changing my home dns
 142 # to resolve on the local network, so that I didnt
 143 # have to send traffic out to the internet or rely
 144 # on that. However, that breaks for a laptop that roams.
 145 # So, we could have a cronjob that updates that dns,
 146 # however, another solution is to just use ipv6,
 147 # and I prefer that.
 148 #
 149 # TODO: enable ipv6 for email. exim config setting disables it.
 150 # need to add vpn support. need to add firewall / routing.
 151 # I think exim will try ipv6 first, so no need to disable
 152 # ipv6 i think.
 153
 154
 155 e Running initial btrbk
 156 if ! m btrbk-run -v $bbk_args $mp_args; then
 157   ret=$?
 158   err "failed initial btrbk"
 159   mexit $ret
 160 fi
 161
 162 m $old_shell /a/exe/primary-setup $new_hostname
 163
 164 e Running main btrbk
 165 if ! m btrbk-run -v $bbk_args -m /o; then
 166   ret=$?
 167   bang="$(printf "$(tput setaf 5)█$(tput sgr0)%.0s" 1 2 3 4 5 6 7)"
 168   e $bang failed btrbk of /o. restoring old host as primary
 169   m $old_shell /a/exe/primary-setup localhost
 170   mexit $ret
 171 fi
 172
 173 m $new_shell /a/exe/primary-setup localhost
 174
 175 mexit 0