#!/bin/sh
# Installs a rollcall binary the rack controller staged (rollcall-rack-update.path).
# The rack checked the region's checksum and the binary's version; this checks
# them again, keeps the running binary as .prev, restarts the rack and puts the
# previous binary back if the rack does not register with the region in 60 s.
set -u
D=/var/lib/rollcall/update
BIN=/usr/local/bin/rollcall
[ -f "$D/ready" ] || exit 0
want=$(cat "$D/ready"); rm -f "$D/ready"
cd "$D" || exit 1
result() { echo "$(date -Is) $*" > "$D/last-result"; echo "$*"; }
sha256sum -c rollcall.new.sha256 >/dev/null 2>&1 || { result "$want: checksum mismatch, not installed"; exit 1; }
got=$(./rollcall.new version 2>/dev/null | awk '{print $2}')
[ "$got" = "$want" ] || { result "$want: binary reports '$got', not installed"; exit 1; }
cur=$("$BIN" version 2>/dev/null | awk '{print $2}')
cp -p "$BIN" "$BIN.prev"
install -m 0755 rollcall.new "$BIN.tmp" && mv -f "$BIN.tmp" "$BIN"
since=$(date +%s)
systemctl restart rollcall-rack.service
for _ in $(seq 1 30); do
  sleep 2
  if journalctl -u rollcall-rack.service --since "@$since" -o cat 2>/dev/null | grep -q "^.*registered with"; then
    rm -f rollcall.new rollcall.new.sha256
    result "updated $cur -> $want"
    exit 0
  fi
done
cp -p "$BIN.prev" "$BIN.tmp" && mv -f "$BIN.tmp" "$BIN"
systemctl restart rollcall-rack.service
result "$want did not register within 60s; rolled back to $cur"
exit 1