#!/usr/bin/env bash
set -Eeuo pipefail

require_var() {
  local name="$1"
  if [ -z "${!name:-}" ]; then
    printf 'Required environment variable %s is missing\n' "$name" >&2
    exit 2
  fi
}

require_var ENVIRONMENT
require_var STACK_NAME

LOCK_FILE="${RELEASE_LOCK_FILE:-/tmp/${STACK_NAME}-${ENVIRONMENT}.lock}"
exec 9>"$LOCK_FILE"
flock -n 9 || {
  echo "Another deployment operation is already running for ${STACK_NAME}/${ENVIRONMENT}" >&2
  exit 75
}

printf '{"event":"rollback_start","environment":"%s","stack":"%s"}\n' "$ENVIRONMENT" "$STACK_NAME"
docker service rollback "${STACK_NAME}_web" || true
printf '{"event":"rollback_requested","environment":"%s","stack":"%s"}\n' "$ENVIRONMENT" "$STACK_NAME"