问shell脚本怎样判断tomcat已经完全启动(docker)？

#!/bin/sh
# wait-for-tomcat.sh

set -e

host="$1"
shift
cmd="$@"

until 
  ...这里应该怎么写
  do
  >&2 echo "tomcat is unavailable - sleeping"
  sleep 1
done

>&2 echo "tomcat is up - executing command"
exec $cmd