====== mqtt ======

===== mosquitto =====
==== install ====
  sudo apt-get install mosquitto mosquitto-clients

==== 設定 ====
https://mosquitto.org/man/mosquitto-conf-5.html

/etc/mosquitto/conf.d/mymqtt.conf
  listener  1883
  listener 11883
  protocol websockets 
  #allow_anonymous false
  #password_file /etc/mosquitto/conf.d/passwd.txt

=== passwordファイルの暗号化 ===
  mosquitto_passwd -U passwd.txt