Mosquitto database

mosquitto.conf中，開啟
# Persistence

# Logging

以下的註解

Error: Invalid user 'mosquitto'.
-->> useradd mosquitto
##創造使用者

1466750350: Saving in-memory database to /var/lib/mosquitto/mosquitto.db.
1466750350: Error saving in-memory database, unable to open /var/lib/mosquitto/mosquitto.db.new for writing.
1466750350: Error: Permission denied.

-->> cche@ubuntu:/var/lib$ sudo chown mosquitto:mosquitto mosquitto

##把它資料夾所有者改成mosquitto

But, database of Mosquitto created can't provide look up (what's it can do??)

So, We will maybe do second dev. from Mosquitto,

doing..

1. Subscribe appoing topic.
2. Daliy system to subscribe topic.
3. A process subscribe and processing data, and sent to B process.