hub: 
  clientid: Client ID of Client connection Hub. It should not be empty when cleansession is false. 
  address: [Must] Address of Client connection Hub. 
  username: [Must] User name of Client connection Hub. 
  password:If you use account password, you must fill out the password of Client connection Hub, outherwise you do not need to fill out it. 
  ca: If certificate two-way authentication is adopted, the CA certificate path of Client connection Hub should be filled out. 
  key: If certificate two-way authentication is adopted, the client private key path of Client connection Hub should be filled out. 
  cert: If certificate two-way authentication is adopted, the client public key path of Client connection Hub should be filled out. 
  timeout: Default value: 30s, Time-out period of Client connection Hub 
  interval: Default value: 1m, Maximum interval time for reconnection of Client connection Hub, increasing to the maximum value from 500 microseconds by doubling. 
  keepalive: Default value: 1m, Holding time of Client connection Hub 
  cleansession: Default value: false, Session persistence of Client connection Hub or not. 
  validatesubs: Default value: false, Client checks Hub subscription result or not; exit after reporting of error in case of subscription failure discovered. 
  buffersize: Default value: 10, Size of memory queue for Client to send messages to Hub; message loss can be caused by abnormal exit, and the messages with QoS = 1 will depend on Hub to resend. 
rules: Routing rule configuration items 
  - clientid: Client ID of Client connection Hub 
    subscribe: 
      topic: [Must] Message subject inscribed by Client from Hub 
      qos: Default value: 0, Message QoS inscribed by Client from Hub 
    function: 
      name: [Must]Function name for message handling 
    publish: 
      topic: [Must] Calculation result published to the Hub subject 
      qos:Default value: 0, QoS of Hub published in the calculation result. 
    retry: 
      max: Default value: 3, Maximum number of retries 
functions: Function list. 
  - name: [Must] Function name, unique in the list 
    service: [Must] Provide the service name of function instance 
    instance: Instance configuration item. 
      min:Default value: 0, Minimum number of instances 
      max:Default value: 1, Maximum number of instances 
      idletime: Default value: 10m, Maximum idle time of instance 
      evicttime: Default value: 1m, Instance check cycle; destroy in case of idle time of instance is discovered to be exceeded. 
    message: 
      length: 
        max: Default value: 4m, Maximum message length allowed to receive/send by function instance. 
    backoff: 
      max: Default value: 1m, Maximum reconnection interval of Client connection function instance. 
    timeout: Default value: 30s, Time-out period of client connection function instance.