Module devicetree This module allows to access the ReadyAgent tree.
This tree is local to the ReadyAgent, and contains a set of variables identified by their paths. These variables can be read, and for some of them written, to determine or change the device's state. Applications can also register to be notified whenever the value of a variable--or of a set of variables--changes.

The list of all variables and their meaning is partially device-dependent, and is given in a separate document.

Type devicetree

devicetree.get(path) Retrieves a variable value from the ReadyAgent variable tree.
devicetree.init() Initialize the module.
devicetree.register(regvars, callback, passivevars) Registers to receive a notification when one or multiple variables change.
devicetree.set(path, value) Sets a variable value into the ReadyAgent variable tree.
devicetree.unregister(userid) Cancels registration to receive a notification when a variable changes.

Type devicetree

Field(s)

devicetree.get(path)

Retrieves a variable value from the ReadyAgent variable tree.
The retrieval is not recursive. Returns the retrieved value if is not a table. If the value is a table, returns nil followed by a list of paths to each child.

Parameter

Return values

  1. the value associated with the path leaf node.
  2. nil + list of direct children paths when path is a non-leaf node.
  3. nil + error string otherwise.

Usage:

devicetree.init()

Initialize the module.

Return values

  1. non-nil upon success;
  2. nil + error message upon failure.

devicetree.register(regvars, callback, passivevars)

Registers to receive a notification when one or multiple variables change.
The callback is triggered everytime one or some of the variables listed in regvars changes. It receives as parameter a table of variable-name / variable-value pairs; these variables are all the variables listed in regvars which have changed, plus every variables listed in passivevars, whether their values changed or not.

Please note that the callback can be called with table param
containing niltoken#niltoken value(s) to indicate variable(s) deletion.

Variables listed in regvars and passivevars can be either FQVN names, or a path which denotes every individual variable below this path.

Parameters

Return values

  1. a registration id, to be passed to devicetree.unregister in order to unsubscribe.
  2. nil + error message in case of error.

devicetree.set(path, value)

Sets a variable value into the ReadyAgent variable tree.

Example: to activate the monitoring, you could send:

 devicetree.set ("config.monitoring.activate", true).



		
Parameters

		
		
Return values

			
    
				
  1. 
				"ok" on success.
				
    2. 
				
  2. 
				nil followed by an error message otherwise.
				
    3. 
			



		



devicetree.unregister(userid)



	 Cancels registration to receive a notification when a variable changes.
	



		
Parameter

		
		
Return values

			
    
				
  1. 
				"ok" on success.
				
    2. 
				
  2. 
				nil + error string otherwise.
				
    3.