hubknowledge.markdown

layout	title	categories	published	alias	tags
default	hubknowledge	Reference Functions hubknowledge	true	reference-functions-hubknowledge.html	reference communication functions functions hubknowledge

This function is only available in CFEngine Enterprise.

Prototype: hubknowledge(id)

Description: Read global knowledge from the CFEngine Database host by id.

This function is only available in CFEngine Enterprise. It is intended for use in distributed orchestration. It is recommended that you use this function sparingly with guards, as it contributes to network traffic and depends on the network for its function. Unlike remotescalar(), the value of hubknowledge is not cached.

This function behaves similarly to the remotescalar function, except that it always gets its information from the CFEngine Database by an encrypted connection. It is designed for spreading globally calibrated information about a CFEngine system back to the client machines. The data available through this channel are generated automatically by discovery, unlike remotescalar which accesses user defined data.

This function asks for an identifier. It is up to the server to interpret what this means and to return a value of its choosing. If the identifier matches a persistent scalar variable (such as is used to count distributed processes in CFEngine Enterprise) then this will be returned preferentially. If no such variable is found, then the server will look for a literal string in a server bundle with a handle that matches the requested object.

Return type: string

Arguments:

• id : identifier, in the range [a-zA-Z0-9_$(){}\[\].:]+

Example:

    vars:

      guard::

       "global_number" string => hubknowledge("number_variable");