NAME

       snmpa_discovery_handler - Behaviour module for the SNMP agent discovery handler.

DESCRIPTION

       This  module  defines  the  behaviour of the agent discovery handler. A snmpa_discovery_handler compliant
       module must export the following functions:

         * stage1_finish/2

       The semantics of them and their exact signatures are explained below.

EXPORTS

       stage1_finish(TargetName, ManagerEngineID, ExtraInfo) -> ignore | {ok,  usm_entry()  |  [usm_entry()]}  |
       {ok, usm_entry() | [usm_entry()], NewExtraInfo}

              Types:

                 TargetName = string()
                 ManagerEngineID = string()
                 ExtraInfo = term()
                 usm_entry() = tuple() compatible with usm.conf
                 NewExtraInfo = term()

              This  function  is  called at the end of stage 1 of the discovery process. It should return either
              the atom ignore or {ok, usm_entry() | [usm_entry()]}. See usm_entry() and  usm_entry/13  for  more
              info.

              If the function returns ignore, then it is assumed that either:

                * The caller (of the discovery function) will make the needed updates later.

                * The callback function itself did the updates.

              In either case, the agent will do nothing, but return the retrieved ManagerEngineID (see discovery
              for more info) and possible continue with stage 2 of the discovery process.

              The ExtraInfo argument is passed on from the discovery function.

              This function may return an updated NewExtraInfo that will be used  in  subsequent  calls  to  the
              callback functions. Intended for future use.

              The  purpose  of  this  function  is  to  generate  the  usm- related security data needed for usm
              processing in the agent. Specifically, updating the usmUserTable.

              When an usm_entry() tuple (or a list of such tuples) is returned, this data is then added  to  the
              usmUserTable by the (master-) agent.

              When  an  usm_entry() tuple (or a list of such tuples) is returned, this data is then added to the
              usmUserTable by the (master-) agent.

          Note:
              Note that the function does not check if this entry already exists.

          Note:
              Note that this function is executed in the context of the master-agent process.