Update the Agency Scope of a Solution

You define the ESX agency scope of a solution by passing the managed object references (MoRefs) of the vSphere compute resources to the solution.

You set the initial ESX agency scope in the scope property of the AgencyConfigInfo object. You can change the scope when a solution runs by calling the Agency.update() method. For example, in the EAM Sample Solution, users select the ESXi hosts on which to run the solution from a list on the EAM Sample Solution Configuration page. The EAM Sample Solution updates the scope of the sample ESX agency according to the hosts that the user selects.

The EAM Sample Solution defines a function to update the scope of the ESX agency in the AgentHandler.java class.

Prerequisites

Download the vSphere ESX Agent Manager SDK.
Verify that you have set up and started the EAM Sample Solution in an application server.
Verify that you have opened eam_work_folder\src\com\vmware\eam\sample\solution\AgentHandler.java in an editor.
Open eam_work_folder\src\com\vmware\eam\sample\solution\utils\VcUtilsjava in an editor.

Procedure

Write a function that implements the vSphere Web Services API to detect compute resources on which to run the solution.
The EAM Sample Solution provides a helper class, VcUtils.java, that defines functions to obtain the compute resources on which to run the solution. AgentHandler.java calls the VcUtils.getComputeResources() method to obtain a list of ManagedObjectReference objects for the ESXi hosts running in vCenter Server.
```
public void updateConfig(String[] updates) throws RuntimeFaultFaultMsg {
   waitForSetup();

   boolean changed = false;
   Map<String, ManagedObjectReference> crs = _vcUtils.getComputeResources();
```

Add the ManagedObjectReference objects for the compute resources to a HashSet that defines the ESX agency scope.

The AgentHandler.java class adds the list of ManagedObjectReference objects that the VcUtils.getComputeResources() method returns to the existing scope and updates the list if additional compute resources are present.

   Set<ManagedObjectReference> newScope = new HashSet<ManagedObjectReference>();

   for (String update : updates) {
       String[] kv = update.split("=", 2);
       if (kv[0].equals("scope")) {
         try { 
            ManagedObjectReference cr = crs.get(kv[1]);
            if (cr == null) {
              continue; 
            }
            ManagedObjectReference moRef = new ManagedObjectReference();
            moRef.setType(cr.getType());
            moRef.setValue(cr.getValue());
            newScope.add(moRef);
         }
          catch (NullPointerException e) {
              // ignore 
         }
       } 
   }

Create an AgencyComputeResourceScope instance to contain the scope HashSet.

   AgencyComputeResourceScope scopeDO = (AgencyComputeResourceScope) _agencyConfigInfo.getScope();
   Set<ManagedObjectReference> oldScope = new HashSet<ManagedObjectReference>(scopeDO.getComputeResource());

Compare the old scope to the new scope to establish whether any compute resources have been added or removed.
The AgentHandler.java class compares the size of the new scope to the initial scope and adds any new compute resources to the HashSet of ManagedObjectReference objects.
```
   if (!oldScope.containsAll(newScope) || oldScope.size() != newScope.size()) {
      AgencyComputeResourceScope scope = new AgencyComputeResourceScope();
      scope.getComputeResource().addAll(newScope);
      agencyConfigInfo.setScope(scope);
      changed = true;
   }
```

If the new scope differs from the old scope, call Agency.update() to add the new scope to the ESX agency.

   if (changed) {
     assert _agency != null;
     try {
        _eamConnection.getStub().update(_agency, agencyConfigInfo);
     } catch (Exception e) {
      _log.error("Failed to update agency. Reason: " + e.getMessage());
     }
     updateConfiguration();
   } 
}

Results

You defined a function in a solution to detect changes of scope and to update an ESX agency.