Fix unhandled exception when REALM not present (#743)

* Fix unhandled exception when REALM not present

* Update use_cases.md

Author: CarolynRountree

core/src/main/python/wlsdeploy/tool/discover/topology_discoverer.py

@@ -358,7 +358,8 @@ def _slim_security_config(self, sc_dict):
         realm_dict = dictionary_utils.get_dictionary_element(sc_dict, model_constants.REALM)
         if 'myrealm' in realm_dict and dictionary_utils.is_empty_dictionary_element(realm_dict, 'myrealm'):
             del sc_dict[model_constants.REALM]['myrealm']
-        if dictionary_utils.is_empty_dictionary_element(sc_dict, model_constants.REALM):
+        if model_constants.REALM in sc_dict and \
+                dictionary_utils.is_empty_dictionary_element(sc_dict, model_constants.REALM):
             del sc_dict[model_constants.REALM]
         return sc_dict
 

site/use_cases.md

@@ -337,7 +337,9 @@
 
  **NOTE:** Creating and updating domains with custom security providers is limited to WebLogic version 12.1.2 and newer.
 
- Prior to using this tooling to create or update a domain with a custom security provider, there are several prerequisites.  First, WebLogic Server requires the custom MBean JAR to be in the Oracle Home directory before it can be configured, `WLSERVER/server/lib/mbeantypes`.  Second, WebLogic Scripting Tool, WLST, requires that the schema JAR be placed in the Oracle Home directory before WLST offline can be used to configure it, `ORACLEHOME/oracle_common/lib/schematypes`.  Generating an MBean JAR documentation can be found in the WebLogic Server [documentation](https://docs.oracle.com/en/middleware/standalone/weblogic-server/14.1.1.0/devsp/generate_mbeantype.html).  Generating the schema JAR can be done with the `prepareCustomProvider` script provided in the WebLogic Server installation.
+ Prior to using this tooling to create or update a domain with a custom security provider, there are several prerequisites.  First, WebLogic Server requires the custom MBean JAR to be in the Oracle Home directory before it can be configured, `WLSERVER/server/lib/mbeantypes`.  Second, WebLogic Scripting Tool, WLST, requires that the schema JAR be placed in the Oracle Home directory before WLST offline can be used to discover it or configure it, `ORACLEHOME/oracle_common/lib/schematypes`.  Generating an MBean JAR documentation can be found in the WebLogic Server [documentation](https://docs.oracle.com/en/middleware/standalone/weblogic-server/14.1.1.0/devsp/generate_mbeantype.html).  Generating the schema JAR can be done with the `prepareCustomProvider` script provided in the WebLogic Server installation.
+ 
+ WebLogic allows you to define an alternate directory other than `WLSERVER/server/lib/mbeantypes` by using the system property `-Dweblogic.alternateTypesDirectory=dir`. In order for the custom provider jars to be loaded correctly by WLST when discovering or configuring a domain, set this system property in the `WLSDEPLOY_PROPERTIES` environment variable.
 
  The format for a custom security provider is slightly different from a built-in provider in that the custom provider must supply the fully-qualified name of the class for the provider in the model between the provider name and the attributes for that provider.  Note that the generated Impl suffix is omitted from the name. In the custom `CredentialMapper` example below, note the location in the model of 'examples.security.providers.SampleCredentialMapper':