protected Object getRequestProperty(Request request, String propertyName) {
    for (Map<String, Object> propertyMap : request.getProperties()) {
      if (propertyMap.containsKey(propertyName)) {
        return propertyMap.get(propertyName);
      }
    }
    return null;
  }
Parse the user contex for the call. Typical structure
{ "operation" : "createCluster" }
{ "operation" : "addService", "services" : "Atlas,Ranger" }
@param request
@return
ambari-server/src/main/java/org/apache/ambari/server/controller/internal/StackAdvisorResourceProvider.java