protected Map<String, String> readUserContext(Request request) {
    Map<String, String> userContext = new HashMap<>();
    if (null != getRequestProperty(request, USER_CONTEXT_OPERATION_PROPERTY)) {
      userContext.put(OPERATION_PROPERTY,
                      (String) getRequestProperty(request, USER_CONTEXT_OPERATION_PROPERTY));
    }
    if (null != getRequestProperty(request, USER_CONTEXT_OPERATION_DETAILS_PROPERTY)) {
      userContext.put(OPERATION_DETAILS_PROPERTY,
                      (String) getRequestProperty(request, USER_CONTEXT_OPERATION_DETAILS_PROPERTY));
    }
    return userContext;
  }
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