change to support thanos exit messages if arg parsing fails

Former-commit-id: f11960b6e74fb2521f47ead4c222f39dc64fb923

tools/thanos/thanos.cpp

@@ -121,7 +121,7 @@ int main(int argc, char* argv[])
 			thanos_log << "A critical step failed: " << plugin->getStepName() << endl;
 			thanos_log << "If DEBUG_STEPS is not on, this failure could "
 			     << "be due to an earlier critical step." << endl;	 
-			return 1; // critical step failed, abort
+			return 2; // critical step failed, abort
 		}
 	}
 	// write back final changes
@@ -132,7 +132,7 @@ int main(int argc, char* argv[])
 		     << endl;
                 thanos_log << "If DEBUG_STEPS is not on, this failure could "
                      << "be due to an earlier critical step." << endl;
-                return 1; // critical step failed, abort
+                return 2; // critical step failed, abort
 	}
 	else
 	{
@@ -299,6 +299,16 @@ int ThanosPlugin_t::executeStep(TransformStep_t& the_step, const bool are_debugg
 	const int parse_retval = the_step.parseArgs(step_args);
 	if(parse_retval != 0)
 	{
+		if(step_optional)
+		{
+
+                        *real_cout<<"Done.  Command failed! ***************************************"<<endl;
+		}
+		else
+		{
+                        *real_cout<<"Done.  Command failed! ***************************************"<<endl;
+                        *real_cout<<"ERROR: The "<<the_step.getStepName()<<" step is necessary, but failed.  Exiting early."<<endl;
+		}
 		return parse_retval;
 	}