move pipeline validation logic after staging step

src/engine/src/core/workflows/executors/WorkflowExecutor.py

@@ -148,6 +148,15 @@ def start(self, ctx, threads):
             # middleware(notification and archivers), queue the tasks
             self._staging(ctx)
 
+            # Validate the submission args against the pipeline's parameters
+            (validated, err) = params_validator(
+                self.state.ctx.pipeline.params,
+                self.state.ctx.args
+            )
+
+            if not validated:
+                self._on_pipeline_terminal_state(event=PIPELINE_FAILED, message=err)
+
             # Get the first tasks
             unstarted_threads = self._fetch_ready_tasks()
 
@@ -173,22 +182,7 @@ def _staging(self, ctx):
         self._set_context(ctx)
 
         # Prepare the file system for this pipeline and handle pipeline templating
-        print("BEFORE PREPARE PIPELINE")
         self._prepare_pipeline()
-        print("AFTER PREPARE PIPELINE")
-
-        # Validate the pipeline submission args against the pipeline's parameters
-        print("BEFORE VALIDATION")
-        (validated, err) = params_validator(
-            self.state.ctx.pipeline.params,
-            self.state.ctx.args
-        )
-        print("AFTER VALIDATION")
-
-        if not validated:
-            print("NOT VALIDATED")
-            self._on_pipeline_terminal_state(event=PIPELINE_FAILED, message=err)
-            print("AFTER NOT VALIDATIED ON PIPELINE TERMINAL STATE")
 
         # Publish the PIPELINE_STAGING event
         # NOTE Events can only be published AFTER the '_prepare_pipeline' method is called