Fix App Check: Container Path

libensemble/executors/executor.py

@@ -673,10 +673,16 @@ def set_worker_info(self, comm=None, workerid=None) -> None:
         self.workerID = workerid
         self.comm = comm
 
-    def _check_app_exists(self, full_path: str) -> None:
+    def _check_app_exists(self, app: Application) -> None:
         """Allows submit function to check if app exists and error if not"""
-        if not os.path.isfile(full_path):
-            raise ExecutorException(f"Application does not exist {full_path}")
+        if app.precedent:
+            # Could be a container call in precedent. In that case,
+            # the executable is not available on the host system and
+            # we just forward what the user provided.
+            return
+
+        if not os.path.isfile(app.full_path):
+            raise ExecutorException(f"Application does not exist {app.full_path}")
 
     def submit(
         self,
@@ -745,7 +751,7 @@ def submit(
         task = Task(app, app_args, default_workdir, stdout, stderr, self.workerID, dry_run)
 
         if not dry_run:
-            self._check_app_exists(task.app.full_path)
+            self._check_app_exists(task.app)
 
         runline = task.app.app_cmd.split()
         if task.app_args is not None:

libensemble/executors/mpi_executor.py

@@ -317,7 +317,7 @@ def submit(
         task = Task(app, app_args, default_workdir, stdout, stderr, self.workerID, dry_run)
 
         if not dry_run:
-            self._check_app_exists(task.app.full_path)
+            self._check_app_exists(task.app)
 
         if stage_inout is not None:
             logger.warning("stage_inout option ignored in this " "executor - runs in-place")

libensemble/tests/unit_tests/test_executor.py

@@ -936,6 +936,25 @@ def test_non_existent_app_mpi():
         assert 0
 
 
+def test_non_existent_app_precedent():
+    """Tests exception on non-existent app is not thrown if precedent is set.
+    This is common when running apps in containers, where the executable is not
+    check-able from the host system."""
+    from libensemble.executors.executor import Executor
+
+    print(f"\nTest: {sys._getframe().f_code.co_name}\n")
+
+    exctr = Executor()
+
+    # Can register a non-existent app in case created as part of workflow.
+    exctr.register_app(full_path=non_existent_app, app_name="nonexist")
+
+    w_exctr = Executor.executor  # simulate on worker
+
+    # all should be ok
+    w_exctr.submit(app_name="nonexist", dry_run=True)
+
+
 def test_man_signal_unrec_tag():
     print(f"\nTest: {sys._getframe().f_code.co_name}\n")
 
@@ -990,5 +1009,6 @@ def test_man_signal_unrec_tag():
     test_dry_run()
     test_non_existent_app()
     test_non_existent_app_mpi()
+    test_non_existent_app_precedent()
     test_man_signal_unrec_tag()
     teardown_module(__file__)