Provide relative workdir

Author: shuds13

libensemble/executors/executor.py

@@ -30,6 +30,9 @@
 # To change logging level for just this module
 # logger.setLevel(logging.DEBUG)
 
+# Placeholder for container support - replaced with simulation directory at runtime
+LIBE_SIM_DIR_PLACEHOLDER = "%LIBENSEMBLE_SIM_DIR%"
+
 STATES = """
 UNKNOWN
 CREATED
@@ -431,6 +434,7 @@ def __init__(self) -> None:
         self.workerID = None
         self.comm = None
         self.last_task = 0
+        self.base_dir = os.getcwd()
         Executor.executor = self
 
     def __enter__(self):
@@ -522,6 +526,10 @@ def register_app(
 
         precedent: str, Optional
             Any str that should directly precede the application full path.
+            Supports the placeholder ``%LIBENSEMBLE_SIM_DIR%`` which is replaced
+            at runtime with the simulation directory as a relative path from
+            where the executor was created. This is useful for container exec
+            commands.
         """
 
         if not app_name:
@@ -684,6 +692,16 @@ def _check_app_exists(self, app: Application) -> None:
         if not os.path.isfile(app.full_path):
             raise ExecutorException(f"Application does not exist {app.full_path}")
 
+    def _set_sim_dir_env(self, task: Task, run_cmd: list[str]) -> list[str]:
+        """Replace simulation directory placeholder in run command if present.
+
+        Supports container-based execution where the simulation directory needs to be
+        passed to container exec commands (e.g., podman-hpc exec --workdir).
+        """
+        sim_dir = os.path.relpath(task.workdir, self.base_dir)
+        task._add_to_env("LIBENSEMBLE_SIM_DIR", sim_dir)
+        return [arg.replace(LIBE_SIM_DIR_PLACEHOLDER, sim_dir) for arg in run_cmd]
+
     def submit(
         self,
         calc_type: str | None = None,
@@ -757,6 +775,9 @@ def submit(
         if task.app_args is not None:
             runline.extend(task.app_args.split())
 
+        runline = self._set_sim_dir_env(task, runline)
+        task.runline = " ".join(runline)
+
         if dry_run:
             logger.info(f"Test (No submit) Runline: {' '.join(runline)}")
         else:

libensemble/executors/mpi_executor.py

@@ -71,8 +71,6 @@ class MPIExecutor(Executor):
 
         from libensemble.executors.mpi_executor import MPIExecutor
         exctr = MPIExecutor(custom_info=customizer)
-
-
     """
 
     def __init__(self, custom_info: dict = {}) -> None:
@@ -363,7 +361,8 @@ def submit(
         if task.app_args is not None:
             runline.extend(task.app_args.split())
 
-        task.runline = " ".join(runline)  # Allow to be queried
+        runline = self._set_sim_dir_env(task, runline)
+        task.runline = " ".join(runline)
 
         if env_script is not None:
             run_cmd = Executor._process_env_script(task, runline, env_script)