Accept multi-token interchange launch commands (#3543)

parsl/executors/high_throughput/executor.py

@@ -56,7 +56,7 @@
                       "--mpi-launcher={mpi_launcher} "
                       "--available-accelerators {accelerators}")
 
-DEFAULT_INTERCHANGE_LAUNCH_CMD = "interchange.py"
+DEFAULT_INTERCHANGE_LAUNCH_CMD = ["interchange.py"]
 
 GENERAL_HTEX_PARAM_DOCS = """provider : :class:`~parsl.providers.base.ExecutionProvider`
        Provider to access computation resources. Can be one of :class:`~parsl.providers.aws.aws.EC2Provider`,
@@ -78,9 +78,9 @@
         cores_per_worker, nodes_per_block, heartbeat_period ,heartbeat_threshold, logdir). For example:
         launch_cmd="process_worker_pool.py {debug} -c {cores_per_worker} --task_url={task_url} --result_url={result_url}"
 
-    interchange_launch_cmd : str
-        Custom command line string to launch the interchange process from the executor. If undefined,
-        the executor will use the default "interchange.py" command.
+    interchange_launch_cmd : Sequence[str]
+        Custom sequence of command line tokens to launch the interchange process from the executor. If
+        undefined, the executor will use the default "interchange.py" command.
 
     address : string
         An address to connect to the main Parsl process which is reachable from the network in which
@@ -238,7 +238,7 @@ def __init__(self,
                  label: str = 'HighThroughputExecutor',
                  provider: ExecutionProvider = LocalProvider(),
                  launch_cmd: Optional[str] = None,
-                 interchange_launch_cmd: Optional[str] = None,
+                 interchange_launch_cmd: Optional[Sequence[str]] = None,
                  address: Optional[str] = None,
                  worker_ports: Optional[Tuple[int, int]] = None,
                  worker_port_range: Optional[Tuple[int, int]] = (54000, 55000),
@@ -548,7 +548,7 @@ def _start_local_interchange_process(self) -> None:
 
         config_pickle = pickle.dumps(interchange_config)
 
-        self.interchange_proc = subprocess.Popen(self.interchange_launch_cmd.encode("utf-8"), stdin=subprocess.PIPE)
+        self.interchange_proc = subprocess.Popen(self.interchange_launch_cmd, stdin=subprocess.PIPE)
         stdin = self.interchange_proc.stdin
         assert stdin is not None, "Popen should have created an IO object (vs default None) because of PIPE mode"
 

parsl/tests/test_htex/test_htex.py

@@ -1,6 +1,6 @@
 import pathlib
-import warnings
 from subprocess import Popen, TimeoutExpired
+from typing import Optional, Sequence
 from unittest import mock
 
 import pytest
@@ -139,13 +139,22 @@ def test_max_workers_per_node():
 
 
 @pytest.mark.local
-def test_htex_launch_cmd():
-    htex = HighThroughputExecutor()
-    assert htex.launch_cmd.startswith("process_worker_pool.py")
-    assert htex.interchange_launch_cmd == "interchange.py"
-
-    launch_cmd = "custom-launch-cmd"
-    ix_launch_cmd = "custom-ix-launch-cmd"
-    htex = HighThroughputExecutor(launch_cmd=launch_cmd, interchange_launch_cmd=ix_launch_cmd)
-    assert htex.launch_cmd == launch_cmd
-    assert htex.interchange_launch_cmd == ix_launch_cmd
+@pytest.mark.parametrize("cmd", (None, "custom-launch-cmd"))
+def test_htex_worker_pool_launch_cmd(cmd: Optional[str]):
+    if cmd:
+        htex = HighThroughputExecutor(launch_cmd=cmd)
+        assert htex.launch_cmd == cmd
+    else:
+        htex = HighThroughputExecutor()
+        assert htex.launch_cmd.startswith("process_worker_pool.py")
+
+
+@pytest.mark.local
+@pytest.mark.parametrize("cmd", (None, ["custom", "launch", "cmd"]))
+def test_htex_interchange_launch_cmd(cmd: Optional[Sequence[str]]):
+    if cmd:
+        htex = HighThroughputExecutor(interchange_launch_cmd=cmd)
+        assert htex.interchange_launch_cmd == cmd
+    else:
+        htex = HighThroughputExecutor()
+        assert htex.interchange_launch_cmd == ["interchange.py"]