Support custom interchange launch command (#3514)

The command used to launch the HTEX interchange process can now be
customized.

parsl/executors/high_throughput/executor.py

@@ -56,6 +56,8 @@
                       "--mpi-launcher={mpi_launcher} "
                       "--available-accelerators {accelerators}")
 
+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`,
         :class:`~parsl.providers.cobalt.cobalt.Cobalt`,
@@ -76,6 +78,10 @@
         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.
+
     address : string
         An address to connect to the main Parsl process which is reachable from the network in which
         workers will be running. This field expects an IPv4 address (xxx.xxx.xxx.xxx).
@@ -231,6 +237,7 @@ def __init__(self,
                  label: str = 'HighThroughputExecutor',
                  provider: ExecutionProvider = LocalProvider(),
                  launch_cmd: Optional[str] = None,
+                 interchange_launch_cmd: Optional[str] = None,
                  address: Optional[str] = None,
                  worker_ports: Optional[Tuple[int, int]] = None,
                  worker_port_range: Optional[Tuple[int, int]] = (54000, 55000),
@@ -329,6 +336,10 @@ def __init__(self,
             launch_cmd = DEFAULT_LAUNCH_CMD
         self.launch_cmd = launch_cmd
 
+        if not interchange_launch_cmd:
+            interchange_launch_cmd = DEFAULT_INTERCHANGE_LAUNCH_CMD
+        self.interchange_launch_cmd = interchange_launch_cmd
+
     radio_mode = "htex"
 
     def _warn_deprecated(self, old: str, new: str):
@@ -544,7 +555,7 @@ def _start_local_interchange_process(self) -> None:
 
         config_pickle = pickle.dumps(interchange_config)
 
-        self.interchange_proc = subprocess.Popen(b"interchange.py", stdin=subprocess.PIPE)
+        self.interchange_proc = subprocess.Popen(self.interchange_launch_cmd.encode("utf-8"), 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/executors/high_throughput/mpi_executor.py

@@ -38,6 +38,7 @@ def __init__(self,
                  label: str = 'MPIExecutor',
                  provider: ExecutionProvider = LocalProvider(),
                  launch_cmd: Optional[str] = None,
+                 interchange_launch_cmd: Optional[str] = None,
                  address: Optional[str] = None,
                  worker_ports: Optional[Tuple[int, int]] = None,
                  worker_port_range: Optional[Tuple[int, int]] = (54000, 55000),
@@ -66,6 +67,7 @@ def __init__(self,
             label=label,
             provider=provider,
             launch_cmd=launch_cmd,
+            interchange_launch_cmd=interchange_launch_cmd,
             address=address,
             worker_ports=worker_ports,
             worker_port_range=worker_port_range,

parsl/tests/test_htex/test_htex.py

@@ -136,3 +136,16 @@ def test_max_workers_per_node():
 
     # Ensure max_workers_per_node takes precedence
     assert htex.max_workers_per_node == htex.max_workers == 1
+
+
+@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