Remove rust-cli fallback in favor of a pure-Python CLI

Summary:
All the working subcommands were falling back to Python anyways.

Moved the (currently unimplemented) subcommand stubs: `bounce` and `stop` to Python.

**Note:** couple of reasons why a Rust CLI for monarch isn't ideal:

1. Uses TorchX under the hood. TorchX is a Python library.
2. Due to #1 we have to run a Python CLI fallback anyways and the mechanics of this is meta specific (won't work for OSS).
3. Reverse pyo3 binding TorchX (call Python from Rust) doesn't work internally due to the way we package Python (hermetic PAR).
4. Any material benefits (e.g. performance?) of implementing the CLI in Rust would be negated by the effort to fix/deal-with #1-3.

**Next:**
~~[6/n] Have kd_monarch use the default component (the custom mast.py is no longer needed). Update the README with updated instructions.~~
~~[7/n] Remove rust CLI in favor of all-python (we delegate to torchx for most things anyways)~~
[8/n] Add E2E unittest using the local_cwd scheduler (actually run a mini-trainer actor)
[9/n] Write an oss hyperactor mesh-worker entrypoint binary
[10/n] Author a Dockerfile that sets up the environment (much like fbpkgs do it for internal runs)
[11/n] Author a TorchXAllocator

Reviewed By: vidhyav, suo

Differential Revision: D75176535

fbshipit-source-id: 29020f4032bd642af26b393ade74f40b868df973

Author: kiukchung

tools/Cargo.toml

@@ -11,10 +11,12 @@
 
 from fastcli.argparse import inject_fastcli
 from monarch.tools.commands import (
+    bounce,
     component_args_from_cli,
     create,
     info,
     kill,
+    stop,
     torchx_runner,
 )
 from monarch.tools.config import (  # @manual=//monarch/tools/config/meta:defaults
@@ -89,14 +91,20 @@ def run(self, args: argparse.Namespace) -> None:
         print(handle)
 
 
-class InfoCmd:
-    def add_arguments(self, subparser: argparse.ArgumentParser) -> None:
+class CommonArguments:
+    @staticmethod
+    def add_server_handle(subparser: argparse.ArgumentParser) -> None:
         subparser.add_argument(
             "server_handle",
             type=str,
-            help="monarch server handle (e.g. mast:///job_id)",
+            help="monarch server handle (e.g. slurm:///job_id)",
         )
 
+
+class InfoCmd:
+    def add_arguments(self, subparser: argparse.ArgumentParser) -> None:
+        CommonArguments.add_server_handle(subparser)
+
     def run(self, args: argparse.Namespace) -> None:
         server_spec = info(args.server_handle)
         if server_spec is None:
@@ -110,16 +118,28 @@ def run(self, args: argparse.Namespace) -> None:
 
 class KillCmd:
     def add_arguments(self, subparser: argparse.ArgumentParser) -> None:
-        subparser.add_argument(
-            "server_handle",
-            type=str,
-            help="monarch server handle (e.g. mast:///job_id)",
-        )
+        CommonArguments.add_server_handle(subparser)
 
     def run(self, args: argparse.Namespace) -> None:
         kill(args.server_handle)
 
 
+class BounceCmd:
+    def add_arguments(self, subparser: argparse.ArgumentParser) -> None:
+        CommonArguments.add_server_handle(subparser)
+
+    def run(self, args: argparse.Namespace) -> None:
+        bounce(args.server_handle)
+
+
+class StopCmd:
+    def add_arguments(self, subparser: argparse.ArgumentParser) -> None:
+        CommonArguments.add_server_handle(subparser)
+
+    def run(self, args: argparse.Namespace) -> None:
+        stop(args.server_handle)
+
+
 def get_parser() -> argparse.ArgumentParser:
     parser = argparse.ArgumentParser(description="Monarch CLI")
     subparser = parser.add_subparsers(title="COMMANDS")
@@ -128,6 +148,9 @@ def get_parser() -> argparse.ArgumentParser:
         "create": CreateCmd(),
         "info": InfoCmd(),
         "kill": KillCmd(),
+        # --- placeholder subcommands (not yet implemented) ---
+        "bounce": BounceCmd(),
+        "stop": StopCmd(),
     }.items():
         cmd_parser = subparser.add_parser(cmd_name)
         cmd.add_arguments(cmd_parser)

tools/cli.py

@@ -177,3 +177,13 @@ def info(server_handle: str) -> Optional[ServerSpec]:
 def kill(server_handle: str) -> None:
     with torchx_runner() as runner:
         runner.cancel(server_handle)
+
+
+def bounce(server_handle: str) -> None:
+    """(re)starts the server's processes without tearing down the server's job."""
+    raise NotImplementedError("`bounce` is not yet implemented")
+
+
+def stop(server_handle: str) -> None:
+    """Stops the server's unix processes without tearing down the server's job."""
+    raise NotImplementedError("`stop` is not yet implemented")