(torchx/runner) Add runner API to parse scheduler config from string literal (#1096)

Summary:
Pull Request resolved: #1096

Adds `cfg_from_str` to the runner API to parse scheduler config options from string literals so this logic doesn't need to be duplicated across usecases.

Also updates CLI exit message with the full `InvalidRunConfigException` reason string, and fixes a dead link.

Differential Revision: D79937463

Author: ethanbwaite

torchx/cli/cmd_run.py

@@ -207,8 +207,7 @@ def _run(self, runner: Runner, args: argparse.Namespace) -> None:
                 " (e.g. `local_cwd`)"
             )
 
-        scheduler_opts = runner.scheduler_run_opts(args.scheduler)
-        cfg = scheduler_opts.cfg_from_str(args.scheduler_args)
+        cfg = dict(runner.cfg_from_str(args.scheduler, args.scheduler_args))
         config.apply(scheduler=args.scheduler, cfg=cfg)
 
         component, component_args = _parse_component_name_and_args(
@@ -263,12 +262,14 @@ def _run(self, runner: Runner, args: argparse.Namespace) -> None:
             sys.exit(1)
         except specs.InvalidRunConfigException as e:
             error_msg = (
-                f"Scheduler arg is incorrect or missing required option: `{e.cfg_key}`\n"
-                f"Run `torchx runopts` to check configuration for `{args.scheduler}` scheduler\n"
-                f"Use `-cfg` to specify run cfg as `key1=value1,key2=value2` pair\n"
-                "of setup `.torchxconfig` file, see: https://pytorch.org/torchx/main/experimental/runner.config.html"
+                "Invalid scheduler configuration: %s\n"
+                "To configure scheduler options, either:\n"
+                "  1. Use the `-cfg` command-line argument, e.g., `-cfg key1=value1,key2=value2`\n"
+                "  2. Set up a `.torchxconfig` file. For more details, visit: https://pytorch.org/torchx/main/runner.config.html\n"
+                "Run `torchx runopts %s` to check all available configuration options for the "
+                "`%s` scheduler."
             )
-            logger.error(error_msg)
+            print(error_msg % (e, args.scheduler, args.scheduler), file=sys.stderr)
             sys.exit(1)
 
     def run(self, args: argparse.Namespace) -> None:

torchx/runner/api.py

@@ -486,6 +486,27 @@ def scheduler_run_opts(self, scheduler: str) -> runopts:
         """
         return self._scheduler(scheduler).run_opts()
 
+    def cfg_from_str(self, scheduler: str, *cfg_literal: str) -> Mapping[str, CfgVal]:
+        """
+        Convenience function around the scheduler's ``runopts.cfg_from_str()`` method.
+
+        Usage:
+
+        .. doctest::
+
+            from torchx.runner import get_runner
+
+            runner = get_runner()
+            cfg = runner.cfg_from_str("local_cwd", "log_dir=/tmp/foobar", "prepend_cwd=True")
+            assert cfg == {"log_dir": "/tmp/foobar", "prepend_cwd": True, "auto_set_cuda_visible_devices": False}
+        """
+
+        opts = self._scheduler(scheduler).run_opts()
+        cfg = {}
+        for cfg_str in cfg_literal:
+            cfg.update(opts.cfg_from_str(cfg_str))
+        return cfg
+
     def scheduler_backends(self) -> List[str]:
         """
         Returns a list of all supported scheduler backends.

torchx/runner/test/api_test.py

@@ -28,6 +28,7 @@
     parse_app_handle,
     Resource,
     Role,
+    runopts,
     UnknownAppException,
 )
 from torchx.specs.finder import ComponentNotFoundException
@@ -701,3 +702,36 @@ def test_runner_manual_close(self, _) -> None:
     def test_get_default_runner(self, _) -> None:
         runner = get_runner()
         self.assertEqual("torchx", runner._name)
+
+    def test_cfg_from_str(self, _) -> None:
+        scheduler_mock = MagicMock()
+        opts = runopts()
+        opts.add("foo", type_=str, default="", help="")
+        opts.add("test_key", type_=str, default="", help="")
+        opts.add("default_time", type_=int, default=0, help="")
+        opts.add("enable", type_=bool, default=True, help="")
+        opts.add("disable", type_=bool, default=True, help="")
+        opts.add("complex_list", type_=List[str], default=[], help="")
+        scheduler_mock.run_opts.return_value = opts
+
+        with Runner(
+            name=SESSION_NAME,
+            scheduler_factories={"local_dir": lambda name, **kwargs: scheduler_mock},
+        ) as runner:
+            self.assertDictEqual(
+                {
+                    "foo": "bar",
+                    "test_key": "test_value",
+                    "default_time": 42,
+                    "enable": True,
+                    "disable": False,
+                    "complex_list": ["v1", "v2", "v3"],
+                },
+                runner.cfg_from_str(
+                    "local_dir",
+                    "foo=bar",
+                    "test_key=test_value",
+                    "default_time=42",
+                    "enable=True,disable=False,complex_list=v1;v2;v3",
+                ),
+            )