[Configurator] Add GymnasiumAdapter for CloudAI envs

pyproject.toml

@@ -48,7 +48,9 @@ requires-python = ">=3.10"
     "import-linter~=2.10",
     "pytest-deadfixtures~=3.1",
     "taplo~=0.9.3",
+    "gymnasium~=1.2",
   ]
+  rl = ["gymnasium~=1.2"]
   docs = [
     "sphinx~=8.1",
     "nvidia-sphinx-theme~=0.0.8",

src/cloudai/configurator/__init__.py

@@ -18,11 +18,13 @@
 from .base_gym import BaseGym
 from .cloudai_gym import CloudAIGymEnv, TrajectoryEntry
 from .grid_search import GridSearchAgent
+from .gymnasium_adapter import GymnasiumAdapter
 
 __all__ = [
     "BaseAgent",
     "BaseGym",
     "CloudAIGymEnv",
     "GridSearchAgent",
+    "GymnasiumAdapter",
     "TrajectoryEntry",
 ]

src/cloudai/configurator/cloudai_gym.py

@@ -76,9 +76,10 @@ def define_observation_space(self) -> list:
         Define the observation space for the environment.
 
         Returns:
-            list: The observation space.
+            list: One float slot per agent metric (at least one), giving the correct shape
+            for adapters that derive ``gymnasium.spaces.Box`` from this output.
         """
-        return [0.0]
+        return [0.0] * max(len(self.test_run.test.agent_metrics), 1)
 
     def reset(
         self,
@@ -100,7 +101,7 @@ def reset(
         if seed is not None:
             lazy.np.random.seed(seed)
         self.test_run.current_iteration = 0
-        observation = [0.0]
+        observation = self.define_observation_space()
         info = {}
         return observation, info
 

src/cloudai/configurator/gymnasium_adapter.py

@@ -0,0 +1,165 @@
+# SPDX-FileCopyrightText: NVIDIA CORPORATION & AFFILIATES
+# Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import annotations
+
+from typing import Any, ClassVar, Optional
+
+from .base_gym import BaseGym
+
+_GYMNASIUM_INSTALL_HINT = "gymnasium is required for GymnasiumAdapter. Install it with: pip install gymnasium"
+
+
+def _import_gymnasium():
+    """
+    Import gymnasium + numpy lazily; raise a clear, actionable error when absent.
+
+    Kept as a single seam so that:
+    * cloudai installs without ``gymnasium`` continue to work for users that don't
+      need this adapter (the import is gated behind ``GymnasiumAdapter()``);
+    * tests can patch this helper to simulate a missing install.
+    """
+    try:
+        import gymnasium
+        import numpy as np
+        from gymnasium import spaces
+
+        return gymnasium, spaces, np
+    except ImportError as exc:
+        raise ImportError(_GYMNASIUM_INSTALL_HINT) from exc
+
+
+class GymnasiumAdapter:
+    """
+    Expose a CloudAI :class:`BaseGym` as a standard ``gymnasium.Env``-shaped object.
+
+    The adapter:
+
+    * builds a ``gymnasium.spaces.Dict`` of ``Discrete`` action spaces over the
+      *tunable* parameters (those with more than one candidate value), and
+      injects the *fixed* parameters (single candidate) automatically on every
+      step so agents never see them.
+    * converts observations to ``float32`` ``numpy`` arrays sized by
+      ``env.define_observation_space()``.
+    * returns the gymnasium 5-tuple ``(obs, reward, terminated, truncated, info)``
+      from :meth:`step` and :meth:`step_raw`.
+    * keeps ``env.test_run.step`` in sync (1-based) so artifact paths produced by
+      ``CloudAIGymEnv`` match those produced by ``handle_dse_job`` (i.e.
+      ``<scenario>/<test>/<iteration>/<step>/`` for every evaluation), which is
+      required when a custom training loop (e.g. RLlib) front-ends the env.
+
+    ``gymnasium`` and ``numpy`` are optional dependencies; importing this module
+    is cheap, but instantiating the adapter without them raises ``ImportError``.
+    """
+
+    metadata: ClassVar[dict[str, Any]] = {"render_modes": ["human"]}
+
+    def __init__(self, env: BaseGym) -> None:
+        _, spaces, np = _import_gymnasium()
+
+        self._np = np
+        self._env = env
+        self._step_count = 0
+
+        raw_action_space = env.define_action_space()
+        self._tunable_params: dict[str, list] = {k: v for k, v in raw_action_space.items() if len(v) > 1}
+        self._fixed_params: dict[str, Any] = {k: v[0] for k, v in raw_action_space.items() if len(v) == 1}
+
+        self.action_space = spaces.Dict(
+            {name: spaces.Discrete(len(values)) for name, values in self._tunable_params.items()}
+        )
+
+        obs_shape = (len(env.define_observation_space()),)
+        self.observation_space = spaces.Box(low=-np.inf, high=np.inf, shape=obs_shape, dtype=np.float32)
+
+    @property
+    def unwrapped(self) -> BaseGym:
+        return self._env
+
+    def decode_action(self, action: dict[str, int]) -> dict[str, Any]:
+        """
+        Map discrete action indices back to the original parameter values.
+
+        Raises:
+            ValueError: if ``action`` is missing tunable params, contains unknown keys,
+                or carries an index outside the discrete range for any tunable param.
+        """
+        self._assert_keys(action.keys(), set(self._tunable_params), "action")
+        decoded: dict[str, Any] = {}
+        for name, idx in action.items():
+            values = self._tunable_params[name]
+            if not 0 <= idx < len(values):
+                raise ValueError(f"Action index out of range for '{name}': {idx} (expected 0..{len(values) - 1})")
+            decoded[name] = values[idx]
+        return decoded
+
+    def reset(
+        self,
+        *,
+        seed: Optional[int] = None,
+        options: Optional[dict[str, Any]] = None,
+    ) -> tuple[Any, dict[str, Any]]:
+        self._step_count = 0
+        obs, info = self._env.reset(seed=seed, options=options)
+        return self._as_obs_array(obs), info
+
+    def step(self, action: dict[str, int]) -> tuple[Any, float, bool, bool, dict[str, Any]]:
+        params = {**self._fixed_params, **self.decode_action(action)}
+        return self._step_with_params(params)
+
+    def step_raw(self, params: dict[str, Any]) -> tuple[Any, float, bool, bool, dict[str, Any]]:
+        """
+        Step the env with an already-decoded parameter dict; bypasses index decoding.
+
+        Raises:
+            ValueError: if ``params`` does not cover exactly the tunable + fixed param keys.
+        """
+        self._assert_keys(params.keys(), set(self._tunable_params) | set(self._fixed_params), "raw params")
+        return self._step_with_params(params)
+
+    def render(self) -> None:
+        self._env.render()
+
+    @staticmethod
+    def _assert_keys(received: Any, expected: set[str], ctx: str) -> None:
+        received_set = set(received)
+        if received_set == expected:
+            return
+        missing = sorted(expected - received_set)
+        extra = sorted(received_set - expected)
+        raise ValueError(f"{ctx} keys mismatch; missing={missing}, extra={extra}")
+
+    def _step_with_params(self, params: dict[str, Any]) -> tuple[Any, float, bool, bool, dict[str, Any]]:
+        self._sync_underlying_step_counter()
+        obs, reward, done, info = self._env.step(params)
+        self._step_count += 1
+        return self._as_obs_array(obs), float(reward), bool(done), False, info
+
+    def _sync_underlying_step_counter(self) -> None:
+        """
+        Mirror ``handle_dse_job``'s 1-based ``test_run.step`` so artifact paths match.
+
+        The first step is written under ``…/<iteration>/1/``, matching how
+        ``handle_dse_job`` numbers steps; this keeps reports and trajectory
+        analysis consistent regardless of whether the env is driven by the
+        DSE loop or by an external training loop wrapping the adapter.
+        """
+        test_run = getattr(self._env, "test_run", None)
+        if test_run is not None:
+            test_run.step = self._step_count + 1
+
+    def _as_obs_array(self, obs: Any) -> Any:
+        return self._np.asarray(obs, dtype=self._np.float32)