Add server/app.py

server/app.py

@@ -0,0 +1,58 @@
+# Copyright (c) Space Robotics Lab, SnT, University of Luxembourg, SpaceR
+# RANS: arXiv:2310.07393 — OpenEnv-compatible implementation
+
+"""
+FastAPI application for the RANS spacecraft navigation environment.
+
+Exposes the RANSEnvironment over HTTP/WebSocket using OpenEnv's
+``create_app`` factory, following the same pattern as echo_env and coding_env.
+
+Usage
+-----
+Development (auto-reload)::
+
+    uvicorn rans_env.server.app:app --reload --host 0.0.0.0 --port 8000
+
+Production::
+
+    uvicorn rans_env.server.app:app --host 0.0.0.0 --port 8000 --workers 4
+
+Docker entry-point::
+
+    uv run --project . server
+
+Task selection (default: GoToPosition)::
+
+    RANS_TASK=GoToPose uvicorn rans_env.server.app:app --host 0.0.0.0 --port 8000
+"""
+
+from rans_env.models import SpacecraftAction, SpacecraftObservation
+from rans_env.server.rans_environment import RANSEnvironment
+
+try:
+    from openenv.core.env_server import create_app
+except ImportError as exc:
+    raise RuntimeError(
+        "openenv-core is required to run the RANS server.  "
+        "Install it with:  pip install openenv-core"
+    ) from exc
+
+# Pass the class (not an instance) so create_app can spin up one environment
+# per WebSocket session, enabling concurrent independent episodes.
+app = create_app(
+    RANSEnvironment,
+    SpacecraftAction,
+    SpacecraftObservation,
+    env_name="rans_env",
+)
+
+
+def main() -> None:
+    """Entry-point for ``uv run --project . server``."""
+    import uvicorn
+
+    uvicorn.run(app, host="0.0.0.0", port=8000)
+
+
+if __name__ == "__main__":
+    main()