Add utilities for remote cubit execution

src/cubitpy/conf.py

@@ -26,8 +26,12 @@
 import glob
 import os
 import shutil
+import warnings
+from pathlib import Path
 from sys import platform
 
+import yaml
+
 from cubitpy.cubitpy_types import (
     BoundaryConditionType,
     CubitItems,
@@ -53,6 +57,8 @@ def get_path(environment_variable, test_function, *, throw_error=True):
 class CubitOptions(object):
     """Object for types in cubitpy."""
 
+    _config = None
+
     def __init__(self):
         # Temporary directory for cubitpy.
         self.temp_dir = os.path.join(
@@ -83,14 +89,115 @@ def __init__(self):
         self.eps_pos = 1e-10
 
     @staticmethod
-    def get_cubit_root_path(**kwargs):
-        """Get Path to cubit root directory."""
-        return get_path("CUBIT_ROOT", os.path.isdir, **kwargs)
+    def get_cubit_config_filepath():
+        """Return path to remote config if it exists, else None."""
+        return get_path("CUBITPY_CONFIG_PATH", os.path.isfile, throw_error=False)
+
+    @classmethod
+    def validate_cubit_config(cls):
+        """Validate the already loaded config dict and raise helpful errors."""
+
+        config = cls._config
+        if config is None:
+            raise RuntimeError(
+                "Config not loaded yet. Call cupy.get_cubit_config(...) first."
+            )
+
+        TEMPLATE = (
+            "\n\nCorrect YAML structure:\n"
+            "----------------------------------------\n"
+            'cubitpy_mode: "remote"  # or "local"\n'
+            "\n"
+            "remote_config:\n"
+            '  user: "<username>"\n'
+            '  host: "<hostname_or_ip>"\n'
+            '  cubit_path: "<remote_cubit_install_path>"\n'
+            "\n"
+            "local_config:\n"
+            '  cubit_path: "<local_cubit_install_path>"\n'
+            "----------------------------------------\n"
+            "- If mode = 'remote': remote_config MUST exist and contain user, host, cubit_path.\n"
+            "- If mode = 'local' : local_config MUST exist and contain cubit_path.\n"
+            "- The unused section may be omitted.\n"
+            "----------------------------------------\n"
+        )
+
+        def fail(msg: str):
+            """Helper to raise a RuntimeError with template."""
+            raise RuntimeError(msg + TEMPLATE)
+
+        # Check mode
+        if "cubitpy_mode" not in config:
+            fail("Missing required key: 'cubitpy_mode'.")
+
+        mode = config["cubitpy_mode"]
+        if mode not in ("remote", "local"):
+            fail(f"Invalid cubitpy_mode '{mode}'. Expected 'remote' or 'local'.")
+
+        if mode == "remote":
+            if "remote_config" not in config:
+                fail("cubitpy_mode='remote' requires a 'remote_config' section.")
+
+            remote_config = config["remote_config"]
+            required = ["user", "host", "cubit_path"]
+            missing = [
+                k for k in required if k not in remote_config or not remote_config[k]
+            ]
+            if missing:
+                fail("remote_config is missing required fields: " + ", ".join(missing))
+
+        if mode == "local":
+            if "local_config" not in config:
+                fail("cubitpy_mode='local' requires a 'local_config' section.")
+
+            local_config = config["local_config"]
+            if "cubit_path" not in local_config or not local_config["cubit_path"]:
+                fail("local_config must contain a non-empty 'cubit_path'.")
+
+            local_cubit_path = local_config["cubit_path"]
+            if not Path(local_cubit_path).expanduser().exists():
+                raise FileNotFoundError(
+                    f"local_config.cubit_path '{local_cubit_path}' does not exist."
+                )
+
+    @classmethod
+    def load_cubit_config(cls, config_path: Path | None = None):
+        """Read the CubitPy YAML config."""
+
+        if config_path is None:
+            config_path = cls.get_cubit_config_filepath()
+
+        if not config_path:
+            warnings.warn(
+                "CubitPy configuration file not found." "Using default config: local",
+                DeprecationWarning,
+            )
+            root_path = get_path("CUBIT_ROOT", os.path.isdir, throw_error=True)
+
+            default_config = {
+                "cubitpy_mode": "local",
+                "local_config": {"cubit_path": root_path},
+                "remote_config": {},
+            }
+
+            cubit_config_dict = default_config
+        else:
+            try:
+                with open(config_path, "r") as f:
+                    cubit_config_dict = yaml.safe_load(f)
+            except Exception as e:
+                raise ImportError(f"Failed to read YAML at '{config_path}': {e}")
+
+            if not isinstance(cubit_config_dict, dict):
+                raise ImportError("YAML top level must be a mapping (dict).")
+
+        cls._config = cubit_config_dict
+        cls.validate_cubit_config()
 
     @classmethod
     def get_cubit_exe_path(cls, **kwargs):
         """Get Path to cubit executable."""
-        cubit_root = cls.get_cubit_root_path(**kwargs)
+        cubit_root = cls._config["local_config"]["cubit_path"]
         if platform == "linux" or platform == "linux2":
             if cupy.is_coreform():
                 return os.path.join(cubit_root, "bin", "coreform_cubit")
@@ -108,7 +215,7 @@ def get_cubit_exe_path(cls, **kwargs):
     @classmethod
     def get_cubit_lib_path(cls, **kwargs):
         """Get Path to cubit lib directory."""
-        cubit_root = cls.get_cubit_root_path(**kwargs)
+        cubit_root = cls._config["local_config"]["cubit_path"]
         if platform == "linux" or platform == "linux2":
             return os.path.join(cubit_root, "bin")
         elif platform == "darwin":
@@ -122,7 +229,7 @@ def get_cubit_lib_path(cls, **kwargs):
     @classmethod
     def get_cubit_interpreter(cls):
         """Get the path to the python interpreter to be used for CubitPy."""
-        cubit_root = cls.get_cubit_root_path()
+        cubit_root = cls._config["local_config"]["cubit_path"]
         if cls.is_coreform():
             pattern = "**/python3"
             full_pattern = os.path.join(cubit_root, pattern)
@@ -153,12 +260,22 @@ def get_cubit_interpreter(cls):
     @classmethod
     def is_coreform(cls):
         """Return if the given path is a path to cubit coreform."""
-        cubit_root = cls.get_cubit_root_path()
-        if "15.2" in cubit_root:
+        cubit_root = cls._config["local_config"]["cubit_path"]
+        if "15.2" in cubit_root and not cls.is_remote():
             return False
         else:
             return True
 
+    @classmethod
+    def is_remote(cls) -> bool:
+        """Return True if cubit is running remotely based on the loaded
+        config."""
+        if cls._config is None:
+            raise RuntimeError(
+                "Config not loaded yet. Call load_cubit_config() first use of is_remote."
+            )
+        return cls._config.get("cubitpy_mode") == "remote"
+
 
 # Global object with options for cubitpy.
 cupy = CubitOptions()

src/cubitpy/cubit_wrapper/cubit_wrapper_host.py

@@ -64,67 +64,73 @@ def __init__(
             Python interpreter to be used for running cubit.
         """
 
-        if interpreter is None:
-            interpreter = f"popen//python={cupy.get_cubit_interpreter()}"
+        # Remote mode – run cubit on a remote machine via SSH
+        if cupy.is_remote():
+            raise NotImplementedError("Remote cubit mode is not yet implemented.")
 
-        if cubit_lib is None:
-            cubit_lib = cupy.get_cubit_lib_path()
+        # Local mode – run cubit on the local machine
+        else:
+            if interpreter is None:
+                interpreter = f"popen//python={cupy.get_cubit_interpreter()}"
 
-        # Set up the client python interpreter
-        self.gw = execnet.makegateway(interpreter)
-        self.gw.reconfigure(py3str_as_py2str=True)
+            if cubit_lib is None:
+                cubit_lib = cupy.get_cubit_lib_path()
 
-        # Load the main code in the client python interpreter
-        client_python_file = os.path.join(
-            os.path.dirname(__file__), "cubit_wrapper_client.py"
-        )
-        with open(client_python_file, "r") as myfile:
-            data = myfile.read()
-
-        # Set up the connection channel
-        self.channel = self.gw.remote_exec(data)
-
-        # Send parameters to the client interpreter
-        parameters = {}
-        parameters["__file__"] = __file__
-        parameters["cubit_lib_path"] = cubit_lib
-
-        # Arguments for cubit
-        if cubit_args is None:
-            arguments = [
-                "cubit",
-                # "-log",  # Write the log to a file
-                # "dev/null",
-                "-information",  # Do not output information of cubit
-                "Off",
-                "-nojournal",  # Do write a journal file
-                "-noecho",  # Do not output commands used in cubit
-            ]
-        else:
-            arguments = ["cubit"] + cubit_args
+            # Set up the client python interpreter
+            self.gw = execnet.makegateway(interpreter)
+            self.gw.reconfigure(py3str_as_py2str=True)
 
-        # Check if a log file was given in the cubit arguments
-        for arg in arguments:
-            if arg.startswith("-log="):
-                log_given = True
-                break
-        else:
-            log_given = False
+            # Load the main code in the client python interpreter
+            client_python_file = os.path.join(
+                os.path.dirname(__file__), "cubit_wrapper_client.py"
+            )
+            with open(client_python_file, "r") as myfile:
+                data = myfile.read()
+
+            # Set up the connection channel
+            self.channel = self.gw.remote_exec(data)
+
+            # Send parameters to the client interpreter
+            parameters = {}
+            parameters["__file__"] = __file__
+            parameters["cubit_lib_path"] = cubit_lib
+
+            # Arguments for cubit
+            if cubit_args is None:
+                arguments = [
+                    "cubit",
+                    # "-log",  # Write the log to a file
+                    # "dev/null",
+                    "-information",  # Do not output information of cubit
+                    "Off",
+                    "-nojournal",  # Do write a journal file
+                    "-noecho",  # Do not output commands used in cubit
+                ]
+            else:
+                arguments = ["cubit"] + cubit_args
+
+            # Check if a log file was given in the cubit arguments
+            for arg in arguments:
+                if arg.startswith("-log="):
+                    log_given = True
+                    break
+            else:
+                log_given = False
 
-        self.log_check = False
+            self.log_check = False
 
-        if not log_given:
-            # Write the log to a temporary file and check the contents after each call to cubit
-            arguments.extend(["-log", cupy.temp_log])
-            parameters["tty"] = cupy.temp_log
-            self.log_check = True
+            if not log_given:
+                # Write the log to a temporary file and check the contents after each call to cubit
+                arguments.extend(["-log", cupy.temp_log])
+                parameters["tty"] = cupy.temp_log
+                self.log_check = True
 
-        # Send the parameters to the client interpreter
-        self.send_and_return(parameters)
+            # Send the parameters to the client interpreter
+            self.send_and_return(parameters)
 
-        # Initialize cubit in the client and create the linking object here
-        cubit_id = self.send_and_return(["init", arguments])
-        self.cubit = CubitObjectMain(self, cubit_id)
+            # Initialize cubit in the client and create the linking object here
+            cubit_id = self.send_and_return(["init", arguments])
+            self.cubit = CubitObjectMain(self, cubit_id)
 
         def cleanup_execnet_gateway():
             """We need to register a function called at interpreter shutdown

src/cubitpy/cubitpy.py

@@ -25,6 +25,7 @@
 import subprocess  # nosec B404
 import time
 import warnings
+from pathlib import Path
 
 import netCDF4
 from fourcipp.fourc_input import FourCInput
@@ -62,26 +63,31 @@ def _get_and_check_ids(name, container, id_list, given_id):
 class CubitPy(object):
     """A wrapper class with additional functionality for cubit."""
 
-    def __init__(self, *, cubit_exe=None, **kwargs):
+    def __init__(self, *, cubit_config_path: Path | None = None, **kwargs):
         """Initialize CubitPy.
 
         Args
         ----
-        cubit_exe: str
-            Path to the cubit executable
+        cubit_config_path: Path
+            Path to the cubitpy configuration file.
 
         kwargs:
             Arguments passed on to the creation of the python wrapper
         """
-
-        # Set paths
-        if cubit_exe is None:
-            cubit_exe = cupy.get_cubit_exe_path()
-        self.cubit_exe = cubit_exe
+        # load config
+        cupy.load_cubit_config(cubit_config_path)
 
         # Set the "real" cubit object
         self.cubit = CubitConnect(**kwargs).cubit
 
+        # Set remote paths
+        if cupy.is_remote():
+            raise NotImplementedError(
+                "Remote cubit connections are not yet supported in CubitPy."
+            )
+        else:
+            self.cubit_exe = cupy.get_cubit_exe_path()
+
         # Reset cubit
         self.cubit.cmd("reset")
         self.cubit.cmd("set geometry engine acis")