feat(cli): Add D-Bus helper functions for CLI commands.

This introduces `simple_call`, a utility function to interact with D-Bus
interfaces within the RevPi system. It facilitates method invocation on
specific interfaces and paths, improving modularity and code reuse in
middleware operations.

src/revpi_middleware/cli_commands/__init__.py

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+# -*- coding: utf-8 -*-
+# SPDX-FileCopyrightText: 2025 KUNBUS GmbH
+# SPDX-License-Identifier: GPL-2.0-or-later
+"""CLI commands to control revpi_middleware."""
+from ..__about__ import __author__, __copyright__, __license__, __version__

src/revpi_middleware/cli_commands/cli_base.py

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+# SPDX-FileCopyrightText: 2025 KUNBUS GmbH
+# SPDX-License-Identifier: GPL-2.0-or-later
+"""Command-line interface base module for RevPi middleware daemon.
+
+This module provides the foundation for the RevPi middleware CLI commands
+and argument parsing setup.
+"""
+from argparse import ArgumentParser
+from logging import getLogger
+
+from revpi_middleware.cli_commands import cli_picontrol
+from revpi_middleware.proginit import StdLogOutput
+from .. import proginit as pi
+
+log = getLogger(__name__)
+
+
+def setup_command_line_arguments():
+    pi.parser.prog = "revpictl"
+
+    # Add all objects here
+    rpictl_obj = pi.parser.add_subparsers(
+        dest="obj",
+        title="object",
+        help="Available RevPi objects",
+    )
+
+    obj_picontrol = rpictl_obj.add_parser(
+        "picontrol",
+        help="RevPi PiControl object",
+    )
+    cli_picontrol.add_subparsers(obj_picontrol)
+
+
+def main() -> int:
+    setup_command_line_arguments()
+    pi.init_app(StdLogOutput.STDERR)
+
+    obj = pi.pargs.obj
+    if obj == "picontrol":
+        rc = cli_picontrol.main()
+
+    else:
+        log.error(f"Unknown object: {obj}")
+        rc = 1
+
+    pi.cleanup()
+
+    return rc
+
+
+if __name__ == "__main__":
+    exit(main())

src/revpi_middleware/cli_commands/cli_picontrol.py

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+# SPDX-FileCopyrightText: 2025 KUNBUS GmbH
+# SPDX-License-Identifier: GPL-2.0-or-later
+"""Command-Line for the picontrol object of CLI."""
+from argparse import ArgumentParser
+from logging import getLogger
+
+from .dbus_helper import simple_call
+from .. import proginit as pi
+from ..dbus_middleware1 import extend_interface
+
+log = getLogger(__name__)
+
+
+def add_subparsers(parent_parser: ArgumentParser):
+    methods = parent_parser.add_subparsers(
+        dest="methods",
+        title="methods",
+        help="Available RevPi PiControl methods",
+    )
+    methods.add_parser(
+        "reset",
+        help="Reset the piControl driver",
+    )
+
+
+def method_reset():
+    log.debug("D-Bus call of method ResetDriver")
+    simple_call("ResetDriver", interface=extend_interface("picontrol"))
+    log.info("ResetDriver called via D-Bus")
+
+
+def main() -> int:
+    method = pi.pargs.methods
+    try:
+
+        if method == "reset":
+            method_reset()
+
+        else:
+            raise Exception(f"Unknown method: {method}")
+
+    except Exception as e:
+        log.error(f"Error: {e}")
+        return 1
+
+    return 0

src/revpi_middleware/cli_commands/dbus_helper.py

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+# SPDX-FileCopyrightText: 2025 KUNBUS GmbH
+# SPDX-License-Identifier: GPL-2.0-or-later
+"""D-Bus helper functions for cli commands."""
+from pydbus import SystemBus
+
+from ..dbus_middleware1 import REVPI_DBUS_BASE_PATH
+from ..dbus_middleware1 import REVPI_DBUS_NAME
+
+PICONTROL_INTERFACE = "com.revolutionpi.middleware1.picontrol"
+RESET_DRIVER_METHOD = "ResetDriver"
+
+
+def simple_call(method: str, *args, interface: str, object_path=REVPI_DBUS_BASE_PATH):
+    """
+    Executes a method on a specific D-Bus object interface within the RevPi system. This function
+    connects to the system bus, retrieves the desired interface and object path, and invokes
+    the specified method with provided arguments.
+
+    Parameters:
+    method: str
+        The name of the method to be invoked on the targeted interface.
+    *args: tuple
+        Positional arguments to be passed to the method being invoked.
+    interface: str
+        The name of the D-Bus interface providing the required functionality.
+    object_path: str, optional
+        The D-Bus object path of the RevPi interface. Defaults to REVPI_DBUS_BASE_PATH.
+
+    Returns:
+    Any
+        The result of the method invocation on the targeted D-Bus interface.
+    """
+    bus = SystemBus()
+    revpi = bus.get(REVPI_DBUS_NAME, object_path)
+    iface = revpi[interface]
+    return getattr(iface, method)(*args)