feat(revpiconfig): Make unit config changes asynchronous

Refactored unit enable/disable actions to run in separate threads,
ensuring non-blocking operations. This enhances performance and avoids
potential delays during systemd operations.

src/revpi_middleware/dbus_middleware1/system_config/revpi_config.py

@@ -10,6 +10,7 @@ from glob import glob
 from logging import getLogger
 from os import X_OK, access
 from os.path import exists, join
+from threading import Thread
 from typing import List, Optional
 
 from pydbus import SystemBus
@@ -26,6 +27,21 @@ CONFIG_TXT_LOCATIONS = ("/boot/firmware/config.txt", "/boot/config.txt")
 
 
 class ComputeModuleTypes(IntEnum):
+    """
+    Enumeration class to represent compute module types.
+
+    This class is an enumeration that defines various types of compute
+    modules and assigns them associated integer values for identifying
+    different module types.
+
+    Attributes:
+        UNKNOWN (int): Represents an unknown or undefined compute module type.
+        CM1 (int): Represents a Compute Module 1.
+        CM3 (int): Represents a Compute Module 3.
+        CM4 (int): Represents a Compute Module 4.
+        CM4S (int): Represents a Compute Module 4S.
+        CM5 (int): Represents a Compute Module 5.
+    """
     UNKNOWN = 0
     CM1 = 6
     CM3 = 10
@@ -35,6 +51,13 @@ class ComputeModuleTypes(IntEnum):
 
 
 class ConfigActions(Enum):
+    """
+    Enumeration class for defining configuration actions.
+
+    This enumeration provides predefined constants for common configuration
+    actions. It can be used to ensure consistency when working with or defining
+    such actions in a system.
+    """
     ENABLE = "enable"
     DISABLE = "disable"
     STATUS = "status"
@@ -42,6 +65,20 @@ class ConfigActions(Enum):
 
 
 class RevPiConfig:
+    """
+    Represents the configuration and hardware details of a Revolution Pi system.
+
+    This class provides methods and properties to initialize and fetch
+    information related to the Revolution Pi device, such as model, serial
+    number, compute module type, WLAN capability, and the presence of a
+    connection bridge. The class works by parsing system-level files (e.g.,
+    `/proc/cpuinfo`) and using this data to identify hardware characteristics
+    and features.
+
+    Attributes:
+        serial (str): The serial number of the Revolution Pi device.
+        model (str): The model name of the Revolution Pi device.
+    """
 
     def __init__(self):
         self._cm_type = ComputeModuleTypes.UNKNOWN
@@ -55,6 +92,29 @@ class RevPiConfig:
         self._init_device_info()
 
     def _init_device_info(self):
+        """
+        Initialize and retrieve detailed hardware information, including CPU details,
+        device type, WLAN interface, and connectivity features.
+
+        This method gathers information from system files and other sources to
+        initialize device-specific attributes such as model, serial number,
+        compute module type, and optional features like integrated WLAN
+        or ConBridge support. It performs checks specific to the detected
+        module type to accurately populate necessary device details.
+
+        Attributes
+        ----------
+        model : str
+            The model of the CPU based on information from /proc/cpuinfo.
+        serial : str
+            The serial number extracted from /proc/cpuinfo.
+        _cm_type : ComputeModuleTypes, optional
+            The type of the compute module derived from the hardware revision value.
+        _wlan_class_path : str, optional
+            Filesystem path to the detected WLAN interface, if any.
+        _revpi_with_con_bridge : bool
+            Indicates whether the device supports the ConBridge feature.
+        """
         dc_cpuinfo = {}
 
         # Extract CPU information
@@ -103,22 +163,75 @@ class RevPiConfig:
 
     @property
     def class_path_wlan(self) -> str:
+        """
+        Provides access to the WLAN class path.
+
+        This property retrieves the stored WLAN class path, allowing the user to access it when
+        needed.
+
+        Returns:
+            str: The WLAN class path.
+        """
         return self._wlan_class_path
 
     @property
     def cm_type(self) -> ComputeModuleTypes:
+        """
+        Gets the type of the compute module.
+
+        The property provides access to the type of the compute
+        module used. The type is represented as an instance of
+        the `ComputeModuleTypes` class.
+
+        Returns
+        -------
+        ComputeModuleTypes
+            The type of the compute module.
+        """
         return self._cm_type
 
     @property
     def with_con_bridge(self) -> bool:
+        """
+        Indicates if the device is configured with a connection bridge.
+
+        This property checks the internal status and determines whether the device setup
+        includes a connection bridge functionality. It is read-only.
+
+        Returns:
+            bool: True if the connection bridge is configured, False otherwise.
+        """
         return self._revpi_with_con_bridge
 
     @property
     def with_wlan(self) -> bool:
+        """
+        Checks if WLAN is available.
+
+        This property evaluates whether WLAN is enabled or available by checking
+        the presence or value of the internal attribute `_wlan_class_path`.
+
+        Returns:
+            bool: True if WLAN is available, False otherwise.
+        """
         return bool(self._wlan_class_path)
 
 
 class ConfigTxt:
+    """
+    Configuration file handler for managing 'config.txt'.
+
+    This class provides an interface to read, modify, save, and reload
+    Raspbian's configuration file `config.txt`. It includes functionalities
+    to manipulate specific parameters within the configuration and supports
+    managing dtoverlay and dtparam entries. The primary aim of this class
+    is to abstract file operations and make modifications user-friendly.
+
+    Attributes:
+        _config_txt_path (str): The path to the configuration file `config.txt`.
+        _config_txt_lines (list[str]): Contains all lines of the configuration
+            file as a list of strings, where each string represents a line.
+    """
     re_name_value = re.compile(r"^\s*(?!#)(?P<name>[^=\s].+?)\s*=\s*(?P<value>\S+)\s*$")
 
     def __init__(self):
@@ -134,6 +247,24 @@ class ConfigTxt:
         self._config_txt_lines = []
 
     def _clear_name_values(self, name: str, values: str or list) -> int:
+        """
+        Removes all occurrences of specified name-value pairs from the configuration.
+
+        This method searches for all name-value pairs in the configuration and
+        removes those that match the given name and value(s). It returns the
+        number of occurrences removed.
+
+        Arguments:
+            name: str
+                The name of the configuration variable to search for.
+            values: str or list
+                The value or list of values to match the configuration variable
+                against.
+
+        Returns:
+            int: The number of name-value pairs removed from the configuration.
+
+        """
         counter = 0
         if type(values) is str:
             values = [values]
@@ -146,6 +277,21 @@ class ConfigTxt:
         return counter
 
     def _get_all_name_values(self) -> List[ConfigVariable]:
+        """
+        Retrieves all name-value pairs from the configuration text lines.
+
+        This method parses the configuration text lines to extract all name-value
+        pairs. If the configuration text lines are not loaded, it reloads the
+        configuration before processing. Each extracted name-value pair is added to a
+        list as a ConfigVariable object, which also holds the index of the match in
+        the text lines. The method returns the compiled list of these ConfigVariable
+        objects.
+
+        Returns:
+            List[ConfigVariable]: A list of ConfigVariable objects representing the
+            name-value pairs found in the configuration text lines, along with their
+            corresponding indexes.
+        """
         if not self._config_txt_lines:
             self.reload_config()
 
@@ -159,10 +305,28 @@ class ConfigTxt:
         return lst_return
 
     def reload_config(self):
+        """
+        Reloads the configuration file and updates the list of configuration lines.
+
+        This method reads the content of the configuration file specified by the
+        attribute `_config_txt_path` and updates `_config_txt_lines` with the file
+        contents as a list of strings, where each string represents a line.
+
+        Returns:
+            None
+        """
         with open(self._config_txt_path, "r") as f:
             self._config_txt_lines = f.readlines()
 
     def save_config(self):
+        """
+        Saves the current configuration to a file. The method ensures atomicity by first writing
+        to a temporary file and then moving it to the desired path. After the configuration is
+        saved, the internal list of configuration lines is cleared.
+
+        Raises:
+            OSError: If there is an issue writing to or moving the file.
+        """
         if not self._config_txt_lines:
             return
 
@@ -174,6 +338,20 @@ class ConfigTxt:
         self._config_txt_lines.clear()
 
     def add_name_value(self, name: str, value: str):
+        """
+        Adds a name-value pair to the configuration if it does not already exist.
+
+        This method checks if the given name-value pair is already present in
+        the configuration. If it is not present, the pair is appended to the
+        configuration text lines.
+
+        Parameters:
+            name (str): The name to be added to the configuration.
+            value (str): The value corresponding to the name to be added.
+
+        Returns:
+            None
+        """
         # Check weather name and value already exists
         for config_var in self._get_all_name_values():
             if config_var.name == name and config_var.value == value:
@@ -182,12 +360,55 @@ class ConfigTxt:
         self._config_txt_lines.append(f"{name}={value}\n")
 
     def clear_dtoverlays(self, dtoverlays: str or list) -> int:
+        """
+        Clears the specified device tree overlays. This method removes one or more
+        device tree overlays by clearing their corresponding name-value pairs.
+
+        Args:
+            dtoverlays (str or list): A device tree overlay name as a string, or a
+            list of such overlay names to be cleared.
+
+        Returns:
+            int: The number of device tree overlay name-value pairs successfully
+            cleared.
+        """
         return self._clear_name_values("dtoverlay", dtoverlays)
 
     def clear_dtparams(self, dtparams: str or list) -> int:
+        """
+        Clears the specified device tree parameters.
+
+        This method removes the given device tree parameters by utilizing
+        the underlying `_clear_name_values` function with a predefined
+        parameter type.
+
+        Parameters:
+        dtparams: str or list
+            A string or list of strings specifying the device tree
+            parameters to remove.
+
+        Returns:
+        int
+            The number of parameters cleared.
+        """
         return self._clear_name_values("dtparam", dtparams)
 
     def get_values(self, var_name: str) -> list:
+        """
+        Get all values associated with a given variable name.
+
+        This method retrieves a list of values corresponding to the specified
+        variable name by iterating through a collection of configuration
+        variables. Each configuration variable is checked for a matching name,
+        and its value is appended to the resulting list if a match is found.
+
+        Parameters:
+        var_name (str): The name of the variable for which values are to
+                        be retrieved.
+
+        Returns:
+        list: A list of values associated with the specified variable name.
+        """
         var_values = []
 
         for config_var in self._get_all_name_values():
@@ -198,6 +419,16 @@ class ConfigTxt:
 
     @property
     def config_txt_path(self) -> str:
+        """
+        Get the file path for the configuration text file.
+
+        This property provides access to the private attribute `_config_txt_path` which
+        stores the file path to the configuration text file.
+
+        Returns:
+        str
+            The file path to the configuration text file.
+        """
         return self._config_txt_path
 
 
@@ -377,6 +608,23 @@ def configure_wlan(action: ConfigActions):
 
 
 def get_rfkill_index(device_class_path: str) -> Optional[int]:
+    """
+    Get the rfkill index for a device under a specific device class path.
+
+    This function searches for and extracts the rfkill index associated with
+    devices located under the given device class path. It uses a regular
+    expression to identify and parse the rfkill index from the paths
+    of matching rfkill device files.
+
+    Parameters:
+        device_class_path: str
+            The path to the device class directory where rfkill entries
+            are located.
+
+    Returns:
+        Optional[int]:
+            The index of the rfkill device if found, otherwise None.
+    """
     re_rfkill_index = re.compile(r"^/.+/rfkill(?P<index>\d+)$")
     for rfkill_path in glob(join(device_class_path, "rfkill*")):
         match_index = re_rfkill_index.match(rfkill_path)
@@ -387,6 +635,29 @@ def get_rfkill_index(device_class_path: str) -> Optional[int]:
 
 
 def simple_systemd(action: ConfigActions, unit: str):
+    """
+    Performs specified actions on systemd units.
+
+    This function allows interaction with systemd units for various operations
+    such as enabling, disabling, checking the status, and verifying availability.
+    It communicates with the systemd manager via the SystemBus and handles units
+    based on the action specified.
+
+    Parameters:
+        action (ConfigActions): Specifies the action to be performed on the
+                                systemd unit. Supported actions include ENABLE,
+                                DISABLE, STATUS, and AVAILABLE.
+        unit (str): The name of the systemd unit on which the action is to be
+                    performed.
+
+    Returns:
+        bool: For STATUS and AVAILABLE actions, returns True if the corresponding
+              criteria are met (e.g., enabled and active for STATUS, or not found
+              for AVAILABLE). Otherwise, returns False.
+
+    Raises:
+        ValueError: If the specified action is not supported.
+    """
     bus = SystemBus()
     systemd = bus.get(
         "org.freedesktop.systemd1",
@@ -395,13 +666,39 @@ def simple_systemd(action: ConfigActions, unit: str):
     systemd_manager = systemd["org.freedesktop.systemd1.Manager"]
 
     if action is ConfigActions.ENABLE:
-        systemd_manager.UnmaskUnitFiles([unit], False)
-        systemd_manager.EnableUnitFiles([unit], False, False)
+
+        def thread_unit_config():
+            """Change configuration asynchronously."""
+            # Dbus call: UnmaskUnitFiles(in as files, in b runtime, out a(sss) changes
+            lst_change_unmask = systemd_manager.UnmaskUnitFiles([unit], False)
+
+            # Dbus call: EnableUnitFiles(in as files, in b runtime, in b force,
+            #                            out b carries_install_info, out a(sss) changes
+            lst_change_enable = systemd_manager.EnableUnitFiles([unit], False, False)
+            if lst_change_unmask or lst_change_enable:
+                # Reload systemd after modified unit property
+                systemd_manager.Reload()
+
+        Thread(target=thread_unit_config, daemon=True).start()
+
+        # Dbus call: StartUnit(in s name, in s mode, out o job
         systemd_manager.StartUnit(unit, "replace")
 
     elif action is ConfigActions.DISABLE:
+
+        def thread_unit_config():
+            """Change configuration asynchronously."""
+            # Dbus call: DisableUnitFiles (in as files, in b runtime, out a(sss) changes)
+            change = systemd_manager.DisableUnitFiles([unit], False)
+            if change:
+                # Reload systemd after modified unit property
+                systemd_manager.Reload()
+
+        Thread(target=thread_unit_config, daemon=True).start()
+
+        # Dbus call: StopUnit(in s name,in s mode, out o job
         systemd_manager.StopUnit(unit, "replace")
-        systemd_manager.DisableUnitFiles([unit], False)
+
 
     elif action is ConfigActions.STATUS:
         try:
@@ -426,6 +723,8 @@ def simple_systemd(action: ConfigActions, unit: str):
     else:
         raise ValueError(f"action {action} not supported")
 
+    return None
+
 
 if __name__ == "__main__":
     rc = RevPiConfig()