various updates v.dev3

compute/utils/config_loader.py

@@ -1,56 +0,0 @@
-# This file is part of Compute
-#
-# Compute is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# Compute is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with Compute.  If not, see <http://www.gnu.org/licenses/>.
-
-"""Configuration loader."""
-
-import tomllib
-from collections import UserDict
-from pathlib import Path
-
-from compute.exceptions import ConfigLoaderError
-
-
-DEFAULT_CONFIGURATION = {}
-DEFAULT_CONFIG_FILE = '/etc/computed/computed.toml'
-
-
-class ConfigLoader(UserDict):
-    """UserDict for storing configuration."""
-
-    def __init__(self, file: Path | None = None):
-        """
-        Initialise ConfigLoader.
-
-        :param file: Path to configuration file. If `file` is None
-            use default path from DEFAULT_CONFIG_FILE constant.
-        """
-        # TODO @ge: load deafult configuration
-        self.file = Path(file) if file else Path(DEFAULT_CONFIG_FILE)
-        super().__init__(self.load())
-
-    def load(self) -> dict:
-        """Load confguration object from TOML file."""
-        try:
-            with Path(self.file).open('rb') as configfile:
-                return tomllib.load(configfile)
-                # TODO @ge: add config schema validation
-        except tomllib.TOMLDecodeError as tomlerr:
-            raise ConfigLoaderError(
-                f'Bad TOML syntax in config file: {self.file}: {tomlerr}'
-            ) from tomlerr
-        except (OSError, ValueError) as readerr:
-            raise ConfigLoaderError(
-                f'Cannot read config file: {self.file}: {readerr}'
-            ) from readerr

compute/utils/diskutils.py

@@ -0,0 +1,45 @@
+# This file is part of Compute
+#
+# Compute is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Compute is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Compute.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Auxiliary functions for working with disks."""
+
+import string
+
+
+def get_disk_target(
+    disks: list[str], prefix: str, *, from_end: bool = False
+) -> str:
+    """
+    Return free disk name.
+
+    .. code-block:: shell-session
+
+       >>> get_disk_target(['vda', 'vdb'], 'vd')
+       'vdc'
+       >>> get_disk_target(['vda', 'vdc'], 'vd')
+       'vdb'
+       >>> get_disk_target(['vda', 'vdd'], 'vd', from_end=True)
+       'vdz'
+       >>> get_disk_target(['vda', 'hda'], 'hd')
+       'hdb'
+
+    :param disks: List of attached disk names.
+    :param prefix: Disk name prefix.
+    :param from_end: If True select a drive letter starting from the
+        end of the alphabet.
+    """
+    index = -1 if from_end else 0
+    devs = [d[-1] for d in disks if d.startswith(prefix)]
+    return prefix + [x for x in string.ascii_lowercase if x not in devs][index]