various improvements

compute/utils/config_loader.py

@@ -0,0 +1,41 @@
+"""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/identifiers.py

@@ -0,0 +1,18 @@
+"""Random identificators."""
+
+# ruff: noqa: S311, C417
+
+import random
+
+
+def random_mac() -> str:
+    """Retrun random MAC address."""
+    mac = [
+        0x00,
+        0x16,
+        0x3E,
+        random.randint(0x00, 0x7F),
+        random.randint(0x00, 0xFF),
+        random.randint(0x00, 0xFF),
+    ]
+    return ':'.join(map(lambda x: '%02x' % x, mac))

compute/utils/units.py

@@ -0,0 +1,39 @@
+"""Tools for data units convertion."""
+
+from enum import StrEnum
+
+
+class DataUnit(StrEnum):
+    """Data units enumerated."""
+
+    BYTES = 'bytes'
+    KIB = 'KiB'
+    MIB = 'MiB'
+    GIB = 'GiB'
+    TIB = 'TiB'
+
+
+class InvalidDataUnitError(ValueError):
+    """Data unit is not valid."""
+
+    def __init__(self, msg: str):
+        """Initialise InvalidDataUnitError."""
+        super().__init__(
+            f'{msg}, valid units are: {", ".join(list(DataUnit))}'
+        )
+
+
+def to_bytes(value: int, unit: DataUnit = DataUnit.BYTES) -> int:
+    """Convert value to bytes. See `DataUnit`."""
+    try:
+        _ = DataUnit(unit)
+    except ValueError as e:
+        raise InvalidDataUnitError(e) from e
+    powers = {
+        DataUnit.BYTES: 0,
+        DataUnit.KIB: 1,
+        DataUnit.MIB: 2,
+        DataUnit.GIB: 3,
+        DataUnit.TIB: 4,
+    }
+    return value * pow(1024, powers[unit])