feat: add independent VM manager

hydra/profiles.py

@@ -0,0 +1,72 @@
+"""Validated, independently editable VM profiles."""
+
+import json
+import re
+import tomllib
+from dataclasses import dataclass
+from pathlib import Path
+
+
+def validate_name(name: str) -> str:
+    if not isinstance(name, str) or not re.fullmatch(r'[a-z][a-z0-9-]{0,31}', name):
+        raise ValueError('VM name must match [a-z][a-z0-9-]{0,31}')
+    return name
+
+
+@dataclass(frozen=True)
+class Profile:
+    name: str
+    iso: Path
+    memory: int = 4096
+    cpus: int = 2
+    disk_size: str = '40G'
+    graphics: str = 'auto'
+    network: str = 'user'
+    bridge: str = 'hydrabr0'
+
+    def __post_init__(self):
+        validate_name(self.name)
+        iso = Path(self.iso).expanduser().resolve()
+        if not iso.is_file():
+            raise ValueError(f'ISO does not exist or is not a file: {iso}')
+        object.__setattr__(self, 'iso', iso)
+        for key, upper in (('memory', 262144), ('cpus', 256)):
+            value = getattr(self, key)
+            if type(value) is not int or not 1 <= value <= upper:
+                raise ValueError(f'{key} must be an integer between 1 and {upper}')
+        if not isinstance(self.disk_size, str) or not re.fullmatch(r'[1-9][0-9]{0,5}[MGT]', self.disk_size):
+            raise ValueError('disk_size must be a positive size with M, G or T suffix')
+        if self.graphics not in ('auto', 'software'):
+            raise ValueError('graphics must be auto or software')
+        if self.network not in ('user', 'bridge'):
+            raise ValueError('network must be user or bridge')
+        if not isinstance(self.bridge, str) or not re.fullmatch(r'[a-zA-Z0-9_-]{1,15}', self.bridge):
+            raise ValueError('bridge must be a valid Linux interface name')
+
+
+def load_profile(path: Path) -> Profile:
+    path = Path(path)
+    with path.open('rb') as stream:
+        data = tomllib.load(stream)
+    unknown = data.keys() - Profile.__dataclass_fields__.keys()
+    if unknown:
+        raise ValueError(f'Unknown profile fields: {", ".join(sorted(unknown))}')
+    name = data.pop('name', path.stem)
+    if name != path.stem:
+        raise ValueError('Profile name must match its filename')
+    try:
+        return Profile(name=name, **data)
+    except TypeError as exc:
+        raise ValueError(f'Invalid profile: {exc}') from exc
+
+
+def save_profile(path: Path, profile: Profile) -> None:
+    path = Path(path)
+    if path.stem != profile.name:
+        raise ValueError('Profile name must match its filename')
+    lines = []
+    for field in Profile.__dataclass_fields__:
+        value = getattr(profile, field)
+        lines.append(f'{field} = {value if type(value) is int else json.dumps(str(value), ensure_ascii=False)}\n')
+    with path.open('x', encoding='utf-8') as stream:
+        stream.write(''.join(lines))