__init__

uvm/validation.py

@@ -0,0 +1,83 @@
+"""Validation and unit conversion for command-line resource options."""
+
+from __future__ import annotations
+
+import math
+import re
+from decimal import Decimal, InvalidOperation
+
+from .errors import ValidationError
+
+
+_RAM_PATTERN = re.compile(r"\s*(\d+(?:\.\d+)?)\s*([BKMG]i?B?)?\s*", re.IGNORECASE)
+_USERNAME_PATTERN = re.compile(r"[a-z_][a-z0-9_-]{0,31}\$?")
+_MIB_FACTORS = {
+    "b": Decimal(1) / Decimal(1024 * 1024),
+    "k": Decimal(1) / Decimal(1024),
+    "kb": Decimal(1) / Decimal(1024),
+    "ki": Decimal(1) / Decimal(1024),
+    "kib": Decimal(1) / Decimal(1024),
+    "m": Decimal(1),
+    "mb": Decimal(1),
+    "mi": Decimal(1),
+    "mib": Decimal(1),
+    "g": Decimal(1024),
+    "gb": Decimal(1024),
+    "gi": Decimal(1024),
+    "gib": Decimal(1024),
+}
+
+
+def parse_ram(value: str) -> int:
+    """Parse a MiB-default RAM value, including B/K/M/G suffixes."""
+
+    match = _RAM_PATTERN.fullmatch(value)
+    if not match:
+        raise ValidationError(f"invalid RAM value: {value}")
+
+    try:
+        amount = Decimal(match.group(1))
+    except InvalidOperation as error:
+        raise ValidationError(f"invalid RAM value: {value}") from error
+
+    unit = (match.group(2) or "MiB").lower()
+    mib = int(amount * _MIB_FACTORS[unit])
+    if mib < 128:
+        raise ValidationError("RAM must be at least 128 MiB")
+    return mib
+
+
+def parse_cpu(value: str) -> float:
+    """Parse a positive finite CPU capacity request."""
+
+    try:
+        cpu = float(value)
+    except ValueError as error:
+        raise ValidationError(f"invalid CPU value: {value}") from error
+
+    if not math.isfinite(cpu) or cpu <= 0:
+        raise ValidationError("CPU must be a finite value greater than 0")
+    return cpu
+
+
+def parse_username(value: str) -> str:
+    """Validate a conventional Linux account name."""
+
+    if not _USERNAME_PATTERN.fullmatch(value):
+        raise ValidationError(
+            "username must start with a lowercase letter or underscore and contain "
+            "at most 32 lowercase letters, digits, underscores, or hyphens"
+        )
+    return value
+
+
+def parse_password(value: str) -> str:
+    """Validate a guest password without including it in error messages."""
+
+    if not value:
+        raise ValidationError("password must not be empty")
+    if len(value) > 128:
+        raise ValidationError("password must be at most 128 characters")
+    if any(ord(character) < 32 or ord(character) == 127 for character in value):
+        raise ValidationError("password must not contain control characters")
+    return value