Import AITURK IDE 1.0.0-beta.1 from Hermes 63279301; preserve MIT license

hermes_cli/image_provenance.py

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+"""Image-authored deployment provenance for immutable Hermes runtimes.
+
+The published image bakes ``/etc/hermes/image-provenance.json`` outside both
+``$HERMES_HOME`` and the mutable checkout.  A bind-mounted checkout (including
+``.git``) therefore cannot hide the build fact, and environment or config
+values cannot forge it.
+
+Absence preserves every pre-existing source/package install path.  Presence
+fails closed: an unreadable, non-regular, or malformed marker still means the
+runtime is image-managed; it is an integrity defect, never permission to
+mutate the image in place.
+"""
+
+from __future__ import annotations
+
+import json
+import stat
+from dataclasses import asdict, dataclass
+from pathlib import Path
+from typing import Any, Optional
+
+IMAGE_PROVENANCE_PATH = Path("/etc/hermes/image-provenance.json")
+IMAGE_PROVENANCE_SCHEMA = 1
+
+
+@dataclass(frozen=True)
+class ImageProvenance:
+    """Validated provenance, or a fail-closed description of an invalid one."""
+
+    schema: int
+    deployment_kind: str
+    manager: str
+    image: Optional[str]
+    version: Optional[str]
+    revision: Optional[str]
+    marker_path: str
+    valid: bool = True
+    error: Optional[str] = None
+
+    def to_dict(self) -> dict[str, Any]:
+        return asdict(self)
+
+
+def _invalid(path: Path, reason: str) -> ImageProvenance:
+    return ImageProvenance(
+        schema=IMAGE_PROVENANCE_SCHEMA,
+        deployment_kind="image",
+        manager="unknown",
+        image=None,
+        version=None,
+        revision=None,
+        marker_path=str(path),
+        valid=False,
+        error=reason,
+    )
+
+
+def read_image_provenance(
+    marker_path: Optional[Path] = None,
+) -> Optional[ImageProvenance]:
+    """Read the baked marker without consulting environment or config.
+
+    ``None`` has one precise meaning: ``lstat`` proved that no marker exists.
+    Every other filesystem or validation failure returns an invalid
+    :class:`ImageProvenance`, so callers refuse image mutation closed.  In
+    particular, ``lstat`` makes a dangling symlink visibly *present* and the
+    regular-file check rejects symlinks, directories, and device nodes.
+
+    ``marker_path`` is a dependency-injection seam for tests and alternate
+    image builders.  Normal callers always use the image-owned absolute path.
+    This function never raises.
+    """
+
+    path = IMAGE_PROVENANCE_PATH
+    try:
+        path = Path(marker_path) if marker_path is not None else path
+    except BaseException as exc:
+        return _invalid(path, f"marker_presence_unreadable:{type(exc).__name__}")
+
+    try:
+        marker_stat = path.lstat()
+    except FileNotFoundError:
+        return None
+    except BaseException as exc:
+        # Permission errors and other lookup failures do not prove absence.
+        return _invalid(path, f"marker_presence_unreadable:{type(exc).__name__}")
+
+    if not stat.S_ISREG(marker_stat.st_mode):
+        return _invalid(path, "marker_not_regular_file")
+
+    try:
+        payload = json.loads(path.read_text(encoding="utf-8"))
+    except Exception as exc:
+        # The file may disappear between lstat/read; it was nevertheless
+        # observed present, so the decision remains fail-closed.
+        return _invalid(path, f"marker_unreadable:{type(exc).__name__}")
+
+    if not isinstance(payload, dict):
+        return _invalid(path, "marker_not_object")
+
+    schema = payload.get("schema")
+    # ``bool`` is an ``int`` subclass in Python.  Schema ``true`` must not be
+    # accepted as schema 1, hence the exact type check.
+    if type(schema) is not int or schema != IMAGE_PROVENANCE_SCHEMA:
+        return _invalid(path, "unsupported_marker_schema")
+    if payload.get("deployment_kind") != "image":
+        return _invalid(path, "invalid_deployment_kind")
+
+    manager = payload.get("manager")
+    if not isinstance(manager, str) or not manager.strip():
+        return _invalid(path, "missing_manager")
+
+    def _optional_string(name: str) -> Optional[str]:
+        value = payload.get(name)
+        if value is None:
+            return None
+        if not isinstance(value, str):
+            raise TypeError(name)
+        value = value.strip()
+        return value or None
+
+    try:
+        image = _optional_string("image")
+        version = _optional_string("version")
+        revision = _optional_string("revision")
+    except TypeError as exc:
+        return _invalid(path, f"invalid_{exc.args[0]}")
+
+    return ImageProvenance(
+        schema=IMAGE_PROVENANCE_SCHEMA,
+        deployment_kind="image",
+        manager=manager.strip(),
+        image=image,
+        version=version,
+        revision=revision,
+        marker_path=str(path),
+    )