Hermes-agent

hermes_cli/build_info.py

@@ -0,0 +1,51 @@
+"""
+Baked-in build metadata for Hermes Agent.
+
+Source installs report their git revision live via ``git rev-parse`` (see
+``hermes_cli/dump.py`` and ``hermes_cli/banner.py``).  That doesn't work inside
+the published Docker image because ``.dockerignore`` excludes ``.git``, so
+those callsites fall back to ``"(unknown)"`` / drop the banner suffix entirely.
+
+To make ``hermes dump`` and the startup banner identify the exact commit the
+image was built from, the Docker build writes the build-time ``$HERMES_GIT_SHA``
+arg into ``<project_root>/.hermes_build_sha``.  This module is the single
+read-side helper consumed by both callsites — keeping the lookup in one place
+so the file path and missing-file behaviour stay consistent.
+
+Behaviour:
+
+- Returns ``None`` when the file is absent.  Source installs and dev images
+  built without the ``HERMES_GIT_SHA`` build-arg fall through to live-git
+  resolution in the caller, so non-Docker installs are unaffected.
+- Returns ``None`` on any IO / decoding error.  The build-sha is a nice-to-have
+  for support triage; nothing in the CLI is allowed to crash because of it.
+- Truncates to ``short`` characters (default 8) to match the format used by
+  ``git rev-parse --short=8`` throughout the codebase.
+"""
+
+from __future__ import annotations
+
+from pathlib import Path
+from typing import Optional
+
+# Path is resolved relative to this module so it works regardless of cwd —
+# matches the pattern used by ``banner._resolve_repo_dir``.
+_BUILD_SHA_FILE = Path(__file__).parent.parent / ".hermes_build_sha"
+
+
+def get_build_sha(short: int = 8) -> Optional[str]:
+    """Return the baked-in build SHA, truncated to ``short`` chars, or None.
+
+    Reads ``<project_root>/.hermes_build_sha`` if present.  The file is
+    written by the Dockerfile's ``HERMES_GIT_SHA`` build-arg and contains
+    the full 40-character commit hash on a single line.
+    """
+    try:
+        if not _BUILD_SHA_FILE.is_file():
+            return None
+        sha = _BUILD_SHA_FILE.read_text(encoding="utf-8").strip()
+    except Exception:
+        return None
+    if not sha:
+        return None
+    return sha[:short] if short and short > 0 else sha