Files
hermes-agent/hermes_cli/runtime_state.py
ethernet 15335df680 fix(pm): collect superseded and aborted PM runtime generations
pm-runtime/generations/<uuid> trees were never collected: a kill -9 during
staging orphaned a venv permanently and every input change left the old
runtime behind. `hermes pm gc` now sweeps them under .prepare.lock with the
same lease model as application generations: entry points (worker.py,
launch.py) pin their own runtime, prepare_runtime marks new generations
lease-managed, and the collector removes unpublished stages outright,
superseded generations only once no worker holds a lease, and never a
pre-lease generation.
2026-09-21 19:01:36 -04:00

259 lines
10 KiB
Python

"""Stdlib-only recovery and lifetime protection for dependency generations."""
from __future__ import annotations
import atexit
import errno
import base64
from collections.abc import Callable
from contextlib import contextmanager, suppress
import hashlib
import json
import logging
import os
from pathlib import Path
import shutil
import tempfile
import time
import uuid
from pm.environments import dependency_home_root, install_state_dir, runtime_facts_path
LOG = logging.getLogger(__name__)
# How long a process that only needs to READ the install state waits for a writer. The holder can
# be another profile's backend rebuilding the whole dependency environment (measured: tens of
# seconds on a bundle, minutes when a sync falls back to an sdist build), and a backend that never
# binds its port is worse than one that binds against the previous generation. Losers skip — the
# same rule boot_bootstrap._RecordLock states for home maintenance.
INSTALL_LOCK_TIMEOUT_SECONDS = 10.0
_LOCK_POLL_SECONDS = 0.05
def _lock(fd: int, *, wait: bool, timeout: float | None = None) -> bool:
"""Take the byte lock; ``timeout`` bounds the retry loop (None waits forever, 0 tries once)."""
deadline = None if timeout is None else time.monotonic() + timeout
if os.name == "nt":
import msvcrt
while True:
try:
os.lseek(fd, 0, os.SEEK_SET)
msvcrt.locking(fd, msvcrt.LK_NBLCK, 1)
return True
except OSError as exc:
if exc.errno not in (errno.EACCES, errno.EAGAIN, errno.EDEADLK):
raise
if not wait or (deadline is not None and time.monotonic() >= deadline):
return False
time.sleep(_LOCK_POLL_SECONDS)
else:
import fcntl
while True:
try:
fcntl.flock(fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
return True
except BlockingIOError:
pass
if not wait or (deadline is not None and time.monotonic() >= deadline):
return False
time.sleep(_LOCK_POLL_SECONDS)
@contextmanager
def runtime_lock(project: Path, *, timeout: float | None = INSTALL_LOCK_TIMEOUT_SECONDS):
"""Hold the per-install dependency lock; yields True when held, False when the wait expired.
Callers decide what a lost race means: readers skip the work the lock guards and carry on
(``activate_dependencies`` still selects and leases the committed generation), writers that
cannot be skipped pass ``timeout=None`` — an install the user asked for is theirs to wait on.
"""
state = install_state_dir(project)
state.mkdir(parents=True, exist_ok=True)
fd = os.open(state / ".install.lock", os.O_CREAT | os.O_RDWR, 0o600)
try:
if not _lock(fd, wait=True, timeout=timeout):
LOG.warning(
"dependency lock still held after %ss; continuing without it (%s)",
timeout, state / ".install.lock")
yield False
return
yield True
finally:
os.close(fd)
def _bytes(path: Path) -> bytes | None:
try:
return path.read_bytes()
except FileNotFoundError:
return None
def _digest(path: Path) -> str | None:
data = _bytes(path)
return hashlib.sha256(data).hexdigest() if data is not None else None
def _atomic_bytes(path: Path, data: bytes):
path.parent.mkdir(parents=True, exist_ok=True)
fd, temporary = tempfile.mkstemp(dir=path.parent, prefix=".publish-")
try:
with os.fdopen(fd, "wb") as stream:
stream.write(data)
stream.flush()
os.fsync(stream.fileno())
os.replace(temporary, path)
if os.name != "nt":
directory = os.open(path.parent, os.O_RDONLY)
try:
os.fsync(directory)
finally:
os.close(directory)
finally:
Path(temporary).unlink(missing_ok=True)
def _recover_plugin_publication(project: Path, row: dict, journal: Path) -> None:
from hermes_cli.fs_utils import rmtree_force
target, backup, metadata = (Path(row[key]) for key in ("target", "backup", "metadata"))
home = dependency_home_root().resolve()
if (not target.resolve().is_relative_to(home) or target.parent.name != "plugins"
or backup.parent != target.parent or not backup.name.startswith(".previous-")
or metadata != target.parent / ".install-metadata.json"):
raise ValueError("plugin publication paths escape their home")
committed = row.get("committed") or _digest(runtime_facts_path(project)) != row["facts_before"]
if committed:
if backup.exists():
rmtree_force(backup)
else:
old = base64.b64decode(row["metadata_before"], validate=True) if row["metadata_before"] is not None else None
current = _bytes(metadata)
new = base64.b64decode(row["metadata_after"], validate=True)
if current not in (old, new):
raise ValueError("plugin metadata changed after publication; preserve it for manual recovery")
if backup.exists():
if target.exists():
rmtree_force(target)
os.replace(backup, target)
elif not row["target_existed"] and target.exists():
rmtree_force(target)
if old is None:
metadata.unlink(missing_ok=True)
else:
_atomic_bytes(metadata, old)
journal.unlink()
def recover_publication(project: Path) -> None:
"""Recover while holding runtime_lock, before activation or another write."""
journal = install_state_dir(project) / "publication.json"
data = _bytes(journal)
if data is None:
return
try:
row = json.loads(data)
if row.get("kind") == "plugin":
_recover_plugin_publication(project, row, journal)
return
config = Path(row["config"])
if config.name != "config.yaml" or not config.resolve().is_relative_to(dependency_home_root().resolve()):
raise ValueError("config path is outside Hermes state")
previous = base64.b64decode(row["previous"], validate=True) if row["previous"] is not None else None
if not row.get("committed") and _digest(runtime_facts_path(project)) == row["facts_before"]:
current = _digest(config)
prior = hashlib.sha256(previous).hexdigest() if previous is not None else None
if current not in (prior, row.get("config_after")):
raise ValueError("config changed after publication began; preserve it for manual recovery")
# No selection was published. Roll back before any plugin is loaded.
if previous is None:
config.unlink(missing_ok=True)
else:
_atomic_bytes(config, previous)
journal.unlink()
except (ValueError, KeyError, TypeError, OSError) as exc:
raise RuntimeError(f"cannot recover dependency publication: {journal}: {exc}") from exc
def finish_publication(project: Path) -> None:
"""Persist a commit even when code/config changed without a new generation."""
journal = install_state_dir(project) / "publication.json"
row = json.loads(journal.read_bytes())
row["committed"] = True
_atomic_bytes(journal, json.dumps(row).encode())
recover_publication(project)
def lease_generation(environment: Path) -> Callable[[], None]:
"""Hold a kernel lock until process exit; the returned callable releases it early.
Call under ``runtime_lock`` at boot. Without the lock (``runtime_lock`` timed out) the
caller must re-read the selection after leasing: an installer may have moved it in between,
and an unselected, unleased generation is exactly what the collector removes.
"""
return lease_directory(environment.parent)
def lease_directory(generation: Path) -> Callable[[], None]:
"""Pin a lease-managed generation directory for this process's lifetime."""
if not (generation / ".lease-managed").is_file():
return lambda: None # Generations produced before leases stay conservatively retained.
leases = generation / ".leases"
leases.mkdir(exist_ok=True)
lease = leases / uuid.uuid4().hex
fd = os.open(lease, os.O_CREAT | os.O_EXCL | os.O_RDWR, 0o600)
try:
_lock(fd, wait=True)
except BaseException:
os.close(fd)
raise
def release() -> None:
atexit.unregister(release)
os.close(fd)
# Best effort: the collector ignores unlocked lease files, but one per
# invocation would otherwise accumulate for the life of the generation.
with suppress(OSError):
lease.unlink()
atexit.register(release)
return release
def collect_generations(project: Path, *, min_age_seconds: float = 86400) -> list[Path]:
"""Remove unselected lease-managed generations after their readers exit."""
from pm.environments import selected_venv
removed = []
root = install_state_dir(project)
if not root.exists():
return removed
with runtime_lock(project) as held:
if not held:
return removed # maintenance: another process owns the install, skip rather than queue
recover_publication(project)
selected = selected_venv(project).parent.resolve()
generations = root / "environments"
if not generations.is_dir():
return removed
for generation in generations.iterdir():
if generation.is_symlink() or not generation.is_dir() or generation.resolve() == selected:
continue
marker = generation / ".lease-managed"
if not marker.is_file() or time.time() - marker.stat().st_mtime < min_age_seconds:
continue
if not leases_held(generation):
shutil.rmtree(generation)
removed.append(generation)
return removed
def leases_held(generation: Path) -> bool:
"""True while any process still holds a lease taken by ``lease_directory``."""
for lease in (generation / ".leases").glob("*"):
fd = os.open(lease, os.O_RDWR)
try:
if not _lock(fd, wait=False):
return True
finally:
os.close(fd)
return False