Files
hermes-agent/gateway/session_persistence.py

657 lines
28 KiB
Python

"""SessionStore storage plumbing: per-profile SessionDB handle resolution and the
routing-index load/save paths (state.db gateway_routing primary, sessions.json
legacy mirror).
Mixin split out of ``gateway/session.py``; bound onto ``SessionStore`` via the MRO.
"""
from __future__ import annotations
import logging
import json
import os
import threading
from pathlib import Path
from typing import Any, Dict, Optional
from utils import atomic_replace
from typing import TYPE_CHECKING
if TYPE_CHECKING:
from gateway.session import SessionEntry
# Log-record parity with the origin module.
logger = logging.getLogger("gateway.session")
class SessionPersistenceMixin:
"""SessionStore storage plumbing: per-profile SessionDB handle resolution and
the routing-index load/save paths (state.db gateway_routing primary,
sessions.json legacy mirror).
"""
def _open_session_db_for_active_scope(self, db_path: Optional[Path] = None):
"""SessionDB for the profile scope active on this task.
``db_path`` pins the store; otherwise ``_default_db_path()`` follows the
context-local HERMES_HOME from ``_profile_runtime_scope`` (resolved per
call so multiplexed profiles reach their own store). Handles are cached
per path; failed opens enter a bounded backoff during which callers keep
using the JSONL fallback.
"""
from hermes_state import _default_db_path, get_shared_session_db
path = Path(db_path) if db_path is not None else Path(_default_db_path())
def _open():
try:
# Process-wide shared registry: one writer connection per path.
return get_shared_session_db(path)
except Exception as e:
if isinstance(e, RuntimeError) and "live-system guard" in str(e):
# Test-isolation guard: must stay a loud failure and is
# deliberately not cached so it fires again next attempt.
raise
print(f"[gateway] Warning: SQLite session store unavailable, falling back to JSONL: {e}")
raise
return self._db_handle_cache.get(
path,
_open,
non_cacheable=lambda exc: (
isinstance(exc, RuntimeError) and "live-system guard" in str(exc)
),
)
def _pinned_db(self):
"""Return the explicitly pinned DB (``store._db = x``), else ``_DB_UNPINNED``."""
from gateway.session import _DB_UNPINNED
return getattr(self, "_db_pinned", _DB_UNPINNED)
@property
def _db(self):
"""The SessionDB for the active profile scope, or a pinned override.
Assigning ``store._db`` pins that value for every subsequent read
(tests install a fake or disable the DB with ``store._db = None``).
Unpinned, each read resolves the scope so a multiplexed profile's
writes reach its own store.
"""
from gateway.session import _DB_UNPINNED
pinned = self._pinned_db()
if pinned is not _DB_UNPINNED:
return pinned
return self._open_session_db_for_active_scope()
@_db.setter
def _db(self, value) -> None:
self._db_pinned = value
@property
def _routing_db(self):
"""The one store that owns the routing index, whatever scope is active.
``_entries`` is one flat dict holding every profile's keys, so it must
persist to ONE file (``_routing_home``), not whichever profile is
scoped — otherwise a mid-turn rewrite and the unscoped startup load see
different copies and crash markers under a secondary profile go
unrecovered. A pinned handle still wins; bare test instances lacking
the handle cache report no DB.
"""
from gateway.session import _DB_UNPINNED
pinned = self._pinned_db()
if pinned is not _DB_UNPINNED:
return pinned
home = getattr(self, "_routing_home", None)
try:
if home is None:
return self._db
return self._open_session_db_for_active_scope(db_path=home / "state.db")
except Exception:
return None
def _named_profile_for_key(self, session_key: Optional[str]) -> Optional[str]:
"""The non-default profile that owns *session_key*, or None.
None means the ambient store is authoritative (multiplexing off, or
legacy ``agent:main`` namespace). It deliberately does NOT cover "that
profile has no directory" — ownership and resolvability are separate
questions that ``_db_for_key`` answers separately.
"""
if not getattr(self.config, "multiplex_profiles", False):
return None
profile = self._profile_from_session_key(session_key)
if not profile or profile == "default":
return None
return profile
def _profile_home_for_key(self, session_key: Optional[str]) -> Optional[Path]:
"""HERMES_HOME of the profile that owns *session_key*, or None.
None means only "no live home to point at" — no named owner, or the
owner's directory could not be resolved.
"""
profile = self._named_profile_for_key(session_key)
if profile is None:
return None
cache = self._profile_home_cache
if profile in cache:
return cache[profile]
home: Optional[Path] = None
try:
from hermes_cli.profiles import get_profile_dir, profile_exists
if profile_exists(profile):
home = Path(get_profile_dir(profile))
except Exception as exc:
logger.debug("Could not resolve profile home for %r: %s", session_key, exc)
home = None
# Only hits are memoized: a profile directory can be provisioned
# *after* startup (enrollment bridge), and a cached miss would pin
# that profile's rows to the ambient store for the process lifetime.
if home is not None:
cache[profile] = home
return home
def _db_for_key(self, session_key: Optional[str]):
"""The SessionDB holding *session_key*'s rows, whatever scope is active.
``_db`` follows the ambient HERMES_HOME that only the inbound message
path installs; background work (expiry watcher) runs unscoped and would
write profile rows into the ROOT store until the stale-route self-heal
drops a live conversation. The owning profile is encoded in the key.
"""
from gateway.session import _DB_UNPINNED
pinned = self._pinned_db()
if pinned is not _DB_UNPINNED:
return pinned
profile = self._named_profile_for_key(session_key)
if profile is None:
return self._db
home = self._profile_home_for_key(session_key)
if home is None:
# Named owner we cannot resolve (not provisioned yet, or lookup
# failed). Falling back to the ambient store would split ONE
# session identity across two physical stores — fail closed;
# callers already handle a missing DB.
logger.warning(
"gateway.session: profile %r has no resolvable home (key %r); "
"refusing to fall back to the ambient store",
profile, session_key,
)
return None
try:
return self._open_session_db_for_active_scope(db_path=home / "state.db")
except Exception:
# Same contract as ``_db``: a failed open degrades to JSONL fallback.
return None
def _owner_key_for_session_id(self, session_id: Optional[str]) -> Optional[str]:
"""The routing key that owns *session_id*, or None.
The published index is authoritative; ``_session_owner_hints`` covers
the window where ownership is proven but routing not yet published.
Deliberately lock-free: several callers already hold ``_lock``.
"""
if not session_id:
return None
try:
for entry in list(self._entries.values()):
if entry.session_id == session_id:
return entry.session_key
except Exception:
pass # bare stores / foreign entry objects in suites
return (getattr(self, "_session_owner_hints", None) or {}).get(session_id)
def _db_for_session_id(self, session_id: Optional[str]):
"""The SessionDB holding *session_id*'s row (owner recovered from the
index or a pre-published hint; unknown ids fall back to the ambient store)."""
if not session_id:
return self._db
return self._db_for_key(self._owner_key_for_session_id(session_id))
def close_all_db_handles(self) -> None:
"""Close every SessionDB handle this store opened (one per path).
Closing only ``store._db`` would strand secondary profiles' handles with
their WAL lock held ('database is locked' on restart). Drained under the
lock, closed outside it; a pinned handle is the pinner's to close.
"""
def _close(db) -> None:
# Shared instances no-op on close(); release the refcount instead.
from hermes_state import release_or_close
try:
release_or_close(db)
except Exception as exc:
logger.debug("SessionDB close error during handle sweep: %s", exc)
self._db_handle_cache.close_all(_close)
def _ensure_loaded(self) -> None:
"""Load sessions index from disk if not already loaded."""
with self._lock:
self._ensure_loaded_locked()
def _entry_locked(self, session_key: str) -> Optional[SessionEntry]:
"""Load the index and return the entry for *session_key*. Lock held."""
self._ensure_loaded_locked()
return self._entries.get(session_key)
def _routing_scope(self) -> str:
"""Namespace for this store's gateway_routing rows: the resolved
sessions_dir, so stores with different dirs never share entries."""
try:
return str(Path(self.sessions_dir).resolve())
except Exception:
return str(self.sessions_dir)
def _routing_db_method(self, name: str):
"""Bound ``_routing_db.<name>`` if the handle exists and has it, else None."""
db = self._routing_db
method = getattr(db, name, None) if db else None
return method if callable(method) else None
@staticmethod
def _routing_entry_from_json(key: str, entry_json: str) -> Optional[SessionEntry]:
"""Parse one gateway_routing row; None (with a warning) when invalid."""
from gateway.session import SessionEntry
try:
entry_data = json.loads(entry_json)
if isinstance(entry_data, dict):
return SessionEntry.from_dict(entry_data)
except (ValueError, KeyError, TypeError) as e:
logger.warning("Skipping invalid routing entry %r: %s", key, e)
return None
def _ensure_loaded_locked(self) -> None:
"""Load the routing index. Must be called with self._lock held.
state.db ``gateway_routing`` is primary; sessions.json is the legacy
import for keys the DB lacks (persisted to the DB on the next _save).
"""
if self._loaded:
self._reconcile_recovered_routing_locked()
return
self.sessions_dir.mkdir(parents=True, exist_ok=True)
db_had_entries = False
db_load_succeeded = False
loader = self._routing_db_method("load_gateway_routing_entries")
if loader is not None:
try:
for key, entry_json in loader(scope=self._routing_scope()).items():
entry = self._routing_entry_from_json(key, entry_json)
if entry is not None:
self._entries[key] = entry
db_had_entries = bool(self._entries)
db_load_succeeded = True
except Exception as e:
logger.warning("gateway.session: state.db routing load failed: %s", e)
self._import_legacy_sessions_json(db_had_entries)
self._loaded = True
self._routing_db_loaded = db_load_succeeded
self._routing_fallback_baseline = (
None
if db_load_succeeded
else {key: entry.to_dict() for key, entry in self._entries.items()}
)
# A hard crash skips graceful shutdown and leaves sessions.json
# pointing at ended sessions; self-heal before the first message.
self._prune_stale_sessions_locked()
def _import_legacy_sessions_json(self, db_had_entries: bool) -> None:
"""Legacy import: sessions.json fills only keys the DB lacks. Lock held."""
from gateway.session import SessionEntry
sessions_file = self.sessions_dir / "sessions.json"
if not sessions_file.exists():
return
try:
with open(sessions_file, "r", encoding="utf-8") as f:
data = json.load(f)
imported = 0
for key, entry_data in data.items():
# "_"-prefixed keys are sentinels (e.g. "_README"), not entries.
if key.startswith("_") or key in self._entries:
continue
# A non-dict entry (corrupt file) must not abort the whole load.
if not isinstance(entry_data, dict):
logger.warning(
"Skipping invalid session entry %r: "
"expected dict, got %s",
key, type(entry_data).__name__,
)
continue
try:
self._entries[key] = SessionEntry.from_dict(entry_data)
imported += 1
except (ValueError, KeyError, TypeError) as e:
logger.warning("Skipping invalid session entry %r: %s", key, e)
if imported and db_had_entries:
logger.info(
"gateway.session: imported %d legacy sessions.json "
"entr%s missing from state.db routing table",
imported, "y" if imported == 1 else "ies",
)
except Exception as e:
print(f"[gateway] Warning: Failed to load sessions: {e}")
def _prune_stale_sessions_locked(self) -> None:
"""Remove routing entries whose session has ended in state.db (startup, lock held).
Stale == ``end_reason IS NOT NULL``. Rows absent from the DB are kept;
a ``None`` DB handle is a no-op; DB errors are non-fatal.
"""
if not self._entries:
return
stale_keys: list = []
recovered_keys = 0
try:
for key, entry in self._entries.items():
# Ask the store that owns the key, not the ambient handle, or a
# live secondary-profile session gets pruned on the root copy.
db = self._db_for_key(key)
if db is None:
continue
row = db.get_session(entry.session_id)
if row is None or row.get("end_reason") is None:
continue
verdict = self._stale_entry_verdict(key, entry, row)
if verdict == "prune":
stale_keys.append(key)
elif verdict is not None:
self._entries[key] = verdict
recovered_keys += 1
except Exception as exc:
logger.warning(
"gateway.session: stale-entry pruning skipped due to DB error: %s",
exc,
)
return
for key in stale_keys:
del self._entries[key]
if stale_keys or recovered_keys:
self._save()
def _stale_entry_verdict(self, key: str, entry, row):
"""For a routing entry whose row has ended: ``"prune"``, a replacement
entry (repoint), or None (keep as-is)."""
from gateway.session import _now
recovered_entry = None
if entry.origin is not None:
try:
recovered_entry = self._recover_session_from_db(
session_key=key,
source=entry.origin,
now=_now(),
raise_on_lookup_error=True,
)
except Exception as exc:
# Indeterminate: keep the only routing handle.
logger.debug(
"gateway.session: recovery lookup failed for stale "
"sessions.json entry %r -> %s: %s",
key,
entry.session_id,
exc,
)
return None
# Compression-ended parent with a newer live child for the same peer:
# repoint instead of dropping, or queued/resume-pending work vanishes
# until the next message.
if recovered_entry is not None and recovered_entry.session_id != entry.session_id:
logger.warning(
"gateway.session: repointing stale sessions.json entry "
"%r from ended %s (end_reason=%r) to recovered %s",
key,
entry.session_id,
row["end_reason"],
recovered_entry.session_id,
)
return recovered_entry
# Same-id recovery == successful resume: keep the ORIGINAL entry object
# (the recovered one is rebuilt minimal and would drop counters,
# model_override, resume markers, metadata). Nothing changes, no save.
if recovered_entry is not None:
logger.info(
"gateway.session: reopened ended session %s for "
"sessions.json entry %r (end_reason=%r); keeping route",
entry.session_id, key, row["end_reason"],
)
return None
logger.warning(
"gateway.session: pruning stale sessions.json entry "
"%r -> %s (end_reason=%r); left by a crashed gateway",
key, entry.session_id, row["end_reason"],
)
return "prune"
def _save(self) -> None:
"""Persist the routing index while the caller holds ``_lock``."""
data, generation = self._snapshot_routing_locked()
self._persist_routing_data(data, generation)
def _next_routing_generation_locked(self) -> int:
"""Bump and return the shared routing counter. Caller holds ``_lock``.
Full snapshots AND single-entry fast saves MUST allocate from this one
counter: the stale-write protection is a total order over
serialization times and silently breaks otherwise.
"""
self._routing_generation = getattr(self, "_routing_generation", 0) + 1
return self._routing_generation
def _reconcile_recovered_routing_locked(self) -> None:
"""Merge authoritative rows after a fallback-only startup load."""
baseline = getattr(self, "_routing_fallback_baseline", None)
if getattr(self, "_routing_db_loaded", False) or baseline is None:
return
loader = self._routing_db_method("load_gateway_routing_entries")
if loader is None:
return
try:
durable = loader(scope=self._routing_scope())
except Exception as exc:
logger.warning("gateway.session: recovered state.db routing load failed: %s", exc)
return
current = {key: entry.to_dict() for key, entry in self._entries.items()}
for key, entry_json in durable.items():
durable_entry = self._routing_entry_from_json(key, entry_json)
if durable_entry is None:
continue
if key not in baseline:
# A key created while on fallback wins over a DB-only key;
# otherwise restore the authoritative row that fallback never saw.
self._entries.setdefault(key, durable_entry)
elif key not in current:
# The key was loaded from fallback and deliberately removed.
continue
elif current[key] == baseline[key]:
# Unchanged fallback data yields to the authoritative DB copy.
self._entries[key] = durable_entry
self._routing_db_loaded = True
self._routing_fallback_baseline = None
def _snapshot_routing_locked(self) -> tuple[Dict[str, Any], int]:
"""Capture immutable routing data and a monotonic generation."""
self._reconcile_recovered_routing_locked()
return (
{key: entry.to_dict() for key, entry in self._entries.items()},
self._next_routing_generation_locked(),
)
def _persist_routing_data(self, data: Dict[str, Any], generation: int) -> None:
"""Serialize all whole-index writers through one durable write lock."""
with self._lazy("_save_lock", threading.Lock):
if generation <= getattr(self, "_persisted_routing_generation", 0):
return
# Fold in fast upserts numbered above this snapshot: they were
# serialized after us and a delayed full rewrite must not regress them.
fast_persisted = getattr(self, "_fast_persisted_entries", None)
if fast_persisted:
for key, (revision, entry_json) in fast_persisted.items():
if revision > generation:
data[key] = json.loads(entry_json)
db_saved = False
replacer = self._routing_db_method("replace_gateway_routing_entries")
if replacer is not None:
try:
replacer(
{k: json.dumps(v) for k, v in data.items()},
scope=self._routing_scope(),
)
db_saved = True
except Exception as exc:
logger.warning("gateway.session: state.db routing save failed: %s", exc)
if getattr(self, "_write_sessions_json", True) or not db_saved:
try:
self._save_sessions_json(data)
except Exception as exc:
if not db_saved:
raise
# state.db is authoritative. A failed legacy mirror must not
# report the already-committed primary write as failed.
logger.warning(
"gateway.session: sessions.json mirror save failed "
"after state.db commit: %s",
exc,
)
self._persisted_routing_generation = generation
# This rewrite supersedes fast records at or below its
# generation; newer ones stay for the next delayed full writer.
if fast_persisted:
for key in [
k for k, (rev, _) in fast_persisted.items()
if rev <= generation
]:
del fast_persisted[key]
def _save_sessions_json(self, data: Dict[str, Any]) -> None:
"""Write the legacy sessions.json mirror of the routing index."""
import tempfile
self.sessions_dir.mkdir(parents=True, exist_ok=True)
sessions_file = self.sessions_dir / "sessions.json"
# Self-documenting sentinel; "_" keys are skipped on load. Ordered
# first so it renders at the top of the file.
data = {
"_README": (
"LEGACY MIRROR of the gateway routing index (the primary copy "
"lives in the gateway_routing table in ~/.hermes/state.db). "
"Maps messaging session keys (agent:main:<platform>:...) to "
"active session IDs. This is NOT the session list. ALL "
"sessions (CLI, TUI, and gateway) live in ~/.hermes/state.db "
"and are shown by `hermes sessions list` and `/sessions`. "
"Disable this file with `gateway.write_sessions_json: false` "
"in config.yaml."
),
**data,
}
fd, tmp_path = tempfile.mkstemp(
dir=str(self.sessions_dir), suffix=".tmp", prefix=".sessions_"
)
try:
with os.fdopen(fd, "w", encoding="utf-8") as f:
json.dump(data, f, indent=2)
f.flush()
os.fsync(f.fileno())
atomic_replace(tmp_path, sessions_file)
except BaseException:
try:
os.unlink(tmp_path)
except OSError as e:
logger.debug("Could not remove temp file %s: %s", tmp_path, e)
raise
def _save_entries(self) -> None:
"""Snapshot latest state under ``_lock`` and persist after releasing it."""
with self._lock:
data, generation = self._snapshot_routing_locked()
self._persist_routing_data(data, generation)
def _save_entry(
self,
session_key: str,
*,
entry_data: Optional[Dict[str, Any]] = None,
lock_held: bool = False,
) -> None:
"""Persist ONE routing entry via UPSERT — the per-turn fast path
(a full rewrite fsyncs a multi-MB sessions.json, ~50ms at ~1100 keys).
Invariants: the key -> session_id mapping never changes here —
structural transitions (create/recover/reset/switch/prune/heal) use the
full rewrite, which also refreshes the sessions.json mirror (it may lag
in metadata only; state.db stays primary). The entry is serialized under
``_lock`` with a revision from the shared routing generation counter
(higher == same-or-newer); under ``_save_lock`` the upsert is skipped if
a full snapshot or a newer fast save of this key already persisted (the
reverse case lives in ``_persist_routing_data``). No DB or a failed
upsert falls back to the full rewrite so DB-less installs stay durable.
``entry_data`` persists a candidate BEFORE it is published to the live
entry (failure-atomic transitions); the fallback carries the same candidate.
"""
def _capture() -> Optional[tuple[str, int, Optional[Dict[str, Any]]]]:
entry = self._entries.get(session_key)
if entry is None:
return None
serialized_entry = (
dict(entry_data) if entry_data is not None else entry.to_dict()
)
entry_json = json.dumps(serialized_entry)
revision = self._next_routing_generation_locked()
# The O(n) full snapshot is deferred to the fallback branch.
return entry_json, revision, serialized_entry if entry_data is not None else None
if lock_held:
captured = _capture()
else:
with self._lock:
captured = _capture()
if captured is None:
return
entry_json, revision, candidate_entry = captured
saver = self._routing_db_method("save_gateway_routing_entry")
if saver is not None:
try:
with self._lazy("_save_lock", threading.Lock):
if getattr(self, "_persisted_routing_generation", 0) >= revision:
return
fast_persisted = self._lazy("_fast_persisted_entries", dict)
persisted = fast_persisted.get(session_key)
if persisted is not None and persisted[0] >= revision:
return
saver(session_key, entry_json, scope=self._routing_scope())
fast_persisted[session_key] = (revision, entry_json)
return
except Exception as exc:
logger.warning(
"gateway.session: single-entry routing save failed for %r "
"(%s); falling back to full index rewrite",
session_key, exc,
)
if candidate_entry is not None:
# Full-snapshot fallback carrying the candidate transition.
def _snapshot() -> Dict[str, Any]:
return {key: current.to_dict() for key, current in self._entries.items()}
if lock_held:
fallback_data = _snapshot()
else:
with self._lock:
fallback_data = _snapshot()
fallback_data[session_key] = candidate_entry
self._persist_routing_data(fallback_data, revision)
else:
self._save_entries()