493 lines
22 KiB
Python
493 lines
22 KiB
Python
import os
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from dataclasses import dataclass
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from typing import Any, final
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from lightrag.base import (
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BaseKVStorage,
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)
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from lightrag.file_atomic import reap_orphan_tmp_files
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from lightrag.utils import (
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_cooperative_yield,
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load_json,
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logger,
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validate_workspace,
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write_json,
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)
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from lightrag.exceptions import StorageNotInitializedError
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from .shared_storage import (
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get_namespace_data,
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get_namespace_lock,
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get_data_init_lock,
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get_update_flag,
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set_all_update_flags,
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clear_all_update_flags,
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try_initialize_namespace,
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)
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@final
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@dataclass
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class JsonKVStorage(BaseKVStorage):
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"""JSON-file-backed KV storage with **shared in-memory state across processes**.
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This class uses a *fundamentally different* cross-process model from
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``NanoVectorDBStorage`` / ``FaissVectorDBStorage`` / ``NetworkXStorage``
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(which keep one in-memory copy per process and reconcile via file
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reloads). Compare carefully before changing either side.
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Storage model:
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``self._data`` is **not** a per-process dict — it is the value
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returned by ``get_namespace_data(namespace, workspace=...)``, i.e.
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a reference into ``shared_storage._shared_dicts``. In multi-
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process mode this is a ``multiprocessing.Manager().dict()`` proxy
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that every worker sees the **same instance** of; in single-
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process mode it degrades to a plain ``dict``. Either way, a
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mutation in any process is *immediately* visible to every other
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process — there is no reload needed.
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The on-disk file at
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``working_dir/[workspace/]kv_store_<namespace>.json`` exists for
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durability only. It is the source of truth at startup and the
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target of ``index_done_callback`` flushes, but is **not** part of
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the steady-state read/write path.
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First-time load (``initialize``):
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``try_initialize_namespace`` is a global init lock that returns
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``True`` to exactly one process per ``(namespace, workspace)``.
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That process reads the JSON file and populates ``self._data``
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under ``_storage_lock``. Other processes skip the load — they
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will see the data through the same shared ``self._data`` proxy.
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Cross-process sync protocol (note: reversed semantics vs file-backed
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classes):
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Anyone writing (``upsert`` / ``delete`` / ``drop``):
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1. Mutate ``self._data`` under ``_storage_lock`` (same lock,
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same dict, all processes see the change immediately).
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2. Call ``set_all_update_flags`` to mark **every** process's
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``storage_updated`` flag ``True``. Here ``True`` means
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*"there is dirty data that still needs to be flushed"*,
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not *"there is fresher data on disk that I need to
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reload"* as in the file-backed implementations.
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Commit (``index_done_callback``):
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1. Under ``_storage_lock``, if ``storage_updated.value`` is
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``True``, snapshot ``self._data`` and write it to disk
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via ``write_json`` (atomic).
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2. ``clear_all_update_flags`` — wipe every process's flag
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back to ``False``. Because the in-memory state is already
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consistent across processes, there is nothing for the
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*other* processes to do; the clear is just a
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"the dirty data has been persisted" signal.
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Lock scope:
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``_storage_lock`` is a per-``(namespace, workspace)`` keyed lock
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spanning intra-process coroutines **and** inter-process workers.
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Unlike the file-backed classes (which only lock reload/commit
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critical sections), this class **holds the lock over every
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``self._data`` access** — read or write — because the underlying
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``Manager().dict()`` is not free-threaded across processes.
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Two places intentionally do work outside the lock for latency
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reasons:
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* ``upsert`` performs its per-key timestamp prep loop inside
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the lock but yields to the event loop via
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``_cooperative_yield`` between keys (safe: ``NamespaceLock``
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is non-reentrant, so siblings blocked on it stay blocked).
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* ``JsonDocStatusStorage.upsert`` prepares its caller-supplied
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dict outside the lock (it only mutates the input, not the
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shared store).
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Who can write:
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Pipeline ``busy`` still serializes the document ingest / purge
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flows, but the *file-flush trigger* is symmetric: any process
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whose ``storage_updated.value`` is ``True`` when
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``index_done_callback`` fires will perform the write. In a
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single-writer pipeline this is always the same process; if you
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ever permit multiple writers, two processes may race to flush
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the same in-memory state — that race is safe (both flush the
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same shared dict, ``write_json`` is atomic per file) but
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wasteful, and the ``clear_all_update_flags`` after each flush
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means subsequent re-flushes are no-ops.
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Caveats vs file-backed implementations:
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* **No reload path.** If something writes to the on-disk file
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out of band, this class will not pick it up until restart.
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The file is only ever written by ``index_done_callback`` and
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read once in ``initialize``.
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* **No ``_get_*`` entry method.** Adding one would be wrong —
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there's nothing to "get fresher than" since the in-memory
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state is already the shared, authoritative view.
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* **``write_json`` may sanitize.** If sanitization happens, the
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on-disk JSON differs from what was in memory; the callback
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re-reads the cleaned file back into ``self._data`` under the
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same lock so the shared view stays consistent with disk.
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Non-pipeline write paths:
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* ``drop`` — destructive, **not** serialized by this storage
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class. Currently gated by the API layer
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(``/documents/clear``); any new caller must hold the pipeline
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``busy`` reservation.
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* ``upsert`` / ``delete`` invoked from non-pipeline admin flows
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(cache management, etc.) — safe under the shared-lock model,
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but consumers should still respect the pipeline gate to avoid
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interleaving with batched ingest work.
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"""
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def __post_init__(self):
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# Reject path traversal before using workspace in a file path
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validate_workspace(self.workspace)
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working_dir = self.global_config["working_dir"]
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if self.workspace:
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# Include workspace in the file path for data isolation
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workspace_dir = os.path.join(working_dir, self.workspace)
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else:
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# Default behavior when workspace is empty
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workspace_dir = working_dir
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self.workspace = ""
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os.makedirs(workspace_dir, exist_ok=True)
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self._file_name = os.path.join(workspace_dir, f"kv_store_{self.namespace}.json")
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self._data = None
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self._storage_lock = None
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self.storage_updated = None
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reap_orphan_tmp_files(self._file_name, self.workspace or "_")
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async def initialize(self):
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"""Bind to the shared namespace dict and load from disk on first init.
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``try_initialize_namespace`` is a global init lock that returns
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``True`` for exactly one process per ``(namespace, workspace)``;
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that process reads the JSON file and populates the shared
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``self._data`` under ``_storage_lock``. Subsequent processes
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skip the file read — they will see the same shared dict via
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``get_namespace_data``.
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For ``*_cache`` namespaces an extra
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``_migrate_legacy_cache_structure`` pass runs against the loaded
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data and may rewrite the on-disk file if a migration was applied.
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"""
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self._storage_lock = get_namespace_lock(
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self.namespace, workspace=self.workspace
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)
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self.storage_updated = await get_update_flag(
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self.namespace, workspace=self.workspace
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)
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async with get_data_init_lock():
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# check need_init must before get_namespace_data
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need_init = await try_initialize_namespace(
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self.namespace, workspace=self.workspace
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)
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self._data = await get_namespace_data(
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self.namespace, workspace=self.workspace
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)
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if need_init:
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loaded_data = load_json(self._file_name) or {}
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async with self._storage_lock:
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# Migrate legacy cache structure if needed
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if self.namespace.endswith("_cache"):
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loaded_data = await self._migrate_legacy_cache_structure(
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loaded_data
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)
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self._data.update(loaded_data)
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data_count = len(loaded_data)
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logger.info(
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f"[{self.workspace}] Process {os.getpid()} KV load {self.namespace} with {data_count} records"
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)
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async def index_done_callback(self) -> None:
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"""Flush dirty in-memory state to disk and clear all dirty flags.
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Commit point in the shared-memory protocol (see class docstring,
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*Cross-process sync protocol*). Steps:
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1. Under ``_storage_lock``, check this process's
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``storage_updated.value``. If ``False``, nothing to do —
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return.
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2. Snapshot ``self._data`` (converting from ``Manager.dict``
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proxy to a plain ``dict`` so the JSON encoder doesn't trip
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over the proxy) and write it via ``write_json``.
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3. If ``write_json`` reports sanitization was applied, the
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on-disk file no longer matches what was in memory — reload
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the cleaned data back into ``self._data`` under the same
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lock so the shared view stays consistent.
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4. ``clear_all_update_flags`` — wipe every process's
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``storage_updated`` flag back to ``False``, signaling
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that the dirty data has been persisted.
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Note the **semantic difference** from the file-backed classes'
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commit: there is no ``set_all_update_flags`` here. The shared
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dict is already consistent across processes; the only thing
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``index_done_callback`` does globally is *clear* the dirty
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flags.
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"""
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async with self._storage_lock:
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if self.storage_updated.value:
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data_dict = (
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dict(self._data) if hasattr(self._data, "_getvalue") else self._data
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)
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# Calculate data count - all data is now flattened
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data_count = len(data_dict)
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logger.debug(
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f"[{self.workspace}] Process {os.getpid()} KV writting {data_count} records to {self.namespace}"
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)
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# Write JSON and check if sanitization was applied
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needs_reload = write_json(data_dict, self._file_name)
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# If data was sanitized, reload cleaned data to update shared memory
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if needs_reload:
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logger.info(
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f"[{self.workspace}] Reloading sanitized data into shared memory for {self.namespace}"
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)
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cleaned_data = load_json(self._file_name)
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if cleaned_data is not None:
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self._data.clear()
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self._data.update(cleaned_data)
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await clear_all_update_flags(self.namespace, workspace=self.workspace)
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async def get_by_id(self, id: str) -> dict[str, Any] | None:
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async with self._storage_lock:
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result = self._data.get(id)
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if result:
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# Create a copy to avoid modifying the original data
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result = dict(result)
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# Ensure time fields are present, provide default values for old data
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result.setdefault("create_time", 0)
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result.setdefault("update_time", 0)
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# Ensure _id field contains the clean ID
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result["_id"] = id
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return result
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async def get_by_ids(self, ids: list[str]) -> list[dict[str, Any]]:
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async with self._storage_lock:
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results = []
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for id in ids:
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data = self._data.get(id, None)
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if data:
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# Create a copy to avoid modifying the original data
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result = {k: v for k, v in data.items()}
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# Ensure time fields are present, provide default values for old data
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result.setdefault("create_time", 0)
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result.setdefault("update_time", 0)
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# Ensure _id field contains the clean ID
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result["_id"] = id
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results.append(result)
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else:
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results.append(None)
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return results
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async def filter_keys(self, keys: set[str]) -> set[str]:
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async with self._storage_lock:
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return set(keys) - set(self._data.keys())
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async def upsert(self, data: dict[str, dict[str, Any]]) -> None:
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"""Insert or update KV records in shared memory; mark all processes dirty.
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Two side effects under ``_storage_lock``:
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1. Stamp ``create_time`` / ``update_time`` / ``_id`` on each
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value, then ``self._data.update(data)``. Because
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``self._data`` is the shared ``Manager.dict()`` proxy, the
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update is visible to all processes immediately — no
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reload needed.
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2. ``set_all_update_flags`` — flip every process's
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``storage_updated.value`` to ``True``. Here ``True``
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means *"there is dirty data that still needs to be
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flushed to disk"*, **not** *"there is fresher data on
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disk"* as in the file-backed classes (see class docstring
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for the contrast).
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Persistence is deferred to the next ``index_done_callback`` (the
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pipeline calls this via ``_insert_done()`` after each batch).
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Note: the per-key prep loop calls ``_cooperative_yield`` inside
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the lock. That is safe because ``NamespaceLock`` is non-
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reentrant — siblings waiting on this lock stay blocked across
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the yield; only unrelated coroutines benefit from the yield.
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"""
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if not data:
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return
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import time
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current_time = int(time.time()) # Get current Unix timestamp
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logger.debug(
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f"[{self.workspace}] Inserting {len(data)} records to {self.namespace}"
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)
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if self._storage_lock is None:
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raise StorageNotInitializedError("JsonKVStorage")
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async with self._storage_lock:
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# Add timestamps to data based on whether key exists.
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# The loop reads self._data (k in self._data) so it must stay inside
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# the lock. _cooperative_yield is safe here: NamespaceLock is
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# non-reentrant, so other coroutines waiting on this lock will block
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# until we release it; the yield only benefits unrelated coroutines.
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for i, (k, v) in enumerate(data.items(), start=1):
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# For text_chunks namespace, ensure llm_cache_list field exists
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if self.namespace.endswith("text_chunks"):
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if "llm_cache_list" not in v:
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v["llm_cache_list"] = []
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# Add timestamps based on whether key exists
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if k in self._data: # Key exists, only update update_time
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v["update_time"] = current_time
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else: # New key, set both create_time and update_time
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v["create_time"] = current_time
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v["update_time"] = current_time
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v["_id"] = k
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await _cooperative_yield(i)
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self._data.update(data)
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await set_all_update_flags(self.namespace, workspace=self.workspace)
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async def delete(self, ids: list[str]) -> None:
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"""Remove records from shared memory; mark all processes dirty if any deleted.
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Under ``_storage_lock``: ``self._data.pop(doc_id, None)`` for
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each id. Only calls ``set_all_update_flags`` if at least one key
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was actually present (avoids creating spurious dirty state for
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no-op deletes).
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See class docstring for the shared-memory + dirty-flag protocol
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and the semantic contrast vs file-backed classes.
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Args:
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ids: List of document IDs to be deleted from storage
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"""
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async with self._storage_lock:
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any_deleted = False
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for doc_id in ids:
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result = self._data.pop(doc_id, None)
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if result is not None:
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any_deleted = True
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if any_deleted:
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await set_all_update_flags(self.namespace, workspace=self.workspace)
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async def is_empty(self) -> bool:
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"""Check if the storage is empty
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Returns:
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bool: True if storage contains no data, False otherwise
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"""
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async with self._storage_lock:
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return len(self._data) == 0
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async def drop(self) -> dict[str, str]:
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"""Clear shared memory and immediately persist the empty state.
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This method will:
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1. Clear the shared ``self._data`` dict under
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``_storage_lock`` (visible to all processes immediately).
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2. ``set_all_update_flags`` so every process knows there is
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dirty state pending persistence.
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3. Call ``index_done_callback`` synchronously to flush the
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empty state to disk and clear the dirty flags.
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Caller contract:
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``drop`` is destructive and **not** serialized by this
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storage class. The caller must hold the pipeline ``busy``
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reservation (the ``/documents/clear`` endpoint does this)
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before invoking it — running ``drop`` concurrently with an
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active document pipeline will wipe out in-flight work and
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silently lose data. See class docstring,
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*Non-pipeline write paths*.
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Returns:
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dict[str, str]: Operation status and message
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- On success: {"status": "success", "message": "data dropped"}
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- On failure: {"status": "error", "message": "<error details>"}
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"""
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try:
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async with self._storage_lock:
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self._data.clear()
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await set_all_update_flags(self.namespace, workspace=self.workspace)
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await self.index_done_callback()
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logger.info(
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f"[{self.workspace}] Process {os.getpid()} drop {self.namespace}"
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)
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return {"status": "success", "message": "data dropped"}
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except Exception as e:
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logger.error(f"[{self.workspace}] Error dropping {self.namespace}: {e}")
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return {"status": "error", "message": str(e)}
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async def _migrate_legacy_cache_structure(self, data: dict) -> dict:
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"""Migrate legacy nested cache structure to flattened structure
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Args:
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data: Original data dictionary that may contain legacy structure
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Returns:
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Migrated data dictionary with flattened cache keys (sanitized if needed)
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"""
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from lightrag.utils import generate_cache_key
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# Early return if data is empty
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if not data:
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return data
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# Check first entry to see if it's already in new format
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first_key = next(iter(data.keys()))
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if ":" in first_key and len(first_key.split(":")) == 3:
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# Already in flattened format, return as-is
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return data
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migrated_data = {}
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migration_count = 0
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for key, value in data.items():
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# Check if this is a legacy nested cache structure
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if isinstance(value, dict) and all(
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isinstance(v, dict) and "return" in v for v in value.values()
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):
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# This looks like a legacy cache mode with nested structure
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mode = key
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for cache_hash, cache_entry in value.items():
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cache_type = cache_entry.get("cache_type", "extract")
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flattened_key = generate_cache_key(mode, cache_type, cache_hash)
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migrated_data[flattened_key] = cache_entry
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migration_count += 1
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else:
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# Keep non-cache data or already flattened cache data as-is
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migrated_data[key] = value
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if migration_count > 0:
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logger.info(
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f"[{self.workspace}] Migrated {migration_count} legacy cache entries to flattened structure"
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)
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# Persist migrated data immediately and check if sanitization was applied
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needs_reload = write_json(migrated_data, self._file_name)
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# If data was sanitized during write, reload cleaned data
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if needs_reload:
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logger.info(
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f"[{self.workspace}] Reloading sanitized migration data for {self.namespace}"
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)
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cleaned_data = load_json(self._file_name)
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if cleaned_data is not None:
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return cleaned_data # Return cleaned data to update shared memory
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return migrated_data
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|
|
|
async def finalize(self):
|
|
"""On shutdown, flush ``*_cache`` namespaces to disk.
|
|
|
|
Cache namespaces are routinely written to during query/extract
|
|
without triggering an immediate ``index_done_callback`` (caches
|
|
churn fast and the pipeline doesn't always end at a natural
|
|
commit point). This hook ensures whatever dirty cache state is
|
|
in shared memory at process exit gets persisted, so the next
|
|
run can pick it up.
|
|
|
|
Non-cache namespaces don't need this — their writes already
|
|
flow through pipeline-driven ``_insert_done()`` commits.
|
|
"""
|
|
if self.namespace.endswith("_cache"):
|
|
await self.index_done_callback()
|