3 Commits

Author SHA1 Message Date
Willem Jiang
c57d57ec63
doc(backend): Fixes the links of the backend documents (#5764) 2026-09-23 15:24:13 +08:00
zeng-bohan
ce3e64242b
feat(gateway): checkpoint retention service on the #4189 deletion contract (#5308)
* feat(gateway): thread checkpoint retention service on the #4189 deletion contract

Implements exactly the two contract-proven deletion shapes (trailing
duration-only leaves, opt-in leaf sibling branches) with head-chain
protection, explicit id protection, a strict pending-writes guard, and
joint writes-row cleanup. Head resolution uses LangGraph's time-ordered
checkpoint ids; storage deletion mirrors the contract's per-backend data
model. Ships without a production trigger by design. Validated against
the contract suite (12 passed) plus 14 service scenarios across memory
and SQLite; Postgres paths are gated on TEST_POSTGRES_URI.

Signed-off-by: zengbohan1 <310902929+zengbohan1@users.noreply.github.com>

* fix(gateway): survivor-reachability blob GC and memory blob stats in retention service

Aligns the deletion service with the review-hardened contract: blob rows
are garbage-collected in a whole-thread pass against surviving
checkpoints' channel_versions (a real duration-only leaf shares its
parent's versions, so per-checkpoint version deletion would corrupt the
surviving state), the memory branch of the stats helper counts
saver.blobs and returns the full normalized shape, and per-node channel
versions are collected during the graph pass that already exists.

Signed-off-by: zengbohan1 <310902929+zengbohan1@users.noreply.github.com>

* fix(gateway): address review findings on checkpoint retention service

Resolves the review at a479cfe (willem-bd):

- Untested savers now fail fast: an explicit isinstance allowlist
  (InMemorySaver / AsyncSqliteSaver / AsyncPostgresSaver) raises
  NotImplementedError before any row is read or deleted, so a shallow or
  third-party saver can never issue partial DELETEs.
- The chain walk ends (break) instead of raising KeyError when the head's
  ancestor row is missing, matching the deletable loop's tolerance for
  missing parents.
- enforce_thread_retention takes an optional per-thread lock and documents
  the concurrency requirement: classification and deletion are two separate
  passes, so callers must serialize per-thread mutation (runtime
  _checkpoint_thread_lock) or guarantee quiescence.
- Dropped the dead mid-run guard: CheckpointTuple has no `next` field in
  langgraph-checkpoint 4.1.1, and pending_writes is populated for committed
  writes too (verified on the list path), so neither is a usable mid-run
  signal; the caller-held thread lock is the actual protection.
- Removed the write-only _node_step/_Node.step and fixed the head-selection
  docstring (newest by checkpoint id, not (step, checkpoint_id)).
- Documented the E1 leaf / history fast-path interaction in the contract doc
  and module docstring: the wiring PR must sequence retention away from
  history reads or adopt a policy that spares cache-carrying leaves.
- Added regression tests: unsupported saver, missing ancestor row, thread
  lock parameter.

Validation: test_checkpoint_retention_service 18 passed / 8 postgres-gated
skipped; contract + lineage suites 18 passed / 6 skipped; ruff check and
format clean.

* fix(retention): count non-empty writes dicts on memory saver

- _checkpoint_ids_with_writes now requires a non-empty writes dict on
  InMemorySaver: the empty phantom entry for checkpoints whose task wrote
  nothing no longer counts as "owns writes rows", so the default E1 pruning
  reaches the memory backend again (it was a silent no-op there).
- test_runtime_duration_leaf_pruned_by_default runs the shipping default
  (strict_pending_write_guard=True) and proves E1 is reachable out of the
  box on every backend; the stale override and its wrong SQLite premise
  are dropped.
- document that _checkpoint_thread_lock is non-reentrant: a caller already
  holding it must not pass it in, or retention self-deadlocks.

* test(checkpoint-retention): fix stray duplicated def token in test_duration_link_protected_after_next_run

The previous push left `async def def test_...` at line 244, which made the
module unimportable and failed collection of the whole suite (and ruff
format --check). Local copy was already correct; this commit re-pushes the
clean file. 18 passed / 8 postgres-skipped verified from a head worktree.

* fix(gateway): make retention correct on Postgres and fail closed on a bad cap

* validate max_delete_per_run before any store read: a negative cap used to
  widen the batch (Python slicing) instead of being rejected;
* report identical before/after stats for an empty thread instead of returning
  before stats_after is collected;
* protect each namespace's resume head and ancestor chain, so a persistent
  subgraph's latest checkpoint is no longer treated as a sibling leaf;
* read Postgres columns through a row-factory-agnostic helper (the PG savers
  open cursors with dict_row, where positional access raises KeyError: 0);
* classify the duration-only leaf without relying on metadata["writes"], which
  the Postgres saver strips via get_serializable_checkpoint_metadata.

Verified locally on memory, SQLite and a real Postgres 16 instance (62 passed,
0 skipped): the E1 shape now fires on Postgres, which no backend test covered
before CI ran the Postgres lig.

Signed-off-by: zeng-bohan <zengbh1@gmail.com>

* test(gateway): pin the Postgres-shape duration classifier; report per-namespace heads

- Deterministic regression for _mark_duration_leaves_without_the_marker:
  hand-put the Postgres round-trip shape (writes marker popped, source=
  update + accumulated run_durations + channel_versions identical to the
  parent) and assert the shipping default prunes it; a control that bumps
  one channel version (the client update_state shape) with otherwise
  identical metadata stays protected. Both legs run on memory and SQLite,
  so the class cannot silently re-widen (a resumable head losing head
  protection) or re-narrow (E1 never firing on Postgres) without a
  locally-executing test failing.
- RetentionReport.protected_head_id -> protected_head_ids: heads are now
  selected per namespace, so the report carries every namespace's head
  (root key = what an unsaved aget_tuple resolves) instead of only the
  global max - reshape it before the wiring PR starts consuming reports
  for audit/aggregation.

---------

Signed-off-by: zengbohan1 <310902929+zengbohan1@users.noreply.github.com>
Signed-off-by: zeng-bohan <zengbh1@gmail.com>
Co-authored-by: zengbohan1 <310902929+zengbohan1@users.noreply.github.com>
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
2026-09-18 16:46:19 +08:00
zeng-bohan
a2808e8292
test(checkpoint): retention deletion contract + growth baseline (#4189 item 3) (#5255)
* test(checkpoint): retention deletion contract + growth baseline

Six contract scenarios x memory/sqlite/postgres pin what retention deletions
must never break (branch ancestors, explicit resume targets, pending writes,
duration-only chain links), prove the two safe shapes (leaf sibling branches,
trailing duration leaves), record the full-vs-delta growth baseline in the
normalized bench shape, and add an item 4 probe showing the default
ToolOutputBudgetMiddleware already externalizes oversized tool results.

Refs #4189

* test(checkpoint): make the retention contract load-bearing per review

Review findings from willem-bd and Ricky-7-Yan:

- scenario D pins its own row: before/after stats delta plus a serde
  round-trip of the stored write, instead of an always-true > 0 check
- _delete_checkpoint now performs the joint delete the doc mandates
  (checkpoint row + writes rows + blobs unreachable from surviving
  checkpoints), so E1/E2 exercise the shape they prescribe
- E1 builds the real runtime duration shape via persist_run_durations
  (parent dict clone, fresh id/ts, real metadata), which surfaces the
  shared-version case: the leaf's blobs are the surviving parent's rows
- contract doc: blob reachability must be computed from surviving
  checkpoints in a whole-thread pass; shared-version/duration-only
  hazard called out explicitly; memory data model includes saver.blobs
- _stats counts memory blob rows and returns the full normalized shape
  (logical byte totals included)
- probe: drops the unused middleware/outputs_dir graph parameters and
  discloses the manual-harness scope limit in the module docstring
- E1/E2 assert default head resolution (protected set item 5); unused
  graph_for helper and DURATION_ONLY_METADATA stand-in removed

Signed-off-by: zengbohan1 <310902929+zengbohan1@users.noreply.github.com>

* fix(checkpoint): scope probe cleanup to owned dirs, key report by backend

Second-round review findings on #5255:

- [P1] bench_tool_result_probe.py removed the whole user-supplied
  --outputs-dir (and the shared .probe-tmp) in its finally block, so
  pre-existing files were deleted on success and failure alike. The run
  now writes into (and removes) a fresh owned probe-run-* child beneath
  the requested directory, and SQLite databases live in a unique
  mkdtemp'd temp directory that is removed with the run. Regression
  tests pin that unrelated pre-existing files survive both a successful
  and a simulated failing run.
- [P2] the optional retention report keyed every backend's measurements
  under one shared name, so a multi-backend invocation kept only the
  last backend's numbers. _report() now takes the parameterized backend
  explicitly (saver_env.kind); regression pins that memory and sqlite
  entries coexist in one report file.

Signed-off-by: zengbohan1 <310902929+zengbohan1@users.noreply.github.com>

---------

Signed-off-by: zengbohan1 <310902929+zengbohan1@users.noreply.github.com>
Co-authored-by: zengbohan1 <310902929+zengbohan1@users.noreply.github.com>
2026-09-08 19:21:57 +08:00