feat: add callback-based push subscription API#12
Merged
Conversation
- Add PyCheckpointResult frozen pyclass with checkpoint_id getter, __bool__, __int__, and __repr__ support - Change Connection.checkpoint() to return CheckpointResult instead of int | None - Add CheckpointResult to type stubs, exports, and __all__ - Add deprecation note to CheckpointStatus in types.py - Add comprehensive test suite (10 tests) covering disabled/enabled checkpointing, result properties, and after-close behavior
Add CallbackSubscription pyclass that runs a background thread polling for new batches and invoking a user-provided Python callable for each one. This provides a push-based alternative to the pull-based iterator subscriptions (Subscription, StreamSubscription, etc.). New methods on Connection: - subscribe_callback(sql, on_data, on_error=None) - subscribe_stream_callback(name, on_data, on_error=None) CallbackSubscription exposes is_active, cancel(), wait(), __repr__, and __del__. Error routing goes through on_error if provided; otherwise the subscription stops and logs to stderr. Also bumps version to 0.15.1.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
CallbackSubscriptionpyclass — a push-based subscription that runs a background thread and invokes a user-provided Python callable for each batch receivedConnection.subscribe_callback(sql, on_data, on_error=None)for SQL continuous queriesConnection.subscribe_stream_callback(name, on_data, on_error=None)for named streamsDesign
std::thread::spawn(not tokio) since the thread needsPython::with_gil()which is blockingtry_next()+ 50ms sleep polling loop gives responsive cancellation without busy-spinon_errorcallback allows transient error recovery; if absent or if it raises, the subscription stops__del__to avoid GIL deadlock when background thread is insidewith_gil()Files changed
src/callback.rsCallbackSubscriptionpyclass, background thread loop, factory methodssrc/connection.rssubscribe_callback()andsubscribe_stream_callback()src/lib.rsmod callbackandCallbackSubscriptionclasspython/laminardb/_laminardb.pyipython/laminardb/__init__.pyCallbackSubscriptiontests/test_callback_subscription.pyCargo.toml/pyproject.tomlTest plan
cargo fmt --check— cleancargo clippy -- -D warnings— cleancargo doc --no-deps— cleanpytest tests/test_callback_subscription.py— 16 passed, 2 skipped (data timing)pytest tests/(full suite) — 242 existing tests pass, zero regressions