feat(server): Add lock to TaskUpdater to prevent race conditions #279
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Summary of Changes
Hello @pankaj-bind, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!
This pull request addresses a potential race condition within the TaskUpdater component. My changes introduce an asyncio.Lock and state management to ensure that task status updates, especially when transitioning to a terminal state (like completed or failed), are handled atomically. This significantly enhances the robustness and stability of task state management by preventing multiple concurrent updates from corrupting the final state.
Highlights
- Concurrency Control: I've integrated an
asyncio.Lockinto theTaskUpdaterto serialize access to theupdate_statusmethod, preventing race conditions during concurrent modifications. - Terminal State Enforcement: The
TaskUpdaternow tracks whether a task has reached a terminal state (completed, canceled, failed, rejected). Once a task is in such a state, any subsequent attempts to update its status will raise aRuntimeError, ensuring state integrity. - Enhanced Test Coverage: I've added new unit tests specifically designed to validate the race condition prevention mechanism and the terminal state enforcement, including a test simulating concurrent updates.
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Code Review
This pull request introduces a lock to the TaskUpdater to prevent race conditions when updating a task's status, particularly to a terminal state. The implementation correctly uses asyncio.Lock to ensure atomic updates and adds a flag to prevent further updates once a terminal state is reached. The accompanying tests are well-written and cover both the new error-handling logic and the concurrent update scenario.
My review includes a high-severity issue regarding the consistency of the final flag for terminal states.
Overall, this is a solid improvement to the robustness of task state management.
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
🤖 I have created a release *beep* *boop* --- ## [0.2.11](v0.2.10...v0.2.11) (2025-07-07) ### ⚠ BREAKING CHANGES * Removes `push_notifier` interface from the SDK and introduces `push_notification_config_store` and `push_notification_sender` for supporting push notifications. ### Features * Add constants for Well-Known URIs ([#271](#271)) ([1c8e12e](1c8e12e)) * Adds support for List and Delete push notification configurations. ([f1b576e](f1b576e)) * Adds support for more than one `push_notification_config` per task. ([f1b576e](f1b576e)) * **server:** Add lock to TaskUpdater to prevent race conditions ([#279](#279)) ([1022093](1022093)) * Support for database backend Task Store ([#259](#259)) ([7c46e70](7c46e70)) ### Code Refactoring * Removes `push_notifier` interface from the SDK and introduces `push_notification_config_store` and `push_notification_sender` for supporting push notifications. ([f1b576e](f1b576e)) --- This PR was generated with [Release Please](https://github.com/googleapis/release-please). See [documentation](https://github.com/googleapis/release-please#release-please). Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>
Description
This PR adds a lock to the
TaskUpdaterto prevent race conditions when updating tasks that are in a terminal state (e.g., completed, failed). This ensures updates are handled atomically, making task state management more robust.File Changes
src/a2a/server/tasks/task_updater.pytests/server/tasks/test_task_updater.pyBenefits
Thank you for opening a Pull Request!
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CONTRIBUTINGGuide.fix:which represents bug fixes, and correlates to a SemVer patch.feat:represents a new feature, and correlates to a SemVer minor.feat!:, orfix!:,refactor!:, etc., which represent a breaking change (indicated by the!) and will result in a SemVer major.nox -s formatfrom the repository root to format)Fixes #278 🦕