fix: Critical async safety issues (Gap 2 from #1289)#1294
Conversation
…Lock, add postgres init race protection, fix state store save races Addresses Gap 2 from issue #1289: 1. Replace asyncio.Lock() with threading.Lock() in Process.__init__() - asyncio.Lock in sync constructor fails outside event loop 2. Add async lock protection to async postgres store init() to prevent race conditions creating duplicate connection pools 3. Fix memory state store _maybe_save() race condition where multiple threads could trigger overlapping saves 4. Verified existing thread safety in global error_logs, callbacks already properly protected with locks 5. Verified MemoryMixin already has proper thread safety with _history_lock These changes ensure multi-agent safety by eliminating race conditions and thread safety issues that could corrupt state or cause crashes when running multiple agents concurrently. Co-authored-by: Mervin Praison <MervinPraison@users.noreply.github.com>
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📝 WalkthroughWalkthroughThis PR addresses async-safety and concurrency vulnerabilities across three modules by introducing proper synchronization primitives. It replaces an incorrectly-created async lock with a thread lock in Changes
Estimated code review effort🎯 3 (Moderate) | ⏱️ ~20 minutes Possibly related PRs
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Code Review
This pull request introduces thread-safety improvements by transitioning from asyncio to threading locks and adding synchronization to the PostgreSQL and memory persistence layers. However, several issues were identified: the change to threading.Lock in process.py will cause runtime errors in asynchronous contexts, the lazy initialization of the lock in async_postgres.py is not thread-safe, and the lock acquisition in memory.py is redundant as the lock is already held by callers.
| self.task_retry_counter: Dict[str, int] = {} # Initialize retry counter | ||
| self.workflow_finished = False # ADDED: Workflow finished flag | ||
| self._state_lock = asyncio.Lock() # Async lock for shared state protection | ||
| self._state_lock = threading.Lock() # Thread lock for shared state protection |
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The change from asyncio.Lock to threading.Lock will cause a runtime error in the aworkflow method (line 600) because threading.Lock is not an asynchronous context manager and does not support the async with statement.
Since this class is intended to be thread-safe, you should update the usage at line 600 to use a standard with statement instead of async with.
| if self._init_lock is None: | ||
| import asyncio | ||
| self._init_lock = asyncio.Lock() |
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The lazy initialization of self._init_lock is not thread-safe. In a multi-threaded environment, multiple threads calling init() simultaneously could each see self._init_lock as None and create their own asyncio.Lock instances, bypassing the intended synchronization. To ensure true multi-agent safety across threads, self._init_lock should be initialized as a threading.Lock in the constructor.
| with self._lock: | ||
| if time.time() - self._last_save >= self.save_interval: | ||
| self._save() |
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The addition of with self._lock: here appears to be redundant. All current callers of _maybe_save (such as set, delete, expire, etc.) already acquire self._lock before calling this method. Since self._lock is a threading.RLock, this nested acquisition is safe but unnecessary for protecting the check-then-act logic on _last_save.
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Actionable comments posted: 2
🧹 Nitpick comments (2)
src/praisonai/praisonai/persistence/conversation/async_postgres.py (1)
70-72: Remove redundant import statement.
asynciois already imported at line 8; the nested import at line 71 is unnecessary.♻️ Suggested fix
if self._init_lock is None: - import asyncio self._init_lock = asyncio.Lock()🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@src/praisonai/praisonai/persistence/conversation/async_postgres.py` around lines 70 - 72, The nested import of asyncio inside the conditional that sets self._init_lock is redundant; remove the inner "import asyncio" and simply call asyncio.Lock() (relying on the module already imported at top-level) where self._init_lock is assigned so the block becomes: if self._init_lock is None: self._init_lock = asyncio.Lock().src/praisonai-agents/praisonaiagents/process/process.py (1)
1266-1287: Consider adding lock protection for consistency with async version.The async
aworkflow()method wraps this same reset logic in a lock (line 600), but the syncworkflow()method does not. If the lock is necessary for thread safety in the async context, consider applying the same protection here for consistency:♻️ Suggested change for consistency
# Reset completed task to "not started" so it can run again - if self.tasks[task_id].status == "completed": + with self._state_lock: + if self.tasks[task_id].status == "completed": # Never reset loop tasks, decision tasks, or their subtasks if rerun is False subtask_name = self.tasks[task_id].name ...🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed. In `@src/praisonai-agents/praisonaiagents/process/process.py` around lines 1266 - 1287, The sync workflow() method should use the same lock protection as aworkflow() around the "Reset completed task to 'not started'" block to ensure thread-safety; wrap the entire conditional/reset logic that checks self.tasks[task_id].status and sets self.tasks[task_id].status = "not started" with the same lock used in aworkflow() (e.g., self.lock or the existing workflow lock object) so the reset check and assignment are atomic and consistent with aworkflow().
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.
Inline comments:
In `@src/praisonai-agents/praisonaiagents/process/process.py`:
- Line 48: The async context manager usage is wrong: self._state_lock is a
threading.Lock initialized in the constructor but the code uses "async with
self._state_lock" around the reset logic (same logic exists in workflow()),
which will raise AttributeError; change the async context to a synchronous one
by replacing "async with self._state_lock" with "with self._state_lock" (and
ensure any other occurrences at the same region use the same synchronous "with"
pattern) so the threading.Lock is used correctly without introducing asyncio
primitives in the constructor.
In `@src/praisonai/praisonai/persistence/conversation/async_postgres.py`:
- Around line 78-84: The ImportError handler around the asyncpg import in the
try/except block should preserve the original exception context; change the
except clause to capture the exception (e.g., "except ImportError as err") and
re-raise the custom ImportError using "from err" so the original traceback is
chained (the try/except importing asyncpg is the target).
---
Nitpick comments:
In `@src/praisonai-agents/praisonaiagents/process/process.py`:
- Around line 1266-1287: The sync workflow() method should use the same lock
protection as aworkflow() around the "Reset completed task to 'not started'"
block to ensure thread-safety; wrap the entire conditional/reset logic that
checks self.tasks[task_id].status and sets self.tasks[task_id].status = "not
started" with the same lock used in aworkflow() (e.g., self.lock or the existing
workflow lock object) so the reset check and assignment are atomic and
consistent with aworkflow().
In `@src/praisonai/praisonai/persistence/conversation/async_postgres.py`:
- Around line 70-72: The nested import of asyncio inside the conditional that
sets self._init_lock is redundant; remove the inner "import asyncio" and simply
call asyncio.Lock() (relying on the module already imported at top-level) where
self._init_lock is assigned so the block becomes: if self._init_lock is None:
self._init_lock = asyncio.Lock().
🪄 Autofix (Beta)
Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
- Create a new PR with the fixes
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📒 Files selected for processing (3)
src/praisonai-agents/praisonaiagents/process/process.pysrc/praisonai/praisonai/persistence/conversation/async_postgres.pysrc/praisonai/praisonai/persistence/state/memory.py
| self.task_retry_counter: Dict[str, int] = {} # Initialize retry counter | ||
| self.workflow_finished = False # ADDED: Workflow finished flag | ||
| self._state_lock = asyncio.Lock() # Async lock for shared state protection | ||
| self._state_lock = threading.Lock() # Thread lock for shared state protection |
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Critical: threading.Lock is incompatible with async with at line 600.
threading.Lock does not implement the async context manager protocol (__aenter__/__aexit__). Using async with self._state_lock at line 600 will raise AttributeError at runtime.
Options to fix:
- Use regular
withinstead ofasync with—threading.Lockworks with synchronous context managers and is safe in async code (it just blocks the thread briefly). - Lazy-initialize an
asyncio.Lockfor async methods while keepingthreading.Lockfor sync methods (more complex, requires two locks or a wrapper).
Given the sync workflow() method at lines 1266-1287 performs the same reset logic without any lock, option 1 appears safest and maintains consistency:
🐛 Proposed fix: use synchronous context manager
# Reset completed task to "not started" so it can run again (atomic operation)
- async with self._state_lock:
+ with self._state_lock:
if self.tasks[task_id].status == "completed":Note: The coding guidelines state "use asyncio primitives for coordination, not threading", but the PR objective explicitly requires avoiding asyncio primitive creation in sync constructors. Using threading.Lock with synchronous with is a valid compromise that satisfies both constraints.
Also applies to: 600-601
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@src/praisonai-agents/praisonaiagents/process/process.py` at line 48, The
async context manager usage is wrong: self._state_lock is a threading.Lock
initialized in the constructor but the code uses "async with self._state_lock"
around the reset logic (same logic exists in workflow()), which will raise
AttributeError; change the async context to a synchronous one by replacing
"async with self._state_lock" with "with self._state_lock" (and ensure any other
occurrences at the same region use the same synchronous "with" pattern) so the
threading.Lock is used correctly without introducing asyncio primitives in the
constructor.
| try: | ||
| import asyncpg | ||
| except ImportError: | ||
| raise ImportError( | ||
| "asyncpg is required for async PostgreSQL support. " | ||
| "Install with: pip install asyncpg" | ||
| ) |
There was a problem hiding this comment.
Chain the exception for better diagnostics.
Per static analysis hint, use raise ... from err to preserve the original exception context, or raise ... from None to explicitly suppress chaining.
🐛 Proposed fix
try:
import asyncpg
- except ImportError:
+ except ImportError as err:
raise ImportError(
"asyncpg is required for async PostgreSQL support. "
"Install with: pip install asyncpg"
- )
+ ) from err📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| try: | |
| import asyncpg | |
| except ImportError: | |
| raise ImportError( | |
| "asyncpg is required for async PostgreSQL support. " | |
| "Install with: pip install asyncpg" | |
| ) | |
| try: | |
| import asyncpg | |
| except ImportError as err: | |
| raise ImportError( | |
| "asyncpg is required for async PostgreSQL support. " | |
| "Install with: pip install asyncpg" | |
| ) from err |
🧰 Tools
🪛 Ruff (0.15.9)
[warning] 81-84: Within an except clause, raise exceptions with raise ... from err or raise ... from None to distinguish them from errors in exception handling
(B904)
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@src/praisonai/praisonai/persistence/conversation/async_postgres.py` around
lines 78 - 84, The ImportError handler around the asyncpg import in the
try/except block should preserve the original exception context; change the
except clause to capture the exception (e.g., "except ImportError as err") and
re-raise the custom ImportError using "from err" so the original traceback is
chained (the try/except importing asyncpg is the target).
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@claude You are the FINAL architecture reviewer. Read ALL comments above from Gemini, Qodo, CodeRabbit, and Copilot carefully before responding. Phase 1: Review per AGENTS.md
Phase 2: FIX Valid Issues Phase 3: Final Verdict |
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Claude finished @MervinPraison's task —— View job I have completed a comprehensive architecture review and successfully implemented fixes for all critical issues identified by previous reviewers. Phase 1: Architecture Review per AGENTS.md ✅
Phase 2: Fix Critical Issues ✅
Phase 3: Final Verdict ✅
Architecture Analysis Results✅ Protocol-driven compliance: Changes are correctly placed in implementation files (not protocol definitions), maintaining the core SDK vs wrapper separation per AGENTS.md §4.1. ✅ Backward compatibility: No breaking API changes. All fixes are internal implementation improvements that maintain existing interfaces. ✅ Performance impact: Changes improve safety without performance penalties. Lazy lock initialization actually reduces memory overhead by only creating locks when needed. Critical Issues Resolved1. CRITICAL FIX: Threading/Async Lock Incompatibility
2. Thread Safety: Async Postgres Lock Race Condition
3. Code Quality: Exception Chaining & Import Cleanup
Files ModifiedCommit e4e2657 pushed to branch
Final Architectural Verdict: ✅ APPROVEDThis PR successfully resolves Gap 2 objectives from Issue #1289 and is now safe for merge. All critical async safety issues have been resolved:
The changes follow AGENTS.md architecture principles, maintain backward compatibility, and eliminate the runtime crash risks identified by all reviewers. |
- Fix threading.Lock used with async with in Process class (issue #1289) * Replace sync lock creation with lazy async lock initialization * Prevents runtime AttributeError in aworkflow method - Improve thread safety in AsyncPostgres lazy lock initialization * Add double-checked locking pattern to prevent race conditions * Ensures only one asyncio.Lock instance created across coroutines - Remove redundant asyncio import in async_postgres.py - Improve exception chaining for better error diagnostics Addresses critical issues raised by Gemini, Qodo, CodeRabbit reviewers. Co-authored-by: Mervin Praison <MervinPraison@users.noreply.github.com>
1 participant
Fixes critical multi-agent and async safety issues identified in #1289 Gap 2.
Changes Made
1. Fixed asyncio.Lock() in sync constructor (High Priority)
2. Added async postgres init race protection
3. Fixed memory state store save race condition
4. Verified existing thread safety
Testing
Architecture Compliance
These fixes address the highest priority issues from #1289 Gap 2, ensuring PraisonAI is safe for concurrent multi-agent execution.
Fixes #1289
Generated with Claude Code
Summary by CodeRabbit
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