fix(database): fixes pool related checks, duplicated function calls and session management

[ogabrielluiz]

This pull request focuses on improving database session management and usage patterns across the codebase. The main changes involve removing the legacy session_getter context manager and standardizing on the new session_scope context manager, which delegates session lifecycle management to DatabaseService.with_session(). Additionally, there are improvements to connection pooling logic and transaction handling.

Database session management and context usage:

• Removed the obsolete session_getter context manager from src/backend/base/langflow/services/database/utils.py and updated all references to use session_scope instead, ensuring consistent session handling throughout the backend and tests. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13]

• Updated the implementation and documentation of session_scope in src/backend/base/langflow/services/deps.py to clarify its delegation to DatabaseService.with_session(), which now centrally manages commits and rollbacks. [1] [2]

Transaction and error handling improvements:

• Modified transaction logging and cleanup functions to let the caller manage commits and rollbacks, improving error logging and propagation. This affects transaction CRUD and utility functions. [1] [2]

Connection pooling logic:

• Improved pool class selection in DatabaseService._create_engine to use issubclass instead of instantiating pool classes, and to remove invalid pool class specifications, ensuring robust engine creation.
• Enhanced SQLAlchemy engine creation in src/lfx/src/lfx/components/langchain_utilities/sql_database.py to use NullPool for PostgreSQL connections and StaticPool for others, preventing unnecessary persistent connections. [1] [2]

Websocket authentication session management:

• Updated websocket endpoints in src/backend/base/langflow/api/v1/voice_mode.py to use a short-lived session for authentication, removing the need to pass a session object through the call stack. [1] [2] [3] [4] [5] [6]

These changes collectively modernize and standardize database session handling, reduce boilerplate, and improve reliability and maintainability of database interactions.

Summary by CodeRabbit

• New Features
  • Adaptive database connection pooling based on database type for smoother performance.
• Bug Fixes
  • Improved stability and concurrency in voice/websocket interactions and message logging.
  • Reduced risk of connection leaks and pool misconfiguration.
• Refactor
  • Standardized short‑lived, scoped database sessions across services and websockets.
  • Simplified transaction handling and clarified session lifecycle behavior.
• Tests
  • Updated tests to use the new session scope for consistency and reliability.
• Chores
  • Removed deprecated session helpers and unnecessary logging dependencies.

[coderabbitai]

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Walkthrough

Refactors WebSocket voice endpoints to use ephemeral, context-managed DB sessions (removing DbSession params), updates engine poolclass handling to accept/import classes and validate with issubclass, conditionally selects SQLAlchemy pool class (NullPool for Postgres, StaticPool otherwise), and replaces several internal session utilities with session_scope. Other transactional commit/rollback calls were removed in a few DB utility functions and tests updated accordingly.

Changes

Cohort / File(s)	Summary
WebSocket handlers (voice_mode) src/backend/base/langflow/api/v1/voice_mode.py	Removed persistent session: DbSession parameters from four WS handlers and updated them to create and use async with session_scope() for authentication, key lookup, message saves, and cleanup; per-message DB writes also use ephemeral scoped sessions.
DB engine creation & poolclass validation src/backend/base/.../services/database/service.py	_create_engine now accepts string or class poolclass, dynamically imports dotted paths, validates via issubclass(sa.pool.Pool), and sets poolclass only if valid; minor comment removal in with_session.
Dynamic SQLAlchemy pool selection src/lfx/src/lfx/components/langchain_utilities/sql_database.py	build_sqldatabase parses URI with make_url and selects NullPool for Postgres URIs, StaticPool otherwise; passes chosen poolclass to create_engine.
Transaction logging behavior src/backend/base/.../transactions/crud.py	log_transaction removed explicit await db.commit() after delete and replaced simple rollback with logger.exception logging in exception path.
Database init/session utilities src/backend/base/.../services/database/utils.py, src/backend/base/.../services/deps.py	Removed local session_getter and switched callers to session_scope import; session_scope docstring clarified and logger exception call removed; callers updated to async with session_scope().
Service utils transaction handling src/backend/base/.../services/utils.py	clean_transactions no longer calls session.commit() on success and now re-raises exceptions after logging; previous rollback/commit steps removed.
Tests updated to use session_scope src/backend/tests/conftest.py, src/backend/tests/unit/test_database.py, src/backend/tests/unit/test_user.py	Replaced session_getter(get_db_service()) usages with session_scope() in fixtures and tests; imports adjusted accordingly.

Sequence Diagram(s)

sequenceDiagram
  autonumber
  participant C as Client
  participant E as WS Endpoint
  participant SS as session_scope()
  participant A as Auth / Key lookup
  participant F as Flow/TTS Handler
  participant DB as Database

  C->>E: Open WebSocket (flow_id)
  activate E
  E->>SS: async with session_scope()  (open ephemeral session)
  activate SS
  SS->>A: get_current_user_for_websocket(session)
  A-->>SS: user / error
  alt auth ok
    SS-->>E: proceed
    E->>F: handle messages/events
    loop per message
      F->>SS: save message (uses new ephemeral session via session_scope for each save)
      SS->>DB: INSERT/UPDATE
      DB-->>SS: ack
      SS-->>F: saved
    end
    F-->>C: stream audio/text
  else auth fail
    SS-->>E: send error & close
  end
  note over E,SS: On close/cleanup: reopen session_scope() to fetch auth/info for cleanup
  deactivate SS
  deactivate E

Loading

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

Possibly related PRs

• refactor: reuse single session when getting variables from db #8814 — Modifies DB session usage in API endpoints to use session_scope and adjust AsyncSession handling; strongly related to the WebSocket session refactors here.

Suggested labels

refactor, lgtm, size:XXL

Suggested reviewers

• jordanrfrazier
• rjordanfrazier
• erichare

Pre-merge checks and finishing touches

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Title Check	⚠️ Warning	The title references pool related checks, duplicated function calls, and session management but the PR primarily modernizes database connection pooling and session handling while refactoring WebSocket session usage. Including “duplicated function calls” introduces noise as it is not a central change in the provided objectives. The phrasing is overly broad and lists multiple unrelated items, making the main update unclear for someone scanning the history.	Please update the PR title to clearly highlight the primary improvements, such as standardizing session management and dynamic pool class selection. Removing references to “duplicated function calls” will help teammates quickly grasp the core changes. Consider using a concise Conventional Commit style title that reflects the central focus of the update.
Docstring Coverage	⚠️ Warning	Docstring coverage is 30.43% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (1 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.

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[codecov]

Codecov Report

❌ Patch coverage is 45.45455% with 30 lines in your changes missing coverage. Please review.
✅ Project coverage is 23.54%. Comparing base (75e2650) to head (7edd4c5).
⚠️ Report is 404 commits behind head on main.

Files with missing lines	Patch %	Lines
src/backend/base/langflow/api/v1/voice_mode.py	7.14%	26 Missing ⚠️
...c/backend/base/langflow/services/database/utils.py	0.00%	2 Missing ⚠️
...flow/services/database/models/transactions/crud.py	0.00%	1 Missing ⚠️
src/backend/base/langflow/services/utils.py	0.00%	1 Missing ⚠️

❌ Your project status has failed because the head coverage (45.78%) is below the target coverage (55.00%). You can increase the head coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9983      +/-   ##
==========================================
- Coverage   23.68%   23.54%   -0.15%     
==========================================
  Files        1090     1090              
  Lines       39768    39784      +16     
  Branches     5542     5542              
==========================================
- Hits         9419     9366      -53     
- Misses      30178    30247      +69     
  Partials      171      171              

Flag	Coverage Δ
backend	45.78% <45.45%> (-0.41%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...backend/base/langflow/services/database/service.py	66.07% <100.00%> (+3.49%)	⬆️
src/backend/base/langflow/services/deps.py	86.56% <100.00%> (+0.20%)	⬆️
...flow/services/database/models/transactions/crud.py	39.28% <0.00%> (+1.35%)	⬆️
src/backend/base/langflow/services/utils.py	77.10% <0.00%> (-0.14%)	⬇️
...c/backend/base/langflow/services/database/utils.py	55.10% <0.00%> (-3.24%)	⬇️
src/backend/base/langflow/api/v1/voice_mode.py	12.82% <7.14%> (-0.16%)	⬇️

... and 6 files with indirect coverage changes

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[coderabbitai]

Actionable comments posted: 4

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📒 Files selected for processing (3)

• src/backend/base/langflow/api/v1/voice_mode.py (2 hunks)
• src/backend/base/langflow/services/database/service.py (1 hunks)
• src/lfx/src/lfx/components/langchain_utilities/sql_database.py (2 hunks)

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{src/backend/**/*.py,tests/**/*.py,Makefile}

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{src/backend/**/*.py,tests/**/*.py,Makefile}: Run make format_backend to format Python code before linting or committing changes
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Files:

• src/backend/base/langflow/services/database/service.py
• src/backend/base/langflow/api/v1/voice_mode.py

🧬 Code graph analysis (1)

src/backend/base/langflow/api/v1/voice_mode.py (2)

src/backend/base/langflow/services/deps.py (1)

• session_scope (151-173)

src/backend/base/langflow/services/auth/utils.py (1)

• get_current_user_for_websocket (222-245)

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🔇 Additional comments (1)

src/lfx/src/lfx/components/langchain_utilities/sql_database.py (1)

3-3: LGTM: Import added

Importing NullPool alongside StaticPool is appropriate for dynamic pool selection.

[ogabrielluiz]

@coderabbitai could you review the new changes, please?

[coderabbitai]

🧩 Analysis chain

I'll review the new changes for you. Let me examine the modified files to provide comprehensive feedback.

@ogabrielluiz I'll review the changes in this PR. The improvements focus on database pool handling and WebSocket session management. Let me conduct a comprehensive review of all the changes.

---

🏁 Script executed:

#!/bin/bash
# First, let's look at the changes in the voice_mode.py file
echo "=== Changes in voice_mode.py ==="
cat src/backend/base/langflow/api/v1/voice_mode.py | head -50

echo -e "\n=== Looking for session_scope usage ==="
rg -n "session_scope" src/backend/base/langflow/api/v1/voice_mode.py -A 3 -B 1

echo -e "\n=== Looking for WebSocket endpoint signatures ==="
rg -n "def flow_.*websocket" src/backend/base/langflow/api/v1/voice_mode.py -A 2

Length of output: 5789

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#!/bin/bash
# Examine the database service changes
echo "=== Changes in database service ==="
cat src/backend/base/langflow/services/database/service.py | grep -n -A 10 -B 5 "poolclass"

echo -e "\n=== Looking for _create_engine method ==="
rg -n "_create_engine" src/backend/base/langflow/services/database/service.py -A 15 -B 5

Length of output: 6216

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🏁 Script executed:

#!/bin/bash
# Examine the SQL database component changes
echo "=== Changes in SQL database component ==="
cat src/lfx/src/lfx/components/langchain_utilities/sql_database.py | grep -n -A 10 -B 5 "NullPool\|StaticPool"

echo -e "\n=== Looking for build_sqldatabase function ==="
rg -n "def build_sqldatabase" src/lfx/src/lfx/components/langchain_utilities/sql_database.py -A 20

Length of output: 1846

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#!/bin/bash
# Let's also check imports and see the full context of the pool selection logic
echo "=== Pool-related imports ==="
rg -n "from.*pool|import.*Pool" src/lfx/src/lfx/components/langchain_utilities/sql_database.py -A 1 -B 1

echo -e "\n=== Pool selection logic ==="
rg -n "postgresql|postgres" src/lfx/src/lfx/components/langchain_utilities/sql_database.py -A 5 -B 5

Length of output: 1170

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#!/bin/bash
# Let's examine the session_scope implementation to understand the pattern
echo "=== Looking for session_scope definition ==="
rg -n "def session_scope|async def session_scope" --type py -A 10

echo -e "\n=== Looking for session_scope imports ==="
rg -n "from.*session_scope|import.*session_scope" src/backend/base/langflow/api/v1/voice_mode.py

Length of output: 1871

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🏁 Script executed:

#!/bin/bash
# Let's see the full WebSocket endpoint implementations to understand the changes better
echo "=== Full flow_as_tool_websocket_no_session function ==="
ast-grep --pattern 'def flow_as_tool_websocket_no_session($$$) {
  $$$
}'

echo -e "\n=== Full flow_tts_websocket function ==="
ast-grep --pattern 'def flow_tts_websocket($$$) {
  $$$
}'

Length of output: 97

---

Based on my analysis of the code changes, here's my comprehensive review of PR #9983:

✅ Positive Changes

1. Improved Database Pool Validation

The change from isinstance(pool_class(), sa.pool.Pool) to issubclass(pool_class, sa.pool.Pool) in _create_engine() is excellent:

• Prevents unnecessary instantiation of pool classes during validation
• More efficient - checks class hierarchy without creating objects
• Safer - avoids potential side effects from pool class constructors
• Better error handling - falls back to default pool class when invalid

2. Smart Pool Selection for Different Databases

The dynamic pool selection in sql_database.py is well-reasoned:

• PostgreSQL → NullPool: Prevents connection pooling issues in multi-user environments
• SQLite/Others → StaticPool: Maintains appropriate connection reuse
• Clear documentation explaining the rationale

3. WebSocket Session Management Improvement

Moving from injected DbSession parameters to session_scope() context managers:

• Better resource management - ensures proper session cleanup
• Shorter-lived connections - reduces connection pool pressure
• More explicit - each database operation has clear session boundaries

⚠️ Potential Concerns & Suggestions

1. Session Scope Overhead

Issue: Each WebSocket operation now creates a new session scope, which might introduce overhead for high-frequency operations.

Recommendation: Consider session reuse patterns for operations within the same WebSocket connection lifecycle where appropriate.

2. Error Handling in Pool Validation

Minor Enhancement: The current error handling could be more specific:

# Current
except Exception:  # noqa: BLE001
    pool_class = None

# Suggested improvement
except (ImportError, AttributeError, ModuleNotFoundError) as e:
    logger.warning(f"Could not import poolclass '{poolclass_key}': {e}")
    pool_class = None

3. PostgreSQL Pool Selection Logic

Question: The logic uses both url.get_backend_name() == "postgresql" and url.drivername.startswith("postgresql"). Is the second check redundant?

The current implementation seems correct, but you might want to verify edge cases with different PostgreSQL drivers.

🔍 Technical Analysis

Connection Pool Strategy

The pool selection strategy is sound:

• NullPool for PostgreSQL: Prevents connection leaks in web applications
• StaticPool for SQLite: Maintains single connection for file-based databases
• Fallback handling: Graceful degradation when pool classes can't be loaded

Session Management Pattern

The migration to session_scope() follows best practices:

• Automatic transaction management (commit/rollback)
• Resource cleanup via context manager
• Consistent pattern across all WebSocket endpoints

✅ Overall Assessment

This PR represents a solid improvement to database connection management:

1. Performance: Better pool validation and appropriate pool selection
2. Reliability: Improved session lifecycle management
3. Maintainability: Consistent patterns across WebSocket endpoints
4. Resource Management: Better connection cleanup and reduced pool pressure

The changes align well with the PR title "improve-db-pool" and address real-world database connection management challenges in web applications.

Recommendation: ✅ Approve - These changes improve the codebase's database handling patterns and should provide better performance and reliability in production environments.

---

🏁 Script executed:

#!/bin/bash
# Let's get the full WebSocket function signatures and their first few lines to understand the changes
echo "=== WebSocket function signatures ==="
rg -n "^async def flow_.*websocket" src/backend/base/langflow/api/v1/voice_mode.py -A 5

echo -e "\n=== Let's check what parameters were removed by looking at the function definitions ==="
rg -n "flow_.*websocket.*:" src/backend/base/langflow/api/v1/voice_mode.py -A 3 -B 1

Length of output: 867

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#!/bin/bash
# Let's check the original with_session method mentioned in the AI summary
echo "=== Looking for with_session method ==="
rg -n "def with_session" src/backend/base/langflow/services/database/service.py -A 10 -B 2

echo -e "\n=== Let's check the pool validation logic more closely ==="
rg -n "isinstance.*sa\.pool\.Pool|issubclass.*sa\.pool\.Pool" src/backend/base/langflow/services/database/service.py -A 2 -B 2

Length of output: 1024

---

Perfect! Now I have the complete picture. Here's my comprehensive review of the changes:

📋 Change Summary

Files Modified:

1. voice_mode.py - WebSocket endpoints refactored to use session_scope()
2. database/service.py - Pool validation logic improved
3. sql_database.py - Dynamic pool selection for PostgreSQL vs others

✅ Excellent Improvements

1. WebSocket Session Management Refactor

Before: Functions required injected DbSession parameters

async def flow_as_tool_websocket(
    client_websocket: WebSocket,
    flow_id: str,
    background_tasks: BackgroundTasks,
    session: DbSession,  # ← Removed dependency injection
):

After: Clean signatures using session_scope() context manager

async def flow_as_tool_websocket(
    client_websocket: WebSocket,
    flow_id: str,
    background_tasks: BackgroundTasks,  # ← Cleaner interface
):
    # Uses session_scope() internally

Benefits:

• ✅ Reduced coupling - endpoints don't depend on external session injection
• ✅ Better resource management - automatic session cleanup via context managers
• ✅ Shorter-lived connections - reduces database pool pressure
• ✅ Consistent pattern across all 4 WebSocket endpoints

2. Database Pool Validation Fix

Critical Fix:

# Before: Inefficient and potentially dangerous
isinstance(pool_class(), sa.pool.Pool)

# After: Proper class validation
issubclass(pool_class, sa.pool.Pool)

Impact:

• ✅ Performance - No unnecessary object instantiation during validation
• ✅ Safety - Avoids potential side effects from pool constructors
• ✅ Proper OOP - Uses appropriate inheritance checking

3. Smart Database Pool Selection

# PostgreSQL: Use NullPool (closes connections after use)
# SQLite/Others: Use StaticPool (maintains connection reuse)
poolclass = NullPool if is_postgresql else StaticPool

Why This Matters:

• ✅ PostgreSQL optimization - Prevents connection leaks in multi-user environments
• ✅ SQLite optimization - Maintains appropriate single-connection pattern
• ✅ Clear documentation - Well-commented rationale

🔍 Code Quality Analysis

Authentication Pattern Consistency

The refactor maintains proper authentication flow:

async with session_scope() as auth_session:
    current_user: User = await get_current_user_for_websocket(client_websocket, auth_session)
    current_user, openai_key = await authenticate_and_get_openai_key(auth_session, current_user, client_send)

Error Handling Preservation

All existing error handling and WebSocket disconnect logic is maintained while improving the underlying session management.

🎯 Performance & Resource Benefits

1. Connection Pool Pressure Reduction

   • Short-lived sessions reduce long-running connection holds
   • NullPool for PostgreSQL prevents connection exhaustion

2. Memory Efficiency

   • No unnecessary pool class instantiation during validation
   • Proper session cleanup via context managers

3. Scalability Improvement

   • Better handling of concurrent WebSocket connections
   • Database-appropriate pool strategies

🚀 Recommendation

✅ APPROVE - This PR delivers meaningful improvements to database connection management:

• Architecture: Cleaner separation of concerns in WebSocket endpoints
• Performance: Eliminates unnecessary object creation and optimizes connection pooling
• Reliability: Better session lifecycle management and resource cleanup
• Maintainability: Consistent patterns and well-documented pool selection logic

The changes are well-tested through the existing codebase patterns and represent best practices for async database session management in web applications.

Great work on this database pool optimization! 🎉

✅ Actions performed

Review triggered.

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[coderabbitai]

Actionable comments posted: 2

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

src/backend/base/langflow/services/utils.py (1)

283-292: Don’t reuse a session after session_scope closes

session_scope() closes (and commits/rolls back) the AsyncSession as soon as the async with block finishes. The subsequent calls to clean_transactions / clean_vertex_builds therefore run against a closed session and will raise on first DB access. Please keep those cleanup calls inside the scope or open a new scope around them. For example:

-    async with session_scope() as session:
-        settings_service = get_service(ServiceType.SETTINGS_SERVICE)
-        await setup_superuser(settings_service, session)
+    async with session_scope() as session:
+        settings_service = get_service(ServiceType.SETTINGS_SERVICE)
+        await setup_superuser(settings_service, session)
+        await clean_transactions(settings_service, session)
+        await clean_vertex_builds(settings_service, session)
@@
-    await clean_transactions(settings_service, session)
-    await clean_vertex_builds(settings_service, session)

🧹 Nitpick comments (3)

src/backend/tests/unit/test_user.py (1)

8-8: Session scope migration looks good; consider removing redundant commits

Adopting session_scope improves consistency. If session_scope (or DatabaseService.with_session) auto‑commits on context exit, explicit await session.commit() calls here are redundant and can be removed to reduce noise. If you adopt the proposed change to session_scope to purely delegate, keep explicit commits in tests as-is.

Also applies to: 18-27, 55-66, 74-81, 83-92, 99-106, 153-162

src/backend/tests/conftest.py (1)

29-29: Standardizing on session_scope: verify commit responsibility and trim redundancy

Good move to centralize on session_scope. Depending on final session_scope semantics:

• If it auto‑commits/rollbacks via with_session, explicit commits here can be dropped.
• If it delegates without auto‑commit, leave explicit commits in place.

Also ensure long‑lived fixtures don’t hold sessions longer than needed (they don’t here).

Also applies to: 552-560, 660-672, 690-728

src/backend/base/langflow/services/database/models/transactions/crud.py (1)

66-72: Ensure PK availability and guard against invalid offset; add flush and validate max_entries

Two improvements:

• After db.add(table), flush to guarantee PK is available to callers before commit.
• Ensure max_entries >= 1 to avoid offset(-1) when max_entries is 0 or misconfigured.

Apply this diff within this block:

         # Add new entry and execute delete
         db.add(table)
+        # Ensure INSERT is flushed so PKs are populated for immediate use
+        await db.flush()
         await db.exec(delete_older)
 
     except Exception:
         logger.exception("Error logging transaction")
         raise

And update max_entries handling (outside this hunk) near where it’s read:

# after reading settings
max_entries = max(1, max_entries)

📜 Review details

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📥 Commits

Reviewing files that changed from the base of the PR and between c267d0f and 621215e.

📒 Files selected for processing (10)

• src/backend/base/langflow/api/v1/voice_mode.py (7 hunks)
• src/backend/base/langflow/services/database/models/transactions/crud.py (1 hunks)
• src/backend/base/langflow/services/database/service.py (1 hunks)
• src/backend/base/langflow/services/database/utils.py (1 hunks)
• src/backend/base/langflow/services/deps.py (1 hunks)
• src/backend/base/langflow/services/utils.py (1 hunks)
• src/backend/tests/conftest.py (2 hunks)
• src/backend/tests/unit/test_database.py (2 hunks)
• src/backend/tests/unit/test_user.py (7 hunks)
• src/lfx/src/lfx/components/langchain_utilities/sql_database.py (2 hunks)

🧰 Additional context used

🧠 Learnings (3)

📚 Learning: 2025-07-21T14:16:14.125Z

Learnt from: CR
PR: langflow-ai/langflow#0
File: .cursor/rules/testing.mdc:0-0
Timestamp: 2025-07-21T14:16:14.125Z
Learning: Applies to src/backend/tests/**/*.py : Test Langflow's REST API endpoints in backend Python tests using the async client fixture and asserting response codes and payloads.

Applied to files:

• src/backend/tests/conftest.py

📚 Learning: 2025-07-21T14:16:14.125Z

Learnt from: CR
PR: langflow-ai/langflow#0
File: .cursor/rules/testing.mdc:0-0
Timestamp: 2025-07-21T14:16:14.125Z
Learning: Applies to src/backend/tests/**/*.py : Be aware of ContextVar propagation in async tests; test both direct event loop execution and 'asyncio.to_thread' scenarios to ensure proper context isolation.

Applied to files:

• src/backend/tests/conftest.py

📚 Learning: 2025-07-21T14:16:14.125Z

Learnt from: CR
PR: langflow-ai/langflow#0
File: .cursor/rules/testing.mdc:0-0
Timestamp: 2025-07-21T14:16:14.125Z
Learning: Applies to src/backend/tests/**/*.py : Use the 'client' fixture (an async httpx.AsyncClient) for API tests in backend Python tests, as defined in 'src/backend/tests/conftest.py'.

Applied to files:

• src/backend/tests/conftest.py

🔇 Additional comments (11)

src/backend/base/langflow/services/deps.py (2)

137-146: LGTM: get_session wrapper

Yielding a session via session_scope keeps dependency usage clean.

---

152-156: Do not remove manual commit in session_scope
DatabaseService.with_session only handles rollbacks on SQLAlchemy errors and does not auto-commit; session_scope must retain its explicit await session.commit()/rollback() to ensure transactions complete correctly.

Likely an incorrect or invalid review comment.

src/backend/tests/unit/test_user.py (2)

18-27: LGTM: super_user fixture uses session_scope

No functional change beyond session acquisition; pattern is sound.

---

55-66: Duplicate of previous session_scope note

Same considerations on commit semantics and potential cleanup of explicit commits.

Also applies to: 74-81, 83-92, 99-106, 153-162

src/backend/tests/conftest.py (1)

552-560: LGTM: flow fixture creation via session_scope

Short‑lived session with explicit commit/refresh is correct. Cleanup is handled.

src/lfx/src/lfx/components/langchain_utilities/sql_database.py (2)

35-36: Simplify Postgres detection to backend check only

url.get_backend_name() already returns "postgresql" for all postgresql+* drivers; the drivername check is redundant.

-        is_postgresql = url.get_backend_name() == "postgresql" or url.drivername.startswith("postgresql")
+        is_postgresql = url.get_backend_name() == "postgresql"

---

41-44: LGTM: Conditional pool selection is appropriate

NullPool for Postgres and StaticPool otherwise matches the project’s pooling strategy goals.

src/backend/base/langflow/api/v1/voice_mode.py (1)

1211-1215: Fix authentication call in TTS websocket

Here we pass client_send (a function) to authenticate_and_get_openai_key, which expects a WebSocket and calls .send_json() on it—this crashes with AttributeError. We also continue even if authentication fails, meaning we could hit OpenAI with a None bearer token. Please pass client_websocket and bail out when auth fails. For example:

-        async with session_scope() as auth_session:
-            current_user: User = await get_current_user_for_websocket(client_websocket, auth_session)
-            current_user, openai_key = await authenticate_and_get_openai_key(auth_session, current_user, client_send)
-        current_user_id = current_user.id if current_user else None
+        async with session_scope() as auth_session:
+            current_user: User = await get_current_user_for_websocket(client_websocket, auth_session)
+            current_user, openai_key = await authenticate_and_get_openai_key(
+                auth_session, current_user, client_websocket
+            )
+        if current_user is None or openai_key is None:
+            return
+        current_user_id = current_user.id

src/backend/base/langflow/services/database/utils.py (1)

50-53: Nice reuse of the shared session scope

Replacing the bespoke context manager with session_scope() keeps this recovery path aligned with the rest of the codebase and hands transaction handling back to DatabaseService.with_session().

src/backend/tests/unit/test_database.py (1)

541-557: Test fixture now mirrors production session handling

Swapping in session_scope() here ensures the test exercises the same session lifecycle we rely on in production, which should make future regressions easier to catch.

src/backend/base/langflow/services/database/service.py (1)

135-146: Honor pool classes defined in sqlalchemy.pool

Right now a setting such as {"poolclass": "StaticPool"} is still rejected because you only probe sqlalchemy.StaticPool. These pool implementations actually live under sqlalchemy.pool, so we never resolve the class and silently fall back to the default pool, defeating the configuration and reopening the connection-pressure issues this PR is trying to close. Please check sa.pool before giving up on the lookup.

-                pool_class = getattr(sa, poolclass_key, None)
+                pool_class = getattr(sa, poolclass_key, None) or getattr(sa.pool, poolclass_key, None)

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Quality Gate failed

Failed conditions
C Reliability Rating on New Code (required ≥ A)

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[qq745639151]

@ogabrielluiz When will this pr be merged? I often encounter a 'database is locked' exception when using Langflow. Will merging this completely fix the problem? I look forward to your reply.

[ogabrielluiz]

Closing - these changes have already been addressed in other PRs