fix part 2

backend/app/database/base.py

@@ -1,6 +1,6 @@
 """Base model for all database models."""
 
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import Any
 from uuid import uuid4
 
@@ -22,7 +22,7 @@ class Base(DeclarativeBase):
 
     # Common columns for all models
     id: Any = Column(UUID(as_uuid=True), primary_key=True, default=uuid4)
-    created_at: Any = Column(DateTime, default=datetime.utcnow, nullable=False)
+    created_at: Any = Column(DateTime, default=lambda: datetime.now(timezone.utc), nullable=False)
 
     def dict(self) -> dict[str, Any]:
         """Convert model to dictionary."""

backend/app/database/models/board.py

@@ -1,6 +1,6 @@
 """Board database model."""
 
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import TYPE_CHECKING
 from uuid import UUID, uuid4
 
@@ -42,9 +42,9 @@ class Board(Base):
         default=lambda: {"x": 0, "y": 0, "zoom": 1.0, "rotation": 0},
     )
 
-    created_at: Mapped[datetime] = mapped_column(DateTime, nullable=False, default=datetime.utcnow)
+    created_at: Mapped[datetime] = mapped_column(DateTime, nullable=False, default=lambda: datetime.now(timezone.utc))
     updated_at: Mapped[datetime] = mapped_column(
-        DateTime, nullable=False, default=datetime.utcnow, onupdate=datetime.utcnow
+        DateTime, nullable=False, default=lambda: datetime.now(timezone.utc), onupdate=lambda: datetime.now(timezone.utc)
     )
     is_deleted: Mapped[bool] = mapped_column(Boolean, nullable=False, default=False)
 

backend/app/database/models/board_image.py

@@ -1,6 +1,6 @@
 """BoardImage database model - junction table for boards and images."""
 
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import TYPE_CHECKING
 from uuid import UUID, uuid4
 
@@ -52,9 +52,9 @@ class BoardImage(Base):
         PGUUID(as_uuid=True), ForeignKey("groups.id", ondelete="SET NULL"), nullable=True
     )
 
-    created_at: Mapped[datetime] = mapped_column(DateTime, nullable=False, default=datetime.utcnow)
+    created_at: Mapped[datetime] = mapped_column(DateTime, nullable=False, default=lambda: datetime.now(timezone.utc))
     updated_at: Mapped[datetime] = mapped_column(
-        DateTime, nullable=False, default=datetime.utcnow, onupdate=datetime.utcnow
+        DateTime, nullable=False, default=lambda: datetime.now(timezone.utc), onupdate=lambda: datetime.now(timezone.utc)
     )
 
     # Relationships

backend/app/database/models/comment.py

@@ -1,7 +1,7 @@
 """Comment model for board annotations."""
 
 import uuid
-from datetime import datetime
+from datetime import datetime, timezone
 
 from sqlalchemy import Boolean, Column, DateTime, ForeignKey, String, Text
 from sqlalchemy.dialects.postgresql import JSONB, UUID
@@ -21,7 +21,7 @@ class Comment(Base):
     author_name = Column(String(100), nullable=False)
     content = Column(Text, nullable=False)
     position = Column(JSONB, nullable=True)  # Optional canvas position reference
-    created_at = Column(DateTime, nullable=False, default=datetime.utcnow)
+    created_at = Column(DateTime, nullable=False, default=lambda: datetime.now(timezone.utc))
     is_deleted = Column(Boolean, nullable=False, default=False)
 
     # Relationships

backend/app/database/models/group.py

@@ -1,6 +1,6 @@
 """Group database model."""
 
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import TYPE_CHECKING
 from uuid import UUID, uuid4
 
@@ -33,9 +33,9 @@ class Group(Base):
     color: Mapped[str] = mapped_column(String(7), nullable=False)  # Hex color #RRGGBB
     annotation: Mapped[str | None] = mapped_column(Text, nullable=True)
 
-    created_at: Mapped[datetime] = mapped_column(DateTime, nullable=False, default=datetime.utcnow)
+    created_at: Mapped[datetime] = mapped_column(DateTime, nullable=False, default=lambda: datetime.now(timezone.utc))
     updated_at: Mapped[datetime] = mapped_column(
-        DateTime, nullable=False, default=datetime.utcnow, onupdate=datetime.utcnow
+        DateTime, nullable=False, default=lambda: datetime.now(timezone.utc), onupdate=lambda: datetime.now(timezone.utc)
     )
 
     # Relationships

backend/app/database/models/image.py

@@ -1,6 +1,6 @@
 """Image database model."""
 
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import TYPE_CHECKING
 from uuid import UUID, uuid4
 
@@ -38,7 +38,7 @@ class Image(Base):
     height: Mapped[int] = mapped_column(Integer, nullable=False)
     image_metadata: Mapped[dict] = mapped_column(JSONB, nullable=False)
 
-    created_at: Mapped[datetime] = mapped_column(DateTime, nullable=False, default=datetime.utcnow)
+    created_at: Mapped[datetime] = mapped_column(DateTime, nullable=False, default=lambda: datetime.now(timezone.utc))
     reference_count: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
 
     # Relationships

backend/app/database/models/share_link.py

@@ -1,7 +1,7 @@
 """ShareLink model for board sharing functionality."""
 
 import uuid
-from datetime import datetime
+from datetime import datetime, timezone
 
 from sqlalchemy import Boolean, Column, DateTime, ForeignKey, Integer, String
 from sqlalchemy.dialects.postgresql import UUID
@@ -19,7 +19,7 @@ class ShareLink(Base):
     board_id = Column(UUID(as_uuid=True), ForeignKey("boards.id", ondelete="CASCADE"), nullable=False)
     token = Column(String(64), unique=True, nullable=False, index=True)
     permission_level = Column(String(20), nullable=False)  # 'view-only' or 'view-comment'
-    created_at = Column(DateTime, nullable=False, default=datetime.utcnow)
+    created_at = Column(DateTime, nullable=False, default=lambda: datetime.now(timezone.utc))
     expires_at = Column(DateTime, nullable=True)
     last_accessed_at = Column(DateTime, nullable=True)
     access_count = Column(Integer, nullable=False, default=0)

backend/app/database/models/user.py

@@ -1,7 +1,7 @@
 """User model for authentication and ownership."""
 
 import uuid
-from datetime import datetime
+from datetime import datetime, timezone
 
 from sqlalchemy import Boolean, Column, DateTime, String
 from sqlalchemy.dialects.postgresql import UUID
@@ -18,8 +18,8 @@ class User(Base):
     id = Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
     email = Column(String(255), unique=True, nullable=False, index=True)
     password_hash = Column(String(255), nullable=False)
-    created_at = Column(DateTime, nullable=False, default=datetime.utcnow)
-    updated_at = Column(DateTime, nullable=False, default=datetime.utcnow, onupdate=datetime.utcnow)
+    created_at = Column(DateTime, nullable=False, default=lambda: datetime.now(timezone.utc))
+    updated_at = Column(DateTime, nullable=False, default=lambda: datetime.now(timezone.utc), onupdate=lambda: datetime.now(timezone.utc))
     is_active = Column(Boolean, nullable=False, default=True)
 
     # Relationships

backend/app/database/session.py

@@ -1,27 +1,33 @@
 """Database session management."""
 
-from sqlalchemy import create_engine
+from sqlalchemy.ext.asyncio import AsyncSession, create_async_engine
 from sqlalchemy.orm import sessionmaker
 
 from app.core.config import settings
 
-# Create SQLAlchemy engine
-engine = create_engine(
-    str(settings.DATABASE_URL),
+# Convert sync DATABASE_URL to async (replace postgresql:// with postgresql+asyncpg://)
+async_database_url = str(settings.DATABASE_URL).replace("postgresql://", "postgresql+asyncpg://")
+
+# Create async SQLAlchemy engine
+engine = create_async_engine(
+    async_database_url,
     pool_size=settings.DATABASE_POOL_SIZE,
     max_overflow=settings.DATABASE_MAX_OVERFLOW,
     pool_pre_ping=True,  # Verify connections before using
     echo=settings.DEBUG,  # Log SQL queries in debug mode
 )
 
-# Create session factory
-SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+# Create async session factory
+SessionLocal = sessionmaker(
+    bind=engine,
+    class_=AsyncSession,
+    autocommit=False,
+    autoflush=False,
+    expire_on_commit=False,
+)
 
 
-def get_db():
-    """Dependency for getting database session."""
-    db = SessionLocal()
-    try:
-        yield db
-    finally:
-        db.close()
+async def get_db():
+    """Dependency for getting async database session."""
+    async with SessionLocal() as session:
+        yield session