Fix database migration conflicts and improve migration safety

Changes:
- Enhanced migration 002 with column existence checks to prevent duplicate column errors
- Added comprehensive migration 003 that syncs database with current model state
- Modified application startup to avoid conflicts between create_all() and Alembic
- Added proper table/column existence checking in migrations
- Improved migration safety for production environments
- Removed automatic table creation when database already exists (relies on migrations)

This resolves the 'duplicate column name' error by ensuring migrations
check for existing columns before attempting to add them.

alembic/versions/002_add_profile_fields.py

@@ -9,6 +9,7 @@ from typing import Sequence, Union
 
 from alembic import op
 import sqlalchemy as sa
+from sqlalchemy.engine.reflection import Inspector
 
 # revision identifiers, used by Alembic.
 revision: str = '002'
@@ -17,27 +18,51 @@ branch_labels: Union[str, Sequence[str], None] = None
 depends_on: Union[str, Sequence[str], None] = None
 
 
+def column_exists(table_name, column_name):
+    """Check if a column exists in a table"""
+    bind = op.get_bind()
+    inspector = Inspector.from_engine(bind)
+    columns = [c['name'] for c in inspector.get_columns(table_name)]
+    return column_name in columns
+
+
 def upgrade() -> None:
-    # Add new profile fields to users table
+    # List of columns to add
-    op.add_column('users', sa.Column('first_name', sa.String(), nullable=True))
+    columns_to_add = [
-    op.add_column('users', sa.Column('last_name', sa.String(), nullable=True))
+        ('first_name', sa.Column('first_name', sa.String(), nullable=True)),
-    op.add_column('users', sa.Column('phone', sa.String(), nullable=True))
+        ('last_name', sa.Column('last_name', sa.String(), nullable=True)),
-    op.add_column('users', sa.Column('bio', sa.String(), nullable=True))
+        ('phone', sa.Column('phone', sa.String(), nullable=True)),
-    op.add_column('users', sa.Column('preferred_language', sa.String(), nullable=True))
+        ('bio', sa.Column('bio', sa.String(), nullable=True)),
-    op.add_column('users', sa.Column('timezone', sa.String(), nullable=True))
+        ('preferred_language', sa.Column('preferred_language', sa.String(), nullable=True)),
-    op.add_column('users', sa.Column('updated_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=True))
+        ('timezone', sa.Column('timezone', sa.String(), nullable=True)),
+        ('updated_at', sa.Column('updated_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=True))
+    ]
     
-    # Set default values for existing users
+    # Add columns only if they don't exist
-    op.execute("UPDATE users SET preferred_language = 'en' WHERE preferred_language IS NULL")
+    for column_name, column_def in columns_to_add:
-    op.execute("UPDATE users SET timezone = 'UTC' WHERE timezone IS NULL")
+        if not column_exists('users', column_name):
+            op.add_column('users', column_def)
+    
+    # Set default values for existing users (only if columns exist)
+    if column_exists('users', 'preferred_language'):
+        op.execute("UPDATE users SET preferred_language = 'en' WHERE preferred_language IS NULL")
+    if column_exists('users', 'timezone'):
+        op.execute("UPDATE users SET timezone = 'UTC' WHERE timezone IS NULL")
 
 
 def downgrade() -> None:
-    # Remove the added columns
+    # List of columns to remove (in reverse order)
-    op.drop_column('users', 'updated_at')
+    columns_to_remove = [
-    op.drop_column('users', 'timezone')
+        'updated_at',
-    op.drop_column('users', 'preferred_language')
+        'timezone', 
-    op.drop_column('users', 'bio')
+        'preferred_language',
-    op.drop_column('users', 'phone')
+        'bio',
-    op.drop_column('users', 'last_name')
+        'phone',
-    op.drop_column('users', 'first_name')
+        'last_name',
+        'first_name'
+    ]
+    
+    # Remove columns only if they exist
+    for column_name in columns_to_remove:
+        if column_exists('users', column_name):
+            op.drop_column('users', column_name)

alembic/versions/003_sync_current_state.py

@@ -0,0 +1,102 @@
+"""Sync database with current model state
+
+Revision ID: 003
+Revises: 002
+Create Date: 2024-01-01 00:00:02.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.engine.reflection import Inspector
+
+# revision identifiers, used by Alembic.
+revision: str = '003'
+down_revision: Union[str, None] = '002'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def table_exists(table_name):
+    """Check if a table exists"""
+    bind = op.get_bind()
+    inspector = Inspector.from_engine(bind)
+    return table_name in inspector.get_table_names()
+
+
+def column_exists(table_name, column_name):
+    """Check if a column exists in a table"""
+    if not table_exists(table_name):
+        return False
+    bind = op.get_bind()
+    inspector = Inspector.from_engine(bind)
+    columns = [c['name'] for c in inspector.get_columns(table_name)]
+    return column_name in columns
+
+
+def upgrade() -> None:
+    """
+    This migration ensures the database is in sync with the current model state.
+    It safely handles the case where tables/columns may already exist.
+    """
+    
+    # Check if users table exists, if not create it with all fields
+    if not table_exists('users'):
+        op.create_table('users',
+            sa.Column('id', sa.Integer(), nullable=False),
+            sa.Column('email', sa.String(), nullable=False),
+            sa.Column('password_hash', sa.String(), nullable=False),
+            sa.Column('first_name', sa.String(), nullable=True),
+            sa.Column('last_name', sa.String(), nullable=True),
+            sa.Column('phone', sa.String(), nullable=True),
+            sa.Column('bio', sa.String(), nullable=True),
+            sa.Column('preferred_language', sa.String(), nullable=True),
+            sa.Column('timezone', sa.String(), nullable=True),
+            sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=True),
+            sa.Column('updated_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=True),
+            sa.PrimaryKeyConstraint('id')
+        )
+        op.create_index(op.f('ix_users_email'), 'users', ['email'], unique=True)
+        op.create_index(op.f('ix_users_id'), 'users', ['id'], unique=False)
+    else:
+        # Table exists, check for missing profile columns and add them
+        profile_columns = [
+            ('first_name', sa.Column('first_name', sa.String(), nullable=True)),
+            ('last_name', sa.Column('last_name', sa.String(), nullable=True)),
+            ('phone', sa.Column('phone', sa.String(), nullable=True)),
+            ('bio', sa.Column('bio', sa.String(), nullable=True)),
+            ('preferred_language', sa.Column('preferred_language', sa.String(), nullable=True)),
+            ('timezone', sa.Column('timezone', sa.String(), nullable=True)),
+            ('updated_at', sa.Column('updated_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=True))
+        ]
+        
+        for column_name, column_def in profile_columns:
+            if not column_exists('users', column_name):
+                op.add_column('users', column_def)
+    
+    # Set default values for profile fields
+    if column_exists('users', 'preferred_language'):
+        op.execute("UPDATE users SET preferred_language = 'en' WHERE preferred_language IS NULL")
+    if column_exists('users', 'timezone'):
+        op.execute("UPDATE users SET timezone = 'UTC' WHERE timezone IS NULL")
+
+
+def downgrade() -> None:
+    """
+    Downgrade removes the profile fields added in this migration
+    """
+    if table_exists('users'):
+        profile_columns = [
+            'updated_at',
+            'timezone',
+            'preferred_language', 
+            'bio',
+            'phone',
+            'last_name',
+            'first_name'
+        ]
+        
+        for column_name in profile_columns:
+            if column_exists('users', column_name):
+                op.drop_column('users', column_name)

main.py

@@ -16,14 +16,24 @@ logger = logging.getLogger(__name__)
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     try:
-        # Create database tables
+        # Create database directory
         logger.info("Starting application initialization...")
         storage_dir = Path("/app/storage/db")
         storage_dir.mkdir(parents=True, exist_ok=True)
         logger.info(f"Created storage directory: {storage_dir}")
         
-        Base.metadata.create_all(bind=engine)
+        # Import all models to ensure they're registered with Base
-        logger.info("Database tables created successfully")
+        
+        # Only create tables if database doesn't exist (for development)
+        # In production, use Alembic migrations instead
+        db_path = storage_dir / "db.sqlite"
+        if not db_path.exists():
+            logger.info("Database file doesn't exist, creating initial tables...")
+            Base.metadata.create_all(bind=engine)
+        else:
+            logger.info("Database file exists, skipping table creation (use Alembic for migrations)")
+        
+        logger.info("Database initialization completed")
         yield
     except Exception as e:
         logger.error(f"Error during application startup: {e}")