feat: add 'gradient' column to Flow model and database schema (#3944)

Add 'gradient' column to Flow model and database schema

src/backend/base/langflow/alembic/versions/d3dbf656a499_add_gradient_column_in_flow.py

@@ -0,0 +1,41 @@
+"""add gradient column in Flow
+
+Revision ID: d3dbf656a499
+Revises: e5a65ecff2cd
+Create Date: 2024-09-27 09:35:19.424089
+
+"""
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+import sqlmodel
+from alembic import op
+from sqlalchemy.engine.reflection import Inspector
+
+from langflow.utils import migration
+
+# revision identifiers, used by Alembic.
+revision: str = 'd3dbf656a499'
+down_revision: Union[str, None] = 'e5a65ecff2cd'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    conn = op.get_bind()
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table('flow', schema=None) as batch_op:
+        if not migration.column_exists(table_name='flow', column_name='gradient', conn=conn):
+            batch_op.add_column(sa.Column('gradient', sqlmodel.sql.sqltypes.AutoString(), nullable=True))
+
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    conn = op.get_bind()
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table('flow', schema=None) as batch_op:
+        if migration.column_exists(table_name='flow', column_name='gradient', conn=conn):
+            batch_op.drop_column('gradient')
+
+    # ### end Alembic commands ###

src/backend/base/langflow/services/database/models/flow/model.py

@@ -28,6 +28,7 @@ class FlowBase(SQLModel):
     description: str | None = Field(default=None, sa_column=Column(Text, index=True, nullable=True))
     icon: str | None = Field(default=None, nullable=True)
     icon_bg_color: str | None = Field(default=None, nullable=True)
+    gradient: str | None = Field(default=None, nullable=True)
     data: dict | None = Field(default=None, nullable=True)
     is_component: bool | None = Field(default=False, nullable=True)
     updated_at: datetime | None = Field(default_factory=lambda: datetime.now(timezone.utc), nullable=True)