Update datetime handling in ApiKey and Variable models (#1673)

* Update datetime handling in ApiKey and Variable models

* Refactor test_login_successful function in test_login.py

* Fix nullable attribute for created_at and updated_at fields in Variable model

src/backend/base/langflow/alembic/versions/e3bc869fa272_fix_nullable.py

@@ -9,7 +9,6 @@ from typing import Sequence, Union
 
 import sqlalchemy as sa
 from alembic import op
-from sqlalchemy.dialects import postgresql
 from sqlalchemy.engine.reflection import Inspector
 
 # revision identifiers, used by Alembic.
@@ -35,7 +34,9 @@ def upgrade() -> None:
                 "created_at",
                 existing_type=sa.TIMESTAMP(timezone=True),
                 nullable=True,
-                existing_server_default=sa.text("now()"),
+                # existing_server_default expects str | bool | Identity | Computed | None
+                # sa.text("now()") is not a valid value for existing_server_default
+                existing_server_default=False,
             )
 
     # ### end Alembic commands ###
@@ -54,7 +55,7 @@ def downgrade() -> None:
                 "created_at",
                 existing_type=sa.TIMESTAMP(timezone=True),
                 nullable=False,
-                existing_server_default=sa.text("now()"),
+                existing_server_default=False,
             )
 
     # ### end Alembic commands ###

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

@@ -1,8 +1,8 @@
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import TYPE_CHECKING, Optional
 from uuid import UUID, uuid4
 
-from pydantic import validator
+from pydantic import field_validator, validator
 from sqlmodel import Field, Relationship, SQLModel, Column, func, DateTime
 
 if TYPE_CHECKING:
@@ -11,7 +11,9 @@ if TYPE_CHECKING:
 
 class ApiKeyBase(SQLModel):
     name: Optional[str] = Field(index=True, nullable=True, default=None)
-    created_at: datetime = Field(sa_column=Column(DateTime(timezone=True), server_default=func.now(), nullable=False))
+    created_at: datetime = Field(
+        default=None, sa_column=Column(DateTime(timezone=True), server_default=func.now(), nullable=False)
+    )
     last_used_at: Optional[datetime] = Field(default=None, nullable=True)
     total_uses: int = Field(default=0)
     is_active: bool = Field(default=True)
@@ -33,6 +35,10 @@ class ApiKeyCreate(ApiKeyBase):
     api_key: Optional[str] = None
     user_id: Optional[UUID] = None
 
+    @field_validator("created_at", mode="before")
+    def set_created_at(cls, v):
+        return v or datetime.now(timezone.utc)
+
 
 class UnmaskedApiKeyRead(ApiKeyBase):
     id: UUID

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

@@ -26,10 +26,12 @@ class Variable(VariableBase, table=True):
     )
     # name is unique per user
     created_at: datetime = Field(
+        default=None,
         sa_column=Column(DateTime(timezone=True), server_default=func.now(), nullable=True),
         description="Creation time of the variable",
     )
     updated_at: Optional[datetime] = Field(
+        default=None,
         sa_column=Column(DateTime(timezone=True), nullable=True),
         description="Last update time of the variable",
     )