db: Add migration for calculated field

Add calculated field to task table to do the end - init calculation at db level. This will be used by work summary calculations.

api/migrations/versions/2a20fa1bde50_add_calculated_field_to_task_table.py

@@ -0,0 +1,28 @@
+"""Add calculated field to task table
+
+Revision ID: 2a20fa1bde50
+Revises: 6a1ad39b566d
+Create Date: 2024-01-09 11:15:22.286210
+
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+# revision identifiers, used by Alembic.
+revision = '2a20fa1bde50'
+down_revision = '6a1ad39b566d'
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.add_column("task", sa.Column("task_total_minutes", sa.Integer(), sa.Computed("_end - init")))
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_column('task', 'task_total_minutes')
+    # ### end Alembic commands ###

api/models/timelog.py

@@ -8,6 +8,7 @@
     ForeignKey,
     CheckConstraint,
     UniqueConstraint,
+    FetchedValue,
 )
 from sqlalchemy.dialects import postgresql
 from sqlalchemy.orm import relationship, Mapped
@@ -33,6 +34,7 @@ class Task(Base):
     phase = Column(String(length=15), nullable=True)
     onsite = Column(Boolean, default=False, nullable=False)
     updated_at = Column(postgresql.TIMESTAMP(), nullable=True)
+    task_total_minutes = Column(Integer, server_default=FetchedValue())
     end_after_init_task = CheckConstraint("_end >= init AND init >= 0", name="end_after_init_task")
     user_id = Column("usrid", Integer, ForeignKey("usr.id"), nullable=False)
     project_id = Column("projectid", Integer, ForeignKey("project.id"), nullable=False)