silly-event-rollup/alembic/versions/394542f24f6c_add_projection_table.py

"""add projection table

Revision ID: 394542f24f6c
Revises: abfbb3d96037
Create Date: 2025-06-14 23:57:39.301255

"""

from typing import Sequence, Union

from alembic import op
import sqlalchemy as sa


# revision identifiers, used by Alembic.
revision: str = "394542f24f6c"
down_revision: Union[str, None] = "abfbb3d96037"
branch_labels: Union[str, Sequence[str], None] = None
depends_on: Union[str, Sequence[str], None] = None


def upgrade() -> None:
    """Upgrade schema."""
    op.create_table(
        "users",
        sa.Column(
            "id",
            sa.UUID(as_uuid=True),
            nullable=False,
        ),
        sa.Column("created_at", sa.DateTime(timezone=True), nullable=False),
        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=False),
        sa.Column("deleted_at", sa.DateTime(timezone=True)),
        sa.Column("last_event_id", sa.UUID(as_uuid=True), nullable=False, unique=True),
        sa.Column(
            "last_event_sequence",
            sa.Integer(),
            nullable=False,
            autoincrement=True,
            unique=True,
        ),
        sa.Column("name", sa.String(), nullable=False),
        sa.Column("age", sa.Integer(), nullable=False),
        sa.Column("hair_color", sa.String(), nullable=False),
        sa.PrimaryKeyConstraint("id"),
    )

    op.execute(
        """
        create or replace function fn_project_user_created(event_id uuid, event_sequence integer, event_timestamp timestamptz, event jsonb) returns uuid
            security definer
            language plpgsql as $$
            declare result uuid;
            begin
                insert into users(
                    id, 
                    created_at, 
                    updated_at, 
                    last_event_id, 
                    last_event_sequence,
                    name,
                    age,
                    hair_color
                )
                values(
                    cast(event->'event_payload'->>'id' as UUID), 
                    event_timestamp,
                    event_timestamp,
                    event_id,
                    event_sequence,
                    event->'event_payload'->>'name',
                    cast(event->'event_payload'->>'age' as INTEGER),
                    event->'event_payload'->>'hair_color'
                )
                returning id into result;
                return result;
            end;
        $$;

        create or replace function fn_trigger_user_created() returns trigger
            security definer
            language plpgsql
        as $$
        begin
            perform fn_project_user_created(
                new.id,
                new.sequence,
                new.created_at,
                new.event_payload
                );
            return new;
        end;
        $$;

        create trigger event_insert_user_created
        after insert on user_events
        for each row
        when ((new.event_payload->>'event_type') = 'user_created')
        execute procedure fn_trigger_user_created();
        """
    )


def downgrade() -> None:
    """Downgrade schema."""
    op.drop_table("users")