feat: add poc type casting reflect op

Author: Timon Viola

src/dagcellent/operators/sql_reflect_with_types.py

@@ -0,0 +1,111 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Any
+
+from airflow.providers.common.sql.operators.sql import SQLExecuteQueryOperator
+from sqlalchemy import ReflectedColumn, cast, inspect, select
+
+from dagcellent.data_utils.sql_reflection import (
+    reflect_meta_data,
+    safe_add_database_to_connection,
+)
+
+if TYPE_CHECKING:
+    from sqlalchemy.engine.interfaces import ReflectedColumn
+
+
+class SQLReflectOperator(SQLExecuteQueryOperator):
+    """Operator to perform SQLAlchemy like database reflection.
+
+    The target_table is returned as a `SELECT` statement DDL.
+
+    Example:
+        The example below illustrates a PostrgeSQL database and the
+        returned SELECT query.
+
+        ```sql
+        CREATE TABLE IF NOT EXISTS ats
+        (
+            departure_id varchar(40) COLLATE pg_catalog."default" NOT NULL,
+            route_leg_code varchar(40) COLLATE pg_catalog."default" NOT NULL,
+            planned_departure_date_time timestamp without time zone NOT NULL,
+            ferry_name varchar(40) COLLATE pg_catalog."default" NOT NULL,
+            cnv_outlet varchar(40) COLLATE pg_catalog."default" NOT NULL,
+            store_name varchar(40) COLLATE pg_catalog."default" NOT NULL,
+            store_item varchar(200) COLLATE pg_catalog."default" NOT NULL,
+            predicted_sales double precision NOT NULL,
+            good boolean DEFAULT false,
+            CONSTRAINT ats_pkey PRIMARY KEY (departure_id, route_leg_code, ferry_name, cnv_outlet, store_name, store_item)
+        );
+        ```
+
+        ```python
+        reflect_table = SQLReflectOperator(
+            table_name="ats",
+            task_id="reflect_database",
+            conn_id=CONN_ID,
+        )
+        ```
+
+        ```sql
+        SELECT
+            ats.departure_id,
+            ats.route_leg_code,
+            ats.planned_departure_date_time,
+            ats.ferry_name,
+            ats.cnv_outlet,
+            ats.store_name,
+            ats.store_item,
+            ats.predicted_sales,
+            ats.good
+        FROM ats
+        ```
+    """
+
+    def __init__(
+        self,
+        *,
+        table_name: str,
+        database: str | None = None,
+        schema: str | None = None,
+        **kwargs: Any,
+    ) -> None:
+        """Init.
+
+        Args:
+            table: target table name
+            kwargs: additional arguments to pass to SQLExecuteQueryOperator
+        """
+        # TODO: deprecate this, for now inheritance needs debugging
+        self.database_name = database
+        kwargs["database"] = database
+        self.table_name = table_name
+        self.schema = schema
+        super().__init__(sql="", **kwargs)  # type: ignore
+
+    def execute(self, context: Any):
+        hook = self.get_db_hook()
+        engine = hook.get_sqlalchemy_engine()  # type: ignore
+        self.log.debug("%s", f"{self.database_name=}")
+        if self.database_name:
+            # inject database name if not defined in connection URI
+            self.log.debug("Target connection: %s", f"{engine.url.database=}")
+            engine = safe_add_database_to_connection(engine, self.database_name)
+        self.log.debug("Target connection: %s", engine.url)
+
+        table = reflect_meta_data(engine, schema=self.schema, table=self.table_name)
+        if table is None:  # type: ignore[reportUnnecessaryCondition]
+            raise ValueError(f"Table {self.table_name} not found in the database.")
+
+        self.log.debug("::group::🦆")
+        self.log.debug("Table: %s", table.__dict__)
+        self.log.debug("::endgroup::")
+
+        reflected_columns: ReflectedColumn = inspect(engine).get_columns(
+            self.table_name
+        )
+        select_ddl = select(
+            *[cast(col["name"], col["type"]) for col in reflected_columns]
+        )
+
+        return select_ddl