Add Snowflake operators based on SQL Checks (#17741)

Add three new Snowflake operators based on SQL Checks

The SnowflakeCheckOperator, SnowflakeValueCheckOperator, and
SnowflakeIntervalCheckOperators are added as subclasses of their respective
SQL Operators. These additions follow the conventions set in the BigQueryOperators
subclassing from the same SQL_CheckOperators.

closes: #17694

airflow/providers/snowflake/operators/snowflake.py

@@ -15,12 +15,31 @@
 # KIND, either express or implied.  See the License for the
 # specific language governing permissions and limitations
 # under the License.
-from typing import Any, Optional
+from typing import Any, Optional, SupportsAbs
 
 from airflow.models import BaseOperator
+from airflow.operators.sql import SQLCheckOperator, SQLIntervalCheckOperator, SQLValueCheckOperator
 from airflow.providers.snowflake.hooks.snowflake import SnowflakeHook
 
 
+def get_db_hook(self) -> SnowflakeHook:
+    """
+    Create and return SnowflakeHook.
+
+    :return: a SnowflakeHook instance.
+    :rtype: SnowflakeHook
+    """
+    return SnowflakeHook(
+        snowflake_conn_id=self.snowflake_conn_id,
+        warehouse=self.warehouse,
+        database=self.database,
+        role=self.role,
+        schema=self.schema,
+        authenticator=self.authenticator,
+        session_parameters=self.session_parameters,
+    )
+
+
 class SnowflakeOperator(BaseOperator):
     """
     Executes SQL code in a Snowflake database
@@ -100,28 +119,293 @@ def __init__(
         self.session_parameters = session_parameters
         self.query_ids = []
 
-    def get_hook(self) -> SnowflakeHook:
-        """
-        Create and return SnowflakeHook.
-        :return: a SnowflakeHook instance.
-        :rtype: SnowflakeHook
-        """
-        return SnowflakeHook(
-            snowflake_conn_id=self.snowflake_conn_id,
-            warehouse=self.warehouse,
-            database=self.database,
-            role=self.role,
-            schema=self.schema,
-            authenticator=self.authenticator,
-            session_parameters=self.session_parameters,
-        )
+    def get_db_hook(self) -> SnowflakeHook:
+        return get_db_hook(self)
 
     def execute(self, context: Any) -> None:
         """Run query on snowflake"""
         self.log.info('Executing: %s', self.sql)
-        hook = self.get_hook()
+        hook = self.get_db_hook()
         execution_info = hook.run(self.sql, autocommit=self.autocommit, parameters=self.parameters)
         self.query_ids = hook.query_ids
 
         if self.do_xcom_push:
             return execution_info
+
+
+class SnowflakeCheckOperator(SQLCheckOperator):
+    """
+    Performs a check against Snowflake. The ``SnowflakeCheckOperator`` expects
+    a sql query that will return a single row. Each value on that
+    first row is evaluated using python ``bool`` casting. If any of the
+    values return ``False`` the check is failed and errors out.
+
+    Note that Python bool casting evals the following as ``False``:
+
+    * ``False``
+    * ``0``
+    * Empty string (``""``)
+    * Empty list (``[]``)
+    * Empty dictionary or set (``{}``)
+
+    Given a query like ``SELECT COUNT(*) FROM foo``, it will fail only if
+    the count ``== 0``. You can craft much more complex query that could,
+    for instance, check that the table has the same number of rows as
+    the source table upstream, or that the count of today's partition is
+    greater than yesterday's partition, or that a set of metrics are less
+    than 3 standard deviation for the 7 day average.
+
+    This operator can be used as a data quality check in your pipeline, and
+    depending on where you put it in your DAG, you have the choice to
+    stop the critical path, preventing from
+    publishing dubious data, or on the side and receive email alerts
+    without stopping the progress of the DAG.
+
+    :param sql: the sql code to be executed. (templated)
+    :type sql: Can receive a str representing a sql statement,
+        a list of str (sql statements), or reference to a template file.
+        Template reference are recognized by str ending in '.sql'
+    :param snowflake_conn_id: Reference to
+        :ref:`Snowflake connection id<howto/connection:snowflake>`
+    :type snowflake_conn_id: str
+    :param autocommit: if True, each command is automatically committed.
+        (default value: True)
+    :type autocommit: bool
+    :param parameters: (optional) the parameters to render the SQL query with.
+    :type parameters: dict or iterable
+    :param warehouse: name of warehouse (will overwrite any warehouse
+        defined in the connection's extra JSON)
+    :type warehouse: str
+    :param database: name of database (will overwrite database defined
+        in connection)
+    :type database: str
+    :param schema: name of schema (will overwrite schema defined in
+        connection)
+    :type schema: str
+    :param role: name of role (will overwrite any role defined in
+        connection's extra JSON)
+    :type role: str
+    :param authenticator: authenticator for Snowflake.
+        'snowflake' (default) to use the internal Snowflake authenticator
+        'externalbrowser' to authenticate using your web browser and
+        Okta, ADFS or any other SAML 2.0-compliant identify provider
+        (IdP) that has been defined for your account
+        'https://<your_okta_account_name>.okta.com' to authenticate
+        through native Okta.
+    :type authenticator: str
+    :param session_parameters: You can set session-level parameters at
+        the time you connect to Snowflake
+    :type session_parameters: dict
+    """
+
+    template_fields = ('sql',)
+    template_ext = ('.sql',)
+    ui_color = '#ededed'
+
+    def __init__(
+        self,
+        *,
+        sql: Any,
+        snowflake_conn_id: str = 'snowflake_default',
+        parameters: Optional[dict] = None,
+        autocommit: bool = True,
+        do_xcom_push: bool = True,
+        warehouse: Optional[str] = None,
+        database: Optional[str] = None,
+        role: Optional[str] = None,
+        schema: Optional[str] = None,
+        authenticator: Optional[str] = None,
+        session_parameters: Optional[dict] = None,
+        **kwargs,
+    ) -> None:
+        super().__init__(sql=sql, **kwargs)
+        self.snowflake_conn_id = snowflake_conn_id
+        self.sql = sql
+        self.autocommit = autocommit
+        self.do_xcom_push = do_xcom_push
+        self.parameters = parameters
+        self.warehouse = warehouse
+        self.database = database
+        self.role = role
+        self.schema = schema
+        self.authenticator = authenticator
+        self.session_parameters = session_parameters
+        self.query_ids = []
+
+    def get_db_hook(self) -> SnowflakeHook:
+        return get_db_hook(self)
+
+
+class SnowflakeValueCheckOperator(SQLValueCheckOperator):
+    """
+    Performs a simple check using sql code against a specified value, within a
+    certain level of tolerance.
+
+    :param sql: the sql to be executed
+    :type sql: str
+    :param pass_value: the value to check against
+    :type pass_value: Any
+    :param tolerance: (optional) the tolerance allowed to accept the query as
+        passing
+    :type tolerance: Any
+    :param snowflake_conn_id: Reference to
+        :ref:`Snowflake connection id<howto/connection:snowflake>`
+    :type snowflake_conn_id: str
+    :param autocommit: if True, each command is automatically committed.
+        (default value: True)
+    :type autocommit: bool
+    :param parameters: (optional) the parameters to render the SQL query with.
+    :type parameters: dict or iterable
+    :param warehouse: name of warehouse (will overwrite any warehouse
+        defined in the connection's extra JSON)
+    :type warehouse: str
+    :param database: name of database (will overwrite database defined
+        in connection)
+    :type database: str
+    :param schema: name of schema (will overwrite schema defined in
+        connection)
+    :type schema: str
+    :param role: name of role (will overwrite any role defined in
+        connection's extra JSON)
+    :type role: str
+    :param authenticator: authenticator for Snowflake.
+        'snowflake' (default) to use the internal Snowflake authenticator
+        'externalbrowser' to authenticate using your web browser and
+        Okta, ADFS or any other SAML 2.0-compliant identify provider
+        (IdP) that has been defined for your account
+        'https://<your_okta_account_name>.okta.com' to authenticate
+        through native Okta.
+    :type authenticator: str
+    :param session_parameters: You can set session-level parameters at
+        the time you connect to Snowflake
+    :type session_parameters: dict
+    """
+
+    def __init__(
+        self,
+        *,
+        sql: str,
+        pass_value: Any,
+        tolerance: Any = None,
+        snowflake_conn_id: str = 'snowflake_default',
+        parameters: Optional[dict] = None,
+        autocommit: bool = True,
+        do_xcom_push: bool = True,
+        warehouse: Optional[str] = None,
+        database: Optional[str] = None,
+        role: Optional[str] = None,
+        schema: Optional[str] = None,
+        authenticator: Optional[str] = None,
+        session_parameters: Optional[dict] = None,
+        **kwargs,
+    ) -> None:
+        super().__init__(sql=sql, pass_value=pass_value, tolerance=tolerance, **kwargs)
+        self.snowflake_conn_id = snowflake_conn_id
+        self.sql = sql
+        self.autocommit = autocommit
+        self.do_xcom_push = do_xcom_push
+        self.parameters = parameters
+        self.warehouse = warehouse
+        self.database = database
+        self.role = role
+        self.schema = schema
+        self.authenticator = authenticator
+        self.session_parameters = session_parameters
+        self.query_ids = []
+
+    def get_db_hook(self) -> SnowflakeHook:
+        return get_db_hook(self)
+
+
+class SnowflakeIntervalCheckOperator(SQLIntervalCheckOperator):
+    """
+    Checks that the values of metrics given as SQL expressions are within
+    a certain tolerance of the ones from days_back before.
+
+    This method constructs a query like so ::
+
+        SELECT {metrics_threshold_dict_key} FROM {table}
+        WHERE {date_filter_column}=<date>
+
+    :param table: the table name
+    :type table: str
+    :param days_back: number of days between ds and the ds we want to check
+        against. Defaults to 7 days
+    :type days_back: int
+    :param metrics_thresholds: a dictionary of ratios indexed by metrics, for
+        example 'COUNT(*)': 1.5 would require a 50 percent or less difference
+        between the current day, and the prior days_back.
+    :type metrics_thresholds: dict
+    :param snowflake_conn_id: Reference to
+        :ref:`Snowflake connection id<howto/connection:snowflake>`
+    :type snowflake_conn_id: str
+    :param autocommit: if True, each command is automatically committed.
+        (default value: True)
+    :type autocommit: bool
+    :param parameters: (optional) the parameters to render the SQL query with.
+    :type parameters: dict or iterable
+    :param warehouse: name of warehouse (will overwrite any warehouse
+        defined in the connection's extra JSON)
+    :type warehouse: str
+    :param database: name of database (will overwrite database defined
+        in connection)
+    :type database: str
+    :param schema: name of schema (will overwrite schema defined in
+        connection)
+    :type schema: str
+    :param role: name of role (will overwrite any role defined in
+        connection's extra JSON)
+    :type role: str
+    :param authenticator: authenticator for Snowflake.
+        'snowflake' (default) to use the internal Snowflake authenticator
+        'externalbrowser' to authenticate using your web browser and
+        Okta, ADFS or any other SAML 2.0-compliant identify provider
+        (IdP) that has been defined for your account
+        'https://<your_okta_account_name>.okta.com' to authenticate
+        through native Okta.
+    :type authenticator: str
+    :param session_parameters: You can set session-level parameters at
+        the time you connect to Snowflake
+    :type session_parameters: dict
+    """
+
+    def __init__(
+        self,
+        *,
+        table: str,
+        metrics_thresholds: dict,
+        date_filter_column: str = 'ds',
+        days_back: SupportsAbs[int] = -7,
+        snowflake_conn_id: str = 'snowflake_default',
+        parameters: Optional[dict] = None,
+        autocommit: bool = True,
+        do_xcom_push: bool = True,
+        warehouse: Optional[str] = None,
+        database: Optional[str] = None,
+        role: Optional[str] = None,
+        schema: Optional[str] = None,
+        authenticator: Optional[str] = None,
+        session_parameters: Optional[dict] = None,
+        **kwargs,
+    ) -> None:
+        super().__init__(
+            table=table,
+            metrics_thresholds=metrics_thresholds,
+            date_filter_column=date_filter_column,
+            days_back=days_back,
+            **kwargs,
+        )
+        self.snowflake_conn_id = snowflake_conn_id
+        self.autocommit = autocommit
+        self.do_xcom_push = do_xcom_push
+        self.parameters = parameters
+        self.warehouse = warehouse
+        self.database = database
+        self.role = role
+        self.schema = schema
+        self.authenticator = authenticator
+        self.session_parameters = session_parameters
+        self.query_ids = []
+
+    def get_db_hook(self) -> SnowflakeHook:
+        return get_db_hook(self)