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airflow.operators.sql

Module Contents

Classes

BaseSQLOperator	This is a base class for generic SQL Operator to get a DB Hook
SQLCheckOperator	Performs checks against a db. The SQLCheckOperator expects
SQLValueCheckOperator	Performs a simple value check using sql code.
SQLIntervalCheckOperator	Checks that the values of metrics given as SQL expressions are within
SQLThresholdCheckOperator	Performs a value check using sql code against a minimum threshold
BranchSQLOperator	Allows a DAG to "branch" or follow a specified path based on the results of a SQL query.

Functions

parse_boolean(val)

Try to parse a string into boolean.

airflow.operators.sql.parse_boolean(val)

Try to parse a string into boolean.

Raises ValueError if the input is not a valid true- or false-like string value.

class airflow.operators.sql.BaseSQLOperator(*, conn_id=None, database=None, hook_params=None, **kwargs)

Bases: airflow.models.BaseOperator

This is a base class for generic SQL Operator to get a DB Hook

The provided method is .get_db_hook(). The default behavior will try to retrieve the DB hook based on connection type. You can custom the behavior by overriding the .get_db_hook() method.

get_db_hook(self)

Get the database hook for the connection.

Returns

the database hook object.

Return type

DbApiHook

class airflow.operators.sql.SQLCheckOperator(*, sql, conn_id=None, database=None, **kwargs)

Bases: BaseSQLOperator

Performs checks against a db. The SQLCheckOperator 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.

Parameters

• sql (str) -- the sql to be executed. (templated)

• conn_id (Optional[str]) -- the connection ID used to connect to the database.

• database (Optional[str]) -- name of database which overwrite the defined one in connection

template_fields :Sequence[str] = ['sql']

template_ext :Sequence[str] = ['.hql', '.sql']

template_fields_renderers

ui_color = #fff7e6

execute(self, context)

This is the main method to derive when creating an operator. Context is the same dictionary used as when rendering jinja templates.

Refer to get_template_context for more context.

class airflow.operators.sql.SQLValueCheckOperator(*, sql, pass_value, tolerance=None, conn_id=None, database=None, **kwargs)

Bases: BaseSQLOperator

Performs a simple value check using sql code.

Parameters

• sql (str) -- the sql to be executed. (templated)

• conn_id (Optional[str]) -- the connection ID used to connect to the database.

• database (Optional[str]) -- name of database which overwrite the defined one in connection

__mapper_args__

template_fields :Sequence[str] = ['sql', 'pass_value']

template_ext :Sequence[str] = ['.hql', '.sql']

template_fields_renderers

ui_color = #fff7e6

execute(self, context=None)

This is the main method to derive when creating an operator. Context is the same dictionary used as when rendering jinja templates.

Refer to get_template_context for more context.

class airflow.operators.sql.SQLIntervalCheckOperator(*, table, metrics_thresholds, date_filter_column='ds', days_back=- 7, ratio_formula='max_over_min', ignore_zero=True, conn_id=None, database=None, **kwargs)

Bases: BaseSQLOperator

Checks that the values of metrics given as SQL expressions are within a certain tolerance of the ones from days_back before.

Parameters

• table (str) -- the table name

• conn_id (Optional[str]) -- the connection ID used to connect to the database.

• database (Optional[str]) -- name of database which will overwrite the defined one in connection

• days_back (SupportsAbs[int]) -- number of days between ds and the ds we want to check against. Defaults to 7 days

• date_filter_column (Optional[str]) -- The column name for the dates to filter on. Defaults to 'ds'

• ratio_formula (Optional[str]) --

  which formula to use to compute the ratio between the two metrics. Assuming cur is the metric of today and ref is the metric to today - days_back.

  max_over_min: computes max(cur, ref) / min(cur, ref) relative_diff: computes abs(cur-ref) / ref

  Default: 'max_over_min'

• ignore_zero (bool) -- whether we should ignore zero metrics

• metrics_thresholds (Dict[str, int]) -- a dictionary of ratios indexed by metrics

__mapper_args__

template_fields :Sequence[str] = ['sql1', 'sql2']

template_ext :Sequence[str] = ['.hql', '.sql']

template_fields_renderers

ui_color = #fff7e6

ratio_formulas

execute(self, context=None)

This is the main method to derive when creating an operator. Context is the same dictionary used as when rendering jinja templates.

Refer to get_template_context for more context.

class airflow.operators.sql.SQLThresholdCheckOperator(*, sql, min_threshold, max_threshold, conn_id=None, database=None, **kwargs)

Bases: BaseSQLOperator

Performs a value check using sql code against a minimum threshold and a maximum threshold. Thresholds can be in the form of a numeric value OR a sql statement that results a numeric.

Parameters

• sql (str) -- the sql to be executed. (templated)

• conn_id (Optional[str]) -- the connection ID used to connect to the database.

• database (Optional[str]) -- name of database which overwrite the defined one in connection

• min_threshold (Any) -- numerical value or min threshold sql to be executed (templated)

• max_threshold (Any) -- numerical value or max threshold sql to be executed (templated)

template_fields :Sequence[str] = ['sql', 'min_threshold', 'max_threshold']

template_ext :Sequence[str] = ['.hql', '.sql']

template_fields_renderers

execute(self, context=None)

This is the main method to derive when creating an operator. Context is the same dictionary used as when rendering jinja templates.

Refer to get_template_context for more context.

push(self, meta_data)

Optional: Send data check info and metadata to an external database. Default functionality will log metadata.

class airflow.operators.sql.BranchSQLOperator(*, sql, follow_task_ids_if_true, follow_task_ids_if_false, conn_id='default_conn_id', database=None, parameters=None, **kwargs)

Bases: BaseSQLOperator, airflow.models.SkipMixin

Allows a DAG to "branch" or follow a specified path based on the results of a SQL query.

Parameters

• sql (str) -- The SQL code to be executed, should return true or false (templated) Template reference are recognized by str ending in '.sql'. Expected SQL query to return Boolean (True/False), integer (0 = False, Otherwise = 1) or string (true/y/yes/1/on/false/n/no/0/off).

• follow_task_ids_if_true (List[str]) -- task id or task ids to follow if query returns true

• follow_task_ids_if_false (List[str]) -- task id or task ids to follow if query returns false

• conn_id (str) -- the connection ID used to connect to the database.

• database (Optional[str]) -- name of database which overwrite the defined one in connection

• parameters (Optional[Union[Mapping, Iterable]]) -- (optional) the parameters to render the SQL query with.

template_fields :Sequence[str] = ['sql']

template_ext :Sequence[str] = ['.sql']

template_fields_renderers

ui_color = #a22034

ui_fgcolor = #F7F7F7

execute(self, context)

This is the main method to derive when creating an operator. Context is the same dictionary used as when rendering jinja templates.

Refer to get_template_context for more context.

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