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.. _python_templater:
Python templater
^^^^^^^^^^^^^^^^
Uses native Python f-strings. As described in
:ref:`generic_variable_templating`, an example usage would look be
configured as follows:
If passed the following *.sql* file:
.. code-block::
SELECT * FROM {tbl_name}
...and the following configuration in *.sqlfluff* in the same directory:
.. code-block:: cfg
[sqlfluff]
templater = python
[sqlfluff:templater:python:context]
tbl_name = my_table
...then before parsing, the sql will be transformed to:
.. code-block:: sql
SELECT * FROM my_table
Complex Python Variable Templating
""""""""""""""""""""""""""""""""""""
`Python string formatting`_ supports accessing object attributes
via dot notation (e.g. :code:`{foo.bar}`). However, since we cannot create Python
objects within configuration files, we need a workaround in order to provide
dummy values to render templates containing these values. The SQLFluff
python templater will interpret any variable containing a "." as a
dictionary lookup on the *magic* fixed context key :code:`sqlfluff`.
.. code-block::
-- this SQL
SELECT * FROM {foo.bar}
-- becomes this
SELECT * FROM {sqlfluff["foo.bar"]}
..which can be populated using the following configuration:
.. code-block:: cfg
[sqlfluff:templater:python:context]
sqlfluff = {"foo.bar": "abc"}
.. _`Python string formatting`: https://docs.python.org/3/library/string.html#format-string-syntax
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