squabble.rules package

class squabble.rules.BaseRule

Bases: object

Base implementation of a linter rule.

Rules work by adding hooks into the abstract syntax tree for a SQL file, and then performing their lint actions inside the callback functions.

Rules represent lint issues using pre-defined message classes, which are defined by creating a child class inheriting from squabble.message.Message.

For example:

>>> import squabble.message
>>> class MyRule(BaseRule):
...     class BadColumnName(squabble.message.Message):
...         TEMPLATE = 'column {name} is not allowed'
...
>>> MyRule.BadColumnName(name='foo').format()
'column foo is not allowed'

classmethod meta()

Return metadata about the Rule. Base implementation should be sane enough for most purposes.

>>> class MyRule(BaseRule):
...     '''
...     Brief description of rule. This can
...     wrap to the next line.
...
...     More details about this rule.
...     '''
>>> m = MyRule.meta()
>>> m['name']
'MyRule'
>>> m['description']
'Brief description of rule. This can wrap to the next line.'
>>> m['help']
'More details about this rule.'

enable(ctx, config)

Called before the root AST node is traversed. Here’s where most callbacks should be registered for different AST nodes.

Each linter is initialized once per file that it is being run against. config will contain the merged base configuration with the file-specific configuration options for this linter.