Commit 8f4877c8 authored by Loic Bistuer's avatar Loic Bistuer
Browse files

Fixed #22583 -- Allowed RunPython and RunSQL to provide hints to the db router. 

Thanks Markus Holtermann and Tim Graham for the review.
parent 665e0aa6

django/db/migrations/operations/base.py

+7 −9
Original line number Diff line number Diff line
@@ -98,17 +98,15 @@ class Operation(object): 
        """

        return self.references_model(model_name, app_label)



    def allowed_to_migrate(self, connection_alias, model):

    def allowed_to_migrate(self, connection_alias, model, hints=None):

        """

        Returns if we're allowed to migrate the model. Checks the router,

        if it's a proxy, if it's managed, and if it's swapped out.

        Returns if we're allowed to migrate the model.

        """

        return (

            not model._meta.proxy and

            not model._meta.swapped and

            model._meta.managed and

            router.allow_migrate(connection_alias, model)

        )

        # Always skip if proxy, swapped out, or unmanaged.

        if model and (model._meta.proxy or model._meta.swapped or not model._meta.managed):

            return False



        return router.allow_migrate(connection_alias, model, **(hints or {}))



    def __repr__(self):

        return "<%s %s%s>" % (

django/db/migrations/operations/special.py

+20 −10
Original line number Diff line number Diff line
@@ -63,10 +63,11 @@ class RunSQL(Operation): 
    """

    noop = ''



    def __init__(self, sql, reverse_sql=None, state_operations=None):

    def __init__(self, sql, reverse_sql=None, state_operations=None, hints=None):

        self.sql = sql

        self.reverse_sql = reverse_sql

        self.state_operations = state_operations or []

        self.hints = hints or {}



    def deconstruct(self):

        kwargs = {
@@ -76,6 +77,8 @@ class RunSQL(Operation): 
            kwargs['reverse_sql'] = self.reverse_sql

        if self.state_operations:

            kwargs['state_operations'] = self.state_operations

        if self.hints:

            kwargs['hints'] = self.hints

        return (

            self.__class__.__name__,

            [],
@@ -91,11 +94,13 @@ class RunSQL(Operation): 
            state_operation.state_forwards(app_label, state)



    def database_forwards(self, app_label, schema_editor, from_state, to_state):

        if self.allowed_to_migrate(schema_editor.connection.alias, None, hints=self.hints):

            self._run_sql(schema_editor, self.sql)



    def database_backwards(self, app_label, schema_editor, from_state, to_state):

        if self.reverse_sql is None:

            raise NotImplementedError("You cannot reverse this operation")

        if self.allowed_to_migrate(schema_editor.connection.alias, None, hints=self.hints):

            self._run_sql(schema_editor, self.reverse_sql)



    def describe(self):
@@ -125,7 +130,7 @@ class RunPython(Operation): 


    reduces_to_sql = False



    def __init__(self, code, reverse_code=None, atomic=True):

    def __init__(self, code, reverse_code=None, atomic=True, hints=None):

        self.atomic = atomic

        # Forwards code

        if not callable(code):
@@ -138,6 +143,7 @@ class RunPython(Operation): 
            if not callable(reverse_code):

                raise ValueError("RunPython must be supplied with callable arguments")

            self.reverse_code = reverse_code

        self.hints = hints or {}



    def deconstruct(self):

        kwargs = {
@@ -147,6 +153,8 @@ class RunPython(Operation): 
            kwargs['reverse_code'] = self.reverse_code

        if self.atomic is not True:

            kwargs['atomic'] = self.atomic

        if self.hints:

            kwargs['hints'] = self.hints

        return (

            self.__class__.__name__,

            [],
@@ -163,6 +171,7 @@ class RunPython(Operation): 
        pass



    def database_forwards(self, app_label, schema_editor, from_state, to_state):

        if self.allowed_to_migrate(schema_editor.connection.alias, None, hints=self.hints):

            # We now execute the Python code in a context that contains a 'models'

            # object, representing the versioned models as an app registry.

            # We could try to override the global cache, but then people will still
@@ -172,6 +181,7 @@ class RunPython(Operation): 
    def database_backwards(self, app_label, schema_editor, from_state, to_state):

        if self.reverse_code is None:

            raise NotImplementedError("You cannot reverse this operation")

        if self.allowed_to_migrate(schema_editor.connection.alias, None, hints=self.hints):

            self.reverse_code(from_state.apps, schema_editor)



    def describe(self):

django/db/utils.py

+2 −2
Original line number Diff line number Diff line
@@ -316,7 +316,7 @@ class ConnectionRouter(object): 
                    return allow

        return obj1._state.db == obj2._state.db



    def allow_migrate(self, db, model):

    def allow_migrate(self, db, model, **hints):

        for router in self.routers:

            try:

                try:
@@ -331,7 +331,7 @@ class ConnectionRouter(object): 
                # If the router doesn't have a method, skip to the next one.

                pass

            else:

                allow = method(db, model)

                allow = method(db, model, **hints)

                if allow is not None:

                    return allow

        return True

docs/ref/migration-operations.txt

+18 −2
Original line number Diff line number Diff line
@@ -206,7 +206,7 @@ Special Operations 
RunSQL

------



.. class:: RunSQL(sql, reverse_sql=None, state_operations=None)

.. class:: RunSQL(sql, reverse_sql=None, state_operations=None, hints=None)



Allows running of arbitrary SQL on the database - useful for more advanced

features of database backends that Django doesn't support directly, like
@@ -235,6 +235,11 @@ operation here so that the autodetector still has an up-to-date state of the 
model (otherwise, when you next run ``makemigrations``, it won't see any

operation that adds that field and so will try to run it again).



The optional ``hints`` argument will be passed as ``**hints`` to the

:meth:`allow_migrate` method of database routers to assist them in making

routing decisions. See :ref:`topics-db-multi-db-hints` for more details on

database hints.



.. versionchanged:: 1.7.1



    If you want to include literal percent signs in a query without parameters
@@ -245,6 +250,8 @@ operation that adds that field and so will try to run it again). 
    The ability to pass parameters to the ``sql`` and ``reverse_sql`` queries

    was added.



    The ``hints`` argument was added.



.. attribute:: RunSQL.noop



    .. versionadded:: 1.8
@@ -258,7 +265,7 @@ operation that adds that field and so will try to run it again). 
RunPython

---------



.. class:: RunPython(code, reverse_code=None, atomic=True)

.. class:: RunPython(code, reverse_code=None, atomic=True, hints=None)



Runs custom Python code in a historical context. ``code`` (and ``reverse_code``

if supplied) should be callable objects that accept two arguments; the first is
@@ -267,6 +274,15 @@ match the operation's place in the project history, and the second is an 
instance of :class:`SchemaEditor

<django.db.backends.schema.BaseDatabaseSchemaEditor>`.



The optional ``hints`` argument will be passed as ``**hints`` to the

:meth:`allow_migrate` method of database routers to assist them in making a

routing decision. See :ref:`topics-db-multi-db-hints` for more details on

database hints.



.. versionadded:: 1.8



    The ``hints`` argument was added.



You are advised to write the code as a separate function above the ``Migration``

class in the migration file, and just pass it to ``RunPython``. Here's an

example of using ``RunPython`` to create some initial objects on a ``Country``

docs/releases/1.8.txt

+14 −0
Original line number Diff line number Diff line
@@ -462,6 +462,12 @@ Migrations 
  attribute/method were added to ease in making ``RunPython`` and ``RunSQL``

  operations reversible.



* The :class:`~django.db.migrations.operations.RunPython` and

  :class:`~django.db.migrations.operations.RunSQL` operations now accept a

  ``hints`` parameter that will be passed to :meth:`allow_migrate`. To take

  advantage of this feature you must ensure that the ``allow_migrate()`` method

  of all your routers accept ``**hints``.



Models

^^^^^^
@@ -1029,6 +1035,14 @@ Miscellaneous 
* :func:`django.utils.translation.get_language()` now returns ``None`` instead

  of :setting:`LANGUAGE_CODE` when translations are temporarily deactivated.



* The migration operations :class:`~django.db.migrations.operations.RunPython`

  and :class:`~django.db.migrations.operations.RunSQL` now call the

  :meth:`allow_migrate` method of database routers. In these cases the

  ``model`` argument of ``allow_migrate()`` is set to ``None``, so the router

  must properly handle this value. This is most useful when used together with

  the newly introduced ``hints`` parameter for these operations, but it can

  also be used to disable migrations from running on a particular database.



.. _deprecated-features-1.8:



Features deprecated in 1.8