[Django] #23749: migrations.RunPython broken with dbrouters.
Django
---------------------------------+---------------------------------
Reporter: alfredperlstein | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.7
Severity: Normal | Keywords: migrations dbrouter
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
---------------------------------+---------------------------------
It seems that the migration system in 1.7 does not properly query the
dbrouter setup when a migrations.RunPython method is invoked.
Running the following command:
{{{
python manage.py migrate mycompany --noinput --traceback --database=logs
--verbosity=2
}}}
Never seems to call the router for the following migration, so as you can
see I've added code to parse sys.argv as an experiment which seems to
sort-of work, but really looks like the wrong way to do this.
{{{
# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import models, migrations
from applianceUI.mycompany.dbrouter import LogRouter
import sys
def bkd_default_ports(apps, schema_editor):
db = None
for arg in sys.argv:
if '=' not in arg:
continue
print "arg: ", arg
k, v = arg.split('=', 2)
print "k: '%s', v: '%s' " % (k,v)
if k == "--database":
print arg
db = v
break
print "db is %s" % db
router = LogRouter()
Blockd = apps.get_model("mycompany", "Blockd")
if router.allow_migrate(db, Blockd) is False:
return
try:
bkd = Blockd.objects.order_by("-id")[0]
except IndexError:
bkd = Blockd.objects.create()
if bkd.bkd_ports is "":
bkd.bkd_ports = "80, 8080, 3128"
bkd.save()
class Migration(migrations.Migration):
dependencies = [
('mycompany', '0005_auto_direction_and_indexes'),
]
operations = [
migrations.RunPython(bkd_default_ports),
]
}}}
The arguments apps and schema_editor didn't give me enough data to make my
decision. How can i properly derive that the database is "logs"?
--
Ticket URL: <https://code.djangoproject.com/ticket/23749>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
Django
Reporter: alfredperlstein | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.7
Keywords: migrations dbrouter | Triage Stage:
Needs tests: 0 | Needs documentation: 0
Easy pickings: 0 | Patch needs improvement: 0
| UI/UX: 0
-------------------------------------+-------------------------------------
Changes (by alfredperlstein):
* needs_better_patch: => 0
* needs_tests: => 0
* needs_docs: => 0
Comment:
Traceback I get is as follows:
{{{
+ psql -U pgsql -d postgres -c 'create database historicallogs'
CREATE DATABASE
+ python manage.py migrate mycompany --noinput --traceback --database=logs
Operations to perform:
Apply all migrations: mycompany
Running migrations:
Applying mycompany.0001_initial... OK
Applying mycompany.0002_auto_20140904_1549... OK
Applying mycompany.0003_auto_20141006_1134... OK
Applying mycompany.0004_blockd_bkd_ports... OK
Applying mycompany.0005_auto_direction_and_indexes... OK
Applying mycompany.0006_auto_20141103_1539...Traceback (most recent call
last):
File "manage.py", line 42, in <module>
execute_from_command_line(sys.argv)
File "/usr/local/lib/python2.7/site-
packages/django/core/management/__init__.py", line 385, in
execute_from_command_line
utility.execute()
File "/usr/local/lib/python2.7/site-
packages/django/core/management/__init__.py", line 377, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/usr/local/lib/python2.7/site-
packages/django/core/management/base.py", line 288, in run_from_argv
self.execute(*args, **options.__dict__)
File "/usr/local/lib/python2.7/site-
packages/django/core/management/base.py", line 338, in execute
output = self.handle(*args, **options)
File "/usr/local/lib/python2.7/site-
packages/django/core/management/commands/migrate.py", line 160, in handle
executor.migrate(targets, plan, fake=options.get("fake", False))
File "/usr/local/lib/python2.7/site-
packages/django/db/migrations/executor.py", line 63, in migrate
self.apply_migration(migration, fake=fake)
File "/usr/local/lib/python2.7/site-
packages/django/db/migrations/executor.py", line 97, in apply_migration
migration.apply(project_state, schema_editor)
File "/usr/local/lib/python2.7/site-
packages/django/db/migrations/migration.py", line 107, in apply
operation.database_forwards(self.app_label, schema_editor,
project_state, new_state)
File "/usr/local/lib/python2.7/site-
packages/django/db/migrations/operations/special.py", line 117, in
database_forwards
self.code(from_state.render(), schema_editor)
File
"/usr/local/www/applianceUI/applianceUI/mycompany/migrations/0006_auto_20141103_1539.py",
line 8, in bkd_default_ports
bkd = Blockd.objects.config()
File
"/usr/local/www/applianceUI/applianceUI/freeadmin/models/__init__.py",
line 59, in config
obj = self.order_by("-id")[0]
File "/usr/local/lib/python2.7/site-packages/django/db/models/query.py",
line 177, in __getitem__
return list(qs)[0]
File "/usr/local/lib/python2.7/site-packages/django/db/models/query.py",
line 141, in __iter__
self._fetch_all()
File "/usr/local/lib/python2.7/site-packages/django/db/models/query.py",
line 966, in _fetch_all
self._result_cache = list(self.iterator())
File "/usr/local/lib/python2.7/site-packages/django/db/models/query.py",
line 265, in iterator
for row in compiler.results_iter():
File "/usr/local/lib/python2.7/site-
packages/django/db/models/sql/compiler.py", line 700, in results_iter
for rows in self.execute_sql(MULTI):
File "/usr/local/lib/python2.7/site-
packages/django/db/models/sql/compiler.py", line 786, in execute_sql
cursor.execute(sql, params)
File "/usr/local/lib/python2.7/site-
packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
File "/usr/local/lib/python2.7/site-packages/django/db/utils.py", line
94, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "/usr/local/lib/python2.7/site-
packages/django/db/backends/utils.py", line 65, in execute
return self.cursor.execute(sql, params)
File "/usr/local/lib/python2.7/site-
packages/django/db/backends/sqlite3/base.py", line 485, in execute
return Database.Cursor.execute(self, query, params)
django.db.utils.OperationalError: no such table: mycompany_blockd
+ su - pgsql -c '/usr/local/bin/pg_ctl stop -w -D /data/pgsql/data'
waiting for server to shut down.... done
server stopped
+ exit 1
}}}
My dbrouter looks like such:
{{{
# Router for DB logs
postgres_models = ('log', 'logrollup', 'ipwhitelist', 'urlwhitelist')
tmplog_models = ('blocklog',)
class LogRouter(object):
'''
A router to control all database operations for historical logs.
'''
def db_for_read(self, model, **hints):
'''
Attempts to read historical logs go to logs db.
'''
if model._meta.model_name in postgres_models:
return 'logs'
if model._meta.model_name in tmplog_models:
return 'tmplogs'
return None
def db_for_write(self, model, **hints):
'''
Attempts to read historical logs go to logs db.
'''
if model._meta.model_name in postgres_models:
return 'logs'
if model._meta.model_name in tmplog_models:
return 'tmplogs'
return None
def allow_relation(self, obj1, obj2, **hints):
# XXX: need cy to revisit this.
# "apps" is not defined during initial migrations for some
# reason and this throws a traceback.
#if obj1._meta.app_label in apps or obj2._meta.app_label in apps:
# return True
return None
def allow_migrate(self, db, model):
'''
Make sure the historical logs only appear in the 'logs'
database.
'''
if db == 'logs':
return model._meta.model_name in postgres_models
elif model._meta.model_name in postgres_models:
return False
if db == 'tmplogs':
return model._meta.model_name in tmplog_models
elif model._meta.model_name in tmplog_models:
return False
# otherwise do not allow migrations for non-logs/tmplogs
migrations.
if db == 'logs' or db == 'tmplogs':
return False
return None
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:1>
Django
Reporter: alfredperlstein | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.7
Keywords: migrations dbrouter | Triage Stage:
Needs tests: 0 | Needs documentation: 0
Easy pickings: 0 | Patch needs improvement: 0
| UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by timgraham):
I think this is a duplicate of #23273 (or at least closely related to).
Have you read that ticket?
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:2>
Django
Reporter: alfredperlstein | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.7
Keywords: migrations dbrouter | Triage Stage:
Needs tests: 0 | Needs documentation: 0
Easy pickings: 0 | Patch needs improvement: 0
| UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by splbio):
To be honest this is more like #22583.
#23273 is too complex for me to parse, there may be some overlap, but I do
not think so.
All that is needed is that we somehow pass the --database=FOO option to
the RunPython method as a kwarg so that the router can provide a function
to query that... OR that the migration itself can decide.
I am not sure why the name of the db is not given to the RunPython method.
This is a relatively simple request, can this please be fixed?
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:3>
Django
Reporter: alfredperlstein | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.7
Keywords: migrations dbrouter | Triage Stage:
Needs tests: 0 | Needs documentation: 0
Easy pickings: 0 | Patch needs improvement: 0
| UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by timgraham):
Ah yes, that was the ticket I was looking for but couldn't find - forgot
it had been closed. Anyway, wouldn't `schema_editor.connection.alias` give
you the name of the database? If so, we should likely document the
solution.
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:4>
Django
--------------------------------------+------------------------------------
Reporter: alfredperlstein | Owner: nobody
Type: Cleanup/optimization | Status: new
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
--------------------------------------+------------------------------------
Changes (by timgraham):
* component: Migrations => Documentation
* stage: Unreviewed => Accepted
* type: Bug => Cleanup/optimization
* easy: 0 => 1
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:5>
Django
--------------------------------------+------------------------------------
Type: Cleanup/optimization | Status: new
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
--------------------------------------+------------------------------------
Comment (by iambibhas):
I just verified that `schema_editor.connection.alias` does return the
current connection in use, even when `--database=foobar` is used. We could
mention this in the
[https://docs.djangoproject.com/en/1.7/topics/migrations/#data-migrations
data migration doc] and/or the [https://docs.djangoproject.com/en/1.7/ref
/schema-editor/ `SchemaEditor` doc]. `SchemaEditor` doc could use a
`Properties` section along with the `Methods` section.
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:6>
Django
--------------------------------------+------------------------------------
Type: Cleanup/optimization | Status: new
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
--------------------------------------+------------------------------------
* cc: me@… (added)
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:7>
Django
Reporter: alfredperlstein | Owner: nobody
Type: | Status: closed
Cleanup/optimization |
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
Changes (by timgraham):
* status: new => closed
* resolution: => worksforme
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:8>
Django
-------------------------------------+-------------------------------------
Type: | Status: closed
Cleanup/optimization |
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
| worksforme
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by splbio):
Can someone give me a pointer to how to edit the page
https://docs.djangoproject.com/en/1.7/topics/migrations/#data-migrations
-Or-
https://docs.djangoproject.com/en/1.7/ref/schema-editor/
?
To be perfectly honest the addition to the RunPython section
(https://github.com/django/django/blob/aa5ef0d4fc67a95ac2a5103810d0c87d8c547bac/docs/ref
/migration-operations.txt#L316-L322) is not something that I would have
been able to find via google, nor is it likely I would have been able to
understand it.
I'm perfectly willing to update the docs for the migration or
schema_editor pages, I just need a pointer how to get started. Is it a
wiki I can log into? Or is there a git repo I can clone?
Please advise.
thank you!
-Alfred
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:9>
Django
Reporter: alfredperlstein | Owner: nobody
Type: Cleanup/optimization | Status: new
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
Changes (by timgraham):
* status: closed => new
* resolution: worksforme =>
Comment:
Please see [https://docs.djangoproject.com/en/dev/internals/contributing
/writing-documentation/ Writing documentation].
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:10>
Django
--------------------------------------+------------------------------------
Type: Cleanup/optimization | Status: assigned
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
--------------------------------------+------------------------------------
* owner: nobody => splbio
* status: new => assigned
Comment:
I have created a pull request against documentation here:
https://github.com/django/django/pull/3822
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:11>
Django
--------------------------------------+------------------------------------
Reporter: alfredperlstein | Owner: splbio
Type: Cleanup/optimization | Status: assigned
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
--------------------------------------+------------------------------------
Comment (by splbio):
If this looks OK I would like to document the {{{connection}}} handle
being inside the {{{schema_editor}}} on another page. Please let me know
if this document addition is in the correct path and if so I will look
into augmenting the {{{schema_editor}}} page.
Is it the norm to document member variables? Is there an existing
example? The reason I ask is that {{{schema_editor}}} only has its
methods documented and no member variables.
thank you.
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:12>
Django
--------------------------------------+------------------------------------
Reporter: alfredperlstein | Owner: splbio
Type: Cleanup/optimization | Status: assigned
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
--------------------------------------+------------------------------------
Comment (by splbio):
Tim,
I've submitted a github pull request and tried my best to follow the guide
on submitting patches.
I have no spelling errors and no warnings that are in files I have
touched.
Can the github pull request be merged at your convenience?
https://github.com/django/django/pull/3822
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:13>
Django
--------------------------------------+------------------------------------
Reporter: alfredperlstein | Owner:
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
--------------------------------------+------------------------------------
* owner: splbio =>
* status: assigned => new
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:14>
Django
--------------------------------------+------------------------------------
Reporter: alfredperlstein | Owner:
Type: Cleanup/optimization | Status: new
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
--------------------------------------+------------------------------------
* has_patch: 0 => 1
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:15>
Django
--------------------------------------+------------------------------------
Reporter: alfredperlstein | Owner:
Type: Cleanup/optimization | Status: new
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Easy pickings: 1 | UI/UX: 0
--------------------------------------+------------------------------------
* needs_better_patch: 0 => 1
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:16>
Django
--------------------------------------+------------------------------------
Reporter: alfredperlstein | Owner:
Type: Cleanup/optimization | Status: new
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 1
Easy pickings: 1 | UI/UX: 0
--------------------------------------+------------------------------------
Comment (by claudep):
#23879 is somewhat related. See this POC branch:
https://github.com/wrwrwr/django/compare/feature/always-test-gis-and-
postgres
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:17>
Django
--------------------------------------+------------------------------------
Reporter: alfredperlstein | Owner:
Type: Cleanup/optimization | Status: new
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 1
Easy pickings: 1 | UI/UX: 0
--------------------------------------+------------------------------------
Comment (by MarkusH):
Replying to [comment:17 claudep]:
> #23879 is somewhat related. See this POC branch:
https://github.com/wrwrwr/django/compare/feature/always-test-gis-and-
postgres
TBH, I don't see any relation to the issue here. It's not about running on
a specific vendor, it's about different databases, probably even of the
same vendor.
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:18>
Django
--------------------------------------+------------------------------------
Reporter: alfredperlstein | Owner:
Type: Cleanup/optimization | Status: new
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 1
Easy pickings: 1 | UI/UX: 0
--------------------------------------+------------------------------------
Comment (by splbio):
Replying to [comment:18 MarkusH]:
> Replying to [comment:17 claudep]:
> > #23879 is somewhat related. See this POC branch:
https://github.com/wrwrwr/django/compare/feature/always-test-gis-and-
postgres
>
> TBH, I don't see any relation to the issue here. It's not about running
on a specific vendor, it's about different databases, probably even of the
same vendor.
+1
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:19>
Django
--------------------------------------+------------------------------------
Reporter: alfredperlstein | Owner:
Type: Cleanup/optimization | Status: new
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 1
Easy pickings: 1 | UI/UX: 0
--------------------------------------+------------------------------------
Comment (by MarkusH):
{{{#!diff
diff --git a/docs/ref/schema-editor.txt b/docs/ref/schema-editor.txt
index 54dd3bf..c503296 100644
--- a/docs/ref/schema-editor.txt
+++ b/docs/ref/schema-editor.txt
@@ -158,9 +158,9 @@ below.
.. attribute:: SchemaEditor.connection
-A connection object to the database. A useful attribute of the
-connection is ``alias`` which can be used to determine the name of
-the database being accessed.
+A connection object to the database. A useful attribute of the connection
is
+``alias`` which can be used to determine the name of the database being
+accessed.
-This in turn is useful when doing data migrations for
-:ref:`migrations with multiple database backends <data-migrations-and-
multiple-databases>`.
+This in turn is useful when doing data migrations for :ref:`migrations
with
+multiple database backends <data-migrations-and-multiple-databases>`.
diff --git a/docs/topics/migrations.txt b/docs/topics/migrations.txt
index 746f4d2..a743bf2 100644
--- a/docs/topics/migrations.txt
+++ b/docs/topics/migrations.txt
@@ -472,71 +472,72 @@ backwards will raise an exception.
Data migrations and multiple databases
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-One of the challenges that can be encountered is figuring out whether
-or not to run a migration when using multiple databases.
-
-For example, you may want to **only** run a migration against a
-particular database.
-
-In order to do that you can filter inside of your data migration
-by looking at the ``schema_editor.connection.alias`` attribute.
-However it is better to have your ``dbrouter`` leverage the same
-``allow_migrate`` call by making the following method in your
-router::
-
- class MyRouter(object):
-
- def allow_migrate(self, db, model):
- # your typical migration code here
-
- def runpython_ok(self, apps, schema_editor, model):
- db = schema_editor.connection.alias
- if self.allow_migrate(db, model):
- return True
- return False
-
-Then to leverage this in your migrations, do the following::
-
- # -*- coding: utf-8 -*-
- from __future__ import unicode_literals
-
- from django.db import models, migrations
- from myappname.dbrouter import MyRouter
- import sys
-
- def forwards(apps, schema_editor):
- # only run this for the correct databases
- MyModel = apps.get_model("myappname", "MyModel")
- if not MyRouter().runpython_ok(apps, schema_editor, MyModel):
- return
-
- """
- This is a global configuration model so there should be only
- row.
- Get the first one -or- create the initial one.
- Only set the default ports if it has not been set by user
- already.
- """
- try:
- my_model = MyModel.objects.order_by("-id").first()
- except IndexError:
- my_model = MyModel.objects.create()
- if my_model.my_model_ports == "":
- my_model.my_model_ports = "80, 8080, 3128"
- my_model.save()
-
- def backwards(apps, schema_editor):
- pass
-
- class Migration(migrations.Migration):
-
- dependencies = [
- # Dependencies to other migrations
- ]
-
- operations = [
- migrations.RunPython(forwards, backwards),
- ]
+One of the challenges that can be encountered is figuring out whether or
not to
+run a migration when using multiple databases.
+
+For example, you may want to **only** run a migration against a
particular
+database.
+
+In order to do that you can check the connection alias inside a
``RunPython``
+forwards and backwards operation by looking at the
+``schema_editor.connection.alias`` attribute.
+
+ # -*- coding: utf-8 -*-
+ from __future__ import unicode_literals
+
+ from django.db import migrations
+
+ def forwards(apps, schema_editor):
+ if not schema_editor.connection.alias == 'master-db':
+ return
+ # Your migration code goes here
+
+ class Migration(migrations.Migration):
+
+ dependencies = [
+ # Dependencies to other migrations
+ ]
+
+ operations = [
+ migrations.RunPython(forwards),
+ ]
+
+You can also use your database router's ``allow_migrate`` method, but
keep in
+mind that the imported router needs to stay around as long as it is
referenced
+inside a migration:
+
+.. snippet::
+ :filename: myapp/dbrouters.py
+
+ class MyRouter(object):
+
+ def allow_migrate(self, db, model):
+ return db == 'default':
+
+Then, to leverage this in your migrations, do the following::
+
+ # -*- coding: utf-8 -*-
+ from __future__ import unicode_literals
+
+ from django.db import models, migrations
+
+ from myappname.dbrouters import MyRouter
+
+ def forwards(apps, schema_editor):
+ MyModel = apps.get_model("myappname", "MyModel")
+ if not MyRouter().allow_migrate(schema_editor.connection.alias,
MyModel):
+ return
+ # Your migration code goes here
+
+ class Migration(migrations.Migration):
+
+ dependencies = [
+ # Dependencies to other migrations
+ ]
+
+ operations = [
+ migrations.RunPython(forwards),
+ ]
More advanced migrations
~~~~~~~~~~~~~~~~~~~~~~~~
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:20>
Django
--------------------------------------+------------------------------------
Reporter: alfredperlstein | Owner:
Type: Cleanup/optimization | Status: new
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 1
Easy pickings: 1 | UI/UX: 0
--------------------------------------+------------------------------------
Comment (by splbio):
Which version of the pull request was this made against? It seems to be
done against an older version and will not apply cleanly.
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:21>
Django
--------------------------------------+------------------------------------
Reporter: alfredperlstein | Owner:
Type: Cleanup/optimization | Status: new
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 1
Easy pickings: 1 | UI/UX: 0
--------------------------------------+------------------------------------
Comment (by splbio):
Oh, it applies, OK. I'll push it shortly thank you.
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:22>
Django
--------------------------------------+------------------------------------
Reporter: alfredperlstein | Owner:
Type: Cleanup/optimization | Status: new
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 1
Easy pickings: 1 | UI/UX: 0
--------------------------------------+------------------------------------
Comment (by splbio):
OK, it is pushed, Thank you Markus.
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:23>
Django
Reporter: alfredperlstein | Owner:
Type: | Status: new
Cleanup/optimization |
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
| checkin
Has patch: 1 | Needs documentation: 0
Easy pickings: 1 | UI/UX: 0
Changes (by MarkusH):
* needs_better_patch: 1 => 0
* stage: Accepted => Ready for checkin
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:24>
Django
-------------------------------------+-------------------------------------
Reporter: alfredperlstein | Owner:
Type: | Status: new
Cleanup/optimization |
Component: Documentation | Version: 1.7
Severity: Normal | Resolution:
Keywords: migrations dbrouter | Triage Stage: Ready for
| checkin
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
-------------------------------------+-------------------------------------
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:25>
Django
-------------------------------------+-------------------------------------
Type: | Graham <timograham@…>
Cleanup/optimization | Status: closed
Component: Documentation | Version: 1.7
Severity: Normal | Resolution: fixed
Keywords: migrations dbrouter | Triage Stage: Ready for
| checkin
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
-------------------------------------+-------------------------------------
* owner: => Tim Graham <timograham@…>
* status: new => closed
* resolution: => fixed
Comment:
In [changeset:"db3f7c15cbf4c9025e83065d1302d0e61d570331"]:
{{{
#!CommitTicketReference repository=""
revision="db3f7c15cbf4c9025e83065d1302d0e61d570331"
Fixed #23749 -- Documented how to use the database alias in RunPython.
Thanks Markus Holtermann for review and feedback.
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:26>
Django
-------------------------------------+-------------------------------------
Reporter: alfredperlstein | Owner: Tim
Type: | Graham <timograham@…>
Cleanup/optimization | Status: closed
Component: Documentation | Version: 1.7
Severity: Normal | Resolution: fixed
Keywords: migrations dbrouter | Triage Stage: Ready for
| checkin
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 1 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by Tim Graham <timograham@…>):
In [changeset:"01487684123342f052e139291175f4ea3d11a09b"]:
{{{
#!CommitTicketReference repository=""
revision="01487684123342f052e139291175f4ea3d11a09b"
[1.7.x] Fixed #23749 -- Documented how to use the database alias in
RunPython.
Thanks Markus Holtermann for review and feedback.
Backport of db3f7c15cbf4c9025e83065d1302d0e61d570331 from master
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/23749#comment:27>