Refactor our migrate command monkeypatching

This commit is contained in:
Raphael Michel
2021-09-17 10:01:23 +02:00
parent 364cfe0131
commit adf40e1d56
3 changed files with 59 additions and 53 deletions

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@@ -0,0 +1,46 @@
"""
Django, for theoretically very valid reasons, creates migrations for *every single thing*
we change on a model. Even the `help_text`! This makes sense, as we don't know if any
database backend unknown to us might actually use this information for its database schema.
However, pretix only supports PostgreSQL, MySQL, MariaDB and SQLite and we can be pretty
certain that some changes to models will never require a change to the database. In this case,
not creating a migration for certain changes will save us some performance while applying them
*and* allow for a cleaner git history. Win-win!
Only caveat is that we need to do some dirty monkeypatching to achieve it...
"""
from django.db import models
from django.db.migrations.operations import models as modelops
from django_countries.fields import CountryField
def monkeypatch_migrations():
modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("verbose_name")
modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("verbose_name_plural")
modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("ordering")
modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("get_latest_by")
modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("default_manager_name")
modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("permissions")
modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("default_permissions")
IGNORED_ATTRS = [
# (field type, attribute name, banlist of field sub-types)
(models.Field, 'verbose_name', []),
(models.Field, 'help_text', []),
(models.Field, 'validators', []),
(models.Field, 'editable', [models.DateField, models.DateTimeField, models.DateField, models.BinaryField]),
(models.Field, 'blank', [models.DateField, models.DateTimeField, models.AutoField, models.NullBooleanField,
models.TimeField]),
(models.CharField, 'choices', [CountryField])
]
original_deconstruct = models.Field.deconstruct
def new_deconstruct(self):
name, path, args, kwargs = original_deconstruct(self)
for ftype, attr, banlist in IGNORED_ATTRS:
if isinstance(self, ftype) and not any(isinstance(self, ft) for ft in banlist):
kwargs.pop(attr, None)
return name, path, args, kwargs
models.Field.deconstruct = new_deconstruct

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@@ -32,53 +32,10 @@
# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations under the License.
"""
Django, for theoretically very valid reasons, creates migrations for *every single thing*
we change on a model. Even the `help_text`! This makes sense, as we don't know if any
database backend unknown to us might actually use this information for its database schema.
However, pretix only supports PostgreSQL, MySQL, MariaDB and SQLite and we can be pretty
certain that some changes to models will never require a change to the database. In this case,
not creating a migration for certain changes will save us some performance while applying them
*and* allow for a cleaner git history. Win-win!
Only caveat is that we need to do some dirty monkeypatching to achieve it...
"""
from django.core.management.commands.makemigrations import Command as Parent
from django.db import models
from django.db.migrations.operations import models as modelops
from django_countries.fields import CountryField
from ._migrations import monkeypatch_migrations
modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("verbose_name")
modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("verbose_name_plural")
modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("ordering")
modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("get_latest_by")
modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("default_manager_name")
modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("permissions")
modelops.AlterModelOptions.ALTER_OPTION_KEYS.remove("default_permissions")
IGNORED_ATTRS = [
# (field type, attribute name, banlist of field sub-types)
(models.Field, 'verbose_name', []),
(models.Field, 'help_text', []),
(models.Field, 'validators', []),
(models.Field, 'editable', [models.DateField, models.DateTimeField, models.DateField, models.BinaryField]),
(models.Field, 'blank', [models.DateField, models.DateTimeField, models.AutoField, models.NullBooleanField,
models.TimeField]),
(models.CharField, 'choices', [CountryField])
]
original_deconstruct = models.Field.deconstruct
def new_deconstruct(self):
name, path, args, kwargs = original_deconstruct(self)
for ftype, attr, banlist in IGNORED_ATTRS:
if isinstance(self, ftype) and not any(isinstance(self, ft) for ft in banlist):
kwargs.pop(attr, None)
return name, path, args, kwargs
models.Field.deconstruct = new_deconstruct
monkeypatch_migrations()
class Command(Parent):

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@@ -32,22 +32,25 @@
# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations under the License.
"""
Django tries to be helpful by suggesting to run "makemigrations" in red font on every "migrate"
run when there are things we have no migrations for. Usually, this is intended, and running
"makemigrations" can really screw up the environment of a user, so we want to prevent novice
users from doing that by going really dirty and filtering it from the output.
"""
import sys
from django.core.management.base import OutputWrapper
from django.core.management.commands.migrate import Command as Parent
from ._migrations import monkeypatch_migrations
monkeypatch_migrations()
class OutputFilter(OutputWrapper):
"""
Django tries to be helpful by suggesting to run "makemigrations" in red font on every "migrate"
run when there are things we have no migrations for. Usually, this is intended, and running
"makemigrations" can really screw up the environment of a user, so we want to prevent novice
users from doing that by going really dirty and filtering it from the output.
"""
banlist = (
"Your models have changes that are not yet reflected",
"Run 'manage.py makemigrations' to make new "
"have changes that are not yet reflected",
"re-run 'manage.py migrate'"
)
def write(self, msg, style_func=None, ending=None):