<p>如果您不愿意使用Django内部构件,另一种方法是使用下面的脚本通过调用一个随机方法生成一个迁移文件,该方法将生成您希望在迁移中运行的Python代码,并将其插入到一个有效的迁移文件中,该文件将成为标准Django迁移的一部分。
你有一个名为“xxx”的应用程序,你在一个文件xxx/scripts中有一个方法/测试.py看起来像这样:</p>
<pre><code>def run(*args, **kwargs):
return "print(\"BINGO!!!!!!!!! {} :: {}\".format(args[0], kwargs['name']))"
</code></pre>
<p>。。。您调用了存储在xxx/scripts/custom中的本文底部显示的脚本_迁移.py使用以下命令</p>
^{pr2}$
<p>然后在xxx/migrations中得到一个迁移文件,该文件具有适当的编号顺序(比如0004_宾果)看起来像这样:</p>
<pre><code> Generated by Django 2.1.2 on 2018-12-14 08:54
from django.db import migrations
def run(*args, **kwargs):
print("BINGO!!!!!!!!! {} :: {}".format(args[0], kwargs['name']))
class Migration(migrations.Migration):
dependencies = [
]
operations = [
migrations.RunPython(run,)
]
</code></pre>
<p>脚本如下:</p>
<pre><code>from django.core.management.base import no_translations
from django.core.management.commands.makemigrations import Command
from django.db.migrations import writer
from django import get_version
from django.utils.timezone import now
import os
import sys
"""
To invoke this script use:
manage.py runscript custom_migrations script-args [app_label [app_label ...]] callable=my_migration_code_gen name=my_special_migration
the "name" argument will be set as part of the migration file generated
the "callable" argument will be the function that is invoked to generate the python code you want to execute in the migration
the callable will be passed all the args and kwargs passed in to this script from the command line as part of script-args
Only app names are allowed in args so use kwargs for custom arguments
"""
class LazyCallable(object):
def __init__(self, name):
self.n, self.f = name, None
def __call__(self, *a, **k):
if self.f is None:
modn, funcn = self.n.rsplit('.', 1)
if modn not in sys.modules:
__import__(modn)
self.f = getattr(sys.modules[modn], funcn)
return self.f(*a, **k)
class MyMigrationMaker(Command):
'''
Override the write method to provide access to script arguments
'''
@no_translations
def handle(self, *app_labels, **options):
self.in_args = app_labels
self.in_kwargs = options
super().handle(*app_labels, **options)
'''
Override the write method to add more stuff before finishing
'''
def write_migration_files(self, changes):
code = LazyCallable(self.in_kwargs['callable'])(self.in_args, self.in_kwargs)
items = {
"replaces_str": "",
"initial_str": "",
}
items.update(
version=get_version(),
timestamp=now().strftime("%Y-%m-%d %H:%M"),
)
items["imports"] = "from django.db import migrations\n\ndef run(*args, **kwargs):\n "
items["imports"] += code.replace("\n", "\n ") + "\n\n"
items["operations"] = " migrations.RunPython(run,)\n"
directory_created = {}
for app_label, app_migrations in changes.items():
for migration in app_migrations:
# Describe the migration
my_writer = writer.MigrationWriter(migration)
dependencies = []
for dependency in my_writer.migration.dependencies:
dependencies.append(" %s," % my_writer.serialize(dependency)[0])
items["dependencies"] = "\n".join(dependencies) + "\n" if dependencies else ""
# Write the migrations file to the disk.
migrations_directory = os.path.dirname(my_writer.path)
if not directory_created.get(app_label):
if not os.path.isdir(migrations_directory):
os.mkdir(migrations_directory)
init_path = os.path.join(migrations_directory, "__init__.py")
if not os.path.isfile(init_path):
open(init_path, "w").close()
# We just do this once per app
directory_created[app_label] = True
migration_string = writer.MIGRATION_TEMPLATE % items
with open(my_writer.path, "w", encoding='utf-8') as fh:
fh.write(migration_string)
if self.verbosity >= 1:
self.stdout.write("Migration file: %s\n" % my_writer.filename)
def run(*args):
glob_args = []
glob_kwargs = {}
# Preload some options with defaults and then can be overridden in the args parsing
glob_kwargs['empty'] = True
glob_kwargs['verbosity'] = 1
glob_kwargs['interactive'] = True
glob_kwargs['dry_run'] = False
glob_kwargs['merge'] = False
glob_kwargs['name'] = 'custom_migration'
glob_kwargs['check_changes'] = False
for arg in args:
kwarg = arg.split('=', 1)
if len(kwarg) > 1:
glob_kwargs[kwarg[0]] = kwarg[1]
else:
glob_args.append(arg)
MyMigrationMaker().handle(*glob_args, **glob_kwargs)
</code></pre>