Python 检查挂起的 Django 迁移

Check for pending Django migrations

提问by Moss Collum

In Django, is there an easy way to check whether all database migrations have been run? I've found manage.py migrate --list, which gives me the information I want, but the format isn't very machine readable.

在 Django 中，是否有一种简单的方法来检查是否所有数据库迁移都已运行？我发现manage.py migrate --list，它给了我我想要的信息，但格式不是很机器可读。

For context: I have a script that shouldn't start running until the database has been migrated. For various reasons, it would be tricky to send a signal from the process that's running the migrations. So I'd like to have my script periodically check the database to see if all the migrations have run.

对于上下文：我有一个脚本，在迁移数据库之前不应开始运行。由于各种原因，从运行迁移的进程发送信号会很棘手。所以我想让我的脚本定期检查数据库以查看是否所有迁移都已运行。

回答by Ernest Ten

Shell

贝壳

The only simple solution I've found so far is running

到目前为止我发现的唯一简单的解决方案是运行

./manage.py showmigrations | grep '\[ \]'

which will output an empty string in case all migrations have been applied.

如果已应用所有迁移，它将输出一个空字符串。

However, it is closely tied to the output format.

但是，它与输出格式密切相关。

Python

Python

I checked the source code of migratecommand and it seems like this should do the trick:

我检查了migrate命令的源代码，看起来这应该可以解决问题：

from django.db.migrations.executor import MigrationExecutor
from django.db import connections, DEFAULT_DB_ALIAS


def is_database_synchronized(database):
    connection = connections[database]
    connection.prepare_database()
    executor = MigrationExecutor(connection)
    targets = executor.loader.graph.leaf_nodes()
    return not executor.migration_plan(targets)

# Usage example.
if is_database_synchronized(DEFAULT_DB_ALIAS):
    # All migrations have been applied.
    pass
else:
    # Unapplied migrations found.
    pass

回答by Parag Tyagi -morpheus-

Using @Ernest code, I've written a manage_custom.pyfor pending migrations. You can get the list of pending migrationsalso migratethose pending migrations (only), hence saving your time.

使用@Ernest 代码，我manage_custom.py为挂起的迁移编写了一个。您可以获得挂起的迁移列表，也可以迁移那些挂起的迁移（仅限），从而节省您的时间。

manage_custom.py

manage_custom.py

__author__ = "Parag Tyagi"

# set environment
import os
import sys
import django
sys.path.append('../')
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'settings')
django.setup()

from django.core.management import execute_from_command_line
from django.db import DEFAULT_DB_ALIAS, connections
from django.db.migrations.executor import MigrationExecutor


class Migration(object):
    """
    A custom manage.py file for managing pending migrations (only)
    """

    def __init__(self, migrate_per_migration_id=False):
        """
        :param migrate_per_migration_id: Setting this to `True` will migrate each pending migration of any
        particular app individually. `False` will migrate the whole app at a time.

        You can add more arguments (viz. showmigrations, migrate) by defining the argument with prefix as 'ARGV_'
        and create its functionality accordingly.
        """
        self.ARG_PREFIX = 'ARGV_'
        self.MIGRATE_PER_MIGRATION_ID = migrate_per_migration_id
        self.ARGV_showmigrations = False
        self.ARGV_migrate = False

    @staticmethod
    def get_pending_migrations(database):
        """
        :param database: Database alias
        :return: List of pending migrations
        """
        connection = connections[database]
        connection.prepare_database()
        executor = MigrationExecutor(connection)
        targets = executor.loader.graph.leaf_nodes()
        return executor.migration_plan(targets)

    def check_arguments(self, args):
        """
        Method for checking arguments passed while running the command
        :param args: Dictionary of arguments passed while running the script file
        :return: Set the argument variable ('ARGV_<argument>') to True if found else terminate the script
        """
        required_args = filter(None, [var.split(self.ARG_PREFIX)[1] if var.startswith(self.ARG_PREFIX)
                                      else None for var in self.__dict__.keys()])
        if any(k in args for k in required_args):
            for arg in required_args:
                if arg in args:
                    setattr(self, '{}{}'.format(self.ARG_PREFIX, arg), True)
                    break
        else:
            print ("Please pass argument: {}"
                   "\ne.g. python manage_custom.py {}".format(required_args, required_args[0]))
            sys.exit()

    def do_migration(self):
        """
        Migrates all the pending migrations (if any)
        """
        pending_migrations = self.get_pending_migrations(DEFAULT_DB_ALIAS)
        if pending_migrations:
            done_app = []
            for mig in pending_migrations:
                app, migration_id = str(mig[0]).split('.')
                commands = ['manage.py', 'migrate'] + ([app, migration_id] if self.MIGRATE_PER_MIGRATION_ID else [app])
                if self.ARGV_migrate and (app not in done_app or self.MIGRATE_PER_MIGRATION_ID):
                    execute_from_command_line(commands)
                    done_app.append(app)
                elif self.ARGV_showmigrations:
                    print (str(mig[0]))
        else:
            print ("No pending migrations")


if __name__ == '__main__':
    args = sys.argv
    migration = Migration()
    migration.check_arguments(args)
    migration.do_migration()

Usage:

用法：

# below command will show all pending migrations
python manage_custom.py showmigrations

# below command will migrate all pending migrations
python manage_custom.py migrate

PS: Please setup environment as per your project structure.

PS：请根据您的项目结构设置环境。

回答by Parag Tyagi -morpheus-

Try,

尝试，

python manage.py migrate --list | grep "\[ \]\|^[a-z]" | grep "[ ]" -B 1

returns,

返回，

<app_1>
 [ ] 0001_initial
 [ ] 0002_auto_01201244
 [ ] 0003_auto_12334333

<app_2>
 [ ] 0031_auto_12344544
 [ ] 0032_auto_45456767
 [ ] 0033_auto_23346566

<app_3>
 [ ] 0008_auto_3446677

Update:

更新：

If you have updated Django version >= 1.11, use below command,

如果您已更新 Django 版本 >= 1.11，请使用以下命令，

python manage.py showmigrations | grep '\[ \]\|^[a-z]' | grep '[  ]' -B 1

回答by minusf

1.10 release notes:

1.10 发行说明：

The new makemigrations --checkoption makes the command exit with a non-zero status when model changes without migrations are detected.

makemigrations --check当检测到没有迁移的模型更改时，新选项使命令以非零状态退出。

If you don't want to create the migrations, combine it with --dry-run:

如果您不想创建迁移，请将其与--dry-run：

python manage.py makemigrations --check --dry-run

Note that this doesn't check whether the migrations were applied, it only checks whether the migration files were created.

请注意，这不会检查是否应用了迁移，它只会检查是否创建了迁移文件。

回答by Jan Kyu Peblik

./manage.py showmigrations#check which already-made migrations have been applied or not
(or: ./manage.py showmigrations someApp#for specific app alone)

./manage.py showmigrations#检查哪些已经进行的迁移已被应用
（或：./manage.py showmigrations someApp#仅针对特定应用程序）

./manage.py makemigrations --dry-run#check for migrations to be made
(or: ./manage.py makemigrations someApp --dry-run#for specific app alone)

./manage.py makemigrations --dry-run#检查要进行的迁移
（或：./manage.py makemigrations someApp --dry-run#仅针对特定应用程序）

./manage.py makemigrations#make the migrations
(or: ./manage.py makemigrations someApp#for specific app alone)

./manage.py makemigrations#make the migrations
(or: ./manage.py makemigrations someApp#for specific app only)

./manage.py showmigrations#check which already-made migrations have been applied or not
(or: ./manage.py showmigrations someApp#for specific app alone)

./manage.py showmigrations#检查哪些已经进行的迁移已被应用
（或：./manage.py showmigrations someApp#仅针对特定应用程序）

./manage.py sqlmigrate someApp 0001#view SQL changes for specific app & migration

./manage.py sqlmigrate someApp 0001#查看特定应用程序和迁移的 SQL 更改

./manage.py migrate#apply migrations
(or: ./manage.py migrate someApp#for specific app alone)

./manage.py migrate#apply 迁移
（或：./manage.py migrate someApp#仅针对特定应用程序）

./manage.py showmigrations#check which already-made migrations have been applied or not
(or: ./manage.py showmigrations someApp#for specific app alone)

./manage.py showmigrations#检查哪些已经进行的迁移已被应用
（或：./manage.py showmigrations someApp#仅针对特定应用程序）

./manage.py makemigrations --dry-run#check for migrations to be made
(or: ./manage.py makemigrations someApp --dry-run#for specific app alone)

./manage.py makemigrations --dry-run#检查要进行的迁移
（或：./manage.py makemigrations someApp --dry-run#仅针对特定应用程序）

PS:
./manage.py migrate someApp zero#unapply all migrations for specific app

PS：
./manage.py migrate someApp zero#unapply 特定应用程序的所有迁移

回答by chsymann

Here is my Python soloution to get some information about the migration-states:

这是我的 Python 解决方案，用于获取有关迁移状态的一些信息：

from io import StringIO  # for Python 2 use from StringIO import StringIO  
from django.core.management import call_command 

def get_migration_state():
    result = []
    out = StringIO()
    call_command('showmigrations', format="plan", stdout=out)
    out.seek(0)
    for line in out.readlines():
        status, name = line.rsplit(' ', 1)
        result.append((status.strip() == '[X]', name.strip()))
    return result

The result of this function looks like that:

此函数的结果如下所示：

[(True, 'contenttypes.0001_initial'),
 (True, 'auth.0001_initial'),
 (False, 'admin.0001_initial'),
 (False, 'admin.0002_logentry_remove_auto_add')]

Maybe it helps some of you guys..

也许它对你们中的一些人有帮助..

回答by Ryabchenko Alexander

I checked it by looking up the table django_migrations, which stores all applied migrations.

我通过查找django_migrations存储所有应用迁移的表来检查它。