Question

我希望模型中的特定字段使用S3存储（如果设置具有AWS_ACCESS_KEY_ID）或回退到default_storage。我正在使用django-storages。

要实现此目的，请在models.py中：

from django.db import models
from django.conf import settings
from .storage_backends import variativeStorage

class Profile(models.Model):
    user = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
    photo = models.ImageField(upload_to='/public', default='dummy-img.png', storage=variativeStorage())

storage_backends.py：

from storages.backends.s3boto3 import S3Boto3Storage
from django.core.files.storage import default_storage
from django.conf import settings


def variativeStorage():
    """Return S3Boto3Storage if access key is defined.
    Fallback to default storage.
    """
    if hasattr(settings, 'AWS_ACCESS_KEY_ID') and settings.AWS_ACCESS_KEY_ID:
        return S3Boto3Storage()
    return default_storage

它工作得很好，但是问题出在迁移上-它评估字段storage当前具有的Django设置。因此，如果我们没有AWS_ACCESS_KEY_ID，makemigrations可以做到：

operations = [
        migrations.AlterField(
            model_name='profile',
            name='photo',
            field=models.ImageField(default='dummy-img.png', upload_to='/public'),
        ),
    ]

并且如果有的话：

operations = [
        migrations.AlterField(
            model_name='profile',
            name='photo',
            field=models.ImageField(default='dummy-img.png', storage=storages.backends.s3boto3.S3Boto3Storage(), upload_to='/public'),
        ),
    ]

因此在生产环境中运行服务器将触发缺少迁移的警告：

remote: Running migrations:
remote: No migrations to apply.
remote: Your models have changes that are not yet reflected in a migration, and so won't be applied.
remote: Run 'manage.py makemigrations' to make new migrations, and then re-run 'manage.py migrate' to apply them.

是否有一致的方式对字段进行动态存储？如何进行variativeStorage的惰性求值，或者也许删除该特定字段的迁移生成？

迁移引用动态存储不一致

0 个答案: