在 Django 中，是否有可能看到哪个方法正在生成 SQL 查询?

Question

创建自定义用户(继承自AbstractUser)时，我们有一个信号，该信号创建一个随机密码(来自Django的get_random_string)，并将其通过电子邮件发送给用户。

# accounts/models.py
class User(AbstractUser):
# ...
def save(self, *args, **kwargs):
if self.avatar:
self.avatar = resized_image(self.avatar, settings.SOCIAL_AVATAR_SIZE)
super().save(*args, **kwargs)

resized_image返回from django.core.files.uploadedfile import InMemoryUploadedFile

# accounts/signals.py
@receiver(post_save, sender=User, dispatch_uid="c_employee")
def create_employee(sender, instance: User, created, **kwargs):
if not instance.has_usable_password():
password = get_random_string(length=12)
email_args = {  # we're collecting information for the celery task
"password": password,
}
email_send_as_task.delay(
email_args, "Sending PASSWORD CREATE email to {{ instance.email }}"
)

if password:
logger.debug(f"CREATE PASSWORD FOR INSTANCE: {instance}")
sender.objects.filter(pk=instance.pk).update(password=make_password(password))  # .update so we don't trigger signal again

查看我的(日志记录级别DEBUG)日志，我可以看到以下内容：

D0121 18:55:35.434 accounts.signals:81 CREATE PASSWORD FOR INSTANCE: Employee @ Example
D0121 18:55:35.641 django.db.backends:123 (0.000) UPDATE "accounts_user" SET "password" = 'pbkdf2_sha256$260000$FKRktQOZAwQ4OjcvD3QHGn$dmg9T1Y3mEwN1nbI5W2EyOAHp2chU4MGvSlaOTORNxY=' WHERE "accounts_user"."id" = 394; args=('pbkdf2_sha256$260000$FKRktQOZAwQ4OjcvD3QHGn$dmg9T1Y3mEwN1nbI5W2EyOAHp2chU4MGvSlaOTORNxY=', 394)

目前为止，一切都好。

但是，稍后在日志中，将显示此查询：

D0121 18:55:35.770 django.db.backends:123 (0.015) UPDATE "accounts_user" SET "password" = '', "last_login" = NULL, "is_superuser" = false, "username" = '[e-mail]', "first_name" = 'First name', "last_name" = 'Employee', "email" = '[e-mail]', "is_staff" = false, "is_active" = true, "date_joined" = '2023-01-21T17:55:35.044046+00:00'::timestamptz, "company_id" = 20, "venue_id" = 297, "avatar" = 'users/avatar.jpg', "is_admin" = false, "is_developer" = true, "role" = 'event', "allow_update" = true, "device_id" = NULL WHERE "accounts_user"."id" = 394; args=('', False, '[e-mail]', 'First name', 'Employee', '[e-mail]', False, True, datetime.datetime(2023, 1, 21, 17, 55, 35, 44046, tzinfo=<UTC>), 20, 297, 'users/avatar.jpg', False, True, 'event', True, 394)

因此，我的问题是：为什么密码被重新设置为空字符串？我如何调试/了解此查询的来源？

蒂亚

Answer 1

显然，我们在写入数据库时似乎遇到了竞争条件。似乎在信号之外调用方法不会触发对post_save信号的另一次调用，而我们已经在信号内部。

这就是工作解决方案的样子 atm：

# accounts/signals.py
from accounts.utils import create_password

@receiver(post_save, sender=User, dispatch_uid="c_employee")
def create_employee(sender, instance: User, created, **kwargs):
if not instance.has_usable_password():
logger.debug(f"CREATE PASSWORD FOR INSTANCE: {instance}")
password = create_password(obj=instance)
email_args = {  # we're collecting information for the celery task
"password": password,
}
email_send_as_task.delay(
email_args, "Sending PASSWORD CREATE email to {{ instance.email }}"
)

并在utils.py文件中：

# accounts/utils.py
from django.utils.crypto import get_random_string

def create_password(obj=None, length=12):
password = get_random_string(length=length)
if obj is not None:
obj.set_password(password)
obj.save()
return password

我不得不推测，有一些姜戈的魔法我还没理解。不幸的是，这并没有回答标题中的问题，但使用.save()而不是.update()解决了我的问题。

@peter-deglopper的评论为我指明了正确的方向。谢谢！