【发布时间】：2020-07-25 17:34:47
【问题描述】：
我正在编写一个代码来频繁地将我们的数据库备份到 Dropbox。以下是我的tasks.py，它有一个测试代码，可以每 1 分钟执行一次 Django 管理命令management.call_command('dbbackup', interactive=False)。但是我遇到了错误django.db.utils.DatabaseError: DatabaseWrapper objects created in a thread can only be used in that same thread. The object with alias 'default' was created in thread id 140423029811616 and this is thread id 140422957233632.。
tasks.py
from __future__ import absolute_import, unicode_literals
from myproject.celery import app
from celery.utils.log import get_task_logger
from celery.schedules import crontab
from django.core import management
@app.task
def db_backup_to_dropbox():
management.call_command('dbbackup', interactive=False)
app.conf.beat_schedule = {
'backup-every-second': {
'task': 'core.tasks.db_backup_to_dropbox',
'schedule': crontab(minute='*/1'),
'args': (),
},
}
来自 celery.log 的回溯
[2020-07-25 16:24:00,050: INFO/MainProcess] Received task: core.tasks.db_backup_to_dropbox[a34653fe-a3c6-4259-a98d-7613c5f3446c]
[2020-07-25 16:24:00,054: INFO/MainProcess] Backing Up Database: myproject
[2020-07-25 16:24:00,213: INFO/MainProcess] Writing file to default-myserver-loc1-2020-07-25-162400.dump
[2020-07-25 16:24:00,215: INFO/MainProcess] Request to files/get_metadata
[2020-07-25 16:24:00,287: ERROR/MainProcess] RecursionError: maximum recursion depth exceeded while calling a Python object
File "/myproject/venv/lib/python3.8/site-packages/dbbackup/utils.py", line 118, in wrapper
func(*args, **kwargs)
File "/myproject/venv/lib/python3.8/site-packages/dbbackup/management/commands/dbbackup.py", line 61, in handle
self._save_new_backup(database)
File "/myproject/venv/lib/python3.8/site-packages/dbbackup/management/commands/dbbackup.py", line 88, in _save_new_backup
self.write_to_storage(outputfile, filename)
File "/myproject/venv/lib/python3.8/site-packages/dbbackup/management/commands/_base.py", line 88, in write_to_storage
self.storage.write_file(file, path)
File "/myproject/venv/lib/python3.8/site-packages/dbbackup/storage.py", line 82, in write_file
self.storage.save(name=filename, content=filehandle)
File "/myproject/venv/lib/python3.8/site-packages/django/core/files/storage.py", line 51, in save
name = self.get_available_name(name, max_length=max_length)
File "/myproject/venv/lib/python3.8/site-packages/django/core/files/storage.py", line 82, in get_available_name
while self.exists(name) or (max_length and len(name) > max_length):
File "/myproject/venv/lib/python3.8/site-packages/storages/backends/dropbox.py", line 93, in exists
return bool(self.client.files_get_metadata(self._full_path(name)))
File "/myproject/venv/lib/python3.8/site-packages/dropbox/base.py", line 1682, in files_get_metadata
r = self.request(
File "/myproject/venv/lib/python3.8/site-packages/dropbox/dropbox.py", line 313, in request
res = self.request_json_string_with_retry(host,
File "/myproject/venv/lib/python3.8/site-packages/dropbox/dropbox.py", line 463, in request_json_string_with_retry
return self.request_json_string(host,
File "/myproject/venv/lib/python3.8/site-packages/dropbox/dropbox.py", line 559, in request_json_string
r = self._session.post(url,
File "/myproject/venv/lib/python3.8/site-packages/requests/sessions.py", line 578, in post
return self.request('POST', url, data=data, json=json, **kwargs)
File "/myproject/venv/lib/python3.8/site-packages/requests/sessions.py", line 530, in request
resp = self.send(prep, **send_kwargs)
File "/myproject/venv/lib/python3.8/site-packages/requests/sessions.py", line 643, in send
r = adapter.send(request, **kwargs)
File "/myproject/venv/lib/python3.8/site-packages/requests/adapters.py", line 439, in send
resp = conn.urlopen(
File "/myproject/venv/lib/python3.8/site-packages/urllib3/connectionpool.py", line 670, in urlopen httplib_response = self._make_request(
File "/myproject/venv/lib/python3.8/site-packages/urllib3/connectionpool.py", line 381, in _make_request
self._validate_conn(conn)
File "/myproject/venv/lib/python3.8/site-packages/urllib3/connectionpool.py", line 978, in _validate_conn
conn.connect()
File "/myproject/venv/lib/python3.8/site-packages/urllib3/connection.py", line 343, in connect
self.ssl_context = create_urllib3_context(
File "/myproject/venv/lib/python3.8/site-packages/urllib3/util/ssl_.py", line 277, in create_urllib3_context
context.options |= options
File "/usr/lib/python3.8/ssl.py", line 602, in options
super(SSLContext, SSLContext).options.__set__(self, value)
File "/usr/lib/python3.8/ssl.py", line 602, in options
super(SSLContext, SSLContext).options.__set__(self, value)
File "/usr/lib/python3.8/ssl.py", line 602, in options
super(SSLContext, SSLContext).options.__set__(self, value)
[Previous line repeated 460 more times]
[2020-07-25 16:24:00,325: ERROR/MainProcess] Task core.tasks.db_backup_to_dropbox[a34653fe-a3c6-4259-a98d-7613c5f3446c] raised unexpected: DatabaseError("DatabaseWrapper objects created in a thread can only be used in that same thread. The object with alias 'default' was created in thread id 140423029811616 and this is thread id 140422957233632.")
Traceback (most recent call last):
File "/myproject/venv/lib/python3.8/site-packages/dbbackup/utils.py", line 118, in wrapper
func(*args, **kwargs)
File "/myproject/venv/lib/python3.8/site-packages/dbbackup/management/commands/dbbackup.py", line 61, in handle
self._save_new_backup(database)
File "/myproject/venv/lib/python3.8/site-packages/dbbackup/management/commands/dbbackup.py", line 88, in _save_new_backup
self.write_to_storage(outputfile, filename)
File "/myproject/venv/lib/python3.8/site-packages/dbbackup/management/commands/_base.py", line 88, in write_to_storage
self.storage.write_file(file, path)
File "/myproject/venv/lib/python3.8/site-packages/dbbackup/storage.py", line 82, in write_file
self.storage.save(name=filename, content=filehandle)
File "/myproject/venv/lib/python3.8/site-packages/django/core/files/storage.py", line 51, in save
name = self.get_available_name(name, max_length=max_length)
File "/myproject/venv/lib/python3.8/site-packages/django/core/files/storage.py", line 82, in get_available_name
while self.exists(name) or (max_length and len(name) > max_length):
File "/myproject/venv/lib/python3.8/site-packages/storages/backends/dropbox.py", line 93, in exists
return bool(self.client.files_get_metadata(self._full_path(name)))
File "/myproject/venv/lib/python3.8/site-packages/dropbox/base.py", line 1682, in files_get_metadata
r = self.request(
File "/myproject/venv/lib/python3.8/site-packages/dropbox/dropbox.py", line 313, in request
res = self.request_json_string_with_retry(host,
File "/myproject/venv/lib/python3.8/site-packages/dropbox/dropbox.py", line 463, in request_json_string_with_retry
return self.request_json_string(host,
File "/myproject/venv/lib/python3.8/site-packages/dropbox/dropbox.py", line 559, in request_json_string
r = self._session.post(url,
File "/myproject/venv/lib/python3.8/site-packages/requests/sessions.py", line 578, in post
return self.request('POST', url, data=data, json=json, **kwargs)
File "/myproject/venv/lib/python3.8/site-packages/requests/sessions.py", line 530, in request
resp = self.send(prep, **send_kwargs)
File "/myproject/venv/lib/python3.8/site-packages/requests/sessions.py", line 643, in send
r = adapter.send(request, **kwargs)
File "/myproject/venv/lib/python3.8/site-packages/requests/adapters.py", line 439, in send
resp = conn.urlopen(
File "/myproject/venv/lib/python3.8/site-packages/urllib3/connectionpool.py", line 670, in urlopen httplib_response = self._make_request(
File "/myproject/venv/lib/python3.8/site-packages/urllib3/connectionpool.py", line 381, in _make_request
self._validate_conn(conn)
File "/myproject/venv/lib/python3.8/site-packages/urllib3/connectionpool.py", line 978, in _validate_conn
conn.connect()
File "/myproject/venv/lib/python3.8/site-packages/urllib3/connection.py", line 343, in connect
self.ssl_context = create_urllib3_context(
File "/myproject/venv/lib/python3.8/site-packages/urllib3/util/ssl_.py", line 277, in create_urllib3_context
context.options |= options
File "/usr/lib/python3.8/ssl.py", line 602, in options
super(SSLContext, SSLContext).options.__set__(self, value)
File "/usr/lib/python3.8/ssl.py", line 602, in options
super(SSLContext, SSLContext).options.__set__(self, value)
File "/usr/lib/python3.8/ssl.py", line 602, in options
super(SSLContext, SSLContext).options.__set__(self, value)
[Previous line repeated 460 more times]
RecursionError: maximum recursion depth exceeded while calling a Python object
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/myproject/venv/lib/python3.8/site-packages/celery/app/trace.py", line 412, in trace_task
R = retval = fun(*args, **kwargs)
File "/myproject/venv/lib/python3.8/site-packages/celery/app/trace.py", line 704, in __protected_call__
return self.run(*args, **kwargs)
File "/myproject/myproject/core/tasks.py", line 11, in db_backup_to_dropbox
management.call_command('dbbackup', interactive=False)
File "/myproject/venv/lib/python3.8/site-packages/django/core/management/__init__.py", line 168, in call_command
return command.execute(*args, **defaults)
File "/myproject/venv/lib/python3.8/site-packages/django/core/management/base.py", line 369, in execute
output = self.handle(*args, **options)
File "/myproject/venv/lib/python3.8/site-packages/dbbackup/utils.py", line 127, in wrapper
connection.close()
File "/myproject/venv/lib/python3.8/site-packages/django/utils/asyncio.py", line 26, in inner
return func(*args, **kwargs)
File "/myproject/venv/lib/python3.8/site-packages/django/db/backends/base/base.py", line 286, in close
self.validate_thread_sharing()
File "/myproject/venv/lib/python3.8/site-packages/django/db/backends/base/base.py", line 553, in validate_thread_sharing
raise DatabaseError(
django.db.utils.DatabaseError: DatabaseWrapper objects created in a thread can only be used in that same thread. The object with alias 'default' was created in thread id 140423029811616 and this is thread id 140422957233632.
【问题讨论】：
标签： python django multithreading celery celerybeat