Cannot connect to MySQL after upgrade to v8

[AivanF]

I have a huge website with Tornado-MySQL which code I haven't modified for almost 2 years because it worked fine all this time. However, a day ago I updated MySQL Server from 5.7 to 8 (because of needs of my another project on that server), and now my Tornado website doesn't work: Tornado-MySQL cannot connect to the new MySQL Server. Here is the error text:

ERROR:tornado.application:Future exception was never retrieved: Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 1141, in run
    yielded = self.gen.throw(*exc_info)
  File "/aivanf/Tornado/database.py", line 33, in execute
    cur = yield POOL.execute(query, params)
  File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 1133, in run
    value = future.result()
  File "/usr/local/lib/python2.7/dist-packages/tornado/concurrent.py", line 261, in result
    raise_exc_info(self._exc_info)
  File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 1141, in run
    yielded = self.gen.throw(*exc_info)
  File "/usr/local/lib/python2.7/dist-packages/tornado_mysql/pools.py", line 122, in execute
    conn = yield self._get_conn()
  File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 1133, in run
    value = future.result()
  File "/usr/local/lib/python2.7/dist-packages/tornado/concurrent.py", line 261, in result
    raise_exc_info(self._exc_info)
  File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 1141, in run
    yielded = self.gen.throw(*exc_info)
  File "/usr/local/lib/python2.7/dist-packages/tornado_mysql/__init__.py", line 88, in connect
    yield conn.connect()
  File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 1133, in run
    value = future.result()
  File "/usr/local/lib/python2.7/dist-packages/tornado/concurrent.py", line 261, in result
    raise_exc_info(self._exc_info)
  File "/usr/local/lib/python2.7/dist-packages/tornado/gen.py", line 1141, in run
    yielded = self.gen.throw(*exc_info)
  File "/usr/local/lib/python2.7/dist-packages/tornado_mysql/connections.py", line 823, in connect
    2003, "Can't connect to MySQL server on %r (%s)" % (self.host, e))
OperationalError: (2003, "Can't connect to MySQL server on '127.0.0.1' (255)")

Below are listed the versions of my packages. I have updated them to last available ones.

• OS: Ubuntu 16.04.5 LTS
• MySQL: 8.0.13
• Python: checked both 2.7 and 3.5
• Tornado: 5.1.1
• Tornado-MySQL: 0.5.1

In addition, during installation of MySQL Server 8, I specified to use legacy users stuff to maintain compatibility with my Python apps, and MySQLdb package (also called mysqlclient, version 1.3.13) works well.

How to fix the problem??

[methane]

This project is not under development.
No plan for support new MySQL auth method.
You need to change default auth method to native_password, or switch to aio-mysql.