superset: Upload a CSV, not working with MySQL

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• I have checked the superset logs for python stacktraces and included it here as text if any
• I have reproduced the issue with at least the latest released version of superset
• I have checked the issue tracker for the same issue and I haven’t found one similar

Superset version

0.22.1

Expected results

CSV upload should create new table and load data into mysql

Actual results

        Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/flask/app.py", line 1982, in wsgi_app
    response = self.full_dispatch_request()
  File "/usr/local/lib/python3.5/dist-packages/flask/app.py", line 1615, in full_dispatch_request
    return self.finalize_request(rv)
  File "/usr/local/lib/python3.5/dist-packages/flask/app.py", line 1632, in finalize_request
    response = self.process_response(response)
  File "/usr/local/lib/python3.5/dist-packages/flask/app.py", line 1858, in process_response
    self.save_session(ctx.session, response)
  File "/usr/local/lib/python3.5/dist-packages/flask/app.py", line 924, in save_session
    return self.session_interface.save_session(self, session, response)
  File "/usr/local/lib/python3.5/dist-packages/flask/sessions.py", line 363, in save_session
    val = self.get_signing_serializer(app).dumps(dict(session))
  File "/usr/local/lib/python3.5/dist-packages/itsdangerous.py", line 565, in dumps
    payload = want_bytes(self.dump_payload(obj))
  File "/usr/local/lib/python3.5/dist-packages/itsdangerous.py", line 847, in dump_payload
    json = super(URLSafeSerializerMixin, self).dump_payload(obj)
  File "/usr/local/lib/python3.5/dist-packages/itsdangerous.py", line 550, in dump_payload
    return want_bytes(self.serializer.dumps(obj))
  File "/usr/local/lib/python3.5/dist-packages/flask/sessions.py", line 85, in dumps
    return json.dumps(_tag(value), separators=(',', ':'))
  File "/usr/local/lib/python3.5/dist-packages/flask/json.py", line 123, in dumps
    rv = _json.dumps(obj, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/simplejson/__init__.py", line 397, in dumps
    **kw).encode(obj)
  File "/usr/local/lib/python3.5/dist-packages/simplejson/encoder.py", line 291, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "/usr/local/lib/python3.5/dist-packages/simplejson/encoder.py", line 373, in iterencode
    return _iterencode(o, 0)
  File "/usr/local/lib/python3.5/dist-packages/flask/json.py", line 80, in default
    return _json.JSONEncoder.default(self, o)
  File "/usr/local/lib/python3.5/dist-packages/simplejson/encoder.py", line 268, in default
    raise TypeError(repr(o) + " is not JSON serializable")
TypeError: OperationalError('(_mysql_exceptions.OperationalError) (1045, "Access denied for user \'superset\'@\'172.21.0.4\' (using password: YES)")',) is not JSON serializable

Steps to reproduce

I’m using the following docker image : https://github.com/amancevice/superset

add the following to mysql/supertset_config.py UPLOAD_FOLDER='/tmp/' I created a new database called TEST and ensured the user has permissions to do stuff with this schema:

GRANT ALL PRIVILEGES ON TEST.* TO ‘superset’@‘%’ WITH GRANT OPTION;

Password was set to superset and I can prove external connection by using sql workbench (external client) to connect directly to the mysql container.

CSV file called x.csv contained the following

XXXXXX,YYYYYYY
1,2