SSHTunnel and MySQL.connector in Python failing

问题

I'm trying to use the MySQL connector in Python, through an SSHTunnel, and I'm getting a MySQL Connection not available. error.

It seems to be talking to the server (I get an access denied message if I change the password), but it fails when I try to create a cursor object (specifically, when the MySQL library runs CMySQLConnection.is_connected().

I can connect to the database by SSHing in using the same credentials, then running mysql in the command line.

Code:

with sshtunnel.SSHTunnelForwarder(
    ('vpn.example.com', 22),
    ssh_username='ssh_username',
    ssh_pkey='~/.ssh/key.pem',

    remote_bind_address=(
        'db.example.com',
        3306
    ),

) as tunnel:
    try:
        backup_cnx = mysql.connector.connect(
            user='vpn_username',
            password='bts5eva',
            host='127.0.0.1',
            port=tunnel.local_bind_port,
            database='pretend_db_name',
            # connection_timeout=5
        )
        cursor = backup_cnx.cursor()
        day_after = day + datetime.timedelta(days=1)

        cursor.execute(
            "SELECT * "
            " FROM mah_table "
            " WHERE timestamp < {day_after} AND timestamp > {day}"
            " ORDER BY timestamp".format(
                day=day.strftime("%Y-%m-%d"),
                day_after=day_after.strftime("%Y-%m-%d")
            )
        )

        results = cursor.fetchall()

    finally:
        backup_cnx.close()

I get this stacktrace:

Traceback (most recent call last):
  File "code/restore_missing_directives.py", line 41, in <module>
    cursor = backup_cnx.cursor()
  File "code/env/lib/python2.7/site-packages/mysql/connector/connection_cext.py", line 524, in cursor
    raise errors.OperationalError("MySQL Connection not available.")
mysql.connector.errors.OperationalError: MySQL Connection not available.

---

Potentially relevant links:

• https://www.pythonanywhere.com/forums/topic/3945/

来源：https://stackoverflow.com/questions/58919186/sshtunnel-and-mysql-connector-in-python-failing