MySQL 错误无法用 python 和 flask 打开命名管道

Question

错误代码为：

mysql.connector.errors.DatabaseError: 2017 (HY000): 无法打开命名管道到主机：。管道：MySQL (2)

我在 MySQL Workbench 设置中看不出这个错误的原因。

db.py:

import mysql.connector

import click
from flask import current_app, g
from flask.cli import with_appcontext
from .schema import instructions

def get_db():
    if 'db' not in g:
        g.db = mysql.connector.connect(
            host=current_app.config['DATABASE_HOST'],
            user=current_app.config['DATABASE_USER'],
            password=current_app.config['DATABASE_PASSWORD'],
            database=current_app.config['DATABASE']
        )
        g.c = g.db.cursor(dictionary=True)
    return g.db, g.c

def close_db(e=None):
    db = g.pop('db', None)

    if db is not None:
        db.close()

def init_db():
    db, c = get_db()

    for i in instructions:
        c.execute(i)

    db.commit()

@click.command('init-db')
@with_appcontext
def init_db_command():
    init_db()
    click.echo('Base de datos inicializada')

def init_app(app):
    app.teardown_appcontext(close_db)
    app.cli.add_command(init_db_command)

init.py（init变成了一个“____”：

import os

from flask import Flask

def create_app():
    app = Flask(__name__)

    app.config.from_mapping(
        SECRET_KEY='mikey',
        DATABASE_HOST=os.environ.get('FLASK_DATABASE_HOST'),
        DATABASE_PASSWORD=os.environ.get('FLASK_DATABASE_PASSWORD'),
        DATABASE_USER=os.environ.get('FLASK_DATABASE_USER'),
        DATABASE=os.environ.get('FLASK_DATABASE'),
    )

    from . import db

    db.init_app(app)

    @app.route('/hola')
    def hola():
        return 'Happy Pig'

    return app

Schema.py:

instructions = [
    'SET FOREIGN_KEY_CHECKS=0;',
    'DROP TABLE IF EXIST todo;',
    'DROP TABLE IF EXIST user;',
    'SET FOREIGN_KEY_CHECKS=1:',
    """
        CREATE TABLE user (
            id INT PRIMARY KEY AUTO_INCREMENT,
            username VARCHAR(50) UNIQUE NOT NULL,
            password VARCHAR(100) NOT NULL
        )
    """,
    """
        CREATE TABLE todo(
            id INT PRIMARY KEY AUTO_INCREMENT,
            created_by INT NOT NULL,
            created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
            description TEXT NOT NULL,
            completed BOOLEAN NOT NULL,
            FOREIGN KEY (created_by) REFERENCES user (id)
        );
    """
]