Flask returns error: Lost connection to MySQL server, system error: 60

Question

I am trying to connect my FLASK app with MySQL on localhost(127.0.0.1:5000) but getting below error.

super(Connection, self).__init__(*args, **kwargs2)
_mysql_exceptions.OperationalError: (2013, "Lost connection to MySQL server at 'waiting for initial communication packet', system error: 60")

I am using "flask_mysqldb" library. When i tried to fill form and hit submit. it tries to connect to db but never got success and returns error.

Please check out my code and help.

from flask import Flask, render_template, flash, redirect, url_for, request, session, logging
from data import Articles
from flask_mysqldb import MySQL 
from wtforms import Form, StringField, TextAreaField, PasswordField, validators
from passlib.hash import sha256_crypt


app = Flask("__name__")

# config MySQL
app.config["MYSQL_HOST"] = "127.0.0.1"
app.config["MYSQL_PORT"] = 5000
app.config["MYSQL_USER"] = "root"
app.config["MYSQL_DB"] = "myflaskapp"
app.config["MYSQL_CURSORCLASS"] = "DictCursor"

# init MySQL
mysql = MySQL(app)



Articles = Articles()


@app.route("/")
def index():
    return render_template("index.html")

@app.route("/about")
def about():
    return render_template("about.html")

@app.route("/articles")
def articles():
    return render_template("articles.html", articles = Articles)

@app.route("/article/<string:id>/")
def article(id):
    return render_template("article.html", id=id)

# collect and validate user data
class RegisterForm(Form):
    name        = StringField('Name', [validators.Length(min=1, max=50)])
    username    = StringField('Username', [validators.Length(min=4, max=25)])
    email       = StringField('Email', [validators.Length(min=6, max=50)])
    password    = PasswordField('Password', [
            validators.DataRequired(),
            validators.EqualTo('confirm', message='Password do not match')
        ])
    confirm     = PasswordField('Confirm Password')

# insert user data to DB
@app.route("/register", methods=['GET', 'POST'])
def register():
    form = RegisterForm(request.form)

    if request.method == 'POST' and form.validate():
        name        = form.name.data
        email       = form.email.data
        username    = form.username.data
        password    = sha256_crypt.encrypt(str(form.password.data))

        # create cursor(handler) to connect DB
        cur = mysql.connection.cursor()

        cur.execute("INSERT INTO users(name, email, username, password) VALUES (%s, %s, %s, %s)", (name, email, username, password))

        # commit to db
        mysql.connection.commit()

        # close the connection
        cur.close()

        flash('You are now Registered', 'success')

        return redirect(url_for('index'))

    return render_template('register.html', form=form)



if __name__ == "__main__":
    app.run(debug=True)

Below are the versions i am using.

Python: 3.6
MySQL: 5.7.21

Q: Is "flask_mysqldb" support python 3.6 or not?

Q: What is the good alternative, if required?

PyMySQL
mysqlclient
SQLalchemy

And yes, mysqlclient is also installed already.

Vivek Kalyanarangan Vivek Kalyanarangan · Accepted Answer · 2018-02-25T07:56:49

Here are some of these troubleshoots you can try (these are independent steps: So try (1), check if it works, try (2), check if it works and so on...) -

Try localhost instead of 127.0.0.1 (thats it!)
Setting bind-address = 0.0.0.0 in mysql/my.cnf. It basically listens to all addresses (but still one port) then.

And don't forget restart your server: systemctl restart mysql

Database directory read-write permission. Just make sure your application is able to rw files on db location. Try chmod 777 for testing.

Let me know if any of this works. If it doesn't, post the error and we can try something.

Note: It is a database level problem not a python problem. Check this mysql forum thread for more clues.

Flask returns error: Lost connection to MySQL server, system error: 60

1 Answers