20161029 py con-mysq-lv3

Copyright © 2016, Oracle and/or its affiliates. All rights reserved. |

Creating Python application with MySQL High Availability Database Service Ivan Ma [email protected] 2016-10-29

Copyright © 2016, Oracle and/or its affiliates. All rights reserved.

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Program Agenda

3

MySQL High Availability Intro

Python – Connecting to Database

Making Query to Database

Python – Failover (HA) connection to Database

Flask – Web App Sample

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4

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Overview

• MySQL as Database – Highly Available Configuration and Setup

• Python – The Programming Language

– Using Framework (e.g. FLASK )

– Database Connection

– Query

– Row Result Processing

– Error Handling


Today • Introducing – MySQL Group Replication – MySQL Replication – MySQL Router – MySQL InnoDB Cluster

• MySQL Connector/Python – Connecting to MySQL – SELECT statements – Looping Result – Executing Stored Procedure – Error Handling in Python with MySQL – multi-host connection with MySQL


A Quick Walk thru of MySQL HA

• MySQL High Availability – Redundancy is the Key

• MySQL Replication

• MySQL Semi-Sync Replication

• MySQL Group Replication

• Shared Storage with OS Clustering

• MySQL Cluster

• Application Connection to MySQL

– Connector / Driver • Connector / Python

• Connector / Java

• Connector / .NET, PHP, etc…


A Quick Walk thru of MySQL HA

• MySQL High Availability – Redundancy is the Key

• MySQL Replication

• MySQL Semi-Sync Replication

• MySQL Group Replication (RC)

• Shared Storage with OS Clustering – MySQL service

• MySQL Cluster

• Application Connection to MySQL

– Connector / Driver • Connector / Python

• Connector / Java

• Connector / .NET, PHP, etc…

MySQL Router


MySQL Group Replication (Release Candidate) Natively distributed and highly available replica sets


MySQL Group Replication: What Does It Provide?

• A highly available distributed MySQL database service – Removes the need for manually handling server fail-over

– Provides distributed fault tolerance

– Enables Active/Active update anywhere setups

– Automates reconfiguration (adding/removing nodes, crashes, failures)

– Automatically detects and handles conflicts

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MySQL Server: Core

• Server calls into the plugin through a generic interface – Most server internals are hidden from the plugin

• Plugin interacts with the server through a generic interface – Replication plugin determines the fate of the commit

operation through a well defined server interface

– The plugin makes use of the relay log infrastructure to inject changes in the receiving server

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GCS API

Replication Plugin

Plugin API

MySQL Server

Group Com. Engine

GCS API

Replication Plugin

Plugin API

MySQL Server

Group Com. Engine

Network


MyQL Connector / Python


MySQL Connector / Python

• To download the Connetor/Python, – https://dev.mysql.com/downloads/connector/python/

https://dev.mysql.com/downloads/connector/python/


Connecting MySQL

• import mysql.connector

• import sys

• _pass = ''

• if len(sys.argv) > 1 :

• _pass = sys.argv[1]

• cnx = mysql.connector.connect(user='root', password=_pass, host='127.0.0.1', port=3306, database='mysql')

• cnx.close()

Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | 14


“connection” – MySQLConnection Class • from mysql.connector import (connection)

• import sys

• _pass='';


• _pass=sys.argv[1]

• cnx = connection.MySQLConnection(user='root', password=_pass, host='127.0.0.1', port=3306, database='mysql')

• cnx.close()


Connection Pooling

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Implicit

Explicit


Connecting MySQL using Dictionary config


• import sys

• _pass='';


• _pass=sys.argv[1]

• config = { 'user': 'root', 'password': '', 'host': '127.0.0.1', 'database': 'mysql',

• 'raise_on_warnings': True, }

• cnx = mysql.connector.connect(**config)

• cnx.close()


Error Handling in Connection (try …. except…finally) • try:

• cnx = mysql.connector.connect(user='root', host='127.0.0.1', port=3306,

• password=_pass,

• database=_db)

• print("connect success")

• except mysql.connector.Error as err:

• if err.errno == errorcode.ER_ACCESS_DENIED_ERROR:

• print("Something is wrong with your user name or password")

• elif err.errno == errorcode.ER_BAD_DB_ERROR:

• print("Database does not exist")

• else:

• print(err)

• finally:

• print ("Finally - close connection")

• cnx.close()


SELECT • cnx = mysql.connector.connect(**config)

• operation = “select ……. from …..; select …. from ….”

• cursor = cnx.cursor()

• try:

• ……


• print(err.msg)

• cursor.close()

• cnx.close()

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for result in cursor.execute(operation, multi=True): if result.with_rows: print("rows producted by statement '{}':".format(result.statement)) row = cursor.fetchone() while row: print(row) row = cursor.fetchone() else: print("Number of rows affeted by statement '{}':{}".format(result.statement, result.rowcount))


Failover Connection Property • operation = 'SELECT @@hostname, @@port, employees.* from employees limit 10‘

• try:

• for result in cursor.execute(operation, multi=True):

• if result.with_rows:

• print("rows producted by statement '{}':".format(result.statement))

• row = cursor.fetchone()

• while row:

• print(row)

• row = cursor.fetchone()

• else:

• print("Number of rows affeted by statement '{}':{}".format(result.statement, result.rowcount))


• print(err.msg)

• cursor.close()

• cnx.close()

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config = { 'raise_on_warnings': True, 'failover' : [ { 'user': 'root‘, 'password': '‘, 'host': '127.0.0.1‘, 'port': 3306, 'database': 'employees', }, { 'user': 'root‘, 'password': '‘, 'host': '127.0.0.1‘, 'port': 3306, 'database': 'employees',} ] } cnx = mysql.connector.connect(**config)


Program Agenda

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MySQL High Availability Intro

Python – Connecting to Database

Making Query to Database

Python – Failover (HA) connection to Database

Flask – Web App Sample

1

2

3

4

5

Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | 22


Home Page with Flask • from flask import Flask, render_template, request, json


• from mysql.connector import errorcode

• app = Flask(__name__)

• @app.route("/")

• @app.route("/main")

• def main():

• return render_template('03-index.html')

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config = { 'user': 'root', 'password': '', 'host': '127.0.0.1', 'port': 3316, 'database': 'pycon2016hk', 'raise_on_warnings': True, }


Register – Calling Stored Procedure • @app.route("/Register", methods=["POST","GET"])

• def register():

• try:

• _name = request.form['inputName']

• _password = request.form['inputPassword']

• # validate the values

• if _name and _password:

•

• else:

• return 'Please Enter the required fields!!'

• except Exception as e:

• return 'DB Error' + str(e) +'</spand>'

• finally:

******************************************

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conn = mysql.connector.connect(**config) cursor = conn.cursor() cursor.callproc("sp_user", [ _name, _password]) if len(list(cursor.stored_results())) is 0: conn.commit() return 'Message:User created successfully!‘ else: data = [] for result in cursor.stored_results(): data.append(str(result.fetchall())) return 'Error:' + str(data) + ''


THANK YOU!

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Presentations & Public Speaking

20161029 py con-mysq-lv3