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
ivan-cs.ma@oracle.com
2016-10-29
Copyright © 2016, Oracle and/or its affiliates. All rights reserved.

Safe Harbor Statement
The following is intended to outline our general product direction. It is intended for
information purposes only, and may not be incorporated into any contract. It is not a
commitment to deliver any material, code, or functionality, and should not be relied upon
in making purchasing decisions. The development, release, and timing of any features or
functionality described for Oracle’s products remains at the sole discretion of Oracle.
2

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
1
2
3
4
5

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
– MySQLGroup Replication
– MySQLReplication
– MySQLRouter
– MySQLInnoDB Cluster
• MySQL Connector/Python
– Connecting to MySQL
– SELECT statements
– Looping Result
– Executing Stored Procedure
– ErrorHandling 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-SyncReplication
• 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-SyncReplication
• 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
9

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
10
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/

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()

“connection” – MySQLConnection Class
• frommysql.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
16
Implicit
Explicit

Connecting MySQL using Dictionary config
• import mysql.connector
• 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()
19
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()
• whilerow:
• 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()
20
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
21
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

Home Page with Flask
• from flask import Flask, render_template, request, json
• importmysql.connector
• from mysql.connector import errorcode
• app = Flask(__name__)
• @app.route("/")
• @app.route("/main")
• defmain():
• return render_template('03-index.html')
23
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:
******************************************
24
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!
25

20161029 py con-mysq-lv3

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