Develop Reference

MySQL to OPC UA Server

I'm trying to read the data from MySql database to OPC UA server. I tested it with the following code and sample database it is working. However, I'm not sure if it runs in a real time environment as the database has 40+ tables and 30+ columns in each table recording 1 minute data. Can someone please suggest the optimal way to do this.
from opcua import ua, uamethod, Server
from time import sleep
import logging
import mysql.connector
mydb = mysql.connector.connect(
host="127.0.0.1",
port=3306,
user="root",
password="root",
database="classicmodels")
mycursor = mydb.cursor(buffered=True , dictionary=True)
sql = "SELECT * FROM classicmodels.customers"
mycursor.execute(sql)
myresult = mycursor.fetchone()
sql1 = "SELECT * FROM classicmodels.employees"
mycursor.execute(sql1)
myresult1 = mycursor.fetchone()
if __name__ == "__main__":
"""
OPC-UA-Server Setup
"""
server = Server()
endpoint = "opc.tcp://127.0.0.1:4848"
server.set_endpoint(endpoint)
servername = "Python-OPC-UA-Server"
server.set_server_name(servername)
"""
OPC-UA-Modeling
"""
root_node = server.get_root_node()
object_node = server.get_objects_node()
idx = server.register_namespace("OPCUA_SERVER")
myobj = object_node.add_object(idx, "DA_UA")
myobj1 = object_node.add_object(idx, "D_U")
"""
OPC-UA-Server Add Variable
"""
for key, value in myresult.items():
myobj.add_variable(idx, key, str(value))
for key, value in myresult1.items():
myobj1.add_variable(idx, key, str(value))
"""
OPC-UA-Server Start
"""
server.start()
'''

i want use sshtunnel reconnect and query database with database of pythonanywhere

import sshtunnel
import time
import logging
import mysql.connector
class SelectCommand():
def __init__(self,dbcmd,value = None, mul = False):
self.dbcmd = dbcmd
self.value = value
self.mul = mul
def execute(self):
try:
print("try1")
connection = mysql.connector.connect(
user='**myuser**', password='**pass**',
host='127.0.0.1', port=server.local_bind_port,
database='**myuser$test**', autocommit = True
)
print("try2")
connection.autocommit = True
mycursor = connection.cursor()
sql = self.dbcmd
val = self.value
mycursor.execute(sql, val)
myresult = mycursor.fetchone()
mycursor.close()
connection.close()
if myresult == None or self.mul == True:
return myresult
return myresult[0]
except Exception as e:
print(e)
return "server disconnect "
sshtunnel.SSH_TIMEOUT = 5.0
sshtunnel.TUNNEL_TIMEOUT = 5.0
def get_server():
#sshtunnel.DEFAULT_LOGLEVEL = logging.DEBUG
server = sshtunnel.SSHTunnelForwarder(
('ssh.pythonanywhere.com'),
ssh_username='**myuser**', ssh_password='**mypass**',
remote_bind_address=('**myuser.mysql.pythonanywhere-services.com**', 3306))
return server
server = get_server()
server.start()
while True :
if(server.is_active):
print("alive... " + (time.ctime()))
print(SelectCommand("SELECT * FROM A_table WHERE id = %s", (1,), mul = True).execute())
else:
print("reconnecting... " + time.ctime())
server.stop()
server = get_server()
server.start()
time.sleep(8)
Now i want use sshtunnel connect with database of pythonanywhere, and i want check connecting of sshtunnel if connect do select command else wait for new connecting. i try do Python: Automatically reconnect ssh tunnel after remote server gone down . but my problem is when i query database i try turn off my WIFI
my console show this message (Could not establish connection from ('127.0.0.1', 54466) to remote side of the tunnel) and Socket exception: An existing connection was forcibly closed by the remote host (10054) then it's result to stopping of my program. How can i fix.

Return response multiline

import sys
import logging
import rds_config
import pymysql
#rds settings
rds_host = "xxxxxx"
name = rds_config.db_username
password = rds_config.db_password
db_name = rds_config.db_name
logger = logging.getLogger()
logger.setLevel(logging.INFO)
try:
conn = pymysql.connect(rds_host, user=name, passwd=password, db=db_name, connect_timeout=5)
except:
logger.error("ERROR: Unexpected error: Could not connect to MySQL instance.")
sys.exit()
logger.info("SUCCESS: Connection to RDS MySQL instance succeeded")
def handler(event, context):
"""
This function fetches content from MySQL RDS instance
"""
data = ''
with conn.cursor() as cur:
cur.execute("Select * from xxxxx where Status = 'Active';")
for row in cur:
logger.info(row)
data+= " ".join(map(str, row)) + "\n"
return data
I am getting the response as below
Response:
"1 xxxxxxx Full Active 2019-12-31\n2 yyyyyyyy Full Active 2019-12-31\n"
I want it as below (is without quotes possible?)
Response:
"1 xxxxxxx Full Active 2019-12-31"
"2 yyyyyyyy Full Active 2019-12-31"
Python newbie. Can anyone please help ?

"1 xxxxxxx Full Active 2019-12-31\n2 yyyyyyyy Full Active 2019-12-31\n"
is a Python representation of the string
1 xxxxxxx Full Active 2019-12-31
2 yyyyyyyy Full Active 2019-12-31
There is nothing to do: you already have a multi-line string; try print(data) to see.

Parse json from mysql in flask to get a field from record

Mind that I am new to flask and python for that matter, I appreciate any help that anyone gives. I'm looking to access one of the fields of my JSON response(just the field not the entire response), how should I go about parsing the response. Image of the response attached below,thanks.
This is my main thread
from flask import Flask,render_template,request
from Qhandler import Qhandler
from MakePlayer import MakePlayer
app = Flask(__name__)
#app.route('/createplayer',methods=['GET','POST'] )
def showCreatePlayer():
if request.method == 'POST':
MakePlayer(request.form['playername'],request.form['playerteam'],request.form['playerrole'], request.form['playerpos'])
return "created player: <br>"+request.form['playername']+" "+request.form['playerteam']+" "+request.form['playerrole']+" "+request.form['playerpos']
return render_template("createPlayer.html")
#app.route('/sucess')
def success():
return "success"
#app.route('/showplayers')
def showPlayers():
Q = Qhandler()
return Q.displayQuery(""" select * from Player""")
if __name__ == '__main__':
app.run(debug=True)
This is my query handler
from flask import Flask, jsonify, json
from flaskext.mysql import MySQL
class Qhandler(object):
#global mysql
global cursor
global connection
global mysql
# database connection
app = Flask(__name__)
mysql = MySQL()
app.config['MYSQL_DATABASE_USER'] = 'root'
app.config['MYSQL_DATABASE_PASSWORD'] = 'root'
app.config['MYSQL_DATABASE_DB'] = 'Optimizer'
app.config['MYSQL_DATABASE_HOST'] = 'localhost'
mysql.init_app(app)
def ins(self,query):
try:
connection=mysql.connect()
cursor = connection.cursor()
cursor.execute(query)
connection.commit()
except:
print "error running query"
finally:
#cursor.close()
connection.close()
def displayQuery(self,query):
try:
connection = mysql.connect()
cursor = connection.cursor()
cursor.execute(query)
fetchedData = cursor.fetchall()
fetchedData = jsonify(fetchedData)
#fetchedData = json.dumps(fetchedData)
#record = json.loads(fetchedData)
#print "the resonse is here:"
return fetchedData
except:
print "error running query"
finally:
#cursor.close()
connection.close()
current response is
screenshot of results

Use "fetchedData = json.dumps(fetchedData)" instead of "fetchedData = jsonify(fetchedData)" then create a json decoder and parse the response, refer to below :
def displayQuery(self,query):
try:
connection = mysql.connect()
cursor = connection.cursor()
cursor.execute(query)
fetchedData = cursor.fetchall()
fetchedData = json.dumps(fetchedData)
#create a json decoder
d = json.JSONDecoder()
fieldPlayerName = d.decode(fetchedData)
#parse the json that is returned ( fieldPlayerName[0][1])
print "should print the field with the player name",fieldPlayerName[0][1]
return fieldPlayerName[0][1]

MySQL server has gone away issue

I am newbie in python, so, it looks like my first project on that lang.
Everytime when I'm trying to run my script - I get different answers from mysql server.
The most frequent answer is OperationalError: (2006, 'MySQL server has gone away')
Sometimes I get output Thread: 11 commited (see code below).
And sometimes emergency stop (traslated, I have russian output in console).
Whatever if output full of commited - records in table still the same.
import MySQLdb
import pyping
import socket, struct
from threading import Thread
def ip2int(addr):
"""Convert ip to integer"""
return struct.unpack("!I", socket.inet_aton(addr))[0]
def int2ip(addr):
"""Convert integer to ip"""
return socket.inet_ntoa(struct.pack("!I", addr))
def ping(ip):
"""Pinging client"""
request = pyping.ping(ip, timeout=100, count=1)
return int(request.max_rtt)
class UpdateThread(Thread):
def __init__(self, records, name):
Thread.__init__(self)
self.database = MySQLdb.connect(host="***", port=3306, user="root", passwd="***", db="dns")
self.cursor = database.cursor()
self.name = name
self.records = records
def run(self):
print(self.name)
for r in self.records:
#latency = ping(int2ip(r[1])) what the hell :x
#ip = str(int2ip(r[1]))
id = str(r[0])
self.cursor.execute("""update clients set has_subn=%s where id=%s""" % (id, id))
self.database.commit()
print(self.name + " commited")
#start
database = MySQLdb.connect(host="***", port=3306, user="root", passwd="***", db="dns")
cursor = database.cursor()
cursor.execute("""select * from clients""")
data = cursor.fetchall() #All records from DataBase
count = len(data)
threads_counter = 10 #We are creating 10 threads for all records
th_count = count / threads_counter #Count of records for each thread
last_thread = count % threads_counter #Last records
threads = []
i = 0
while i < (count - last_thread):
temp_list = data[i:(i+th_count)]
#print(temp_list)
threads.append(UpdateThread(records = temp_list, name = "Thread: " + str((i/3) + 1)).start())
i += th_count
threads.append(UpdateThread(records = data[i: count], name = "Thread: 11").start())
P.S.
Another answers I found here is not helping me.
UPD:
I found that some(everytime another) thread print
OperationalError: (2013, 'Lost connection to MySQL server during query') and all next threads print OperationalError: (2013, 'Lost connection to MySQL server during query')

You need to close your DB connections when you're done with them or else the DB server will become overwhelmed and make your connections expire. For your program, I would change your code so that you have only one DB connection. You can pass a reference to it to your UpdateThread instances and close it when you're done.
database.close()