Use Dash to Build to Web Apps on SingleStore Data

The rich ecosystem of Python modules lets you get to work quickly and integrate your systems more effectively. With the CData Python Connector for SingleStore, the pandas module, and the Dash framework, you can build SingleStore-connected web applications for SingleStore data. This article shows how to connect to SingleStore with the CData Connector and use pandas and Dash to build a simple web app for visualizing SingleStore data.

With built-in, optimized data processing, the CData Python Connector offers unmatched performance for interacting with live SingleStore data in Python. When you issue complex SQL queries from SingleStore, the driver pushes supported SQL operations, like filters and aggregations, directly to SingleStore and utilizes the embedded SQL engine to process unsupported operations client-side (often SQL functions and JOIN operations).

Connecting to SingleStore Data

Connecting to SingleStore data looks just like connecting to any relational data source. Create a connection string using the required connection properties. For this article, you will pass the connection string as a parameter to the create_engine function.

The following connection properties are required in order to connect to data.

• Server: The host name or IP of the server hosting the SingleStore database.
• Port: The port of the server hosting the SingleStore database.
• Database (Optional): The default database to connect to when connecting to the SingleStore Server. If this is not set, tables from all databases will be returned.

Connect Using Standard Authentication

To authenticate using standard authentication, set the following:

• User: The user which will be used to authenticate with the SingleStore server.
• Password: The password which will be used to authenticate with the SingleStore server.

Connect Using Integrated Security

As an alternative to providing the standard username and password, you can set IntegratedSecurity to True to authenticate trusted users to the server via Windows Authentication.

Connect Using SSL Authentication

You can leverage SSL authentication to connect to SingleStore data via a secure session. Configure the following connection properties to connect to data:

• SSLClientCert: Set this to the name of the certificate store for the client certificate. Used in the case of 2-way SSL, where truststore and keystore are kept on both the client and server machines.
• SSLClientCertPassword: If a client certificate store is password-protected, set this value to the store's password.
• SSLClientCertSubject: The subject of the TLS/SSL client certificate. Used to locate the certificate in the store.
• SSLClientCertType: The certificate type of the client store.
• SSLServerCert: The certificate to be accepted from the server.

Connect Using SSH Authentication

Using SSH, you can securely login to a remote machine. To access SingleStore data via SSH, configure the following connection properties:

• SSHClientCert: Set this to the name of the certificate store for the client certificate.
• SSHClientCertPassword: If a client certificate store is password-protected, set this value to the store's password.
• SSHClientCertSubject: The subject of the TLS/SSL client certificate. Used to locate the certificate in the store.
• SSHClientCertType: The certificate type of the client store.
• SSHPassword: The password that you use to authenticate with the SSH server.
• SSHPort: The port used for SSH operations.
• SSHServer: The SSH authentication server you are trying to authenticate against.
• SSHServerFingerPrint: The SSH Server fingerprint used for verification of the host you are connecting to.
• SSHUser: Set this to the username that you use to authenticate with the SSH server.

After installing the CData SingleStore Connector, follow the procedure below to install the other required modules and start accessing SingleStore through Python objects.

Install Required Modules

Use the pip utility to install the required modules and frameworks:

pip install pandas
pip install dash
pip install dash-daq

Visualize SingleStore Data in Python

Once the required modules and frameworks are installed, we are ready to build our web app. Code snippets follow, but the full source code is available at the end of the article.

First, be sure to import the modules (including the CData Connector) with the following:

import os
import dash
import dash_core_components as dcc
import dash_html_components as html
import pandas as pd
import cdata.singlestore as mod
import plotly.graph_objs as go

You can now connect with a connection string. Use the connect function for the CData SingleStore Connector to create a connection for working with SingleStore data.

cnxn = mod.connect("User=myUser;Password=myPassword;Database=NorthWind;Server=myServer;Port=3306;")

Execute SQL to SingleStore

Use the read_sql function from pandas to execute any SQL statement and store the result set in a DataFrame.

df = pd.read_sql("SELECT ShipName, ShipCity FROM Orders WHERE ShipCountry = 'USA'", cnxn)

Configure the Web App

With the query results stored in a DataFrame, we can begin configuring the web app, assigning a name, stylesheet, and title.

app_name = 'dash-singlestoreedataplot'

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)
app.title = 'CData + Dash'

Configure the Layout

The next step is to create a bar graph based on our SingleStore data and configure the app layout.

trace = go.Bar(x=df.ShipName, y=df.ShipCity, name='ShipName')

app.layout = html.Div(children=[html.H1("CData Extension + Dash", style={'textAlign': 'center'}),
	dcc.Graph(
		id='example-graph',
		figure={
			'data': [trace],
			'layout':
			go.Layout(title='SingleStore Orders Data', barmode='stack')
		})
], className="container")

Set the App to Run

With the connection, app, and layout configured, we are ready to run the app. The last lines of Python code follow.

if __name__ == '__main__':
    app.run_server(debug=True)

Now, use Python to run the web app and a browser to view the SingleStore data.

python singlestore-dash.py

Free Trial & More Information

Download a free, 30-day trial of the CData Python Connector for SingleStore to start building Python apps with connectivity to SingleStore data. Reach out to our Support Team if you have any questions.

Full Source Code

import os
import dash
import dash_core_components as dcc
import dash_html_components as html
import pandas as pd
import cdata.singlestore as mod
import plotly.graph_objs as go

cnxn = mod.connect("User=myUser;Password=myPassword;Database=NorthWind;Server=myServer;Port=3306;")

df = pd.read_sql("SELECT ShipName, ShipCity FROM Orders WHERE ShipCountry = 'USA'", cnxn)
app_name = 'dash-singlestoredataplot'

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)
app.title = 'CData + Dash'
trace = go.Bar(x=df.ShipName, y=df.ShipCity, name='ShipName')

app.layout = html.Div(children=[html.H1("CData Extension + Dash", style={'textAlign': 'center'}),
	dcc.Graph(
		id='example-graph',
		figure={
			'data': [trace],
			'layout':
			go.Layout(title='SingleStore Orders Data', barmode='stack')
		})
], className="container")

if __name__ == '__main__':
    app.run_server(debug=True)