Connect with the Python driver

Because Astra DB is based on Apache Cassandra®, you can use Cassandra drivers to connect to your Astra DB Classic databases.

To use the Python driver, you need to install the driver and its dependencies, and then connect the driver to your Astra DB Classic database. Once connected, you can write scripts that use the driver to run commands against your database.

Prerequisites

Install Python 3.7 or later.

CPython (the standard Python implementation) and PyPy are supported and tested.

Python 3.4, 3.5, and 3.6 can be used if necessary for legacy applications that require an earlier version of the Python driver.
Create a database.
Download your database’s Secure Connect Bundle (SCB).

For multi-region databases, download the Secure Connect Bundle (SCB) for a region that is geographically close to your application to reduce latency.

If you need to connect to multiple regions in the same application, you need the Secure Connect Bundle (SCB) for each region, and your driver code must instantiate one root object (session) for each region. For more information, see Best practices for Cassandra drivers.
Set the following environment variables:
- ASTRA_DB_ID: The database ID.
- ASTRA_DB_KEYSPACE: A keyspace in your database, such as default_keyspace.
- ASTRA_DB_APPLICATION_TOKEN: An application token with the Database Administrator role.

Driver authentication methods

There are two driver authentication methods: token authentication, or clientId and secret authentication.

Token authentication
Client ID and secret authentication

This authentication method is supported and recommended for most recent driver versions.

In your driver authentication code, pass the literal string token as the username and your application token value (AstraCS:…) as the password. For example:

("token", "AstraCS:...")

If you are on an older driver version that doesn’t support token authentication, then you might need to use clientId and secret.

When you generate an application token, download or copy the token.json that contains the following values:

{
  "clientId": "CLIENT_ID",
  "secret": "CLIENT_SECRET",
  "token": "APPLICATION_TOKEN"
}

In your driver authentication code, pass clientId as the username and secret as the password. For example:

("CLIENT_ID", "SECRET")

For more information, see Token details.

Install the Python driver

Install the Python driver:
```
pip install cassandra-driver
```
If you choose to install an earlier version, make sure you choose a version that is compatible with Astra DB. For more information, see Cassandra drivers supported by DataStax.
Verify the installation:
```
pip show cassandra-driver
```
Make sure the returned Version is the latest version or the specific version that you installed.

Connect the Python driver

In the root of your Python project, create a connect_database.py file:
```
cd python_project
touch connect_database.py
```

Copy the following connection code into connect_database.py, and then replace PATH_TO_SCB with the absolute path to your database’s Secure Connect Bundle (SCB) (secure-connect-DATABASE_NAME.zip):

connect_database.py

import os
from cassandra.cluster import Cluster
from cassandra.auth import PlainTextAuthProvider
import json

with open(ASTRA_TOKEN_PATH, "r") as f:
    creds = json.load(f)
    ASTRA_DB_APPLICATION_TOKEN = creds["token"]

cluster = Cluster(
    cloud={
        "secure_connect_bundle": PATH_TO_SCB,
    },
    auth_provider=PlainTextAuthProvider(
        "token",
        ASTRA_DB_APPLICATION_TOKEN,
    ),
)

session = cluster.connect()

This code creates a Cluster instance to connect to your Astra DB database. You typically have one instance of Cluster for each Astra DB database that you want to interact with.

Add code that runs a CQL query and prints the output to the console:

connect_database.py

row = session.execute("select release_version from system.local").one()
if row:
    print(row[0])
else:
    print("An error occurred.")

Save and run your Python script:
```
python ./connect_database.py
```
The output prints the release_version value from the system.local table in your Astra DB database.
Extend or modify this script to run other commands against your database or connect to other databases. For more information, see Python driver documentation and DataStax-compatible Cassandra drivers.

Connect with the Python driver

Prerequisites

Driver authentication methods

Install the Python driver

Connect the Python driver

See also

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