Quickstart: Use Azure Cache for Redis with a Python app

In this quickstart, you incorporate Azure Cache for Redis into a Python script for access to a secure, dedicated cache that is accessible from any application in Azure.

Skip to the code

This article describes how to create a Python app and then modify the code to end up with a working sample app.

If you want to skip straight to the code, see the Python quickstart sample on GitHub.

Prerequisites

• An Azure subscription. Create one for free
• Python 3
  • For macOS or Linux, download from python.org.
  • For Windows 11, use the Windows Store.

Create a cache

1. To create a cache, sign in to the Azure portal. On the portal menu, select Create a resource.

   

2. On the Get Started pane, enter Azure Cache for Redis in the search bar. In the search results, find Azure Cache for Redis, and then select Create.

   

3. On the New Redis Cache pane, on the Basics tab, configure the following settings for your cache:

   Setting	Action	Description
   Subscription	Select your Azure subscription.	The subscription to use to create the new instance of Azure Cache for Redis.
   Resource group	Select a resource group, or select Create new and enter a new resource group name.	A name for the resource group in which to create your cache and other resources. By putting all your app resources in one resource group, you can easily manage or delete them together.
   DNS name	Enter a unique name.	The cache name must be a string of 1 to 63 characters that contains only numbers, letters, and hyphens. The name must start and end with a number or letter, and it can't contain consecutive hyphens. Your cache instance's host name is \<DNS name>.redis.cache.windows.net.
   Location	Select a location.	An Azure region that is near other services that use your cache.
   Cache SKU	Select a SKU.	The SKU determines the size, performance, and feature parameters that are available for the cache. For more information, see Azure Cache for Redis overview.
   Cache size	Select a cache size.	For more information, see Azure Cache for Redis overview.

4. Select the Networking tab or select Next: Networking.

5. On the Networking tab, select a connectivity method to use for the cache.

6. Select the Advanced tab or select Next: Advanced.

7. On the Advanced pane, verify or select an authentication method based on the following information:

   

   • By default, for a new Basic, Standard, or Premium cache, Microsoft Entra Authentication is enabled and Access Keys Authentication is disabled.
   • For Basic or Standard caches, you can choose the selection for a non-TLS port.
   • For Standard and Premium caches, you can choose to enable availability zones. You can't disable availability zones after the cache is created.
   • For a Premium cache, configure the settings for non-TLS port, clustering, managed identity, and data persistence.

   Important

   For optimal security, we recommend that you use Microsoft Entra ID with managed identities to authorize requests against your cache if possible. Authorization by using Microsoft Entra ID and managed identities provides superior security and ease of use over shared access key authorization. For more information about using managed identities with your cache, see Use Microsoft Entra ID for cache authentication.

8. (Optional) Select the Tags tab or select Next: Tags.

9. (Optional) On the Tags tab, enter a tag name and value if you want to categorize your cache resource.

10. Select the Review + create button.

    On the Review + create tab, Azure automatically validates your configuration.

11. After the green Validation passed message appears, select Create.

A new cache deployment occurs over several minutes. You can monitor the progress of the deployment on the Azure Cache for Redis Overview pane. When Status displays Running, the cache is ready to use.

Install the redis-py library

Redis-py is a Python interface to Azure Cache for Redis. Use the Python packages tool pip to install the redis-py package at a command line.

The following example uses pip3 for Python 3 to install redis-py on Windows 11 in an Administrator Command Prompt window.

Create a Python script to access your cache

Create a Python script that uses either Microsoft Entra ID or access keys to connect to Azure Cache for Redis. We recommend that you use Microsoft Entra ID.

Microsoft Entra ID authentication (recommended)

Enable Microsoft Entra ID authentication on your cache

For an existing cache, first check to see if Microsoft Entra authentication is enabled. If it's not, complete the following steps to enable Microsoft Entra authentication. We recommend that you use Microsoft Entra ID for authentication in your applications.

1. In the Azure portal, select the Azure Cache for Redis instance where you'd like to use Microsoft Entra token-based authentication.

2. On the service menu, under Settings, select Authentication.

3. On the Authentication pane, check to see whether the Enable Microsoft Entra Authentication checkbox is selected. If it is, you can move on to the next section.

4. Otherwise, select the Enable Microsoft Entra Authentication checkbox. Then, enter the name of a valid user. Select Save. The user name that you enter is automatically assigned the Data Owner Access Policy.

   You also can enter a managed identity or a service principal to connect to your cache.

   

5. In a dialog box, you're asked if you want to update your configuration, and you're informed that making the update takes several minutes to finish. Select Yes.

   Important

   When the enable operation is finished, the nodes in your cache reboot to load the new configuration. We recommend that you complete this operation during your standard maintenance window or outside your peak business hours. The process can take up to 30 minutes.

For information about using Microsoft Entra ID with the Azure CLI, see the identity reference pages.

Install Microsoft Authentication Library

Microsoft Authentication Library (MSAL) gets security tokens from the Microsoft identity platform to authenticate users.

To install MSAL:

1. Install MSAL for Python.

2. Install the Python Azure identity client library. The library uses MSAL to provide token authentication support.

   Install this library by using pip:

pip install azure-identity

Create a Python script by using Microsoft Entra ID

1. Create a text file. Save the file as PythonApplication1.py.

2. In PythonApplication1.py, add and modify the following script.

   In the script:

   • Replace <Your Host Name> with the value from your Azure Cache for Redis instance. Your host name has the form <DNS name>.redis.cache.windows.net.
   • Replace <Your Username> with the value for your Microsoft Entra ID user.

   import redis
   from azure.identity import DefaultAzureCredential
   
   scope = "https://redis.azure.com/.default"
   host = "<Your Host Name>"
   port = 6380
   user_name = "<Your Username>"
   
   
   def hello_world():
       cred = DefaultAzureCredential()
       token = cred.get_token(scope)
       r = redis.Redis(host=host,
                       port=port,
                       ssl=True,    # ssl connection is required.
                       username=user_name,
                       password=token.token,
                       decode_responses=True)
       result = r.ping()
       print("Ping returned : " + str(result))
   
       result = r.set("Message", "Hello!, The cache is working with Python!")
       print("SET Message returned : " + str(result))
   
       result = r.get("Message")
       print("GET Message returned : " + result)
   
       result = r.client_list()
       print("CLIENT LIST returned : ")
       for c in result:
           print(f"id : {c['id']}, addr : {c['addr']}")
   
   if __name__ == '__main__':
       hello_world()
   

3. Before you run your Python code in a terminal, authorize the terminal to use Microsoft Entra ID:

   azd auth login

4. Run the PythonApplication1.py file by using Python. Verify that the output looks similar to this example:

   

Create a Python script by using reauthentication

A Microsoft Entra ID access token has a limited lifespan of approximately 75 minutes. To maintain a connection to your cache, you must refresh the token.

This example demonstrates how to refresh a token by using Python.

1. Create a text file. Save the file as PythonApplication2.py.

2. In PythonApplication2.py, add and modify the following script.

   In the script:

   • Replace <Your Host Name> with the value from your Azure Cache for Redis instance. Your host name has the form <DNS name>.redis.cache.windows.net.
   • Replace <Your Username> with the value for your Microsoft Entra ID user.

   import time
   import logging
   import redis
   from azure.identity import DefaultAzureCredential
   
   scope = "https://redis.azure.com/.default"
   host = "<Your Host Name>"
   port = 6380
   user_name = "<Your Username>"
   
   def re_authentication():
       _LOGGER = logging.getLogger(__name__)
       cred = DefaultAzureCredential()
       token = cred.get_token(scope)
       r = redis.Redis(host=host,
                       port=port,
                       ssl=True,   # ssl connection is required.
                       username=user_name,
                       password=token.token,
                       decode_responses=True)
       max_retry = 3
       for index in range(max_retry):
           try:
               if _need_refreshing(token):
                   _LOGGER.info("Refreshing token...")
                   tmp_token = cred.get_token(scope)
                   if tmp_token:
                       token = tmp_token
                   r.execute_command("AUTH", user_name, token.token)
               result = r.ping()
               print("Ping returned : " + str(result))
   
               result = r.set("Message", "Hello!, The cache is working with Python!")
               print("SET Message returned : " + str(result))
   
               result = r.get("Message")
               print("GET Message returned : " + result)
   
               result = r.client_list()
               print("CLIENT LIST returned : ")
               for c in result:
                   print(f"id : {c['id']}, addr : {c['addr']}")
               break
           except redis.ConnectionError:
               _LOGGER.info("Connection lost. Reconnecting.")
               token = cred.get_token(scope)
               r = redis.Redis(host=host,
                               port=port,
                               ssl=True,   # ssl connection is required.
                               username=user_name,
                               password=token.token,
                               decode_responses=True)
           except Exception:
               _LOGGER.info("Unknown failures.")
               break
   
   
   def _need_refreshing(token, refresh_offset=300):
       return not token or token.expires_on - time.time() < refresh_offset
   
   if __name__ == '__main__':
       re_authentication()
   

3. Run the PythonApplication2.py file by using Python. Verify that the output looks similar to this example:

   

   Unlike in the preceding example, if your token expires, the code in this example automatically refreshes the token.

Access key authentication

Get the host name, ports, and access key

To connect to your Azure Cache for Redis server, the cache client needs the cache's host name, ports, and an access key. Some clients might refer to these items by using slightly different names. You can get the host name, ports, and keys in the Azure portal.

• To get an access key for your cache:

  1. In the Azure portal, go to your cache.
  2. On the service menu, under Settings, select Authentication.
  3. On the Authentication pane, select the Access keys tab.
  4. To copy the value for an access key, select the Copy icon in the key field.

  

• To get the host name and ports for your cache:

  1. In the Azure portal, go to your cache.
  2. On the service menu, select Overview.
  3. Under Essentials, for Host name, select the Copy icon to copy the host name value. The host name value has the form <DNS name>.redis.cache.windows.net.
  4. For Ports, select the Copy icon to copy the port values.

  

Read and write to the cache at the command line

To test your cache, run Python from the command line.

1. Initiate the Python interpreter in your command line by entering py.

2. Modify and then run the following code.

   In the code, replace <Your Host Name> and <Your Access Key> with the values from your Azure Cache for Redis instance. Your host name has the form <DNS name>.redis.cache.windows.net.

   >>> import redis
   >>> r = redis.Redis(host='<Your Host Name>',
           port=6380, db=0, password='<Your Access Key>', ssl=True)
   >>> r.set('foo', 'bar')
   True
   >>> r.get('foo')
   b'bar'
   

Create a Python script by using access keys

1. Create a new text file. Save the file as PythonApplication1.py.

2. In PythonApplication1.py, add and modify the following script.

   In the script:

   • Replace <Your Host Name> with the value from your Azure Cache for Redis instance. Your host name has the form <DNS name>.redis.cache.windows.net.
   • Replace <Your Access Key> with the value for your Microsoft Entra ID user.

   import redis
   
   myHostname = "<Your Host Name>"
   myPassword = "<Your Access Key>"
   
   r = redis.Redis(host=myHostname, port=6380,
                         password=myPassword, ssl=True)
   
   result = r.ping()
   print("Ping returned : " + str(result))
   
   result = r.set("Message", "Hello!, The cache is working with Python!")
   print("SET Message returned : " + str(result))
   
   result = r.get("Message")
   print("GET Message returned : " + result)
   
   result = r.client_list()
   print("CLIENT LIST returned : ")
   for c in result:
       print(f"id : {c['id']}, addr : {c['addr']}")
   

3. Run the PythonApplication1.py file by using Python. Verify that results like the following example appear as output:

   

Clean up resources

If you want to continue to use the resources you created in this article, keep the resource group.

Otherwise, to avoid charges related to the resources, if you're finished using the resources, you can delete the Azure resource group that you created.

Warning

Deleting a resource group is irreversible. When you delete a resource group, all the resources in the resource group are permanently deleted. Make sure that you do not accidentally delete the wrong resource group or resources. If you created the resources inside an existing resource group that has resources you want to keep, you can delete each resource individually instead of deleting the resource group.

Delete a resource group

1. Sign in to the Azure portal, and then select Resource groups.

2. Select the resource group to delete.

   If there are many resource groups, in Filter for any field, enter the name of the resource group you created to complete this article. In the list of search results, select the resource group.

   

3. Select Delete resource group.

4. In the Delete a resource group pane, enter the name of your resource group to confirm, and then select Delete.

   

Within a few moments, the resource group and all of its resources are deleted.

Related content

• Create a ASP.NET web app that uses Azure Cache for Redis