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Quickstart: Azure Key Vault certificate client library for Python

  • Artikkeli

Get started with the Azure Key Vault certificate client library for Python. Follow these steps to install the package and try out example code for basic tasks. By using Key Vault to store certificates, you avoid storing certificates in your code, which increases the security of your app.

API reference documentation | Library source code | Package (Python Package Index)

Prerequisites

This quickstart assumes you're running Azure CLI or Azure PowerShell in a Linux terminal window.

Set up your local environment

This quickstart uses the Azure Identity library with Azure CLI or Azure PowerShell to authenticate the user to Azure services. Developers can also use Visual Studio or Visual Studio Code to authenticate their calls. For more information, see Authenticate the client with Azure Identity client library.

Sign in to Azure

  1. Run the login command.

    az login

    If the CLI can open your default browser, it will do so and load an Azure sign-in page.

    Otherwise, open a browser page at https://aka.ms/devicelogin and enter the authorization code displayed in your terminal.

  2. Sign in with your account credentials in the browser.

Install the packages

  1. In a terminal or command prompt, create a suitable project folder, and then create and activate a Python virtual environment as described on Use Python virtual environments

  2. Install the Microsoft Entra identity library:

    pip install azure.identity

  3. Install the Key Vault certificate client library:

    pip install azure-keyvault-certificates

Create a resource group and key vault

  1. Use the az group create command to create a resource group:

    az group create --name myResourceGroup --location eastus

    You can change "eastus" to a location nearer to you, if you prefer.

  2. Use az keyvault create to create the key vault:

    az keyvault create --name <your-unique-keyvault-name> --resource-group myResourceGroup

    Replace <your-unique-keyvault-name> with a name that's unique across all of Azure. You typically use your personal or company name along with other numbers and identifiers.

Set the KEY_VAULT_NAME environmental variable

Our script will use the value assigned to the KEY_VAULT_NAME environment variable as the name of the key vault. You must therefore set this value using the following command:

export KEY_VAULT_NAME=<your-unique-keyvault-name>

Grant access to your key vault

To gain permissions to your key vault through Role-Based Access Control (RBAC), assign a role to your "User Principal Name" (UPN) using the Azure CLI command az role assignment create.

az role assignment create --role "Key Vault Certificate Officer" --assignee "<upn>" --scope "/subscriptions/<subscription-id>/resourceGroups/<resource-group-name>/providers/Microsoft.KeyVault/vaults/<your-unique-keyvault-name>"

Replace <upn>, <subscription-id>, <resource-group-name> and <your-unique-keyvault-name> with your actual values. Your UPN will typically be in the format of an email address (e.g., username@domain.com).

Create the sample code

The Azure Key Vault certificate client library for Python allows you to manage certificates. The following code sample demonstrates how to create a client, set a certificate, retrieve a certificate, and delete a certificate.

Create a file named kv_certificates.py that contains this code.

import os
from azure.keyvault.certificates import CertificateClient, CertificatePolicy
from azure.identity import DefaultAzureCredential

keyVaultName = os.environ["KEY_VAULT_NAME"]
KVUri = "https://" + keyVaultName + ".vault.azure.net"

credential = DefaultAzureCredential()
client = CertificateClient(vault_url=KVUri, credential=credential)

certificateName = input("Input a name for your certificate > ")

print(f"Creating a certificate in {keyVaultName} called '{certificateName}' ...")

policy = CertificatePolicy.get_default()
poller = client.begin_create_certificate(certificate_name=certificateName, policy=policy)
certificate = poller.result()

print(" done.")

print(f"Retrieving your certificate from {keyVaultName}.")

retrieved_certificate = client.get_certificate(certificateName)

print(f"Certificate with name '{retrieved_certificate.name}' was found'.")
print(f"Deleting your certificate from {keyVaultName} ...")

poller = client.begin_delete_certificate(certificateName)
deleted_certificate = poller.result()

print(" done.")

Run the code

Make sure the code in the previous section is in a file named kv_certificates.py. Then run the code with the following command:

python kv_certificates.py

Code details

Authenticate and create a client

Application requests to most Azure services must be authorized. Using the DefaultAzureCredential class provided by the Azure Identity client library is the recommended approach for implementing passwordless connections to Azure services in your code. DefaultAzureCredential supports multiple authentication methods and determines which method should be used at runtime. This approach enables your app to use different authentication methods in different environments (local vs. production) without implementing environment-specific code.

In this quickstart, DefaultAzureCredential authenticates to key vault using the credentials of the local development user logged into the Azure CLI. When the application is deployed to Azure, the same DefaultAzureCredential code can automatically discover and use a managed identity that is assigned to an App Service, Virtual Machine, or other services. For more information, see Managed Identity Overview.

In the example code, the name of your key vault is expanded to the key vault URI, in the format https://\<your-key-vault-name>.vault.azure.net.

credential = DefaultAzureCredential()
client = CertificateClient(vault_url=KVUri, credential=credential)

Save a certificate

Once you've obtained the client object for the key vault, you can create a certificate using the begin_create_certificate method:

policy = CertificatePolicy.get_default()
poller = client.begin_create_certificate(certificate_name=certificateName, policy=policy)
certificate = poller.result()

Here, the certificate requires a policy obtained with the CertificatePolicy.get_default method.

Calling a begin_create_certificate method generates an asynchronous call to the Azure REST API for the key vault. The asynchronous call returns a poller object. To wait for the result of the operation, call the poller's result method.

When Azure handles the request, it authenticates the caller's identity (the service principal) using the credential object you provided to the client.

Retrieve a certificate

To read a certificate from Key Vault, use the get_certificate method:

retrieved_certificate = client.get_certificate(certificateName)

You can also verify that the certificate has been set with the Azure CLI command az keyvault certificate show or the Azure PowerShell cmdlet Get-AzKeyVaultCertificate

Delete a certificate

To delete a certificate, use the begin_delete_certificate method:

poller = client.begin_delete_certificate(certificateName)
deleted_certificate = poller.result()

The begin_delete_certificate method is asynchronous and returns a poller object. Calling the poller's result method waits for its completion.

You can verify that the certificate is deleted with the Azure CLI command az keyvault certificate show or the Azure PowerShell cmdlet Get-AzKeyVaultCertificate.

Once deleted, a certificate remains in a deleted but recoverable state for a time. If you run the code again, use a different certificate name.

Clean up resources

If you want to also experiment with secrets and keys, you can reuse the Key Vault created in this article.

Otherwise, when you're finished with the resources created in this article, use the following command to delete the resource group and all its contained resources:

az group delete --resource-group myResourceGroup

Next steps