Quickstart: Azure Key Vault certificate client library for JavaScript

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Get started with the Azure Key Vault certificate client library for JavaScript. Azure Key Vault is a cloud service that provides a secure store for certificates. You can securely store keys, passwords, certificates, and other secrets. Azure key vaults may be created and managed through the Azure portal. In this quickstart, you learn how to create, retrieve, and delete certificates from an Azure key vault using the JavaScript client library.

Key Vault client library resources:

API reference documentation | Library source code | Package (npm)

For more information about Key Vault and certificates, see:

Prerequisites

This quickstart assumes you're running Azure CLI.

Sign in to Azure

  1. Run the login command.

    az cloud set -n AzureChinaCloud
az login
# az cloud set -n AzureCloud   //means return to Public Azure.

    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/deviceloginchina and enter the authorization code displayed in your terminal.

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

Create new Node.js application

Create a Node.js application that uses your key vault.

  1. In a terminal, create a folder named key-vault-node-app and change into that folder:

    mkdir key-vault-node-app && cd key-vault-node-app

  2. Initialize the Node.js project:

    npm init -y

Install Key Vault packages

  1. Using the terminal, install the Azure Key Vault secrets library, @azure/keyvault-certificates for Node.js.

    npm install @azure/keyvault-certificates

  2. Install the Azure Identity client library, @azure/identity, to authenticate to a Key Vault.

    npm install @azure/identity

Grant access to your key vault

To grant your application permissions to your key vault through Role-Based Access Control (RBAC), assign a role using the Azure CLI command az role assignment create.

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

Replace <app-id>, <subscription-id>, <resource-group-name> and <your-unique-keyvault-name> with your actual values. <app-id> is the Application (client) ID of your registered application in Azure Entra.

Set environment variables

This application is using key vault endpoint as an environment variable called KEY_VAULT_URL.

set KEY_VAULT_URL=<your-key-vault-endpoint>

Authenticate and create a client

Application requests to most Azure services must be authorized. Using the DefaultAzureCredential method 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 this code, the endpoint of your key vault is used to create the key vault client. The endpoint format looks like https://<your-key-vault-name>.vault.azure.cn but may change for sovereign clouds. For more information about authenticating to key vault, see Developer's Guide.

Code example

This code uses the following Key Vault Certificate classes and methods:

Set up the app framework

  • Create new text file and paste the following code into the index.js file.

    const { CertificateClient, DefaultCertificatePolicy } = require("@azure/keyvault-certificates");
const { DefaultAzureCredential } = require("@azure/identity");

async function main() {
  // If you're using MSI, DefaultAzureCredential should "just work".
  // Otherwise, DefaultAzureCredential expects the following three environment variables:
  // - AZURE_TENANT_ID: The tenant ID in Microsoft Entra ID
  // - AZURE_CLIENT_ID: The application (client) ID registered in the AAD tenant
  // - AZURE_CLIENT_SECRET: The client secret for the registered application
  const credential = new DefaultAzureCredential();

  const keyVaultUrl = process.env["KEY_VAULT_URL"];
  if(!keyVaultUrl) throw new Error("KEY_VAULT_URL is empty");

  const client = new CertificateClient(keyVaultUrl, credential);

  const uniqueString = new Date().getTime();
  const certificateName = `cert${uniqueString}`;

  // Creating a self-signed certificate
  const createPoller = await client.beginCreateCertificate(
    certificateName,
    DefaultCertificatePolicy
  );

  const pendingCertificate = createPoller.getResult();
  console.log("Certificate: ", pendingCertificate);

  // To read a certificate with their policy:
  let certificateWithPolicy = await client.getCertificate(certificateName);
  // Note: It will always read the latest version of the certificate.

  console.log("Certificate with policy:", certificateWithPolicy);

  // To read a certificate from a specific version:
  const certificateFromVersion = await client.getCertificateVersion(
    certificateName,
    certificateWithPolicy.properties.version
  );
  // Note: It will not retrieve the certificate's policy.
  console.log("Certificate from a specific version:", certificateFromVersion);

  const updatedCertificate = await client.updateCertificateProperties(certificateName, "", {
    tags: {
      customTag: "value"
    }
  });
  console.log("Updated certificate:", updatedCertificate);

  // Updating the certificate's policy:
  await client.updateCertificatePolicy(certificateName, {
    issuerName: "Self",
    subject: "cn=MyOtherCert"
  });
  certificateWithPolicy = await client.getCertificate(certificateName);
  console.log("updatedCertificate certificate's policy:", certificateWithPolicy.policy);

  // delete certificate
  const deletePoller = await client.beginDeleteCertificate(certificateName);
  const deletedCertificate = await deletePoller.pollUntilDone();
  console.log("Recovery Id: ", deletedCertificate.recoveryId);
  console.log("Deleted Date: ", deletedCertificate.deletedOn);
  console.log("Scheduled Purge Date: ", deletedCertificate.scheduledPurgeDate);
}

main().catch((error) => {
  console.error("An error occurred:", error);
  process.exit(1);
});

Run the sample application

  1. Run the app:

    node index.js

  2. The create and get methods return a full JSON object for the certificate:

    {
  "keyId": undefined,
  "secretId": undefined,
  "name": "YOUR-CERTIFICATE-NAME",
    "reuseKey": false,
    "keyCurveName": undefined,
    "exportable": true,
    "issuerName": 'Self',
    "certificateType": undefined,
    "certificateTransparency": undefined
  },
  "properties": {
    "createdOn": 2021-11-29T20:17:45.000Z,
    "updatedOn": 2021-11-29T20:17:45.000Z,
    "expiresOn": 2022-11-29T20:17:45.000Z,
    "id": "https://YOUR-KEY-VAULT-NAME.vault.azure.cn/certificates/YOUR-CERTIFICATE-NAME/YOUR-CERTIFICATE-VERSION",
    "enabled": false,
    "notBefore": 2021-11-29T20:07:45.000Z,
    "recoveryLevel": "Recoverable+Purgeable",
    "name": "YOUR-CERTIFICATE-NAME",
    "vaultUrl": "https://YOUR-KEY-VAULT-NAME.vault.azure.cn",
    "version": "YOUR-CERTIFICATE-VERSION",
    "tags": undefined,
    "x509Thumbprint": undefined,
    "recoverableDays": 90
  }
}

Integrating with App Configuration

The Azure SDK provides a helper method, parseKeyVaultCertificateIdentifier, to parse the given Key Vault certificate ID. This is necessary if you use App Configuration references to Key Vault. App Config stores the Key Vault certificate ID. You need the parseKeyVaultCertificateIdentifier method to parse that ID to get the certificate name. Once you have the certificate name, you can get the current certificate using code from this quickstart.

Next steps

In this quickstart, you created a key vault, stored a certificate, and retrieved that certificate. To learn more about Key Vault and how to integrate it with your applications, continue on to these articles.