JSPM

Azure Identity client library for JavaScript

This library simplifies authentication against Azure Active Directory for Azure SDK libraries. It provides a set of TokenCredential implementations which can be passed into SDK libraries to authenticate API requests. It supports token authentication using an Azure Active Directory service principal or managed identity.

Getting started

Prerequisites

• Node.js 8 LTS or higher
• An Azure subscription.
  • You can sign up for a free account.
• The Azure CLI can also be useful for authenticating in a development environment, creating accounts, and managing account roles.

Authenticating via Visual Studio Code

Developers using Visual Studio Code can use the Azure Account Extension, to authenticate via the IDE. Applications using the DefaultAzureCredential or the VisualStudioCodeCredential can then use this account to authenticate calls in their application when running locally.

To authenticate in Visual Studio Code, first ensure the Azure Account Extension is installed. Once the extension is installed, press F1 to open the command palette and run the Azure: Sign In command.

Authenticating via the Azure CLI

Applications using the AzureCliCredential, rather directly or via the DefaultAzureCredential, can use the Azure CLI account to authenticate calls in the application when running locally.

To authenticate with the Azure CLI users can run the command az login. For users running on a system with a default web browser the azure cli will launch the browser to authenticate the user.

For systems without a default web browser, the az login command will use the device code authentication flow. The user can also force the Azure ClI to use the device code flow rather than launching a browser by specifying the --use-device-code argument.

Install the package

Install Azure Identity with npm:

npm install --save @azure/identity

Key concepts

If this is your first time using @azure/identity or the Microsoft identity platform (Azure Active Directory), we recommend that you read Using @azure/identity with Microsoft Identity Platform first. This document will give you a deeper understanding of the platform and how to configure your Azure account correctly.

Credentials

A credential is a class which contains or can obtain the data needed for a service client to authenticate requests. Service clients across Azure SDK accept credentials when they are constructed, and service clients use those credentials to authenticate requests to the service.

The Azure Identity library focuses on OAuth authentication with Azure Active directory, and it offers a variety of credential classes capable of acquiring an AAD token to authenticate service requests. All of the credential classes in this library are implementations of the TokenCredential abstract class, and any of them can be used by to construct service clients capable of authenticating with a TokenCredential.

See Credential Classes.

DefaultAzureCredential

The DefaultAzureCredential is appropriate for most scenarios where the application is intended to ultimately be run in the Azure Cloud. This is because the DefaultAzureCredential combines credentials commonly used to authenticate when deployed, with credentials used to authenticate in a development environment. The DefaultAzureCredential will attempt to authenticate via the following mechanisms in order.

• Environment - The DefaultAzureCredential will read account information specified via environment variables and use it to authenticate.
• Managed Identity - If the application is deployed to an Azure host with Managed Identity enabled, the DefaultAzureCredential will authenticate with that account.
• Visual Studio Code - If the developer has authenticated via the Visual Studio Code Azure Account plugin, the DefaultAzureCredential will authenticate with that account.
• Azure CLI - If the developer has authenticated an account via the Azure CLI az login command, the DefaultAzureCredential will authenticate with that account.

Environment variables

DefaultAzureCredential and EnvironmentCredential are configured for service principal authentication with these environment variables:

Examples

Authenticating with the DefaultAzureCredential

This example demonstrates authenticating the KeyClient from the @azure/keyvault-keys client library using the DefaultAzureCredential.

// The default credential first checks environment variables for configuration as described above.
// If environment configuration is incomplete, it will try managed identity.
const { KeyClient } = require("@azure/keyvault-keys");
const { DefaultAzureCredential } = require("@azure/identity");

// Azure SDK clients accept the credential as a parameter
const credential = new DefaultAzureCredential();
const client = new KeyClient(vaultUrl, credential);
const getResult = await client.getKey("MyKeyName");

Specifying a user assigned managed identity with the DefaultAzureCredential

Many Azure hosts allow the assignment of a user assigned managed identity. This example demonstrates configuring the DefaultAzureCredential to authenticate a user assigned identity when deployed to an azure host. It then authenticates a KeyClient from the @azure/keyvault-keys client library with credential.

const { KeyClient } = require("@azure/keyvault-keys");
const { DefaultAzureCredential } = require("@azure/identity");

// when deployed to an azure host the default azure credential will authenticate the specified user assigned managed identity
var credential = new DefaultAzureCredential({ managedIdentityClientId: userAssignedClientId });

const client = new KeyClient(vaultUrl, credential);

Define a custom authentication flow with the ChainedTokenCredential

While the DefaultAzureCredential is generally the quickest way to get started developing applications for Azure, more advanced users may want to customize the credentials considered when authenticating. The ChainedTokenCredential enables users to combine multiple credential instances to define a customized chain of credentials. This example demonstrates creating a ChainedTokenCredential which will attempt to authenticate using two differently configured instances of ClientSecretCredential, to then authenticate the KeyClient from the @azure/keyvault-keys:

const { ClientSecretCredential, ChainedTokenCredential } = require("@azure/identity");

// When an access token is requested, the chain will try each
// credential in order, stopping when one provides a token
const firstCredential = new ClientSecretCredential(tenantId, clientId, clientSecret);
const secondCredential = new ClientSecretCredential(tenantId, anotherClientId, anotherSecret);
const credentialChain = new ChainedTokenCredential(firstCredential, secondCredential);

// The chain can be used anywhere a credential is required
const { KeyClient } = require("@azure/keyvault-keys");
const client = new KeyClient(vaultUrl, credentialChain);

Credential Classes

Authenticating Azure Hosted Applications

Authenticating Service Principals

Authenticating Users

Authenticating via Development Tools

Troubleshooting

Error Handling

Credentials raise AuthenticationError when they fail to authenticate. This class has a message field which describes why authentication failed. An AggregateAuthenticationError will be raised by ChainedTokenCredential with an errors field containing an array of errors from each credential in the chain.

Logging

Enabling logging may help uncover useful information about failures. In order to see a log of HTTP requests and responses, set the AZURE_LOG_LEVEL environment variable to info. Alternatively, logging can be enabled at runtime by calling setLogLevel in the @azure/logger:

import { setLogLevel } from "@azure/logger";

setLogLevel("info");

Next steps

Client libraries supporting authentication with Azure Identity

Currently, the following client libraries support authenticating with TokenCredential and the Azure Identity library. You can learn more about their use, and find additional documentation on use of these client libraries along samples with can be found in the links below.

• @azure/event-hubs
• @azure/keyvault-keys
• @azure/keyvault-secrets
• @azure/keyvault-certificates
• @azure/storage-blob
• @azure/storage-queue

Read the documentation

API documentation for this library can be found on our documentation site.

Provide Feedback

If you encounter bugs or have suggestions, please open an issue.

Contributing

If you'd like to contribute to this library, please read the contributing guide to learn more about how to build and test the code.