@azure/msal-node
Version:
Microsoft Authentication Library for Node
109 lines (106 loc) • 6.73 kB
JavaScript
/*! @azure/msal-node v5.0.3 2026-01-28 */
;
import { ManagedIdentityRequestParameters } from '../../config/ManagedIdentityRequestParameters.mjs';
import { BaseManagedIdentitySource } from './BaseManagedIdentitySource.mjs';
import { ManagedIdentityEnvironmentVariableNames, ManagedIdentitySourceNames, ManagedIdentityHeaders, ManagedIdentityQueryParameters, ManagedIdentityIdType, HttpMethod } from '../../utils/Constants.mjs';
import { ImdsRetryPolicy } from '../../retry/ImdsRetryPolicy.mjs';
/*
* Copyright (c) Microsoft Corporation. All rights reserved.
* Licensed under the MIT License.
*/
// Documentation for IMDS is available at https://docs.microsoft.com/azure/active-directory/managed-identities-azure-resources/how-to-use-vm-token#get-a-token-using-http
const IMDS_TOKEN_PATH = "/metadata/identity/oauth2/token";
const DEFAULT_IMDS_ENDPOINT = `http://169.254.169.254${IMDS_TOKEN_PATH}`;
const IMDS_API_VERSION = "2018-02-01";
/**
* Managed Identity source implementation for Azure Instance Metadata Service (IMDS).
*
* IMDS is available on Azure Virtual Machines and Virtual Machine Scale Sets and provides
* a REST endpoint to obtain OAuth tokens for managed identities. This implementation
* handles both system-assigned and user-assigned managed identities.
*
* Original source of code: https://github.com/Azure/azure-sdk-for-net/blob/main/sdk/identity/Azure.Identity/src/ImdsManagedIdentitySource.cs
*/
class Imds extends BaseManagedIdentitySource {
/**
* Constructs an Imds instance with the specified configuration.
*
* @param logger - Logger instance for recording debug information and errors
* @param nodeStorage - NodeStorage instance used for token caching operations
* @param networkClient - Network client implementation for making HTTP requests to IMDS
* @param cryptoProvider - CryptoProvider for generating correlation IDs and other cryptographic operations
* @param disableInternalRetries - When true, disables the built-in retry logic for IMDS requests
* @param identityEndpoint - The complete IMDS endpoint URL including the token path
*/
constructor(logger, nodeStorage, networkClient, cryptoProvider, disableInternalRetries, identityEndpoint) {
super(logger, nodeStorage, networkClient, cryptoProvider, disableInternalRetries);
this.identityEndpoint = identityEndpoint;
}
/**
* Creates an Imds instance with the appropriate endpoint configuration.
*
* This method checks for the presence of the AZURE_POD_IDENTITY_AUTHORITY_HOST environment
* variable, which is used in Azure Kubernetes Service (AKS) environments with Azure AD
* Pod Identity. If found, it uses that endpoint; otherwise, it falls back to the standard
* IMDS endpoint (169.254.169.254).
*
* @param logger - Logger instance for recording endpoint discovery and validation
* @param nodeStorage - NodeStorage instance for token caching
* @param networkClient - Network client for HTTP requests
* @param cryptoProvider - CryptoProvider for cryptographic operations
* @param disableInternalRetries - Whether to disable built-in retry logic
*
* @returns A configured Imds instance ready to make token requests
*/
static tryCreate(logger, nodeStorage, networkClient, cryptoProvider, disableInternalRetries) {
let validatedIdentityEndpoint;
if (process.env[ManagedIdentityEnvironmentVariableNames
.AZURE_POD_IDENTITY_AUTHORITY_HOST]) {
logger.info(`[Managed Identity] Environment variable ${ManagedIdentityEnvironmentVariableNames.AZURE_POD_IDENTITY_AUTHORITY_HOST} for ${ManagedIdentitySourceNames.IMDS} returned endpoint: ${process.env[ManagedIdentityEnvironmentVariableNames
.AZURE_POD_IDENTITY_AUTHORITY_HOST]}`, "");
validatedIdentityEndpoint = Imds.getValidatedEnvVariableUrlString(ManagedIdentityEnvironmentVariableNames.AZURE_POD_IDENTITY_AUTHORITY_HOST, `${process.env[ManagedIdentityEnvironmentVariableNames
.AZURE_POD_IDENTITY_AUTHORITY_HOST]}${IMDS_TOKEN_PATH}`, ManagedIdentitySourceNames.IMDS, logger);
}
else {
logger.info(`[Managed Identity] Unable to find ${ManagedIdentityEnvironmentVariableNames.AZURE_POD_IDENTITY_AUTHORITY_HOST} environment variable for ${ManagedIdentitySourceNames.IMDS}, using the default endpoint.`, "");
validatedIdentityEndpoint = DEFAULT_IMDS_ENDPOINT;
}
return new Imds(logger, nodeStorage, networkClient, cryptoProvider, disableInternalRetries, validatedIdentityEndpoint);
}
/**
* Creates a properly configured HTTP request for acquiring an access token from IMDS.
*
* This method builds a complete request object with all necessary headers, query parameters,
* and retry policies required by the Azure Instance Metadata Service.
*
* Key request components:
* - HTTP GET method to the IMDS token endpoint
* - Metadata header set to "true" (required by IMDS)
* - API version parameter (currently "2018-02-01")
* - Resource parameter specifying the target audience
* - Identity-specific parameters for user-assigned managed identities
* - IMDS-specific retry policy
*
* @param resource - The target resource/scope for which to request an access token (e.g., "https://graph.microsoft.com/.default")
* @param managedIdentityId - The managed identity configuration specifying whether to use system-assigned or user-assigned identity
*
* @returns A configured ManagedIdentityRequestParameters object ready for network execution
*/
createRequest(resource, managedIdentityId) {
const request = new ManagedIdentityRequestParameters(HttpMethod.GET, this.identityEndpoint);
request.headers[ManagedIdentityHeaders.METADATA_HEADER_NAME] = "true";
request.queryParameters[ManagedIdentityQueryParameters.API_VERSION] =
IMDS_API_VERSION;
request.queryParameters[ManagedIdentityQueryParameters.RESOURCE] =
resource;
if (managedIdentityId.idType !== ManagedIdentityIdType.SYSTEM_ASSIGNED) {
request.queryParameters[this.getManagedIdentityUserAssignedIdQueryParameterKey(managedIdentityId.idType, true // indicates source is IMDS
)] = managedIdentityId.id;
}
// The bodyParameters are calculated in BaseManagedIdentity.acquireTokenWithManagedIdentity.
request.retryPolicy = new ImdsRetryPolicy();
return request;
}
}
export { Imds };
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