Azure Event Hubs Developer's Guide

Authentication Methods

Securing your Azure Event Hubs is critical for protecting your data. Event Hubs supports several authentication mechanisms to control access to your namespaces and entities.

1. Shared Access Signatures (SAS)

Shared Access Signatures provide a way to grant limited access rights to Event Hubs resources. You can create SAS tokens with specific permissions (Send, Listen, Manage) and a defined expiry time.

SAS Token Generation

SAS tokens are typically generated using the SharedAccessKey associated with a shared access policy. This key should be kept confidential.

The token is constructed as a URI-encoded string.

Example Structure:

sr=&sig=&se=&skn=
  • sr: The URI-escaped resource URI.
  • sig: URI-escaped Base64-encoded HMAC-SHA256 hash of the string-to-sign.
  • se: Expiration time in ISO 8601 format.
  • skn: The name of the shared access policy.

Using SAS with Client Libraries (Conceptual)

When using Azure SDKs, you often provide the connection string which includes the SAS key and policy name, or you can construct the token manually.

// Conceptual C# example (actual implementation may vary by SDK version)
var credentials = new AzureSasCredential("");
var producer = new EventHubProducerClient("", "", credentials);
// ... send events ...

2. Azure Active Directory (Azure AD) Integration

For more robust security and centralized identity management, Event Hubs integrates with Azure Active Directory. This allows you to use Azure AD identities (users, groups, service principals) to authenticate.

Service Principals

Service principals are identities for applications. You can create a service principal in Azure AD and assign it appropriate roles (e.g., Azure Event Hubs Data Sender, Azure Event Hubs Data Receiver) on your Event Hubs namespace.

Obtaining Credentials for Azure AD

You'll need credentials like client ID, client secret (for service principals), or certificate to authenticate with Azure AD.

# Conceptual Python example
from azure.identity import ClientSecretCredential
from azure.eventhub import EventHubProducerClient

credential = ClientSecretCredential(
    tenant_id="",
    client_id="",
    client_secret=""
)

producer = EventHubProducerClient(
    fully_qualified_namespace="",
    event_hub_path="",
    credential=credential
)
# ... send events ...

3. Managed Identities

Managed identities provide an Azure AD identity for Azure resources (like Virtual Machines, App Services, Azure Functions) to use when connecting to Event Hubs. This eliminates the need to manage credentials within your application code.

Enabling Managed Identity

Enable a system-assigned or user-assigned managed identity for your Azure resource. Then, grant this managed identity the necessary Azure Event Hubs roles on your namespace.

Using Managed Identity with Client Libraries (Conceptual)

// Conceptual JavaScript example
import { DefaultAzureCredential } from "@azure/identity";
import { EventHubProducerClient } from "@azure/event-hubs";

const credential = new DefaultAzureCredential();

const producer = new EventHubProducerClient(
    "",
    "",
    credential
);
// ... send events ...

Best Practices