Azure Event Hubs Developers Guide

Best Practices for Azure Event Hubs Development

This guide outlines essential best practices for developing robust, scalable, and cost-effective applications with Azure Event Hubs. Adhering to these practices will help you avoid common pitfalls and maximize the benefits of the service.

1. Event Production

  • Batching: Send events in batches to improve throughput and reduce latency. Event Hubs supports batching up to 1MB.
  • Compression: Utilize compression (e.g., Gzip, Snappy) for large events to reduce bandwidth usage and improve performance.
  • Partitioning Strategy: Choose an effective partitioning key. A good key ensures even distribution of events across partitions, preventing hot spots and enabling parallel processing. Consider using a GUID or a high-cardinality identifier that is relevant to your business logic.
  • Retry Mechanisms: Implement robust retry logic with exponential backoff for transient network errors or throttling.
  • Idempotent Producers: Design your producers to be idempotent if possible, especially when dealing with retries, to avoid duplicate events. Use sequence numbers or unique identifiers for this purpose.
Tip: When batching, ensure your producer client handles the `ServerBusyException` gracefully by backing off and retrying.

2. Event Consumption

  • Offset Management: Carefully manage consumer offsets. For reliable processing, use checkpointing to record the last successfully processed event for each partition within a consumer group.
  • Consumer Group Strategy: Create distinct consumer groups for different applications or processing tasks. This prevents interference between consumers and allows for independent scaling.
  • Parallel Processing: Leverage partitions for parallel processing. Design your consumers to process events from multiple partitions concurrently.
  • Error Handling: Implement comprehensive error handling for message processing. Decide whether to dead-letter problematic messages or retry processing.
  • Resource Management: Ensure your consumers are designed to handle backpressure and gracefully shut down, releasing resources.
  • Connection Management: Reuse connections where possible to reduce overhead.

3. Throughput and Scaling

  • Throughput Units (TUs): Understand your expected throughput and provision an adequate number of Throughput Units (TUs). Monitor usage and scale TUs up or down as needed.
  • Partition Count: The number of partitions directly impacts the maximum scale of your event producers and consumers. Choose a partition count that aligns with your anticipated maximum processing capacity. You cannot increase the partition count after creation without creating a new namespace.
  • Throttling: Be aware of Event Hubs throttling limits. Monitor `IncomingBandwidth` and `OutgoingBandwidth` metrics. If you encounter throttling, consider increasing TUs, optimizing batching, or improving your partitioning strategy.
Important: The maximum number of partitions is fixed at the time of namespace creation. Plan carefully.

4. Schema Management

  • Schema Registry: Use a schema registry (e.g., Azure Schema Registry) to manage event schemas. This ensures data consistency and allows for schema evolution without breaking consumers.
  • Versioning: Implement a clear schema versioning strategy to handle changes over time.

5. Security

  • Managed Identities: Use Managed Identities for Azure resources (e.g., App Services, Functions) to authenticate with Event Hubs without managing credentials.
  • SAS Tokens/Azure AD: If not using Managed Identities, use Shared Access Signature (SAS) tokens or Azure Active Directory (Azure AD) for authentication and authorization. Restrict permissions to the minimum required.
  • Network Security: Configure firewalls, private endpoints, and virtual network rules to restrict network access to your Event Hubs namespace.

6. Monitoring and Diagnostics

  • Key Metrics: Monitor critical metrics such as `Incoming Bandwidth`, `Outgoing Bandwidth`, `Requests`, `UserErrors`, `Incoming Messages`, `Outgoing Messages`, and `Captured Messages`.
  • Diagnostic Logs: Enable diagnostic logs for detailed insights into operations and potential issues.
  • Alerting: Set up alerts for key metrics (e.g., high latency, throttled requests, significant error rates) to proactively address problems.

By integrating these best practices into your development workflow, you can build reliable and efficient event-driven solutions with Azure Event Hubs.