Azure Event Hubs is a highly scalable data streaming platform and event ingestion service. It can capture, transform, and store millions of events per second. The data sent to an Event Hub can be processed by numerous applications and data processing frameworks, such as stream analytics and big data analytics services.
Understanding the following core concepts is crucial when working with Azure Event Hubs:
An event is a lightweight record of something that happened in the system. It represents a fact about the business domain. It can be any type of data, such as a customer making a purchase, a sensor reading, or a server log entry.
Event producers are applications or services that send (publish) events to an Event Hub. These can be web servers, IoT devices, application logs, or any source generating data streams.
Event consumers are applications or services that read (subscribe to) events from an Event Hub. Consumers can process events in real-time or in batches. Multiple consumers can process the same events independently.
An Event Hub namespace is a logical container for Event Hubs. It provides a unique DNS name for the Event Hubs endpoint. A namespace is required to send or receive from any Event Hub. A namespace can contain multiple Event Hubs.
An Event Hub is the central entity within an Event Hubs namespace. It's a named collection of event data. Producers send events to a specific Event Hub, and consumers read events from it. Each Event Hub is a partitioned stream.
Partitions are the fundamental unit of parallelism in Event Hubs. An Event Hub is composed of one or more partitions. Each partition is an ordered, immutable sequence of events. Event Hubs guarantees that events sent with the same partition key are stored and delivered to the same partition. This ensures ordering for events with the same key.
Choosing an appropriate partitioning strategy is critical for load balancing and maintaining order. If ordering is important for all events, a single partition might be used. For high throughput and parallel processing, multiple partitions are recommended. Producers can specify a partition ID or a partition key to direct events to specific partitions.
Consumer groups allow multiple applications to read from an Event Hub independently and at their own pace. Each consumer group maintains its own offset within each partition. This means that different applications can process the same stream of events without interfering with each other. Every Event Hub has a default consumer group named $Default.
Imagine a scenario where you have a single Event Hub capturing website clickstream data. You could have one consumer group processing the data for real-time analytics, another consumer group archiving the data to a data lake, and a third consumer group processing the data for A/B testing. Each consumer group would read the data from the beginning (or from a specified offset) and process it according to its own logic.
Azure Event Hubs is ideal for a wide range of scenarios:
To start using Azure Event Hubs:
You can use various SDKs and protocols (like AMQP or Kafka) to interact with Event Hubs.
For more detailed information and tutorials, please refer to the Azure Event Hubs Tutorials.