Solution Idea
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This solution idea shows a variation of a serverless event-driven architecture using Azure Event Hubs and Azure Functions to ingest and process a stream of data. Once de-batched and filtered, the results are written to a database for storage and future review.
To learn more about the basic concepts, considerations, and approaches for serverless event processing, consult the Serverless event processing reference architecture.
Potential use cases
A popular use case for implementing an end-to-end event stream processing pattern includes the Event Hubs streaming ingestion service to receive and process events per second using a de-batching and transformation logic implemented with highly scalable, event hub–triggered functions.
Architecture

- Events arrive at the Input Event Hub.
- The De-batching and Filtering Azure Function is triggered to handle the event. This step filters out unwanted events and de-batches the received events before submitting them to the Output Event Hub.
- If the De-batching and Filtering Azure Function fails to store the event successfully, the event is submitted to the Deadletter Event Hub 1.
- Events arriving at the Output Event Hub trigger the Transforming Azure Function. This Azure Function transforms the event into a message for the Cosmos DB.
- The event is stored in a Cosmos DB database.
- If the Transforming Azure Function fails to store the event successfully, the event is saved to the Deadletter Event Hub 2.
Components
- Event Hubs ingests the data stream. Event Hubs is designed for high-throughput data streaming scenarios.
- Azure Functions is a serverless compute option. It uses an event-driven model, where a piece of code (a function) is invoked by a trigger.
- Azure Cosmos DB is a multi-model database service that is available in a serverless, consumption-based mode. For this scenario, the event-processing function stores JSON records, using the Cosmos DB SQL API.
Next steps
- Serverless event processing is a reference architecture detailing a typical architecture of this type, with code samples and discussion of important considerations.
- Monitoring serverless event processing provides an overview and guidance on monitoring serverless event-driven architectures like this one.
- Azure Kubernetes in event stream processing describes a variation of a serverless event-driven architecture running on Azure Kubernetes with KEDA scaler.
- Private link scenario in event stream processing is a solution idea for implementing a similar architecture in a virtual network (VNet) with private endpoints, in order to enhance security.