Parallel API Composition in AWS
Publication date: May 17, 2022 (Diagram history)
This architecture shows how to call multiple downstream API endpoints, in parallel or in sequence, to compose a single aggregated response. You build a generic, parameterized circuit-breaker workflow using AWS Step Functions Express Workflows and use command query responsibility segregation (CQRS) to maintain a persistent eventually-consistent cache.
Parallel API Composition in AWS
The following steps describe the architecture:
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Create an API gateway using Amazon API Gateway to allow clients to send synchronous web requests to your microservices.
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Use Step Functions Express Workflows to create a workflow with parallel steps that invoke multiple microservices at the same time.
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Use an AWS Lambda function to compose the multiple responses from downstream microservices into a single aggregated response for clients.
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Handle parallel requests with circuit breakers built with parameterized nested Step Functions Express Workflows to increase resilience.
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Use API Gateway to proxy HTTP requests when invoking on-premises microservices.
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Create an Amazon MemoryDB for Redis database to cache microservice responses using the write-through caching pattern. When a downstream microservice becomes unavailable or its latency reaches a threshold, the circuit closes and reads all responses directly from cache.
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Complement cached data with domain events from downstream microservices using the CQRS pattern. Create an event bus with Amazon EventBridge, then handle events with a Lambda function to persist the domain aggregates in MemoryDB.
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Enable the API Gateway response cache and adjust time-to-live (TTL) values and filters according to each request type to increase performance.
Further reading
For additional information, refer to the following resources:
Diagram history
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| Change | Description | Date |
|---|---|---|
Initial publication | Reference architecture diagram first published. | May 17, 2022 |
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