Data Caching Across Microservices in a Serverless Architecture

Organizations are re-architecting their traditional monolithic applications to incorporate microservices. This helps them gain agility and scalability and accelerate time-to-market for new features.

Each microservice performs a single function. However, a microservice might need to retrieve and process data from multiple disparate sources. These can include data stores, legacy systems, or other shared services deployed on premises in data centers or in the cloud. These scenarios add latency to the microservice response time because multiple real-time calls are required to the backend systems. The latency often ranges from milliseconds to a few seconds depending on size of the data, network bandwidth, and processing logic. In certain scenarios, it makes sense to maintain a cache close to the microservices layer to improve performance by reducing or eliminating the need for the real-time backend calls.

Caches reduce latency and service-to-service communication of microservice architectures. A cache is a high-speed data storage layer that stores a subset of data. When data is requested from a cache, it is delivered faster than if you accessed the data’s primary storage location.

While working with our customers, we have observed use cases where data caching helps reduce latency in the microservices layer. Caching can be implemented in several ways. In this blog post, we discuss a couple of these use cases that customers have built. In both use cases, the microservices layer is created using Serverless on AWS offerings. It requires data from multiple data sources deployed locally in the cloud or on premises. The compute layer is built using AWS Lambda. Though Lambda functions are short-lived, the cached data can be used by subsequent instances of the same microservice to avoid backend calls.

In this use case, the Cache-Aside design pattern is used for lazy loading of frequently accessed data. This means that an object is only cached when it is requested by a consumer, and the respective microservice decides if the object is worth saving.

This use case is typically useful when the microservices layer makes multiple real-time calls to fetch and process data. These calls can be greatly reduced by caching frequently accessed data for a short period of time.

Let’s discuss a real-world scenario. Figure 1 shows a customer portal that provides a list of car loans, their status, and the net outstanding amount for a customer…