Flexible HTTP Client Design Strategy for MSA Environments

In an MSA environment, HTTP communication for inter-service interaction is essential, and flexible handling of failure scenarios in particular determines system stability.

The three key factors to consider for effective design are as follows.

• Flexible handling based on business requirements: Beyond simply throwing exceptions or returning null, sufficient context information must be provided so that the caller can establish a concrete error handling strategy.
• Minimizing impact in preparation for library replacement: Directly returning a specific library's type, such as RestTemplate's ResponseEntity, increases the cost of replacement. Dependencies should be managed inside the communication module to block impact on the outside.
• Error propagation in MSA environments: Errors that occur during a call flow in a distributed environment must be accurately propagated back to the original caller. Simply using a Triple object or similar to convey the status code and response can be unintuitive and make null handling tricky.