This guide describes approaches and best practices for implementing the strangler fig pattern to modernize legacy ASP.NET web services on Amazon Web Services (AWS). The strangler fig pattern is a modernization approach in which the existing functionalities of a legacy system are incrementally replaced with new applications and services until the new system eventually replaces all the old or key parts of the legacy system. As functionality is replaced, the inactive parts of the legacy (and often monolithic) system can be removed or retired.
The guide discusses a modified branch by abstraction approach, which is a common technique for incrementally changing software systems, combined with service delegation, where a service defers its behavior to another, newer service, to help manage breaking changes to service consumers.
