Transition strategies and the Strangler pattern?

Transition Strategies are approaches to gradually moving from an old system to a new one, minimizing risks and downtime.

Strangler Pattern (Strangler Fig Pattern) is a migration strategy where the new system gradually replaces the old one, surrounding it until the old system is fully displaced.

The idea is not to rewrite the entire system at once, but to gradually redirect functionality to the new implementation. This reduces risks and allows for phased testing of new parts.

Example:

• There is a monolithic application.
• A new service is created that handles part of the functionality.
• Traffic is gradually redirected to the new service.
• The old code is gradually disabled and removed.

In Python projects, this can look like gradual refactoring and microservice extraction, while the old code remains operational until the new part is ready.