Strangler Pattern¶

Description¶

The Strangler Pattern is a modernization strategy used to incrementally migrate functionality from a legacy system to a new system. The new system is developed alongside the old one, gradually “strangling” and replacing parts of the legacy system until it can be retired.

How It Works¶

A proxy or routing layer intercepts requests.
New functionality is implemented in the new system.
Requests for migrated features are routed to the new system.
The legacy system is gradually decommissioned.

Advantages¶

Low Risk: Incremental migration reduces the risk of failures.
Continuous Delivery: New features can be delivered iteratively.

Challenges¶

Complexity: Requires careful planning and routing of requests.
Dual Systems: Maintaining both systems during migration increases operational overhead.

Example Use Case¶

An e-commerce platform migrates its monolithic inventory management system to microservices. A routing layer gradually shifts inventory queries to the new microservices while the old system remains operational.