23-7-24---Stragler-pattern.md

Strangler Pattern

Inspiration - is derived from Banyan tree - that has roots which grow with support of host tree. but then over time the host is strangled.

How do you migrate a legacy monolithic application to a microservice architecture?

1. Do full-blown cut-over replacement of old to new

OR

2. Gradually create a new system around the edges of the old, letting it grow slowly over several years until the old system is strangled. i.e. One can Modernize a legacy application by incrementally developing a new (strangler) application around the legacy application. and slowly cutting down the older legacy.

Refer for more : https://martinfowler.com/bliki/StranglerFigApplication.html

How to get our stragler running ?

Through EventInterception

Basically there should be a way to get updates on the legacy by tapping into this stream of events.

Example you can intercept the

1. kafka messages
2. DB entries --> DB triggers
3. API built on top of DB
4. DB table initial snapshot --> then monitor updates

Once you've tapped into the event stream, you can then build application functionality in the strangler.

Refer : https://martinfowler.com/bliki/EventInterception.html