Dissecting the Strangler pattern

The overarching theme of this book is that we want to move fast, but we do not want to break things. This applies to our legacy systems as well. Our legacy architectures may impede change, but these systems provide valuable capabilities to our end users that they rely on every day. We must ensure that our legacy systems continue to work.

However, we do need to modernize our legacy systems, and they are filled with a lot of functionality. This means that if we follow a traditional approach, then it will take a long time to port the functionality, and in the meantime, the teams will not deliver any new business value. And when the time comes to cut over from the old system to the new system, this traditional all-or-nothing approach will put everything at risk. There is just too much risk to justify using the traditional approach.

Instead, we will build up new features and replacement features around the existing systems and integrate them. Slowly...