Modernise search before replacing the whole system

Identify the business reason

If finding orders makes work difficult, a bounded modernisation may make sense. It need not replace every other function at the same time. Microsoft describes gradually replacing individual functions with the Strangler Fig pattern. This implies neither a requirement for microservices nor a general recommendation to retain the old system indefinitely.

Fowler argues that desired outcomes and suitable seams should shape the approach. Agree with business owners which search rules should apply. Existing behaviour may contain important rules as well as defects.

Example: a customer portal with new search

This example is entirely fictional. A portal aims to make orders easier to find; editing remains in the existing core. The split is a proposal, not an implemented or measured improvement.

The new search does not write order data. Its index is a derived view, not a second authoritative source. A new search service guarantees neither faster responses nor current results. Define how update failures are detected and resolved and when results become too stale to display.

Include the transition effort

Operating both parts needs ownership, monitoring and maintenance of the connection. OWASP requires permission checks on every request. A protected detail screen is insufficient if a result has already disclosed a confidential title. The new search must reliably account for current rights.

First route clearly selected search calls and check agreed results and error cases. Returning to the old search requires it to remain available, compatible and suitable for that use. If a reliable boundary for data, rights and updates cannot be established, this split is not viable. If the entire old core must be retired soon, a broader replacement plan is needed.

Sources

• Microsoft · Strangler Fig pattern

• Martin Fowler · Strangler Fig Application

• OWASP · Authorization Cheat Sheet