This trace follows the actual state transitions behind the companion Choosing an Architecture Style From Constraints. It describes a common execution path; implementation details can vary, so keep the contract separate from the mechanism.
Step 1: Describe workload and ownership
An architecture style shapes how components communicate, deploy, and fail. A modular monolith can preserve one deployment unit while enforcing code-level boundaries. Services add independent deployment and scaling but also require network contracts, operations, and failure handling.
Step 2: Set the deployment boundary
A small team with one release cadence may benefit from a monolith whose internal modules have explicit interfaces. A high-volume subsystem with a distinct scaling profile may justify extraction once measurement shows deployment or resource isolation is valuable. The decision should account for team ownership as well as runtime behavior.
Step 3: Choose local or remote calls
Extracting a module into a service changes a local call into a network interaction; include timeout, data ownership, deployment, and on-call costs in the choice.
At this point, record the state that changed and check the invariant before advancing. If the operation repeats, make clear which values persist and which are recomputed.
Step 4: Account for failure behavior
Microservices turn local calls into remote interactions with timeouts, partial failure, data ownership, and observability requirements. A monolith can still have poor boundaries, and splitting it does not repair them automatically. Architecture should follow constraints that exist, not scale imagined for later.
Step 5: Revisit with operating evidence
Your team proposes extracting search into a service. List the evidence that would justify the operational cost and the data ownership boundary the new service would need.
The trace is complete when the result satisfies the stated contract. Compare this model with the concrete runtime or system you are studying before making a performance claim.