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Cross-cutting Concepts Flashcards

7 cards from real CPSA practice questions. Tap to flip, then mark Knew It or Still Learning โ€” missed cards come back until you master them.

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  1. Which pattern provides a single, reusable implementation of a cross-cutting concern (e.g., retry logic) that is injected into multiple services without code duplication?

    Answer: Sidecar / proxy pattern

    The sidecar pattern deploys a co-located proxy that transparently handles cross-cutting concerns like retries, mTLS, and circuit breaking for the main service.

  2. In CPSA terms, which quality attribute is directly addressed by implementing a circuit breaker as a cross-cutting mechanism?

    Answer: Resilience / fault tolerance

    A circuit breaker prevents cascading failures by stopping calls to a failing dependency, directly improving fault tolerance and system resilience.

  3. Which approach best handles idempotency as a cross-cutting concern for HTTP POST endpoints?

    Answer: Accepting a client-generated idempotency key and deduplicating on the server

    An idempotency key lets the server detect and suppress duplicate requests, ensuring retried POSTs do not create duplicate effects.

  4. A CPSA candidate is reviewing an architecture where transaction boundaries span multiple services. Which cross-cutting pattern manages eventual consistency without distributed locking?

    Answer: Saga pattern with compensating transactions

    The Saga pattern decomposes a distributed transaction into a sequence of local transactions with compensating actions, achieving eventual consistency without 2PC overhead.

  5. Which cross-cutting technique allows teams to release new features to a subset of users without changing code between deployments?

    Answer: Feature toggles (feature flags)

    Feature toggles let you switch functionality on or off at runtime for specific user segments without deploying new code.

  6. When securing inter-service communication in a microservices system, which cross-cutting mechanism provides mutual authentication at the transport layer?

    Answer: Mutual TLS (mTLS)

    mTLS requires both client and server to present certificates, ensuring that only authenticated services can communicate with each other.

  7. Which architectural decision treats caching as a cross-cutting concern rather than embedding cache logic in each service?

    Answer: Using a shared caching layer (e.g., Redis) accessed via a common library or proxy

    A shared caching layer with a common access abstraction centralizes cache management and prevents duplicated, inconsistent caching logic across services.