Integration Patterns

The Outbox Pattern addresses the challenge of reliably publishing events in a transactional context. When an application modifies its data and needs to publish an event to notify other services, ensuring both operations occur atomically is crucial. Directly publishing events from the application can lead to eventual …

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The Transactional Consumer pattern ensures that messages received from a message broker are processed reliably and atomically. It handles message consumption within a database transaction, allowing for either complete processing of a message batch or a full rollback in case of failure. This prevents partial updates and …

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The Idempotent Receiver is a pattern used in distributed systems to ensure that a receiver can safely reprocess the same message multiple times without causing unintended side effects. This is crucial in scenarios where message delivery is not guaranteed – a message might be retried due to network issues or receiver …

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The Transactional Outbox pattern solves the problem of reliably publishing events in a microservices architecture when an event needs to be triggered as a direct result of a database transaction. It ensures that events are not published if the transaction fails, maintaining data consistency. Instead of directly …

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The Message Bus pattern provides a loosely coupled architecture that facilitates communication between different components (services, modules, applications) within a system. It acts as a central intermediary, allowing publishers to send messages without knowing specifically who the subscribers are, and allowing …

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The Event-Carried State Transfer pattern focuses on transferring state between components using events. Instead of directly exposing and modifying an object’s state, a component publishes an event that contains a complete snapshot of the state to be transferred as a Value Object (or Transfer Object). Another …

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The Open Host Service pattern addresses the need for exposing functionality or data from an internal system (the Host) to external services (the Service) in a controllable and scalable way. It acts as an intermediary, preventing direct access to the Host and offering a standardized interface. This separation of …

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The Conformist pattern focuses on integrating with a pre-existing system or interface, even if that interface is poorly designed or doesn’t fully meet the needs of the integrating component. It prioritizes compatibility and “fitting in” over ideal design principles, often acting as a wrapper or translator to …

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The Adapter Container pattern addresses integration challenges when a client requires a service through a specific interface, but the available service provides a different, incompatible interface. This pattern encapsulates the legacy service within an adapter, translating requests from the client’s interface to the …

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The Aggregator pattern provides a unified interface to a number of disparate subsystems. Instead of a client having to interact with each subsystem directly, it interacts with the aggregator, which then dispatches requests to the appropriate subsystems. The aggregator then combines the results from these subsystems …

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