Patterns

Shared Kernel

The Shared Kernel pattern addresses the challenge of integrating two or more distinct bounded contexts in Domain-Driven Design. It arises when a small, well-defined part of the domain model is inherently shared and crucial to the operation of multiple contexts. Instead of duplicating this logic (leading to …

Aggregate

DDD behavioral

The Aggregate pattern is a core concept in Domain-Driven Design (DDD). It defines a cluster of domain objects (Entities and Value Objects) that are treated as a single unit. This unit is responsible for maintaining data consistency within its boundaries and presenting a cohesive interface to the outside world. An …

API Gateway

architectural integration microservices

The API Gateway pattern provides a single entry point for all clients accessing a set of backend services. It sits in front of these services, abstracting their complexity and providing features like request routing, composition, transformation, and authentication. This simplifies client development, improves security, …

Circuit Breaker

behavioral resilience

The Circuit Breaker pattern protects a system from repeated failures of a dependent service. It monitors calls to the dependency and, upon observing a certain failure rate, “opens the circuit” to prevent further requests from being sent. This allows the dependent service to recover without being …

Content-Based Router

behavioral integration

The Content-Based Router pattern dynamically routes messages to different recipients or endpoints based on the content of the message itself. Unlike address-based routing which uses a header field to determine the destination, content-based routing examines the message body, properties, or payload to make a routing …

Defense in Depth

security architectural

Defense in Depth is a security strategy that employs multiple layers of security controls to protect valuable assets. Instead of relying on a single line of defense, this pattern aims to make it more difficult for an attacker to succeed by requiring them to overcome numerous obstacles. Each layer represents a different …

Fail Fast

behavioral robustness

The Fail Fast pattern is a strategy for dealing with errors as quickly as possible. Instead of attempting to continue execution after detecting a problem, the system immediately halts and reports the error. This minimizes the potential for cascading failures, reduces debugging time, and makes error handling more …

Gateway Offloading

architecture scalability performance

The Gateway Offloading pattern addresses scalability and performance issues in systems with a central gateway component. It involves distributing the load from the gateway to other services or infrastructure components – such as Content Delivery Networks (CDNs), alternative backend services, or dedicated processing …

Saga (Choreography)

behavioral distributed systems DDD

The Saga pattern is a distributed transaction management pattern for coordinating a sequence of local transactions across multiple microservices. Unlike traditional distributed transactions (like two-phase commit), Sagas don’t rely on centralized locking or coordination. Instead, each local transaction updates …

Write-Behind Cache

behavioral performance

The Write-Behind Cache pattern improves performance by allowing operations that modify data to complete quickly, without the latency associated with directly updating persistent storage. Instead of synchronously writing to the database or file system, modifications are first applied to the cache, and a background …