Publish/Subscribe Pattern

Kind: pattern

Layer: Execution Core

Aliases: Pub/Sub

Record: architecture:publish-subscribe-pattern

Severity: contextual

Scope: integration, eventing

Canonical: Ontology

A design pattern in which publishers send messages to a topic and every subscriber to that topic receives them.

Listed in Architecture principles, after Event-Driven Architecture and before Message Queue.

Requires

• Publisher
• Subscriber
• Broker/Event Bus

Reinforces

• Low Coupling

Enables

• Fan-Out Notification

Conflicts with

• Direct Point-to-Point Calls

In tension with

• Delivery Ordering

Tensions

• Publish/Subscribe Pattern / Delivery Ordering

Violated by

• Point-to-Point Coupling

Refactored by

• Event Bus

Severity

• contextual

Category

• Event / Messaging / Asynchronous Architecture

Enabled by

• Message Broker

Linked from

• Posting and waiting are one operation
• Execution joins the halves
• Core Modular Design
• Event / Messaging / Asynchronous Architecture
• Event Messaging Async
• Severity levels
• The resolutions

in this codebase

• emitEvent
• subscribeEvent
• core/buses