In an event-driven microservice system, if Service A publishes an event and Service B listens to it, what will happen if Service B is down when the event is published?

medium📝 Analysis Q5 of 15

Microservices - Event-Driven Architecture

AService A will wait until Service B is back online

BService A will retry sending the event synchronously

CService B will receive the event immediately after restart without broker support

DThe event is lost unless the message broker supports persistence

Step-by-Step Solution

Solution:

Step 1: Understand event delivery guarantees
If the message broker does not persist events, events sent while a consumer is down can be lost.
Step 2: Analyze options
Service A does not wait or retry synchronously in event-driven systems; delivery depends on broker persistence.
Final Answer:
The event is lost unless the message broker supports persistence -> Option D
Quick Check:
Event loss depends on broker persistence = B [OK]

Quick Trick: Event loss happens without broker persistence [OK]

Common Mistakes:

MISTAKES

Assuming synchronous wait in event-driven
Thinking service auto-receives missed events without broker
Confusing retries with synchronous calls

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More Microservices Quizzes

In an event-driven microservice system, if Service A publishes an event and Service B listens to it, what will happen if Service B is down when the event is published?

Step 1: Understand event delivery guarantees

Step 2: Analyze options

Final Answer:

Quick Check:

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