Chris Richardson: 4.2 Communication Patterns API Gateway Event Driven Microservices

 April 1, 2021

Here is the link. 

Forces

• Mismatch between the fine-grained microservices and needs of the clients
• Different clients need different data
• LAN vs. WAN vs. Mobile network performance 
• The number of service instances and their locations (host + port) changes dynamically 
• Partitioning into services can change over time and should be hidden from clients

Directly connecting the front-end to the backend 

API gateway pattern vs directly talk to Microservice 

Pattern: API gateway 

Single entry point - API Gateway 

Client specific APIs 

REST catalog service

REST Recommendation service

Thrift Review service 

Protocol translation 

Example: Netflix API 

thousand streaming clients - Device specific end points 

Benefits of the API gateway

• Insulates the clients from the partitioning
• Insulates the clients from the problem of discovery
• Provides the optimal API for each client
• Reduces the number of requests/ roundtrips
• Simplifies the client by moving logic for calling multiple services from the client to API gateway
• Gateway translates between web-unfriendly protocols and HTTP/WebSockets