more on API Gateways

[Ken Laskey <klaskey@mitre.org>]

Looking at the range of API Gateway discussions

microservices.io gives Example that uses API Gateway or Storefront WebApp  as integration point.  Details in the post include mention of Protocol translation.  In addition, 

The API gateway might also implement security, e.g. verify that the client is authorized to perform the request

RedHat said in a phone call a while ago that the major purpose of API Gateway is to enforce policies.  This could include security.  However, the RedHat folks didn’t mention anything about composition, protocol translation, …  I didn’t know enough to ask.

In the microservices.io Q&A at the end of the post, Richardson states 

The purpose of the API gateway is to handle external traffic.

Services [as part of app] should communicate directly without a gateway/ESB-style mediator.

Richardson also notes: You would always run multiple instances to avoid being a SPOF [single point of failure]

But as part of the same Q&A, someone else tears apart the idea of an API Gateway with arguments that remind me of railing against ESBs.  Worth reading

https://networknt.github.io/li…

https://networknt.github.io/li...

To get everything in one place, I copy from my beginning of the thread yesterday:

Just listened to Neal Ford - Building Microservice Architectures on Youtube.  If you’ve looked at the NGINX Microservices — From Design to Deployment, you find things like

- The API Gateway is responsible for request routing, composition, and protocol translation. 

- The API Gateway will often handle a request by invoking multiple microservices and aggregating the results.

There are some other things here that raises Martin’s question o whether the API Gateway starts looking like an ESB.

Neal Ford, working for ThoughtWorks at the time of the video, pillories the ESB and emphasizes dumb pipes and smart endpoints.  While the NGINX story has the API Gateway doing things like composition, Ford talks about the first (micro)service called will take on the role of the orchestration controller or each service knows the next service in the pipeline and choreography is used for control.  

Certainly no lack of interpretations.

Ken

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Dr. Kenneth Laskey
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