title: Clean architecture for proxy applications
body: <p>If to develop an http proxy application for example to implement a rate limiter and data pre-processing for communicating of inner micro services and third party API. I want this application appropriate to Clean Architecture framework. I see a significant problem in this situation: a third party API caller intuitively belongs to a lowest level of abstraction aka <strong>entitys</strong> (e.g. a way of entities creation) but it uses http client and it looks like a superfluous dependence for that layer.</p>
  
  <p>Pure data flow of the application will look like:</p>
  
  <ol>
  <li>Receive a request (http, amqp...) from a client</li>
  <li>Compose a third party API query url</li>
  <li>Call the API using rate limit</li>
  <li>Pre-process obtained data</li>
  <li>Return pre-processed data to the client</li>
  </ol>
  
  <p><strong>Where should I place the client (API caller) with all it's calls to third party API? Should it be entities or controllers?</strong></p>