http connection manager

First of all, http connection manager(HCM) is a Network Filter from the Listener’s point of view.

For scalability, Envoy’s http connection manager uses the classic filter chain design pattern. This is similar to Listener Filter Chain:

Figure: http connection manager Design model

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The filter flow of http request:

source: life_of_a_request

The filter flow of http response:

source: life_of_a_request

http filter abstract object definition

HttpFilter is called StreamFilter or more precisely Http::StreamFilterBase in the source code. An http connection manager has an Http::FilterManager and a FilterManager has list<StreamFilterBase*> filters_.

Figure: http filter abstract object

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http filter C++ class relationships

Figure: http filter C++ class relationships

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• HTTP Reverse Proxy for HCM upstream/downstream Event-Driven Collaboration
  • General flow of HTTP reverse proxy
    • Downstream Read Request Module Collaboration
      • Downstream Request Router Module Collaboration
    • Upstream Write Request Module Collaboration
    • Upstream Read Response Module Collaboration
    • Downstream Write Response Module Collaboration
  • Demonstration