envoyproxy/envoy

Support one-to-one mapping of upstream/downstream connections

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#12,370 opened on Jul 29, 2020

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area/httpdesign proposalhelp wanted

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Description

I’d like to have the ability to have exactly one upstream connection for every downstream connection that we decide to route. That is, streams on the same downstream connection should share the same upstream connection, but no other streams should use that upstream connection.

The rationale for this is twofold:

  1. I want to ensure that only the traffic for a single downstream client is carried over a given upstream connection. I do not want mixing of client traffic over an upstream connection. This would be solved by creating a new connection for every stream if it weren't for the second rationale
  2. I want to avoid the overhead of the TCP handshake that would be needed in the connection-per-stream case.

I have time to work on this feature if there is a consensus that it makes sense.

Contributor guide

Research direction
Study Envoy's connection multiplexing logic and connection pool implementation. Focus on the HttpConnectionManager and how downstream connections are mapped to upstream connections. Implement a new configuration option to enforce one to one mapping.
Tech stack
cpp
Domain
backend
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C++Networking
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30