envoyproxy/envoy

Multi-value header matching API

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#13,751 opened on Oct 25, 2020

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api/v3area/httphelp wanted

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Description

While the mechanics of plumbing multiple-valued headers to matchers have been taken care of by https://github.com/envoyproxy/envoy/security/advisories/GHSA-2v25-cjjq-5f4w and its aftermath, we still do not have a particularly ergonomic way to match on multiple header values. We now have a canonicalized flat string of all header values, which requires gymnastics with regular expressions etc. to do a multi-value match.

Ideally we have a match interface that is capable of expressing first-class matchers that operate on a multimap, e.g. the ability to model multiple matchers and apply semantics to match such as "any of" or "all of".

Contributor guide

Research direction
Review the current header matching infrastructure in Envoy, particularly the canonicalized flat string approach. Design a multimap based matching interface with 'any of' and 'all of' semantics. Consider integration with existing matchers and configuration.
Tech stack
c
Domain
backendapi
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
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.
Mostly clear
Prerequisites
C++Envoy development
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40