envoyproxy/envoy

Add documentation about Wasm extension internals

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#15,361 opened on Mar 8, 2021

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area/docsarea/wasmhelp wanted

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Description

Given that Wasm extension mechanism seems more complex than standard built-in extensions, it is useful provide the dedicated documentation about Wasm extension internals for end-users and Envoy core developers.

This would include, for example,

  • How Envoy is integrated with Proxy-Wasm C++ Host
  • How runtimes interact with Envoy
  • The Threading model
  • How VMs are initialized and Wasm binaries are loaded
  • Envoy specific implementation details
  • How to provide Envoy specific ABI
  • Considerations and limitations (e.g. memory consumptions, etc.)
  • How to develop statically linked NullVm Wasm plugins

and could be based on https://github.com/proxy-wasm/spec/blob/master/docs/WebAssembly-in-Envoy.md

Related issues:

Contributor guide

Research direction
Study the existing Proxy Wasm specification and Envoy's implementation to document the internals of Wasm extension mechanism, including integration with Proxy Wasm C++ Host, runtime interaction, threading model, VM initialization, and ABI details.
Tech stack
cppwasm
Domain
backenddocumentation
Issue type
Documentation
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.
3-5 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++WebAssemblyEnvoy
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50