envoyproxy/envoy

Allow setting a destination for log messages from wasm plugins

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#22,669 opened on Aug 12, 2022

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area/wasmenhancementhelp wanted

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Description

Title: Allow setting a destination for log messages from wasm plugins

Description:

Currently, logging from wasm plugins all go to envoy's app logs. However, there are use cases for separating out log files for specific domains - for example, a WAF filter will often need to have a separate audit log which is used for actioning on suspicious events.

One approach could be for the config to define log destinations

message LogDestination {
  oneof {
    string file_path = 1;
    
    string remote_log_service = 2;
  }
}

message VmConfig {
  ...
  map<string, LogDestination> log_destination

And the log ABI would be extended to accept a log destination string which would be mapped with that config.

[optional Relevant Links:]

https://github.com/envoyproxy/envoy/issues/22557#issuecomment-1205785100

Contributor guide

Research direction
Understand the current logging mechanism for WASM plugins in Envoy (source/extensions/wasm/config.cc and related files). Then extend the VmConfig protobuf to include log destinations and modify the ABI functions (proxy log) to accept a destination name, mapping it to the configured dest. Coordinate with the existing logging infrastructure.
Tech stack
cpp
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.
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++Envoy development setupWASM plugin concepts
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50