envoyproxy/envoy

Tracing for WASM plugins

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#40,859 opened on Aug 26, 2025

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area/tracingarea/wasmenhancementhelp wanted

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Description

Title: Tracing for WASM plugins

Description: Currently, when one has enabled OpenTelemetry tracing and has enabled a WASM plugin, the WASM plugin is not visible in the trace. Depending on the plugin, in our case the Coraza Web Application Firewall, significant time can be spent there. So it would be cool to create a span whilst the proxy is executing the WASM plugin :)

In !10563 a ABI to trace inside WASM plugins is requested, this request however only focuses on the execution time of the plugin itself, nothing in the plugin.

Contributor guide

Research direction
Trace the execution path of a WASM plugin in Envoy's filter chain. Identify where to add an OpenTelemetry span that covers the entire plugin execution. Look at existing span creation code for other filters to follow the same pattern. The implementation will likely require changes in either the WasmHttpFilter or the underlying Wasm runtime integration.
Tech stack
cppopentelemetrywasm
Domain
backendobservability
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
5
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++Git
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
55