[adityareddy-dev]

This is a proof of concept. Jay suggested trying browser instrumentation here while I was researching it for the ecosystem explorer (open-telemetry/opentelemetry-ecosystem-explorer#1187). It adds a browser domain with three scenarios for @opentelemetry/browser-instrumentation 0.8.1 (errors, console, web-vitals). Each one opens a page in the Chrome already on the machine, and the page's OTLP exports go through its own origin to the runner's HTTP bridge, since the bridge doesn't answer CORS.

It covers events only and sits beside #162 and #163, which cover the older fetch and XHR span packages with their own browser runner. The earlier Windows and fork Ubuntu runs produced the committed data.json. On October 15 I reran all three scenarios on macOS with Weaver 0.26.1 and registry v1.44.0, and the coverage matched again. Each scenario reports warnings, including the missing browser.console event and method attribute in that registry. The web-vitals scenario waits for one event, it does not establish coverage of every web vital.

Validation on October 15: npm ci, the six launcher unit tests, browser workspace formatting, and all three otel-conformance ... --report-only scenarios passed. This remains a proof of concept with an unpinned browser and the HTTP runner registry.

[opentelemetry-pr-dashboard]

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Waiting on reviewers · refreshed 2026-10-17 01:49 UTC

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[Copilot]

Copilot review overview

🟢 Approval recommended

The launcher, scenarios, generated coverage, tests, documentation, and CI integration are consistent and complete.

Review effort: Balanced
Findings: None

What changed in this PR

Adds browser event conformance coverage using headless Chrome and an OTLP/HTTP relay.

Changes:

• Adds reusable browser launching, event synchronization, and OTLP relay support.
• Adds errors, console, and web-vitals scenarios.
• Integrates browser scenarios into CI and documentation.

File	Description
README.md	Lists the browser domain.
.github/​workflows/​runner.yml	Builds and tests browser scenarios.
tools/​js/​README.md	Documents browser scenario support.
tools/​js/​browser-launcher/​index.js	Implements browser execution and OTLP relay.
tools/​js/​browser-launcher/​page.js	Configures browser log collection.
tools/​js/​browser-launcher/​package.json	Declares launcher dependencies.
tools/​js/​browser-launcher/​test/​index.test.js	Tests page serving and relaying.
scenarios/​browser/​README.md	Documents browser coverage.
scenarios/​browser/​js/​README.md	Documents JavaScript scenarios.
scenarios/​browser/​js/​package.json	Defines the browser workspace.
scenarios/​browser/​js/​package-lock.json	Locks browser dependencies.
scenarios/​browser/​js/​.npmrc	Configures local package installation.
scenarios/​browser/​js/​.prettierignore	Excludes generated artifacts.
scenarios/​browser/​js/​chromium/​scenarios/​package.json	Defines workload package metadata.
scenarios/​browser/​js/​chromium/​scenarios/​errors.js	Generates unhandled errors.
scenarios/​browser/​js/​chromium/​scenarios/​console.js	Generates console events.
scenarios/​browser/​js/​chromium/​scenarios/​web-vitals.js	Generates page content for web vitals.
scenarios/​browser/​js/​chromium/​opentelemetry-browser-instrumentation/​package.json	Declares instrumentation dependencies.
scenarios/​browser/​js/​chromium/​opentelemetry-browser-instrumentation/​run.js	Selects and launches scenario pages.
scenarios/​browser/​js/​chromium/​opentelemetry-browser-instrumentation/​pages/​errors.js	Configures errors instrumentation.
scenarios/​browser/​js/​chromium/​opentelemetry-browser-instrumentation/​pages/​console.js	Configures console instrumentation.
scenarios/​browser/​js/​chromium/​opentelemetry-browser-instrumentation/​pages/​web-vitals.js	Configures web-vitals instrumentation.
scenarios/​browser/​js/​chromium/​opentelemetry-browser-instrumentation/​conformance.yaml	Declares conformance scenarios.
scenarios/​browser/​js/​chromium/​opentelemetry-browser-instrumentation/​data.json	Records generated coverage.

Files not reviewed (1)

• scenarios/browser/js/package-lock.json: Generated file

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[adityareddy-dev]

A few things I wasn't sure about and would change if you prefer.

The scenarios declare runner: http-conformance. No runner package covers browser conventions yet, and that one pins the upstream registry at v1.44.0, which is where exception and browser.web_vital are defined. Its span classifier only acts on spans with http.request.method, and these scenarios emit no spans. The report files the target under browser cause it goes by path. If you'd rather have a small browser runner package I can add one.

The path is scenarios/browser/js/chromium/opentelemetry-browser-instrumentation, with chromium in the slot where the HTTP scenarios put the instrumented library. Not sure that's the right word for it.

The browser isn't pinned. playwright-core drives the Chrome that's already installed, on CI the one in the ubuntu-latest image, so nothing is downloaded. Installing a pinned Chromium in the workflow is the alternative.

#162 adds tools/js/browser-runner and this adds tools/js/browser-launcher. They overlap a lot. Both bundle a page with esbuild, serve it from 127.0.0.1 and take its exports on the same origin. 162's sends traces to the collector over gRPC itself and proxies every other path to the HTTP mock server, mine posts /v1/* on to the runner's OTLP/HTTP bridge. One launcher is probably the right end state. We also both add a line to tools/js/README.md at the same spot, so whichever lands second has a one-line conflict.

What it reports right now:

==== instrumented: chromium, instrumentation: @opentelemetry/browser-instrumentation, package: opentelemetry-browser-instrumentation
! scenario: errors, status: WARN
! Violations:
  - [instrumentation_scope_schema_url_missing] Instrumentation scope '@opentelemetry/browser-instrumentation/errors' does not have schema_url
! scenario: console, status: WARN
! Violations:
  - [instrumentation_scope_schema_url_missing] Instrumentation scope '@opentelemetry/browser-instrumentation/console' does not have schema_url
  - [missing_attribute] Attribute 'browser.console.method' does not exist in the registry
  - [missing_event] Event 'browser.console' does not exist in the registry
! scenario: web_vitals, status: WARN
! Violations:
  - [instrumentation_scope_schema_url_missing] Instrumentation scope '@opentelemetry/browser-instrumentation/web-vitals' does not have schema_url

browser.console isn't in the registry at v1.44.0, so its findings are recorded and its attributes aren't.

The workflows here are waiting on approval to run. The same commit ran green in my fork, adityareddy-dev#1

[adityareddy-dev]

Nudge on this one, it adds the browser events scenarios and every upstream check passed on ffdf6a1eb on 2026-10-03.
It's ready for a look.

[adityareddy-dev]

@jaydeluca could you take a look at the browser events scenarios? Checks and CLA passed. The main question is whether to share the launcher with the Fetch scenarios.