ContextQMD
Back to K6

V2.1.0

release notes/v2.1.0.md

2.1.010.2 KB
Original Source

k6 v2.1.0 is here 🎉! This release includes:

  • An opt-in feature-flag system — --features, the K6_FEATURES environment variable, and a k6 features discovery command — shipping with experimental native histograms for trend metrics as its first flag.
  • A context-level proxy option for browser contexts.
  • Subcommand discovery in k6 x, so binaries can report which extension commands they expose.

Breaking changes

There are no breaking changes in this release.

New features

k6 cloud test list command #6007

A new k6 cloud test command group has been added, with a k6 cloud test list subcommand that lists the load tests of a Grafana Cloud k6 project. It complements the k6 cloud project list command introduced in v2.0.0.

The project to list tests for is resolved in the following order:

  1. The --project-id flag.
  2. The K6_CLOUD_PROJECT_ID environment variable (cloud config projectID).
  3. The default project of the configured stack, populated by k6 cloud login.

Output defaults to a human-readable table. Pass --json to emit a JSON array instead, mirroring the format established by k6 cloud project list.

shell
k6 cloud test list
k6 cloud test list --project-id 12345
k6 cloud test list --json

Feature flags and experimental native histograms #6055, #6056

k6 now has an opt-in feature-flag mechanism for trialing new, not-yet-stable behavior without affecting existing runs. Flags can be enabled on k6 run and k6 cloud run through the --features flag (comma-separated or repeated), the K6_FEATURES environment variable, or the features key in config.json. Enabled flags are surfaced as metric tags and propagated into archives and cloud workers so a run behaves consistently wherever it executes.

Use k6 features (or k6 features --json) to discover the available flags and their lifecycle:

console
$ k6 features
FEATURE             LIFECYCLE      DESCRIPTION
native-histograms   Experimental   Use native histograms for trend metrics

The first flag shipped is native-histograms, an experimental flag that makes k6 use native histograms for trend metrics:

shell
k6 run --features native-histograms script.js
# or
K6_FEATURES=native-histograms k6 run script.js

Subcommand discovery in k6 x #5972

Running k6 x now lists the available subcommands — both the ones baked into the binary and those advertised by the extension registry (official and community). Tab-completion surfaces the same set once the catalog has been cached locally by a prior k6 x run, so completion never blocks on the network.

text
$ k6 x
...
Available Commands:
  agent       Bootstrap an AI-assisted k6 testing workflow in any editor
  docs        CLI k6 docs for AI agents and users
  explore     Explore k6 extensions for Automatic Resolution
  mcp         An MCP server for k6 for AI agents

This makes a k6 binary self-describing — particularly useful for AI agents driving k6, which previously had no way to introspect which extension subcommands were available.

Browser context proxy option #5924

Browser contexts can now be configured with a context-level proxy option, letting you route a context's traffic through a proxy without launching a custom-built binary or relying on environment proxy variables (which only affected k6's DevTools WebSocket connection). The option is wired to Chromium through Target.createBrowserContext, and invalid proxy configuration now fails early when proxy.server is missing. Thanks, @nightt5879!

js
const context = await browser.newContext({
  proxy: {
    server: 'http://proxy.test:8080',
    bypass: 'localhost,127.0.0.1',
  },
});

Browser locator.isInViewport() #6023

A new locator.isInViewport() method reports whether an element intersects the browser viewport. It accepts an optional ratio (0 to 1) that sets how much of the element must be visible, defaulting to 0 so any visible pixel counts, matching Playwright's toBeInViewport semantics. The call waits for the element to attach, honoring the timeout option, then measures the intersection once. Thanks, @Anuragp22!

js
const button = page.locator('button#submit');
if (await button.isInViewport()) {
  await button.click();
}

Basic auth for the OpenTelemetry HTTP exporter #5997

The OpenTelemetry output's HTTP exporter can now send HTTP Basic Auth credentials. Set them through the K6_OTEL_HTTP_EXPORTER_USERNAME and K6_OTEL_HTTP_EXPORTER_PASSWORD environment variables, or the username and password keys in the output config.

shell
K6_OTEL_HTTP_EXPORTER_USERNAME=user \
K6_OTEL_HTTP_EXPORTER_PASSWORD=secret \
k6 run --out opentelemetry script.js

single() selection helper in k6/html #6002

Selection.single(selector) returns at most one matching element, backed by goquery's Single matcher for a faster lookup than find() when you only need the first match. Thanks, @rohan-patnaik!

js
import { parseHTML } from 'k6/html';

const doc = parseHTML(content);
const title = doc.single('h1').text();

UX improvements and enhancements

  • #5971 Tags browser API failures with module=browser so that browser errors surfaced in Grafana Cloud Logs can be filtered separately from other log sources.

Bug fixes

  • #5794 Makes the --vus flag work as a standalone execution shortcut instead of being silently ignored when a script defines scenarios. Running k6 run script.js --vus N now creates a shared-iterations scenario with N VUs and N iterations, overriding any script-defined scenarios with a warning — consistent with how --iterations, --duration, and --stages already behave. Thanks, @Reranko05!
  • #6013 Rejects invalid threshold percentiles. A percentile aggregation value outside the 0 to 100 range (or NaN) now fails parsing with a clear message instead of being silently accepted. Thanks, @immanuwell!
  • #6011 Writes the on-disk k6 config file with owner-only permissions (0o600, inside a 0o700 directory). The file can hold the Grafana Cloud API token (collectors.cloud.token), so tightening it keeps other local users on shared hosts (CI runners, multi-user boxes, sidecar containers) from reading the token. Existing configs are upgraded on the next write, for example the next k6 cloud login.

Maintenance and internal improvements

  • #6033 Moves Docker Hub image publishing to a Google Artifact Registry mirror.
  • #5953 Installs s3cmd via apt instead of pip to fix the k6packager image build.
  • #6052 Fixes the browser end-to-end test workflow.
  • #5984 Routes per-test logger output to the test instance instead of the global logrus, improving test isolation.
  • #5985 Fixes the flaky TestPageScreenshotFullpage browser test.
  • #5981 Lets Renovate track the Go minor version in the setup-go workflows.
  • #5968 Honors the caller-pinned ref in the shared lint action.
  • #6041, #6054 Aligns the Go module directive and toolchain (1.25.0 / 1.25.11).
  • #5967 Updates the release notes template after v2.0.0.
  • #6015 Updates golang.org/x/net to v0.55.0 [security].
  • #6026 Updates golang.org/x/crypto to v0.52.0 [security].
  • #5962, #6028 Updates google.golang.org/grpc to v1.81.1.
  • #5960 Updates grafana/shared-workflows/get-vault-secrets to v1.3.2.
  • #5958 Updates grafana/shared-workflows/azure-trusted-signing to v1.0.2.
  • #5957 Updates github/codeql-action to v4.35.4.
  • #5959 Updates grafana/shared-workflows/dockerhub-login to v1.0.4.
  • #6009 Moves the browser PageScreenshotOptions parsing into the mapping layer.
  • #5964 Adds the k6 feature-flags specification under openspec/.
  • #6067 Forces the legacy x/net/http2 implementation on the gotip CI test job.
  • #6065 Lets Renovate update the Dockerfile on the v1.x branch.
  • #6031 Updates go.opentelemetry.io/otel to v1.44.0.
  • #6086 Updates golang.org/x dependencies (crypto to v0.53.0, net to v0.56.0, term to v0.44.0).
  • #6061 Updates golang.org/x/sync to v0.21.0.
  • #6030 Updates github.com/tidwall/gjson to v1.19.0.
  • #6029 Updates github.com/mccutchen/go-httpbin/v2 to v2.23.0.
  • #6063 Updates github.com/mattn/go-colorable to v0.1.15.
  • #6062 Updates the Golang Docker image to 1.26.4.
  • #6084 Updates the Alpine Docker image to 3.24.0.
  • #6027 Updates the Debian Docker image to trixie-20260518.

External contributors

A huge thank you to the external contributors who helped during this release: @nightt5879, @Reranko05, @rohan-patnaik, @immanuwell, and @Anuragp22! 🙏