CaptureRunner

Defined in: packages/core/src/adapters/capture-runner.ts:149

A pure capture renderer.

Adapters implementing CaptureRunner render screenshots from an already-extracted Storybook directory and return PNG buffers. They are intentionally pure: they perform no database, storage, or build-state management. Loading the build, extracting the uploaded archive, persisting snapshots/baselines/diffs, and advancing build status are the capture orchestrator’s job (see capture/orchestrator.ts), keeping every adapter implementation free of server concerns.

Extends

• Adapter<{ category: "capture-runner"; targets?: readonly RunnerTarget[]; }>

Properties

lifecycle?

readonly optional lifecycle?: AdapterLifecycle

Defined in: packages/core/src/adapters/metadata.ts:84

Optional lifecycle hooks.

Inherited from

Adapter.lifecycle

---

metadata

readonly metadata: AdapterMetadata & object

Defined in: packages/core/src/adapters/metadata.ts:82

Adapter identity (mandatory).

Type Declaration

category

readonly category: "capture-runner"

targets?

readonly optional targets?: readonly RunnerTarget[]

Every target the runner offers, default first (ADR 0007, decision 1), with whether each can render now. A runner that omits it offers any target.

Inherited from

Adapter.metadata

Methods

cancel()

cancel(buildId, runId?): Promise<void>

Defined in: packages/core/src/adapters/capture-runner.ts:255

Cancel in-flight renders of a build: the ones started with runId, or every one of the build when it is absent. Runners can track their calls with RenderRuns.

Parameters

buildId

string

runId?

string

Returns

Promise<void>

---

extractParameters()?

optional extractParameters(input): Promise<Record<string, StoryParameters>>

Defined in: packages/core/src/adapters/capture-runner.ts:216

Optional pre-pass reading each story’s fully resolved parameters (project, component and story levels stacked) from the running preview. Storybook’s index rarely carries parameters, so this is how the orchestrator learns which modes a story declares before it builds the capture matrix. Absent or failing, the orchestrator falls back to index parameters.

Parameters

input

adapter?

StorySourceAdapter

buildId

string

logger?

Logger

stories

StoryEntry[]

storybookDir

string

storybookUrl?

string

As on render: the URL a reach: "url" target’s browser opens.

target?

CaptureTarget

Target to read the parameters on: the project’s primary (chromium when absent).

Returns

Promise<Record<string, StoryParameters>>

---

render()

render(input): Promise<RenderResult>

Defined in: packages/core/src/adapters/capture-runner.ts:163

Render configured viewports for the given stories of an extracted Storybook and return the screenshot buffers.

Parameters

input

Render request with the extracted Storybook directory.

adapter?

StorySourceAdapter

Test/extension seam: override the story source adapter (defaults to StorybookAdapter). Only the renderer uses it; discovery stays the orchestrator’s job.

buildId

string

Build being captured, used to correlate cancels with in-flight work.

executePlay?

boolean

Whether to execute Storybook play functions before screenshot.

logger?

Logger

Optional logger for render-time diagnostics.

onCapture?

(capture) => Promise<void>

Optional streaming hand-off. When provided, the runner awaits it with each capture as soon as it is taken, then drops the buffer instead of adding the capture to RenderResult.captures, so a large build never holds every screenshot in memory. A rejection is reported as a render failure for that story/viewport. Runners that do not support it return captures as usual.

playTimeoutMs?

number

Timeout for play function execution in ms.

runA11y?

boolean

Whether to run a11y checks (axe) before screenshot; annotated as non-blocking.

runId?

string

This call’s handle within the build, for cancel(buildId, runId): several renders of one build (its shards) can be in flight in one process. Absent, the build id is used.

stories

StoryEntry[]

Stories to render.

storybookDir

string

Root of the already-extracted Storybook build.

storybookUrl?

string

An absolute URL to the build’s Storybook that the target’s browser can reach, set for a reach: "url" target (ADR 0007, decision 5). The runner navigates there instead of to its loopback server; a reach: "url" target given none fails to start. Never logged.

target?

CaptureTarget

Target to render on (chromium when absent).

viewports

Viewport[]

Viewports to capture.

Returns

Promise<RenderResult>

---

runTests()?

optional runTests(input): Promise<TestOutcome[]>

Defined in: packages/core/src/adapters/capture-runner.ts:235

Optional: run Storybook 10 .test() entries (index subtype: "test") as interaction tests. Each entry’s iframe URL renders the story it is written under and runs the test body as the play function; the runner reports pass or fail per entry from Storybook’s own events, and takes no screenshot. A runner without it leaves projects that turn tests on with a warning. Cancellable with cancel, like render.

Parameters

input

adapter?

StorySourceAdapter

buildId

string

logger?

Logger

playTimeoutMs?

number

Timeout for one test (render plus body) in ms.

runId?

string

storybookDir

string

storybookUrl?

string

As on render: the URL a reach: "url" target’s browser opens.

target?

CaptureTarget

Target to run on: the project’s primary (chromium when absent).

tests

StoryEntry[]

The test entries to run (StoryEntry.parentId is set).

Returns

Promise<TestOutcome[]>

---

setLogger()?

optional setLogger(logger): void

Defined in: packages/core/src/adapters/metadata.ts:90

Bind the host-owned runtime logger. Called by the app/worker when present; factories must never create their own loggers — they only store what they are given (explicit options.logger wins over bound).

Parameters

logger

Logger

Returns

void

Inherited from

Adapter.setLogger