@actions/artifact should allow downloading artifacts cross-workflow

[CAD97]

Describe the enhancement

Accept an optional workflow run ID for which workflow run to download artifacts from. This will allow passing artifacts cross-workflow without falling back to using the REST API directly.

Code Snippet

const artifact = require('@actions/artifact');
const artifactClient = artifact.create()
const artifactName = 'my-artifact';
const path = 'some/directory'
const options = {
    createArtifactFolder: false
    runId: 'RUN_ID'
}

const downloadResponse = await artifactClient.downloadArtifact(artifactName, path, options)

With an actions/download-artifact action:

steps:
- uses: actions/checkout@v2
- uses: actions/download-artifact@v3
  with:
    name: my-artifact
    path: some/directory
    run-id: RUN_ID

Additional information

Targets for the patch:

toolkit/packages/artifact/src/internal/download-http-client.ts

Lines 45 to 46 in 01e1ff7

	async listArtifacts(): Promise<ListArtifactsResponse> {
	const artifactUrl = getArtifactUrl()

toolkit/packages/artifact/src/internal/utils.ts

Lines 221 to 225 in 01e1ff7

	export function getArtifactUrl(): string {
	const artifactUrl = `${getRuntimeUrl()}_apis/pipelines/workflows/${getWorkFlowRunId()}/artifacts?api-version=${getApiVersion()}`
	debug(`Artifact Url: ${artifactUrl}`)
	return artifactUrl
	}

toolkit/packages/artifact/src/internal/config-variables.ts

Lines 49 to 55 in 01e1ff7

	export function getWorkFlowRunId(): string {
	const workFlowRunId = process.env['GITHUB_RUN_ID']
	if (!workFlowRunId) {
	throw new Error('Unable to get GITHUB_RUN_ID env variable')
	}
	return workFlowRunId
	}

• DownloadOptions gains a new runId which can be used to specify the workflow run id to download artifacts from instead of using process.env['GITHUB_RUN_ID'].
• downloadAllArtifacts gains a new options?: DownloadAllOptions parameter which just contains the runId option.
• This is passed down, replacing uses of getWorkFlowRunId() with options.runId ?? getWorkFlowRunId().

[CAD97]

See also actions/download-artifact#172 for exposing this functionality in the actions/download-artifact action.

[konradpabjan]

With v4 upload-artifact and download-artifacts this is now supported! See actions/download-artifact#172 (comment)

https://github.com/actions/download-artifact?tab=readme-ov-file#download-artifacts-from-other-workflow-runs-or-repositories