add new @actions/attest package

Signed-off-by: Brian DeHamer <[email protected]>
2026-08-29 00:00:23 +02:00 · 2024-02-26 08:52:20 -08:00
parent 415c42d27c
commit 6079dea4c4
24 changed files with 4224 additions and 3 deletions
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+# `@actions/attest`
+
+Functions for generating signed attestations for workflow artifacts.
+
+Attestations bind some subject (a named artifact along with its digest) to a
+predicate (some assertion about that subject) using the [in-toto
+statement](https://github.com/in-toto/attestation/tree/main/spec/v1) format. A
+signature is generated for the attestation using a
+[Sigstore](https://www.sigstore.dev/)-issued signing certificate.
+
+Once the attestation has been created and signed, it will be uploaded to the GH
+attestations API and associated with the repository from which the workflow was
+initiated.
+
+## Usage
+
+### `attest`
+
+The `attest` function takes the supplied subject/predicate pair and generates a
+signed attestation.
+
+```js
+const { attest } = require('@actions/attest');
+const core = require('@actions/core');
+
+async function run() {
+    // In order to persist attestations to the repo, this should be a token with
+    // repository write permissions.
+    const ghToken = core.getInput('gh-token');
+
+    const attestation = await attest({
+        subjectName: 'my-artifact-name',
+        subjectDigest: { 'sha256': '36ab4667...'},
+        predicateType: 'https://in-toto.io/attestation/release',
+        predicate: { . . . },
+        token: ghToken
+    });
+
+    console.log(attestation);
+}
+
+run();
+```
+
+The `attest` function supports the following options:
+
+```typescript
+export type AttestOptions = {
+  // The name of the subject to be attested.
+  subjectName: string
+  // The digest of the subject to be attested. Should be a map of digest
+  // algorithms to their hex-encoded values.
+  subjectDigest: Record<string, string>
+  // URI identifying the content type of the predicate being attested.
+  predicateType: string
+  // Predicate to be attested.
+  predicate: object
+  // GitHub token for writing attestations.
+  token: string
+  // Sigstore instance to use for signing. Must be one of "public-good" or
+  // "github".
+  sigstore?: 'public-good' | 'github'
+  // Whether to skip writing the attestation to the GH attestations API.
+  skipWrite?: boolean
+}
+```
+
+### `attestProvenance`
+
+The `attestProvenance` function accepts the name and digest of some artifact and
+generates a build provenance attestation over those values.
+
+The attestation is formed by first generating a [SLSA provenance
+predicate](https://slsa.dev/spec/v1.0/provenance) populated with
+[metadata](https://github.com/slsa-framework/github-actions-buildtypes/tree/main/workflow/v1)
+pulled from the GitHub Actions run.
+
+```js
+const { attestProvenance } = require('@actions/attest');
+const core = require('@actions/core');
+
+async function run() {
+    // In order to persist attestations to the repo, this should be a token with
+    // repository write permissions.
+    const ghToken = core.getInput('gh-token');
+
+    const attestation = await attestProvenance({
+        subjectName: 'my-artifact-name',
+        subjectDigest: { 'sha256': '36ab4667...'},
+        token: ghToken
+    });
+
+    console.log(attestation);
+}
+
+run();
+```
+
+The `attestProvenance` function supports the following options:
+
+```typescript
+export type AttestProvenanceOptions = {
+  // The name of the subject to be attested.
+  subjectName: string
+  // The digest of the subject to be attested. Should be a map of digest
+  // algorithms to their hex-encoded values.
+  subjectDigest: Record<string, string>
+  // GitHub token for writing attestations.
+  token: string
+  // Sigstore instance to use for signing. Must be one of "public-good" or
+  // "github".
+  sigstore?: 'public-good' | 'github'
+  // Whether to skip writing the attestation to the GH attestations API.
+  skipWrite?: boolean
+}
+```
+
+### `Attestation`
+
+The `Attestation` returned by `attest`/`attestProvenance` has the following
+fields:
+
+```typescript
+export type Attestation = {
+  /*
+   * JSON-serialized Sigstore bundle containing the provenance attestation,
+   * signature, signing certificate and witnessed timestamp.
+   */
+  bundle: SerializedBundle
+  /*
+   * PEM-encoded signing certificate used to sign the attestation.
+   */
+  certificate: string
+  /*
+   * ID of Rekor transparency log entry created for the attestation (if
+   * applicable).
+   */
+  tlogID?: string
+  /*
+   * ID of the persisted attestation (accessible via the GH API).
+   */
+  attestationID?: string
+}
+```
+
+For details about the Sigstore bundle format, see the [Bundle protobuf
+specification](https://github.com/sigstore/protobuf-specs/blob/main/protos/sigstore_bundle.proto).
+
+## Sigstore Instance
+
+When generating the signed attestation there are two different Sigstore
+instances which can be used to issue the signing certificate. By default,
+workflows initiated from public repositories will use the Sigstore public-good
+instance and persist the attestation signature to the public [Rekor transparency
+log](https://docs.sigstore.dev/logging/overview/). Workflows initiated from
+private/internal repositories will use the GitHub-internal Sigstore instance
+which uses a signed timestamp issued by GitHub's timestamp authority in place of
+the public transparency log.
+
+The default Sigstore instance selection can be overridden by passing an explicit
+value of either "public-good" or "github" for the `sigstore` option when calling
+either `attest` or `attestProvenance`.
+
+## Storage
+
+Attestations created by `attest`/`attestProvenance` will be uploaded to the GH
+attestations API and associated with the appropriate repository. Attestation
+storage is only supported for public repositories or repositories which belong
+to a GitHub Enterprise Cloud account.
+
+In order to generate attestations for private, non-Enterprise repositories, the
+`skipWrite` option should be set to `true`.