Add push option for dry-run (#326)

* Add `push` option for dry-run

* Fix up

.github/workflows/e2e-docker.yaml

@@ -57,6 +57,14 @@ jobs:
       - run: yarn package
 
       # run the action
+      - name: docker-manifest-create-action (dry-run)
+        uses: ./
+        with:
+          push: false
+          sources: |
+            ${{ needs.build-linux-amd64.outputs.image-uri }}
+            ${{ needs.build-linux-arm64.outputs.image-uri }}
+
       - uses: docker/login-action@343f7c4344506bcbf9b4de18042ae17996df046d # v3.0.0
         with:
           registry: ghcr.io

.github/workflows/e2e-kaniko.yaml

@@ -66,6 +66,13 @@ jobs:
       - run: yarn package
 
       # run the action
+      - name: docker-manifest-create-action (dry-run)
+        uses: ./
+        with:
+          push: false
+          sources: |
+            ${{ needs.build-linux-amd64.outputs.image-uri }}
+
       - uses: docker/login-action@343f7c4344506bcbf9b4de18042ae17996df046d # v3.0.0
         with:
           registry: ghcr.io

README.md

@@ -188,10 +188,13 @@ This action requires Docker Buildx.
 
 ### Inputs
 
-| Name      | Default    | Description                                    |
-| --------- | ---------- | ---------------------------------------------- |
-| `tags`    | (required) | Tags of destination images (multi-line string) |
-| `sources` | (required) | Image URIs of sources (multi-line string)      |
+| Name      | Default                      | Description                                        |
+| --------- | ---------------------------- | -------------------------------------------------- |
+| `push`    | `true`                       | Push the manifest to the registry                  |
+| `tags`    | (required if `push` is true) | Tags of the destination images (multi-line string) |
+| `sources` | (required)                   | Image URIs of the sources (multi-line string)      |
+
+If `push` is false, this action runs `docker buildx imagetools create --dry-run`.
 
 ### Outputs
 

action.yaml

@@ -2,11 +2,15 @@ name: docker-manifest-create-action
 description: Create a multi-architecture Docker image in GitHub Actions
 
 inputs:
+  push:
+    description: Push the manifest to the registry
+    required: false
+    default: 'true'
   tags:
-    description: Tags of destination images (multi-line string)
-    required: true
+    description: Tags of the destination images (multi-line string)
+    required: false
   sources:
-    description: Image URIs of sources (multi-line string)
+    description: Image URIs of the sources (multi-line string)
     required: true
 
 outputs:

src/main.ts

@@ -3,11 +3,14 @@ import { run } from './run'
 
 const main = async (): Promise<void> => {
   const outputs = await run({
-    tags: core.getMultilineInput('tags', { required: true }),
+    push: core.getBooleanInput('push', { required: true }),
+    tags: core.getMultilineInput('tags'),
     sources: core.getMultilineInput('sources', { required: true }),
   })
-  core.info(`Setting outputs: ${JSON.stringify(outputs, undefined, 2)}`)
-  core.setOutput('digest', outputs.digest)
+  if (outputs.digest) {
+    core.info(`Setting outputs.digest=${outputs.digest}`)
+    core.setOutput('digest', outputs.digest)
+  }
 }
 
 main().catch((e: Error) => {

src/run.ts

@@ -1,28 +1,39 @@
+import assert from 'assert'
 import * as core from '@actions/core'
 import * as exec from '@actions/exec'
 
 type Inputs = {
+  push: boolean
   tags: string[]
   sources: string[]
 }
 
 type Outputs = {
-  digest: string
+  digest: string | undefined
 }
 
 export const run = async (inputs: Inputs): Promise<Outputs> => {
   core.startGroup('Buildx version')
   await exec.exec('docker', ['buildx', 'version'])
   core.endGroup()
 
+  if (!inputs.push) {
+    await dryRunCreateManifest(inputs.sources)
+    return { digest: undefined }
+  }
+
+  assert(inputs.tags.length > 0, 'tags must be set')
   for (const tag of inputs.tags) {
     await createManifest(tag, inputs.sources)
   }
-
   const digest = await getDigest(inputs.tags[0])
   return { digest }
 }
 
+const dryRunCreateManifest = async (sources: string[]) => {
+  await exec.exec('docker', ['buildx', 'imagetools', 'create', '--dry-run', ...sources])
+}
+
 const createManifest = async (destination: string, sources: string[]) => {
   await exec.exec('docker', ['buildx', 'imagetools', 'create', '-t', destination, ...sources])
   await exec.exec('docker', ['buildx', 'imagetools', 'inspect', destination])

tests/run.test.ts

@@ -13,6 +13,7 @@ it('should run docker buildx imagetools', async () => {
   })
 
   const outputs = await run({
+    push: true,
     tags: ['ghcr.io/int128/docker-manifest-create-action:main'],
     sources: [
       'ghcr.io/int128/docker-manifest-create-action@sha256:0000000000000000000000000000000000000000000000000000000000000000',
@@ -39,3 +40,24 @@ it('should run docker buildx imagetools', async () => {
     'ghcr.io/int128/docker-manifest-create-action:main',
   ])
 })
+
+it('should run docker buildx imagetools --dry-run if push is false', async () => {
+  const outputs = await run({
+    push: false,
+    tags: [],
+    sources: [
+      'ghcr.io/int128/docker-manifest-create-action@sha256:0000000000000000000000000000000000000000000000000000000000000000',
+      'ghcr.io/int128/docker-manifest-create-action@sha256:0000000000000000000000000000000000000000000000000000000000000001',
+    ],
+  })
+  expect(outputs).toStrictEqual({ digest: undefined })
+
+  expect(exec.exec).toHaveBeenCalledWith('docker', [
+    'buildx',
+    'imagetools',
+    'create',
+    '--dry-run',
+    'ghcr.io/int128/docker-manifest-create-action@sha256:0000000000000000000000000000000000000000000000000000000000000000',
+    'ghcr.io/int128/docker-manifest-create-action@sha256:0000000000000000000000000000000000000000000000000000000000000001',
+  ])
+})