feat: allow images input to be empty to output bare tags

.github/workflows/ci.yml

@@ -427,3 +427,23 @@ jobs:
             ${{ steps.docker_meta.outputs.bake-file-annotations }}
           targets: |
             release
+
+  no-images:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        name: Checkout
+        uses: actions/checkout@v4
+      -
+        name: Docker meta
+        uses: ./
+        with:
+          tags: |
+            type=schedule
+            type=ref,event=branch
+            type=ref,event=tag
+            type=ref,event=pr
+            type=sha
+      -
+        name: Print envs
+        run: env|sort

README.md

@@ -383,6 +383,8 @@ images: |
 * `name=<string>` image base name
 * `enable=<true|false>` enable this entry (default `true`)
 
+If `images` is empty, tags will be generated without base name.
+
 ## `flavor` input
 
 `flavor` defines a global behavior for [`tags`](#tags-input):

__tests__/meta.test.ts

@@ -733,6 +733,50 @@ describe('push', () => {
         "org.opencontainers.image.url=https://github.com/octocat/Hello-World",
         "org.opencontainers.image.version=sha-860c1904a1ce19322e91ac35af1ab07466440c37"
       ]
+    ],
+    [
+      'push21',
+      'event_push_master.env',
+      {
+        images: [] as string[],
+        tags: [
+          `type=raw,value=mytag-{{branch}}`,
+          `type=raw,value=mytag-{{date 'YYYYMMDD'}}`,
+          `type=raw,value=mytag-{{date 'YYYYMMDD-HHmmss' tz='Asia/Tokyo'}}`,
+          `type=raw,value=mytag-tag-{{tag}}`,
+          `type=raw,value=mytag-baseref-{{base_ref}}`,
+          `type=raw,value=mytag-defbranch,enable={{is_default_branch}}`
+        ],
+      } as Inputs,
+      {
+        main: 'mytag-master',
+        partial: [
+          'mytag-20200110',
+          'mytag-20200110-093000',
+          'mytag-tag-',
+          'mytag-baseref-',
+          'mytag-defbranch'
+        ],
+        latest: false
+      } as Version,
+      [
+        'mytag-master',
+        'mytag-20200110',
+        'mytag-20200110-093000',
+        'mytag-tag-',
+        'mytag-baseref-',
+        'mytag-defbranch'
+      ],
+      [
+        "org.opencontainers.image.created=2020-01-10T00:30:00.000Z",
+        "org.opencontainers.image.description=This your first repo!",
+        "org.opencontainers.image.licenses=MIT",
+        "org.opencontainers.image.revision=266574110acf203503badf966df2ea24b5d732d7",
+        "org.opencontainers.image.source=https://github.com/octocat/Hello-World",
+        "org.opencontainers.image.title=Hello-World",
+        "org.opencontainers.image.url=https://github.com/octocat/Hello-World",
+        "org.opencontainers.image.version=mytag-master"
+      ]
     ]
   ])('given %p with %p event', tagsLabelsTest);
 });
@@ -1780,6 +1824,43 @@ describe('tag', () => {
         "org.opencontainers.image.version=v1.2.3rc2"
       ]
     ],
+    [
+      'tag33',
+      'event_tag_v1.1.1.env',
+      {
+        images: [] as string[],
+        tags: [
+          `type=pep440,pattern={{version}}`,
+          `type=pep440,pattern={{major}}.{{minor}}.{{patch}}`,
+          `type=pep440,pattern={{major}}.{{minor}}`,
+          `type=pep440,pattern={{major}}`
+        ]
+      } as Inputs,
+      {
+        main: '1.1.1',
+        partial: [
+          "1.1",
+          "1"
+        ],
+        latest: true
+      } as Version,
+      [
+        '1.1.1',
+        '1.1',
+        '1',
+        'latest'
+      ],
+      [
+        "org.opencontainers.image.created=2020-01-10T00:30:00.000Z",
+        "org.opencontainers.image.description=This your first repo!",
+        "org.opencontainers.image.licenses=MIT",
+        "org.opencontainers.image.revision=860c1904a1ce19322e91ac35af1ab07466440c37",
+        "org.opencontainers.image.source=https://github.com/octocat/Hello-World",
+        "org.opencontainers.image.title=Hello-World",
+        "org.opencontainers.image.url=https://github.com/octocat/Hello-World",
+        "org.opencontainers.image.version=1.1.1"
+      ]
+    ]
   ])('given %p with %p event', tagsLabelsTest);
 });
 
@@ -2066,6 +2147,35 @@ describe('latest', () => {
         "org.opencontainers.image.version=v1.1.1"
       ]
     ],
+    [
+      'latest10',
+      'event_tag_v2.0.8-beta.67.env',
+      {
+        images: [] as string[],
+        tags: [
+          `type=match,"pattern=\\d.\\d.\\d"`
+        ]
+      } as Inputs,
+      {
+        main: '2.0.8',
+        partial: [],
+        latest: true
+      } as Version,
+      [
+        '2.0.8',
+        'latest',
+      ],
+      [
+        "org.opencontainers.image.created=2020-01-10T00:30:00.000Z",
+        "org.opencontainers.image.description=This your first repo!",
+        "org.opencontainers.image.licenses=MIT",
+        "org.opencontainers.image.revision=860c1904a1ce19322e91ac35af1ab07466440c37",
+        "org.opencontainers.image.source=https://github.com/octocat/Hello-World",
+        "org.opencontainers.image.title=Hello-World",
+        "org.opencontainers.image.url=https://github.com/octocat/Hello-World",
+        "org.opencontainers.image.version=2.0.8"
+      ]
+    ]
   ])('given %p with %p event', tagsLabelsTest);
 });
 

action.yml

@@ -13,7 +13,7 @@ inputs:
     required: true
   images:
     description: 'List of Docker images to use as base name for tags'
-    required: true
+    required: false
   tags:
     description: 'List of tags as key-value pair attributes'
     required: false

src/main.ts

@@ -15,10 +15,6 @@ actionsToolkit.run(
   // main
   async () => {
     const inputs: Inputs = getInputs();
-    if (inputs.images.length == 0) {
-      throw new Error(`images input required`);
-    }
-
     const toolkit = new Toolkit({githubToken: inputs.githubToken});
     const context = await getContext(inputs.context);
     const repo = await toolkit.github.repoData();

src/meta.ts

@@ -440,16 +440,29 @@ export class Meta {
     if (!this.version.main) {
       return [];
     }
-    const tags: Array<string> = [];
-    for (const imageName of this.getImageNames()) {
-      tags.push(`${imageName}:${this.version.main}`);
+
+    const generateTags = (imageName: string, version: string): Array<string> => {
+      const tags: Array<string> = [];
+      const prefix = imageName !== '' ? `${imageName}:` : '';
+      tags.push(`${prefix}${version}`);
       for (const partial of this.version.partial) {
-        tags.push(`${imageName}:${partial}`);
+        tags.push(`${prefix}${partial}`);
       }
       if (this.version.latest) {
         const latestTag = `${this.flavor.prefixLatest ? this.flavor.prefix : ''}latest${this.flavor.suffixLatest ? this.flavor.suffix : ''}`;
-        tags.push(`${imageName}:${Meta.sanitizeTag(latestTag)}`);
+        tags.push(`${prefix}${Meta.sanitizeTag(latestTag)}`);
       }
+      return tags;
+    };
+
+    const tags: Array<string> = [];
+    const images = this.getImageNames();
+    if (images.length > 0) {
+      for (const imageName of images) {
+        tags.push(...generateTags(imageName, this.version.main));
+      }
+    } else {
+      tags.push(...generateTags('', this.version.main));
     }
     return tags;
   }