Add compressOnly mode and also update README to discuss forks

README.md

@@ -1,6 +1,12 @@
 # Image Actions
 
+<<<<<<< HEAD
+Image Actions automatically compress JPEG, PNG and WebP images in GitHub Pull Requests within the same repository.
+
+It can also run in "Compress Only" mode to allow this to be used for non-Pull Requests, and also for Pull Requests from forks.
+=======
 Image Actions automatically compresses JPEG, PNG and WebP images in GitHub Pull Requests.
+>>>>>>> upstream/master
 
 - **Fast, efficient and near-lossless compression**
 - Uses the best image compression algorithms available: [mozjpeg](https://github.com/mozilla/mozjpeg) and [libvips](https://github.com/libvips/libvips)
@@ -37,6 +43,8 @@ on:
       - "**.webp"
 jobs:
   build:
+    # Only run on Pull Requests within the same repository, and not from forks
+    if: github.event.pull_request.head.repo.full_name == github.repository
     name: calibreapp/image-actions
     runs-on: ubuntu-latest
     steps:
@@ -49,7 +57,7 @@ jobs:
           githubToken: ${{ secrets.GITHUB_TOKEN }}
 ```
 
-_The `GITHUB_TOKEN` secret is [automatically generated by GitHub](https://help.github.com/en/articles/virtual-environments-for-github-actions#github_token-secret). This automatic token is [scoped only to the repository that is currently running the action.](https://help.github.com/en/articles/virtual-environments-for-github-actions#token-permissions)_
+_The `GITHUB_TOKEN` secret is [automatically generated by GitHub](https://help.github.com/en/articles/virtual-environments-for-github-actions#github_token-secret). This automatic token is [scoped only to the repository that is currently running the action.](https://help.github.com/en/articles/virtual-environments-for-github-actions#token-permissions). What this means is that by default the Action cannot update pull requests initiated from forked repositories._
 
 ## Configuration
 
@@ -73,6 +81,7 @@ Set custom configuration by adding arguments to the action workflow definition:
     webpQuality: "80"
     ignorePaths: "node_modules/**,build"
     # No spaces allowed
+    compressOnly: "false"
 ```
 
 Options:
@@ -82,8 +91,66 @@ Options:
 - [webpQuality](http://sharp.pixelplumbing.com/en/stable/api-output/#webp): Number, integer 1-100, default 80 stored in a string
 - [jpegProgressive](http://sharp.pixelplumbing.com/en/stable/api-output/#jpeg): Boolean, true or false, default false
 - `ignorePaths`: a comma separated string with [globbing](https://www.npmjs.com/package/glob) support of paths to ignore when looking for images to compress
+- `compressOnly`: Boolean, true or false, default false
+
+
+## Running just the compression
+
+By default this Action will add the updated image to the current pull request. It is also possible to set the `compressOnly` option to `true` to skip the commit, if you want to handle this separately - including for forks - see below.
+
+```yml
+      - name: Compress Images
+        uses: calibreapp/image-actions@master
+        with:
+          githubToken: ${{ secrets.GITHUB_TOKEN }}
+          compressOnly: "true"
+```
+
+## Handling pull requests from forked repos
+
+GitHub actions, by default, do not have permission to alter forked repositories. This means this action, by default, only works for pull requests from branches in the same repository as the destination branch.
+
+You can replace the default `GITHUB_TOKEN` with a [personal access token (PAT)](https://help.github.com/en/actions/configuring-and-managing-workflows/authenticating-with-the-github_token#permissions-for-the-github_token) which does have permission for forked repositaries, but this introduces other security considerations (which is why it not available by default).
+
+Alternatively you can run this action only for Pull Requests for the current repo, which is advised when not using PATs to avoid wasting time and compute for compressions that will not be committed using the following syntax (as shown in the example yml files in this README):
+
+```
+    if: github.event.pull_request.head.repo.full_name == github.repository
+```
+
+It is also possible to run an addition instance of this action in `compressOnly` mode on pushes to master, and then raise a new pull request for any images commited from a forked repositary pull request as shown in the below example which uses the [create-pull-request](https://github.com/peter-evans/create-pull-request) GitHub Action to open this new Pull Request (note this only raises a Pull Request if any fules are changed).
 
 
+```yml
+name: Compress images on Push to Master
+on:
+  push:
+    branches:
+      - master
+jobs:
+  build:
+    name: calibreapp/image-actions
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout Repo
+        uses: actions/checkout@master
+
+      - name: Compress Images
+        id: calibre
+        uses: calibreapp/image-actions@master
+        with:
+          githubToken: ${{ secrets.GITHUB_TOKEN }}
+          compressOnly: "true"
+
+      - name: Create New Pull Request
+        uses: peter-evans/create-pull-request@master
+        with:
+          title: Compressed Images
+          branch-suffix: timestamp
+          commit-message: Compressed Images
+          body: ${{ steps.calibre.outputs.markdown }}
+```
+
 ## Migrate legacy configuration
 
 - uses: docker://calibreapp/github-image-actions

action.yml

@@ -32,6 +32,15 @@ inputs:
     required: false
     default: "node_modules/**"
 
+  compressOnly:
+    description: "Only runs the compression, without adding to Pull Request"
+    required: false
+    default: "false"
+
+outputs:
+  markdown:
+    description: "Output param used to store the Markdown summary for subsequent actions to use"
+
 runs:
   using: "docker"
   image: "docker://calibreapp/github-image-actions" 

entrypoint.js

@@ -1,6 +1,6 @@
 #!/usr/bin/env node
 
-const { GITHUB_TOKEN, GITHUB_EVENT_NAME } = require("./src/constants");
+const { GITHUB_TOKEN, GITHUB_EVENT_NAME, COMPRESS_ONLY } = require("./src/constants");
 
 const githubEvent = require("./src/github-event");
 const run = require("./src/index.js");
@@ -11,21 +11,25 @@ if (!GITHUB_TOKEN) {
 }
 
 const main = async () => {
-  // Bail out if the event that executed the action wasn’t a pull_request
-  if (GITHUB_EVENT_NAME !== "pull_request") {
-    console.log("::error:: This action only runs for pushes to PRs");
-    process.exit(78);
-  }
 
-  // Bail out if the pull_request event wasn't synchronize or opened
-  const event = await githubEvent();
-  if (event.action !== "synchronize" && event.action !== "opened") {
-    console.log(
-      "::error:: Check run has action",
-      event.action,
-      ". Wants: synchronize or opened"
-    );
-    process.exit(78);
+  if (!COMPRESS_ONLY) {
+
+    // Bail out if the event that executed the action wasn’t a pull_request
+    if (GITHUB_EVENT_NAME !== "pull_request") {
+      console.log("::error:: This action only runs for pushes to PRs");
+      process.exit(78);
+    }
+
+    // Bail out if the pull_request event wasn't synchronize or opened
+    const event = await githubEvent();
+    if (event.action !== "synchronize" && event.action !== "opened") {
+      console.log(
+        "::error:: Check run has action",
+        event.action,
+        ". Wants: synchronize or opened"
+      );
+      process.exit(78);
+    }
   }
 
   await run();

src/config.js

@@ -8,7 +8,8 @@ const {
   JPEG_PROGRESSIVE,
   PNG_QUALITY,
   WEBP_QUALITY,
-  IGNORE_PATHS
+  IGNORE_PATHS,
+  COMPRESS_ONLY
 } = require("./constants");
 
 // Deprecated configuration method
@@ -26,7 +27,8 @@ const getConfig = async () => {
     jpeg: { quality: JPEG_QUALITY, progressive: JPEG_PROGRESSIVE },
     png: { quality: PNG_QUALITY },
     webp: { quality: WEBP_QUALITY },
-    ignorePaths: IGNORE_PATHS
+    ignorePaths: IGNORE_PATHS,
+    compressOnly: COMPRESS_ONLY
   };
 
   const ymlConfig = await getYamlConfig();

src/constants.js

@@ -16,6 +16,7 @@ const WEBP_QUALITY = parseInt(process.env["INPUT_WEBPQUALITY"]) || 80;
 const IGNORE_PATHS = process.env["INPUT_IGNOREPATHS"]
   ? process.env["INPUT_IGNOREPATHS"].split(",")
   : ["node_modules/**"];
+const COMPRESS_ONLY = process.env["INPUT_COMPRESSONLY"] === "true";
 
 const JPEG_PROGRESSIVE = process.env["INPUT_JPEGPROGRESSIVE"] === "true";
 
@@ -57,5 +58,6 @@ module.exports = {
   JPEG_QUALITY,
   PNG_QUALITY,
   WEBP_QUALITY,
-  IGNORE_PATHS
+  IGNORE_PATHS,
+  COMPRESS_ONLY
 };

src/image-processing.js

@@ -4,8 +4,6 @@ const path = require("path");
 const glob = util.promisify(require("glob"));
 const sharp = require("sharp");
 
-const getConfig = require("./config");
-
 const {
   REPO_DIRECTORY,
   EXTENSION_TO_SHARP_FORMAT_MAPPING,
@@ -19,10 +17,9 @@ const printSharpInfo = () => {
   console.log("=== Sharp library info ===");
 };
 
-const processImages = async () => {
+const processImages = async (config) => {
   printSharpInfo();
 
-  const config = await getConfig();
   const globPaths = `${REPO_DIRECTORY}/**/*.{${FILE_EXTENSIONS_TO_PROCESS.join(
     ","
   )}}`;

src/index.js

@@ -2,11 +2,14 @@ const generateMarkdownReport = require("./github-markdown");
 const processImages = require("./image-processing");
 const createComment = require("./github-pr-comment");
 const createCommit = require("./github-commit");
+const getConfig = require("./config");
 
 const run = async () => {
+  const config = await getConfig();
+
   console.log("->> Locating images…");
 
-  const results = await processImages();
+  const results = await processImages(config);
 
   const optimisedImages = results.images.filter(
     img => img.compressionWasSignificant
@@ -21,6 +24,17 @@ const run = async () => {
   console.log("->> Generating markdown…");
   const markdown = await generateMarkdownReport(results);
 
+  // Expose the markdown to an Action output
+  // https://github.community/t/set-output-truncates-multiline-strings/16852
+  const escaped_markdown = markdown.replace(/\%/g,'%25').replace(/\n/g,'%0A').replace(/\r/g,'%0D')
+  console.log("::set-output name=markdown::" + escaped_markdown)
+
+  // If compress only mode, then we're done
+  if (config.compressOnly) {
+    console.log("->> compressOnly was set. Stopping.");
+    return results;
+  }
+
   console.log("->> Committing files…");
   await createCommit(optimisedImages);