WIP: refactor: port to JS

This should hopefully reduce the complexity of the action

.editorconfig

@@ -2,7 +2,7 @@
 end_of_line = lf
 charset = utf-8
 
-[*.{nix,json,sh}]
+[*.{nix,json,sh,js}]
 indent_style = space
 indent_size = 2
 trim_trailing_whitespace = true

.forgejo/workflows/check.yml

@@ -8,7 +8,7 @@ jobs:
         check:
           - treefmt
     steps:
-      - uses: "https://git.salame.cl/actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683" # v4
+      - uses: 'https://git.salame.cl/actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683' # v4
       - name: Run checks
         run: |
           nix --version
@@ -18,23 +18,25 @@ jobs:
     runs-on: nixos
     needs: check
     steps:
-      - uses: "https://git.salame.cl/actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683" # v4
+      - uses: 'https://git.salame.cl/actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683' # v4
       - run: nix --version
       - name: Create Size Report
         uses: ./
         with:
+          system: x86_64-linux
           # Create a comment on the associated PR
-          comment-on-pr: 'false'
+          comment-on-pr: ${{ github.ref_name != 'main' }}
           # Generate artifacts on main (to speed up comparisons)
           # generate-artifact: ${{ github.ref_name == 'main' }}
           # Always generate artifacts for testing purposes
           generate-artifact: 'true'
-          # This job's name (so we can find the previous artifacts)
+          # Generate comparisons to main
+          do-comparison: 'true'
+          # This job's name (so we can find the artifacts)
           job-name: report-size
   report-download-check:
     runs-on: nixos
-    needs: report-size-push
+    needs: report-size
-    if: github.event_name == 'push'
     steps:
       - name: Download previous report
         uses: https://git.salame.cl/actions/download-artifact@d8d0a99033603453ad2255e58720b460a0555e1e # v4

.forgejo/workflows/renovate.yml

@@ -7,7 +7,7 @@ jobs:
   check-renovaterc:
     runs-on: nixos
     steps:
-      - uses: "https://git.salame.cl/actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683" # v4
+      - uses: 'https://git.salame.cl/actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683' # v4
       - name: Validate renovaterc.json
         run: |
           nix --version

.forgejo/workflows/test-pr.yml

@@ -1,33 +0,0 @@
-on:
-  pull_request:
-jobs:
-  report-size-pr:
-    runs-on: nixos
-    steps:
-      - uses: "https://git.salame.cl/actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683" # v4
-      - run: nix --version
-      - name: Create Size Report
-        uses: ./
-        with:
-          # Create a comment on the associated PR
-          comment-on-pr: 'true'
-          # Generate artifacts on main (to speed up comparisons)
-          # generate-artifact: ${{ github.ref_name == 'main' }}
-          # Always generate artifacts for testing purposes
-          generate-artifact: 'true'
-          # Generate comparisons to main
-          do-comparison: 'true'
-          # Get the previous artifacts from report-size-push (since those run on main)
-          job-name: report-size
-          artifact-name: report.json
-  report-download-check-pr:
-    runs-on: nixos
-    needs: report-size-pr
-    steps:
-      - name: Download previous report
-        uses: https://git.salame.cl/actions/download-artifact@d8d0a99033603453ad2255e58720b460a0555e1e # v4
-        with:
-          name: report.json
-      - name: Verify report exists
-        run: |
-          cat report.json

.gitattributes

@@ -0,0 +1,3 @@
+* text=auto eol=lf
+
+dist/** -diff linguist-generated=true

.gitignore

@@ -1 +1,104 @@
 result*
+
+# Dependency directory
+node_modules
+
+# Rest pulled from https://github.com/github/gitignore/blob/master/Node.gitignore
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+lerna-debug.log*
+
+# Diagnostic reports (https://nodejs.org/api/report.html)
+report.[0-9]*.[0-9]*.[0-9]*.[0-9]*.json
+
+# Runtime data
+pids
+*.pid
+*.seed
+*.pid.lock
+
+# Directory for instrumented libs generated by jscoverage/JSCover
+lib-cov
+
+# Coverage directory used by tools like istanbul
+coverage
+*.lcov
+
+# nyc test coverage
+.nyc_output
+
+# Grunt intermediate storage (https://gruntjs.com/creating-plugins#storing-task-files)
+.grunt
+
+# Bower dependency directory (https://bower.io/)
+bower_components
+
+# node-waf configuration
+.lock-wscript
+
+# Compiled binary addons (https://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directories
+jspm_packages/
+
+# TypeScript v1 declaration files
+typings/
+
+# TypeScript cache
+*.tsbuildinfo
+
+# Optional npm cache directory
+.npm
+
+# Optional eslint cache
+.eslintcache
+
+# Optional REPL history
+.node_repl_history
+
+# Output of 'npm pack'
+*.tgz
+
+# Yarn Integrity file
+.yarn-integrity
+
+# dotenv environment variables file
+.env
+.env.test
+
+# parcel-bundler cache (https://parceljs.org/)
+.cache
+
+# next.js build output
+.next
+
+# nuxt.js build output
+.nuxt
+
+# vuepress build output
+.vuepress/dist
+
+# Serverless directories
+.serverless/
+
+# FuseBox cache
+.fusebox/
+
+# DynamoDB Local files
+.dynamodb/
+
+# OS metadata
+.DS_Store
+Thumbs.db
+
+# Ignore built ts files
+__tests__/runner/*
+
+# IDE files
+.idea
+*.code-workspace

.prettierignore

@@ -0,0 +1,5 @@
+.DS_Store
+.licenses/
+dist/
+node_modules/
+coverage/

.prettierrc.yml

@@ -0,0 +1,15 @@
+# See: https://prettier.io/docs/en/configuration
+printWidth: 80
+tabWidth: 2
+useTabs: false
+semi: false
+singleQuote: true
+quoteProps: as-needed
+jsxSingleQuote: false
+trailingComma: none
+bracketSpacing: true
+bracketSameLine: true
+arrowParens: always
+proseWrap: always
+htmlWhitespaceSensitivity: css
+endOfLine: lf

README.md

@@ -2,9 +2,11 @@
 
 Use `nix path-info` to query the size of flake outputs and produce a report.
 
-This repost can be posted to a PR (as formatted markdown) and/or uploaded as a workflow artifact.
+This repost can be posted to a PR (as formatted markdown) and/or uploaded as a
+workflow artifact.
 
-Requires `nix`, `jq`, `curl`, `sed`, `gunzip`, `tar` and `coreutils` to be in the runner's path.
+Requires `nix`, `jq`, `curl`, `sed`, `gunzip`, `tar` and `coreutils` to be in
+the runner's path.
 
 ## Example
 
@@ -39,26 +41,32 @@ For more details see the [action.yaml](./action.yml) file.
 **Definitions:**
 
 - `Name`: the name of the package/configuration.
-- `Size`: the closure size (size on disk/NAR size + all transitive dependencies).
+- `Size`: the closure size (size on disk/NAR size + all transitive
+  dependencies).
 - `NAR Size`: the size of the build output (package without the dependencies).
 - `[NAR] Size Change`: the amount changed compared to the main branch.
 
 **Tips on reading this data:**
 
-- For NixOS configurations you generally care only about the `Size` (closure size/size on disk).
+- For NixOS configurations you generally care only about the `Size` (closure
+  size/size on disk).
   - Reduce the `Size` by disabling unneeded services/default packages.
 - For Packages you care about both the `Size` and the `NAR Size`.
-  - Reduce the `NAR Size` by reducing the size of the build outputs, e.g. don't copy unnecessary data to the $out dir, optimize binaries for size, etc.
+  - Reduce the `NAR Size` by reducing the size of the build outputs, e.g. don't
+    copy unnecessary data to the $out dir, optimize binaries for size, etc.
   - Reduce the `Size` by reducing the dependencies (e.g. `buildInputs`).
-  - Don't worry too much about size, some dependencies are deduplicated, e.g. `glibc` adds ~40MiB to the `Size`, but is generally shared by ~every binary on the system, so, chances are, you are already including it from somewhere else and statically linking with e.g. `musl` is not gonna improve things.
+  - Don't worry too much about size, some dependencies are deduplicated, e.g.
+    `glibc` adds ~40MiB to the `Size`, but is generally shared by ~every binary
+    on the system, so, chances are, you are already including it from somewhere
+    else and statically linking with e.g. `musl` is not gonna improve things.
 
 # NixOS Configurations
 
-| Name | Size | Size Change | NAR Size | NAR Size Change |
+| Name     |  Size | Size Change | NAR Size | NAR Size Change |
-|------|-----:|------------:|---------:|----------------:|
+| -------- | ----: | ----------: | -------: | --------------: |
-| `gemini` | 11Gi | -2.4Mi | 28Ki | 0 |
+| `gemini` |  11Gi |      -2.4Mi |     28Ki |               0 |
-| `leo` | 1.6Gi | 0 | 25Ki | 0 |
+| `leo`    | 1.6Gi |           0 |     25Ki |               0 |
-| `libra` | 9.4Gi | -2.4Mi | 28Ki | 0 |
+| `libra`  | 9.4Gi |      -2.4Mi |     28Ki |               0 |
-| `taurus` | 7.6Gi | 0 | 34Ki | 0 |
+| `taurus` | 7.6Gi |           0 |     34Ki |               0 |
 
 </details>

action.yml

@@ -32,6 +32,9 @@ inputs:
 
       This is a no-op in case no PR is associated with the current branch.
     default: 'true'
+  system:
+    description: |
+      The nix system name to query the packages of (e.g. x86_64-linux)
   # Generate workflow artifact
   generate-artifact:
     description: Export the generated markdown document as a workflow artifact.
@@ -65,58 +68,5 @@ inputs:
     default: ${{ github.base_ref }}
 outputs:
 runs:
-  using: 'composite'
+  using: node20
-  steps:
+  main: dist/index.js
-    - name: Run
-      id: pr-number
-      env:
-        BASE_BRANCH: ${{ inputs.base-branch }}
-        COMMENT: ${{ inputs.comment-on-pr }}
-        DO_COMPARISON: ${{ inputs.do-comparison }}
-        GENERATE_ARTIFACT: ${{ inputs.generate-artifact }}
-        JOB_NAME: ${{ inputs.job-name }}
-      run: |
-        "$GITHUB_ACTION_PATH/scripts/run.sh"
-    - name: Find previous comment (if present)
-      # We want to generate a comment and we we able to find the PR number
-      if: inputs.comment-on-pr == 'true' && steps.pr-number.outputs.pr-number != ''
-      id: find-comment
-      uses: https://github.com/peter-evans/find-comment@3eae4d37986fb5a8592848f6a574fdf654e61f9e # v3
-      with:
-        issue-number: ${{ steps.pr-number.outputs.pr-number }}
-        direction: first
-        body-includes: "<!-- AUTOGENERATED by nix-flake-outputs-size action -->"
-    - name: Create report and comment on PR
-      # We want to generate a comment and we we able to find the PR number
-      if: inputs.comment-on-pr == 'true' && steps.pr-number.outputs.pr-number != ''
-      env:
-        ARTIFACT_NAME: ${{ inputs.artifact-name }}
-        BASE_BRANCH: ${{ inputs.base-branch }}
-        COMMENT_ID: ${{ steps.find-comment.outputs.comment-id }}
-        DO_COMPARISON: ${{ inputs.do-comparison }}
-        JOB_NAME: ${{ inputs.job-name }}
-        PR_ID: ${{ steps.pr-number.outputs.pr-number }}
-      run: |
-        . "$GITHUB_ACTION_PATH/scripts/utils.sh"
-
-        # Try to do a comparison report
-        if [ "$DO_COMPARISON" = 'true' ]; then
-          if "$GITHUB_ACTION_PATH/scripts/retrieve-old-report.sh" && [ -f old-report.json ]; then
-            log "Reporting on sizes and comparing to sizes in $BASE_BRANCH"
-
-            "$GITHUB_ACTION_PATH/scripts/comment_on_pr.sh" report.json old-report.json
-            exit 0
-          else
-            error 'Failed to do comparison, fallback to posting the report without them'
-          fi
-        fi
-
-        # Just report values
-        log 'Reporting on sizes'
-        "$GITHUB_ACTION_PATH/scripts/comment_on_pr.sh" report.json
-    - name: Upload Artifact
-      uses: https://git.salame.cl/actions/upload-artifact@v4
-      if: inputs.generate-artifact == 'true'
-      with:
-        path: report.json
-        name: ${{ inputs.artifact-name }}

eslint.config.mjs

@@ -0,0 +1,61 @@
+// See: https://eslint.org/docs/latest/use/configure/configuration-files
+
+import { fixupPluginRules } from '@eslint/compat'
+import { FlatCompat } from '@eslint/eslintrc'
+import js from '@eslint/js'
+import _import from 'eslint-plugin-import'
+import jest from 'eslint-plugin-jest'
+import prettier from 'eslint-plugin-prettier'
+import globals from 'globals'
+import path from 'node:path'
+import { fileURLToPath } from 'node:url'
+
+const __filename = fileURLToPath(import.meta.url)
+const __dirname = path.dirname(__filename)
+const compat = new FlatCompat({
+  baseDirectory: __dirname,
+  recommendedConfig: js.configs.recommended,
+  allConfig: js.configs.all
+})
+
+export default [
+  {
+    ignores: ['**/coverage', '**/dist', '**/linter', '**/node_modules']
+  },
+  ...compat.extends(
+    'eslint:recommended',
+    'plugin:jest/recommended',
+    'plugin:prettier/recommended'
+  ),
+  {
+    plugins: {
+      import: fixupPluginRules(_import),
+      jest,
+      prettier
+    },
+
+    languageOptions: {
+      globals: {
+        ...globals.node,
+        ...globals.jest,
+        Atomics: 'readonly',
+        SharedArrayBuffer: 'readonly'
+      },
+
+      ecmaVersion: 2023,
+      sourceType: 'module'
+    },
+
+    rules: {
+      camelcase: 'off',
+      'eslint-comments/no-use': 'off',
+      'eslint-comments/no-unused-disable': 'off',
+      'i18n-text/no-en': 'off',
+      'import/no-namespace': 'off',
+      'no-console': 'off',
+      'no-shadow': 'off',
+      'no-unused-vars': 'off',
+      'prettier/prettier': 'error'
+    }
+  }
+]

flake.nix

@@ -26,10 +26,12 @@
           # Setup formatters
           treefmt = {
             # Ignore images
-            settings.global.excludes = [ "*.png" ];
+            settings.global.excludes = [
+              "*.png"
+              "dist/*"
+            ];
             projectRootFile = "flake.nix";
             programs = {
-              mdformat.enable = true;
               nixfmt.enable = true;
               shfmt.enable = true;
               shellcheck.enable = true;

jest.config.js

@@ -0,0 +1,30 @@
+// See: https://jestjs.io/docs/configuration
+
+/** @type {import('jest').Config} */
+const jestConfig = {
+  clearMocks: true,
+  collectCoverage: true,
+  collectCoverageFrom: ['./src/**'],
+  coverageDirectory: './coverage',
+  coveragePathIgnorePatterns: ['/node_modules/', '/dist/'],
+  coverageReporters: ['json-summary', 'text', 'lcov'],
+  // Uncomment the below lines if you would like to enforce a coverage threshold
+  // for your action. This will fail the build if the coverage is below the
+  // specified thresholds.
+  // coverageThreshold: {
+  //   global: {
+  //     branches: 100,
+  //     functions: 100,
+  //     lines: 100,
+  //     statements: 100
+  //   }
+  // },
+  moduleFileExtensions: ['js'],
+  reporters: ['default'],
+  testEnvironment: 'node',
+  testMatch: ['**/*.test.js'],
+  testPathIgnorePatterns: ['/dist/', '/node_modules/'],
+  verbose: true
+}
+
+export default jestConfig

package.json

@@ -0,0 +1,66 @@
+{
+  "name": "nix-flake-outputs-size-report",
+  "description": "Use 'nix-path-info' to query the size of outputs and produce a markdown report",
+  "version": "0.1.0",
+  "author": "Jalil David Salamé Messina",
+  "type": "module",
+  "private": true,
+  "homepage": "https://git.salame.cl/jalil/nix-flake-outputs-size#readme",
+  "repository": {
+    "type": "git",
+    "url": "git+https://git.salame.cl/jalil/nix-flake-outputs-size.git"
+  },
+  "bugs": {
+    "url": "https://git.salame.cl/jalil/nix-flake-outputs-size/issues"
+  },
+  "keywords": [
+    "actions"
+  ],
+  "exports": {
+    ".": "./dist/index.js"
+  },
+  "engines": {
+    "node": ">=20"
+  },
+  "scripts": {
+    "bundle": "npm run format:write && npm run package",
+    "ci-test": "NODE_OPTIONS=--experimental-vm-modules NODE_NO_WARNINGS=1 npx jest",
+    "coverage": "npx make-coverage-badge --output-path ./badges/coverage.svg",
+    "format:write": "npx prettier --write .",
+    "format:check": "npx prettier --check .",
+    "lint": "npx eslint .",
+    "local-action": "npx @github/local-action . src/main.js .env",
+    "package": "npx rollup --config rollup.config.js",
+    "package:watch": "npm run package -- --watch",
+    "test": "NODE_OPTIONS=--experimental-vm-modules NODE_NO_WARNINGS=1 npx jest",
+    "all": "npm run format:write && npm run lint && npm run test && npm run coverage && npm run package"
+  },
+  "license": "MIT",
+  "dependencies": {
+    "@actions/artifact": "^2.3.2",
+    "@actions/core": "^1.11.1",
+    "@actions/exec": "^1.1.1",
+    "@actions/github": "^6.0.1"
+  },
+  "devDependencies": {
+    "@eslint/compat": "^1.3.1",
+    "@github/local-action": "^3.2.1",
+    "@jest/globals": "^30.0.4",
+    "@rollup/plugin-commonjs": "^28.0.6",
+    "@rollup/plugin-json": "^6.1.0",
+    "@rollup/plugin-node-resolve": "^16.0.1",
+    "eslint": "^9.30.1",
+    "eslint-config-prettier": "^10.1.5",
+    "eslint-plugin-import": "^2.32.0",
+    "eslint-plugin-jest": "^29.0.1",
+    "eslint-plugin-prettier": "^5.5.1",
+    "jest": "^30.0.4",
+    "make-coverage-badge": "^1.2.0",
+    "prettier": "^3.6.2",
+    "prettier-eslint": "^16.4.2",
+    "rollup": "^4.44.2"
+  },
+  "optionalDependencies": {
+    "@rollup/rollup-linux-x64-gnu": "*"
+  }
+}

report.json

@@ -0,0 +1,11 @@
+{
+  "packages": [
+    {
+      "name": "hello",
+      "size": 33159640,
+      "narSize": 234680
+    }
+  ],
+  "nixosConfigurations": [],
+  "homeConfigurations": []
+}

rollup.config.js

@@ -0,0 +1,18 @@
+// See: https://rollupjs.org/introduction/
+
+import commonjs from '@rollup/plugin-commonjs'
+import json from '@rollup/plugin-json'
+import { nodeResolve } from '@rollup/plugin-node-resolve'
+
+const config = {
+  input: 'src/index.js',
+  output: {
+    esModule: true,
+    file: 'dist/index.js',
+    format: 'es',
+    sourcemap: true
+  },
+  plugins: [commonjs(), json(), nodeResolve({ preferBuiltins: true })]
+}
+
+export default config

scripts/create-report.sh

@@ -7,25 +7,24 @@ util_path="${GITHUB_ACTION_PATH:-.}/scripts/utils.sh"
 # shellcheck source=scripts/utils.sh
 . "${util_path}"
 
+group 'Retrieving Flake information'
+flake_info=$(nix flake show --json --quiet --quiet)
+endgroup
+
 system=$(nix eval --impure --json --expr 'builtins.currentSystem')
 
-# Extract the names of a flake attrset
+group 'Show Packages'
-get_names() {
+packages=$(echo "$flake_info" | jq --raw-output --argjson system "$system" 'getpath(["packages", $system]) | select(. != null) | keys[]')
-  nix eval --json --apply builtins.attrNames "$1" 2>/dev/null | jq --raw-output '.[]'
-}
-
-group "Show Packages for $system"
-packages=$(get_names .#packages."$system")
 [ -z "$packages" ] || log "$packages"
 endgroup
 
 group 'Show Home Manager Configurations'
-hmConfigs=$(get_names .#homeConfigurations)
+hmConfigs=$(echo "$flake_info" | jq --raw-output '.homeConfigurations | select(. != null) | keys[]')
 [ -z "$hmConfigs" ] || log "$hmConfigs"
 endgroup
 
 group 'Show NixOS Configurations'
-nixosConfigs=$(get_names .#nixosConfigurations)
+nixosConfigs=$(echo "$flake_info" | jq --raw-output '.nixosConfigurations | select(. != null) | keys[]')
 [ -z "$nixosConfigs" ] || log "$nixosConfigs"
 endgroup
 
@@ -52,7 +51,7 @@ pkgs_json() {
 hm_configs_json() {
   for config in $hmConfigs; do
     log "Building $config"
-    path=$(nix build --print-out-paths ".#homeConfigurations.$config.config.home.activationPackage")
+    path=$(nix build --print-out-paths ".#homeConfigurations.$config.activationPackages")
     closure_size "$config" "$path"
   done
 }

scripts/retrieve-old-report.sh

@@ -40,9 +40,7 @@ has_report() {
 # If a base branch is not provided, use the default branch
 base_branch=${BASE_BRANCH:-$(default_branch)}
 
-if in_private_repo; then
+if [ "$(in_private_repo)" != 'true' ] && [ "$JOB_NAME" ]; then
-  warn 'Detected that this is a private repo cannot retrieve old report'
-elif [ "$JOB_NAME" ]; then
   url=$(base_report_url "$base_branch")
 
   log "Found previous run at: $url"
@@ -58,14 +56,13 @@ elif [ "$JOB_NAME" ]; then
     exit 0
   fi
   error "Failed to find previous report, expected at: $report_url"
-else
-  panic 'job-name is missing, therefore we cannot find the previous report'
 fi
 
-warn "Couldn't retrieve old report:
+warn "Couldn't retrieve old report:"
-  note: This usually happens when running on private repos or when job-name is not set.
+warn '    This usuially happens when running on private repos'
-
+warn '    or when job-name is not set.'
-        See the README for more details"
+warn
+warn '    See the README for more details'
 
 error "Falling back to slow method (checkout $base_branch and generate the report)"
 

scripts/run.sh

@@ -1,61 +0,0 @@
-#!/bin/sh
-
-. "$GITHUB_ACTION_PATH/scripts/utils.sh"
-
-# Input validation
-if [ "$COMMENT" != "true" ] && [ "$GENERATE_ARTIFACT" != "true" ]; then
-  panic 'Neither comment-on-pr nor generate-artifact is set
-    note: this looks like an error; if it isn'"'"'t disable this action with "step.if"'
-fi
-
-if [ "$DO_COMPARISON" = 'true' ] && [ -z "$JOB_NAME" ]; then
-  panic 'Requested a comparison report but job-name wasn'"'"'t set'
-fi
-
-# Create Size Report (will be uploaded by the upload-artifact action)
-"$GITHUB_ACTION_PATH/scripts/create-report.sh" report.json
-
-# Nothing else to do
-if [ "$COMMENT" != "true" ]; then exit 0; fi
-
-# Find the PR for this commit so we can post a comment on it
-pr_number=
-case "$GITHUB_EVENT_NAME" in
-"pull_request")
-  pr_number=$(jq .number "$GITHUB_EVENT_PATH")
-  log "Triggered by a pull request with index: $pr_number"
-  ;;
-"push")
-  log "Triggered by a push to $GITHUB_REF_NAME autodetecting PR number"
-
-  log "Get PR number for $GITHUB_REF_NAME"
-  prs=$(curl -X 'GET' \
-    "$GITHUB_API_URL/repos/$GITHUB_REPOSITORY/pulls?state=open&sort=recentupdate" \
-    -H "Authorization: token $GITHUB_TOKEN" \
-    -H 'Accept: application/json')
-
-  log "Found these open PRs: $(echo "$prs" | jq '[.[] | .number]')"
-
-  pr_number=$(echo "$prs" |
-    jq --arg ref "$GITHUB_REF_NAME" '.[] | select(.head.ref == $ref) | .number')
-
-  # Protect against running before a PR is made or if it is triggered on the main branch
-  if [ -z "$pr_number" ]; then
-    warn "No PR created for this commit"
-    exit 0
-  fi
-
-  log "The PR we found for $GITHUB_REF_NAME is $pr_number"
-  ;;
-*)
-  panic "Unexpected event $GITHUB_EVENT_NAME for commenting on a PR, expected push or pull_request"
-  ;;
-esac
-
-log "Expected PR URL: $GITHUB_SERVER_URL/$GITHUB_REPOSITORY/pulls/$pr_number"
-
-# This seems to create the file???
-log "GITHUB_OUTPUT=$GITHUB_OUTPUT"
-log "$(ls -l "$GITHUB_OUTPUT")"
-
-echo "pr-number=$pr_number" >>"$GITHUB_OUTPUT"

scripts/utils.sh

@@ -12,11 +12,6 @@ error() {
   log "\e[0;31m[WARN]:" "$@" "\e[0m"
 }
 
-panic() {
-  error "$@"
-  exit 1
-}
-
 group() {
   echo "::group::$1"
 }

src/index.js

@@ -0,0 +1,8 @@
+/**
+ * The entrypoint for the action. This file simply imports and runs the action's
+ * main logic.
+ */
+import { run } from './main.js'
+
+/* istanbul ignore next */
+run()

src/main.js

@@ -0,0 +1,145 @@
+import * as core from '@actions/core'
+import * as exec from '@actions/exec'
+import * as github from '@actions/github'
+import { DefaultArtifactClient } from '@actions/artifact'
+import * as fs from 'node:fs/promises'
+
+/**
+ * The main function for the action.
+ *
+ * @returns {Promise<void>} Resolves when the action is complete.
+ */
+export async function run() {
+  try {
+    const comment = core.getBooleanInput('comment-on-pr', { required: false })
+    const upload = core.getBooleanInput('generate-artifact', {
+      required: false
+    })
+    const artifactName = core.getInput('artifact-name', { required: false })
+    const compare = core.getBooleanInput('do-comparison', { required: false })
+    const jobName = core.getInput('job-name', { required: false })
+    const baseBranch = core.getInput('base-branch', { required: false })
+    const system = core.getInput('system', { required: true })
+
+    if (!comment && !upload) {
+      core.error(
+        'Both comment-on-pr and generate-artifact were set to false, nothing to do, consider disabling the action instead'
+      )
+      core.setFailed('Neither commenting nor uploading a report ... why?')
+      return
+    }
+
+    const flakeInfo = JSON.parse(
+      await collectOutput('nix', ['flake', 'show', '--json'])
+    )
+    core.debug(`nix flake show --json: ${flakeInfo}`)
+
+    const report = await core.group('Generating size report', () =>
+      generateReport(flakeInfo, system)
+    )
+
+    if (upload) {
+      const artifact = new DefaultArtifactClient()
+      await fs.writeFile(artifactName, JSON.stringify(report))
+      const { id, size } = artifact.uploadArtifact(artifactName, [artifactName])
+
+      core.info(`Uploaded report ${artifactName} (${size}B) with id ${id}`)
+    }
+
+    // Done
+    if (!comment) {
+      return
+    }
+
+    // TODO: compare reports and create comment
+  } catch (error) {
+    // Fail the workflow run if an error occurs
+    if (error instanceof Error) core.setFailed(error.message)
+  }
+}
+
+async function generateReport(flakeInfo, system) {
+  const packages = getPackages(flakeInfo, system)
+  const hmConfigs = getKeys(flakeInfo, 'homeConfigurations')
+  const nixosConfigs = getKeys(flakeInfo, 'nixosConfigurations')
+
+  core.info(`packages: ${packages}`)
+  core.info(`homeConfigurations: ${hmConfigs}`)
+  core.info(`nixosConfigurations: ${nixosConfigs}`)
+
+  const pkgSizes = await core.group('Calculating size of packages', () =>
+    calculateSizeOf(packages, (pkg) => `.#${pkg}`)
+  )
+
+  const hmConfigsSizes = await core.group(
+    'Calculating size of Home-Manager Configurations',
+    () =>
+      calculateSizeOf(
+        hmConfigs,
+        (config) => `.#homeConfigurations.${config}.activationPackages`
+      )
+  )
+
+  const nixosConfigsSizes = await core.group(
+    'Calculating size of NixOS Configurations',
+    () =>
+      calculateSizeOf(
+        nixosConfigs,
+        (config) =>
+          `.#nixosConfigurations.${config}.config.system.build.toplevel`
+      )
+  )
+
+  return {
+    packages: pkgSizes,
+    nixosConfigurations: nixosConfigsSizes,
+    homeConfigurations: hmConfigsSizes
+  }
+}
+
+async function calculateSizeOf(names, nameToInstallable) {
+  let sizes = []
+  for (const name of names) {
+    sizes.push(await calculateSize(nameToInstallable(name)))
+  }
+  return sizes
+}
+
+/**
+ * Get the packages from a `nix flake show --json` blob
+ *
+ * @returns {Array<String>} the packages in the current flake for the specific system
+ */
+function getPackages(flakeInfo, system) {
+  return 'packages' in flakeInfo ? getKeys(flakeInfo.packages, system) : []
+}
+
+function getKeys(flakeInfo, key) {
+  return key in flakeInfo ? Object.keys(flakeInfo[key]) : []
+}
+
+async function calculateSize(installable) {
+  const path = await collectOutput('nix', [
+    'build',
+    '--print-out-paths',
+    installable
+  ])
+  const data = JSON.parse(
+    await collectOutput('nix', ['path-info', '--closure-size', '--json', path])
+  )
+  data.path = path
+
+  return data
+}
+
+async function collectOutput(cmd, args) {
+  let output = ''
+  await exec.exec(cmd, args, {
+    listeners: {
+      stdout: (data) => {
+        output += data.toString()
+      }
+    }
+  })
+  return output.trim()
+}