Allow overriding container image

action.yml

@@ -19,6 +19,9 @@ inputs:
   save-always:
     default: "false"
     description: "Run the post step to save the cache even if another step before fails"
+  utility-image:
+    default: "ghcr.io/containerd/busybox:latest"
+    description: "The container image to use for injecting and extracting the cache"
 runs:
   using: 'node20'
   main: 'dist/index.js'

src/extract-cache.ts

@@ -3,7 +3,7 @@ import path from 'path';
 import { CacheOptions, Opts, getCacheMap, getMountArgsString, getTargetPath } from './opts.js';
 import { run, runPiped } from './run.js';
 
-async function extractCache(cacheSource: string, cacheOptions: CacheOptions, scratchDir: string) {
+async function extractCache(cacheSource: string, cacheOptions: CacheOptions, scratchDir: string, containerImage: string) {
     // Prepare Timestamp for Layer Cache Busting
     const date = new Date().toISOString();
 
@@ -15,7 +15,7 @@ async function extractCache(cacheSource: string, cacheOptions: CacheOptions, scr
     const mountArgs = getMountArgsString(cacheOptions);
 
     const dancefileContent = `
-FROM busybox:1
+FROM ${containerImage}
 COPY buildstamp buildstamp
 RUN --mount=${mountArgs} \
     mkdir -p /var/dance-cache/ \
@@ -54,9 +54,10 @@ export async function extractCaches(opts: Opts) {
 
     const cacheMap = getCacheMap(opts);
     const scratchDir = opts['scratch-dir'];
+    const containerImage = opts['utility-image'];
 
     // Extract Caches for each source-target pair
     for (const [cacheSource, cacheOptions] of Object.entries(cacheMap)) {
-        await extractCache(cacheSource, cacheOptions, scratchDir);
+        await extractCache(cacheSource, cacheOptions, scratchDir, containerImage);
     }
 }

src/inject-cache.ts

@@ -4,7 +4,7 @@ import { CacheOptions, Opts, getCacheMap, getMountArgsString, getTargetPath, get
 import { run } from './run.js';
 import { notice } from '@actions/core';
 
-async function injectCache(cacheSource: string, cacheOptions: CacheOptions, scratchDir: string) {
+async function injectCache(cacheSource: string, cacheOptions: CacheOptions, scratchDir: string, containerImage: string) {
     // Clean Scratch Directory
     await fs.rm(scratchDir, { recursive: true, force: true });
     await fs.mkdir(scratchDir, { recursive: true });
@@ -29,7 +29,7 @@ async function injectCache(cacheSource: string, cacheOptions: CacheOptions, scra
 
     // Prepare Dancefile to Access Caches
     const dancefileContent = `
-FROM busybox:1
+FROM ${containerImage}
 COPY buildstamp buildstamp
 RUN --mount=${mountArgs} \
     --mount=type=bind,source=.,target=/var/dance-cache \
@@ -54,9 +54,10 @@ RUN --mount=${mountArgs} \
 export async function injectCaches(opts: Opts) {
     const cacheMap = getCacheMap(opts);
     const scratchDir = opts['scratch-dir'];
+    const containerImage = opts['utility-image'];
 
     // Inject Caches for each source-target pair
     for (const [cacheSource, cacheOptions] of Object.entries(cacheMap)) {
-        await injectCache(cacheSource, cacheOptions, scratchDir);
+        await injectCache(cacheSource, cacheOptions, scratchDir, containerImage);
     }
 }

src/opts.ts

@@ -6,6 +6,7 @@ export type Opts = {
   "cache-map": string
   "scratch-dir": string
   "skip-extraction": boolean
+  "utility-image": string
   help: boolean
   /** @deprecated Use `cache-map` instead */
   "cache-source"?: string
@@ -20,9 +21,10 @@ export function parseOpts(args: string[]): mri.Argv<Opts> {
       "scratch-dir": getInput("scratch-dir") || "scratch",
       "skip-extraction": (getInput("skip-extraction") || "false") === "true",
       "extract": process.env[`STATE_POST`] !== undefined,
+      "utility-image": getInput("utility-image") || "ghcr.io/containerd/busybox:latest",
       "help": false,
     },
-    string: ["cache-map", "scratch-dir", "cache-source", "cache-target"],
+    string: ["cache-map", "scratch-dir", "cache-source", "cache-target", "utility-image"],
     boolean: ["skip-extraction", "help", "extract"],
     alias: {
       "help": ["h"],
@@ -49,6 +51,7 @@ Options:
   --cache-map    The map of actions source paths to container destination paths or mount arguments
   --scratch-dir  Where the action is stores some temporary files for its processing. Default: 'scratch'
   --skip-extraction  Skip the extraction of the cache from the docker container
+  --utility-image  The container image to use for injecting and extracting the cache. Default: 'ghcr.io/containerd/busybox:latest'
   --help         Show this help
 `);
 }

tests/opts.test.ts

@@ -10,7 +10,8 @@ test('parseOpts with no arguments', () => {
         "skip-extraction": false,
         "extract": false,
         "h": false,
-        "help": false
+        "help": false,
+        "utility-image": "ghcr.io/containerd/busybox:latest"
     })
 })
 
@@ -23,7 +24,8 @@ test('parseOpts with cache-map argument', () => {
         "skip-extraction": false,
         "extract": false,
         "h": false,
-        "help": false
+        "help": false,
+        "utility-image": "ghcr.io/containerd/busybox:latest"
     })
 })
 
@@ -38,7 +40,22 @@ test('parseOpts with deprecated cache-source and cache-target arguments', () =>
         "h": false,
         "help": false,
         "cache-source": 'source',
-        "cache-target": 'target'
+        "cache-target": 'target',
+        "utility-image": "ghcr.io/containerd/busybox:latest"
+    })
+})
+
+test('parseOpts with utility-image argument', () => {
+    const opts = parseOpts(['--utility-image', 'alpine:1'])
+    expect(opts).toEqual({
+        "_": [],
+        "cache-map": '{}',
+        "scratch-dir": "scratch",
+        "skip-extraction": false,
+        "extract": false,
+        "h": false,
+        "help": false,
+        "utility-image": "alpine:1"
     })
 })
 
@@ -52,6 +69,7 @@ test('parseOpts with help argument', () => {
         "extract": false,
         "h": true,
         "help": true,
+        "utility-image": "ghcr.io/containerd/busybox:latest"
     })
 })
 
@@ -131,4 +149,4 @@ test('getGID with object with gid', () => {
     const cacheOptions = { target: 'targetPath', shared: true, id: 1, gid: 1000 }
     const gid = getGID(cacheOptions)
     expect(gid).toBe('1000')
-})
+})