feat: support arbitrary mount options for each cache

Signed-off-by: Amin Yahyaabadi <[email protected]>

README.md

@@ -85,6 +85,21 @@ Real-world examples:
 - <https://github.com/rootless-containers/slirp4netns/blob/v1.2.2/.github/workflows/release.yaml#L18-L36>
 - <https://github.com/containers/fuse-overlayfs/blob/40e0f3c/.github/workflows/release.yaml#L17-L36>
 
+## CacheMap Options
+
+Optionally, instead of a single string for the `target`, you can provide an object with additional options that should be passed to `--mount=type=cache` in the values `cache-map` JSON. The `target` path must be present in the object as a property.
+
+```json
+{
+  "var-cache-apt": {
+    "target": "/var/cache/apt",
+    "sharing": "locked",
+    "id": "1"
+  },
+  "var-lib-apt": "/var/lib/apt"
+}
+```
+
 ## CLI Usage
 
 In other CI systems, you can run the script directly via `node`:

action.yml

@@ -3,7 +3,7 @@ description: "Injects the cached data into the docker build(x|kit) process"
 inputs:
   cache-map:
     required: true
-    description: "The map of actions source to container destination paths for the cache paths"
+    description: "The map of actions source paths to container destination paths or mount arguments"
   cache-source:
     deprecationMessage: "Use `cache-map` instead"
     description: "Where the cache is stored in the calling workspace. Default: `cache`"

src/extract-cache.ts

@@ -1,21 +1,24 @@
 import fs from 'fs/promises';
 import path from 'path';
-import { Opts, getCacheMap } from './opts.js';
+import { CacheOptions, Opts, getCacheMap, getMountArgsString, getTargetPath } from './opts.js';
 import { run, runPiped } from './run.js';
 import { spawn } from 'child_process';
 
-async function extractCache(cacheSource: string, cacheTarget: string, scratchDir: string) {
+async function extractCache(cacheSource: string, cacheOptions: CacheOptions, scratchDir: string) {
     // Prepare Timestamp for Layer Cache Busting
     const date = new Date().toISOString();
     await fs.writeFile(path.join(scratchDir, 'buildstamp'), date);
 
     // Prepare Dancefile to Access Caches
+    const targetPath = getTargetPath(cacheOptions);
+    const mountArgs = getMountArgsString(cacheOptions);
+
     const dancefileContent = `
 FROM busybox:1
 COPY buildstamp buildstamp
-RUN --mount=type=cache,target=${cacheTarget} \
+RUN --mount=${mountArgs} \
     mkdir -p /var/dance-cache/ \
-    && cp -p -R ${cacheTarget}/. /var/dance-cache/ || true
+    && cp -p -R ${targetPath}/. /var/dance-cache/ || true
 `;
     await fs.writeFile(path.join(scratchDir, 'Dancefile.extract'), dancefileContent);
     console.log(dancefileContent);
@@ -52,7 +55,7 @@ export async function extractCaches(opts: Opts) {
     const scratchDir = opts['scratch-dir'];
 
     // Extract Caches for each source-target pair
-    for (const [cacheSource, cacheTarget] of Object.entries(cacheMap)) {
-        await extractCache(cacheSource, cacheTarget, scratchDir);
+    for (const [cacheSource, cacheOptions] of Object.entries(cacheMap)) {
+        await extractCache(cacheSource, cacheOptions, scratchDir);
     }
 }

src/inject-cache.ts

@@ -1,9 +1,9 @@
 import fs from 'fs/promises';
 import path from 'path';
-import { Opts, getCacheMap } from './opts.js';
+import { CacheOptions, Opts, getCacheMap, getMountArgsString, getTargetPath } from './opts.js';
 import { run } from './run.js';
 
-async function injectCache(cacheSource: string, cacheTarget: string, scratchDir: string) {
+async function injectCache(cacheSource: string, cacheOptions: CacheOptions, scratchDir: string) {
     // Clean Scratch Directory
     await fs.rm(scratchDir, { recursive: true, force: true });
     await fs.mkdir(scratchDir, { recursive: true });
@@ -15,13 +15,16 @@ async function injectCache(cacheSource: string, cacheTarget: string, scratchDir:
     const date = new Date().toISOString();
     await fs.writeFile(path.join(cacheSource, 'buildstamp'), date);
 
+    const targetPath = getTargetPath(cacheOptions);
+    const mountArgs = getMountArgsString(cacheOptions);
+
     // Prepare Dancefile to Access Caches
     const dancefileContent = `
 FROM busybox:1
 COPY buildstamp buildstamp
-RUN --mount=type=cache,target=${cacheTarget} \
+RUN --mount=${mountArgs} \
     --mount=type=bind,source=.,target=/var/dance-cache \
-    cp -p -R /var/dance-cache/. ${cacheTarget} || true
+    cp -p -R /var/dance-cache/. ${targetPath} || true
 `;
     await fs.writeFile(path.join(scratchDir, 'Dancefile.inject'), dancefileContent);
     console.log(dancefileContent);
@@ -39,7 +42,7 @@ export async function injectCaches(opts: Opts) {
     const scratchDir = opts['scratch-dir'];
 
     // Inject Caches for each source-target pair
-    for (const [cacheSource, cacheTarget] of Object.entries(cacheMap)) {
-        await injectCache(cacheSource, cacheTarget, scratchDir);
+    for (const [cacheSource, cacheOptions] of Object.entries(cacheMap)) {
+        await injectCache(cacheSource, cacheOptions, scratchDir);
     }
 }

src/opts.ts

@@ -45,17 +45,54 @@ Save 'RUN --mount=type=cache' caches on GitHub Actions or other CI platforms
 
 Options:
   --extract      Extract the cache from the docker container (extract step). Otherwise, inject the cache (main step)
-  --cache-map    The map of actions source to container destination paths for the cache paths
+  --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
   --help         Show this help
 `);
 }
 
-export function getCacheMap(opts: Opts): Record<string, string> {
+export type SourcePath = string
+export type TargetPath = string
+export type ToStringable = {
+  toString(): string;
+}
+export type CacheOptions = TargetPath | { target: TargetPath } & Record<string, ToStringable>
+export type CacheMap = Record<SourcePath, CacheOptions>
+
+export function getCacheMap(opts: Opts): CacheMap {
   try {
-    return JSON.parse(opts["cache-map"]) as Record<string, string>;
+    return JSON.parse(opts["cache-map"]) as CacheMap;
   } catch (e) {
     throw new Error(`Failed to parse cache map. Expected JSON, got:\n${opts["cache-map"]}\n${e}`);
   }
 }
+
+export function getTargetPath(cacheOptions: CacheOptions): TargetPath {
+  if (typeof cacheOptions === "string") {
+    // only the target path is provided
+    return cacheOptions;
+  } else {
+    // object is provided
+    try {
+      return cacheOptions.target;
+    } catch (e) {
+      throw new Error(`Expected the 'target' key in the cache options, got:\n${cacheOptions}\n${e}`);
+    }
+  }
+}
+
+/**
+ * Convert a cache options to a string that is passed to --mount=
+ * @param CacheOptions The cache options to convert to a string
+ */
+export function getMountArgsString(cacheOptions: CacheOptions): string {
+  if (typeof cacheOptions === "string") {
+    // only the target path is provided
+    return `type=cache,target=${cacheOptions}`;
+  } else {
+    // other options are provided
+    const otherOptions = Object.entries(cacheOptions).map(([key, value]) => `${key}=${value}`).join(",");
+    return `type=cache,${otherOptions}`;
+  }
+}