Create cache destination manually.

We have to do it with sudo (to create dirs in root) and make sure that the resulting dirs are owned by the runner user.

In order to do that, implement `mkdir -p` manually.

dist/index/index.js

@@ -27147,6 +27147,27 @@ function resolveHome(filepath) {
     }
     return filepath;
 }
+async function sudoMkdirP(path, userColonGroup) {
+    const anc = ancestors(path);
+    for (const p of anc) {
+        if (external_fs_.existsSync(p))
+            continue;
+        await lib_exec.exec("sudo", ["mkdir", p]);
+        await lib_exec.exec("sudo", ["chown", userColonGroup, p]);
+    }
+}
+function ancestors(filepath) {
+    const res = [];
+    let norm = external_path_.normalize(filepath);
+    while (norm !== "." && norm !== "/") {
+        res.unshift(norm);
+        const next = external_path_.dirname(norm);
+        if (next === norm)
+            break;
+        norm = next;
+    }
+    return res;
+}
 async function getCacheUtil(cachePath) {
     const { stdout } = await exec.getExecOutput(`/bin/sh -c "du -sb ${cachePath} | cut -f1"`, [], {
         silent: true,
@@ -27245,9 +27266,8 @@ async function restoreLocalCache(cachePaths) {
         }
         const expandedFilePath = resolveHome(p.mountTarget);
         await io.mkdirP(p.pathInCache);
-        // Sudo to be able to create dirs in root (e.g. /nix).
-        // Use `install` instead of `mkdir -p` to easily set owners.
-        await lib_exec.exec(`sudo install -d -o runner -g docker ${expandedFilePath}`);
+        // Sudo to be able to create dirs in root (e.g. /nix), but set the runner as owner.
+        await sudoMkdirP(expandedFilePath, "runner:docker");
         await lib_exec.exec(`sudo mount --bind ${p.pathInCache} ${expandedFilePath}`);
     }
     return cacheMisses;

src/index.ts

@@ -87,9 +87,8 @@ export async function restoreLocalCache(
 
     const expandedFilePath = utils.resolveHome(p.mountTarget);
     await io.mkdirP(p.pathInCache);
-    // Sudo to be able to create dirs in root (e.g. /nix).
-    // Use `install` instead of `mkdir -p` to easily set owners.
-    await exec.exec(`sudo install -d -o runner -g docker ${expandedFilePath}`);
+    // Sudo to be able to create dirs in root (e.g. /nix), but set the runner as owner.
+    await utils.sudoMkdirP(expandedFilePath, "runner:docker");
     await exec.exec(`sudo mount --bind ${p.pathInCache} ${expandedFilePath}`);
   }
 

src/utils.ts

@@ -25,6 +25,27 @@ export function resolveHome(filepath: string): string {
   return filepath;
 }
 
+export async function sudoMkdirP(path: string, userColonGroup: string) {
+  const anc = ancestors(path);
+  for (const p of anc) {
+    if (fs.existsSync(p)) continue;
+    await exec.exec("sudo", ["mkdir", p]);
+    await exec.exec("sudo", ["chown", userColonGroup, p]);
+  }
+}
+
+function ancestors(filepath: string) {
+  const res: string[] = [];
+  let norm = path.normalize(filepath);
+  while (norm !== "." && norm !== "/") {
+    res.unshift(norm);
+    const next = path.dirname(norm);
+    if (next === norm) break;
+    norm = next;
+  }
+  return res;
+}
+
 export async function getCacheUtil(cachePath: string): Promise<number> {
   const { stdout } = await exec.getExecOutput(
     `/bin/sh -c "du -sb ${cachePath} | cut -f1"`,