Install rustup.

.eslintrc.js

@@ -7,4 +7,7 @@ module.exports = {
 		project: 'tsconfig.json',
 		tsconfigRootDir: __dirname,
 	},
+	rules: {
+		'unicorn/prefer-top-level-await': 'off',
+	},
 };

CHANGELOG.md

@@ -1,5 +1,6 @@
 # 1.0.0
 
+- Will now install `rustup` if it does not exist in the environment.
 - Added musl support to `cargo-binstall`.
 
 # 0.6.0

README.md

@@ -147,11 +147,6 @@ Outside of being evergreen, this action also supports the following features:
 - Assumes `rustup`, `cargo`, and other commands are available globally. This allows you to use them
   directly in a `run` command, without having to use `actions-rs/cargo`.
 
-However, this action _does not_:
-
-- Install `rustup` if it does not exist, while `actions-rs` will. This is typically fine if using
-  GitHub provided runners as all Rust tooling comes pre-installed.
-
 ### `dtolnay/rust-toolchain`
 
 Our action is very similar to theirs, which was a great implementation reference, but our action

index.ts

@@ -1,8 +1,39 @@
-import path from 'path';
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
 import * as core from '@actions/core';
+import * as exec from '@actions/exec';
+import * as io from '@actions/io';
+import * as tc from '@actions/tool-cache';
 import { CARGO_HOME, installBins, restoreCache } from './src/cargo';
 import { installToolchain } from './src/rust';
 
+export async function installRustup() {
+	try {
+		await io.which('rustup', true);
+		return;
+	} catch {
+		// Doesn't exist
+	}
+
+	core.info('rustup does not exist, attempting to install');
+
+	const scriptPath = path.join(os.tmpdir(), 'rustup-init');
+	const script = await tc.downloadTool(
+		process.platform === 'win32' ? 'https://win.rustup.rs' : 'https://sh.rustup.rs',
+		scriptPath,
+	);
+
+	core.info(`Downloaded installation script to ${script}`);
+
+	// eslint-disable-next-line no-magic-numbers
+	await fs.promises.chmod(script, 0o755);
+
+	await exec.exec(script, ['--default-toolchain', 'none', '-y']);
+
+	core.info('Installed rustup');
+}
+
 async function run() {
 	core.info('Setting cargo environment variables');
 
@@ -14,6 +45,7 @@ async function run() {
 	core.addPath(path.join(CARGO_HOME, 'bin'));
 
 	try {
+		await installRustup();
 		await installToolchain();
 		await installBins();
 

package.json

@@ -34,5 +34,8 @@
     "prettier-config-moon": "^1.1.2",
     "tsconfig-moon": "^1.3.0",
     "typescript": "^5.1.6"
+  },
+  "engines": {
+    "node": ">=16.0.0"
   }
 }

src/cargo.ts

@@ -1,7 +1,7 @@
-import crypto from 'crypto';
-import fs from 'fs';
-import os from 'os';
-import path from 'path';
+import crypto from 'node:crypto';
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
 import * as cache from '@actions/cache';
 import * as core from '@actions/core';
 import * as exec from '@actions/exec';

src/rust.ts

@@ -1,7 +1,7 @@
 /* eslint-disable import/no-mutable-exports */
 
-import fs from 'fs';
-import path from 'path';
+import fs from 'node:fs';
+import path from 'node:path';
 import * as core from '@actions/core';
 import * as exec from '@actions/exec';
 import TOML from '@ltd/j-toml';