Add restore cache.

helpers.ts

@@ -3,3 +3,11 @@ import path from 'path';
 
 // eslint-disable-next-line @typescript-eslint/prefer-nullish-coalescing
 export const CARGO_HOME = process.env.CARGO_HOME || path.join(os.homedir(), '.cargo');
+
+export function getPrimaryCacheKey(): string {
+	return `setup-rustcargo-${process.platform}`;
+}
+
+export function getPathsToCache(): string[] {
+	return [path.join(CARGO_HOME, 'registry')];
+}

index.ts

@@ -1,10 +1,11 @@
 import fs from 'fs';
 import path from 'path';
+import * as cache from '@actions/cache';
 import * as core from '@actions/core';
 import * as exec from '@actions/exec';
 import * as tc from '@actions/tool-cache';
 import TOML from '@ltd/j-toml';
-import { CARGO_HOME } from './helpers';
+import { CARGO_HOME, getPathsToCache, getPrimaryCacheKey } from './helpers';
 
 interface Toolchain {
 	channel: string;
@@ -185,6 +186,35 @@ async function installBins() {
 	await exec.exec('cargo', ['binstall', '--no-confirm', '--log-level', 'info', ...bins]);
 }
 
+async function restoreCache() {
+	const enabled = core.getBooleanInput('cache');
+
+	if (!cache.isFeatureAvailable() || !enabled) {
+		return;
+	}
+
+	core.info('Attempting to restore cache');
+
+	const primaryKey = await getPrimaryCacheKey();
+	const cacheKey = await cache.restoreCache(
+		getPathsToCache(),
+		primaryKey,
+		[`setup-rustcargo-${process.platform}`, 'setup-rustcargo'],
+		{},
+		false,
+	);
+
+	if (cacheKey) {
+		core.saveState('cacheHitKey', cacheKey);
+		core.info(`Cache restored using key ${primaryKey}`);
+	} else {
+		core.warning(`Cache does not exist using key ${primaryKey}`);
+	}
+
+	core.setOutput('cache-key', cacheKey ?? primaryKey);
+	core.setOutput('cache-hit', !!cacheKey);
+}
+
 async function run() {
 	core.info('Setting cargo environment variables');
 
@@ -195,6 +225,7 @@ async function run() {
 	core.exportVariable('CARGO_TERM_COLOR', 'always');
 
 	try {
+		await restoreCache();
 		await installToolchain(detectToolchain());
 		await installBins();
 	} catch (error: unknown) {

post.ts

@@ -1,23 +1,15 @@
-import fs from 'fs';
-import path from 'path';
 import * as cache from '@actions/cache';
 import * as core from '@actions/core';
-import { CARGO_HOME } from './helpers';
+import { getPathsToCache, getPrimaryCacheKey } from './helpers';
 
-async function run() {
+async function saveCache() {
 	const enabled = core.getBooleanInput('cache');
 
 	if (!cache.isFeatureAvailable() || !enabled) {
 		return;
 	}
 
-	if (!fs.existsSync(CARGO_HOME)) {
-		core.warning(`~/.cargo does not exist, not saving cache`);
-		return;
-	}
-
-	try {
-		const primaryKey = 'v0-test';
+	const primaryKey = getPrimaryCacheKey();
 	const cacheHitKey = core.getState('cacheHitKey');
 
 	if (cacheHitKey === primaryKey) {
@@ -27,7 +19,12 @@ async function run() {
 
 	core.info(`Saving cache with key ${primaryKey}`);
 
-		await cache.saveCache([path.join(CARGO_HOME, 'registry')], primaryKey, {}, false);
+	await cache.saveCache(getPathsToCache(), primaryKey, {}, false);
+}
+
+async function run() {
+	try {
+		await saveCache();
 	} catch (error: unknown) {
 		core.setFailed((error as Error).message);
 	}