new: Add cache base warmup strategy. (#16)

src/cache.ts

@@ -0,0 +1,92 @@
+import crypto from 'node:crypto';
+import os from 'node:os';
+import path from 'node:path';
+import * as cache from '@actions/cache';
+import * as core from '@actions/core';
+import * as glob from '@actions/glob';
+import { RUST_HASH, RUST_VERSION } from './rust';
+
+export const CARGO_HOME = process.env.CARGO_HOME ?? path.join(os.homedir(), '.cargo');
+
+export const WORKSPACE_ROOT = process.env.GITHUB_WORKSPACE ?? process.cwd();
+
+export function isCacheEnabled(): boolean {
+	return core.getBooleanInput('cache') && cache.isFeatureAvailable();
+}
+
+export function getCacheTarget(): string {
+	return core.getInput('cache-target') || 'debug';
+}
+
+export function getCachePaths(): string[] {
+	return [
+		// ~/.cargo/registry
+		path.join(CARGO_HOME, 'registry'),
+		// /workspace/target/debug
+		path.join(WORKSPACE_ROOT, 'target', getCacheTarget()),
+	];
+}
+
+export function getCachePrefixes(): string[] {
+	return [`setup-rustcargo-v1-${process.platform}`, 'setup-rustcargo-v1'];
+}
+
+export async function getPrimaryCacheKey() {
+	const hasher = crypto.createHash('sha1');
+
+	core.info('Generating cache key');
+
+	core.debug(`Hashing Rust version = ${RUST_VERSION}`);
+	hasher.update(RUST_VERSION);
+
+	core.debug(`Hashing Rust commit hash = ${RUST_HASH}`);
+	hasher.update(RUST_HASH);
+
+	const cacheTarget = getCacheTarget();
+
+	core.debug(`Hashing target profile = ${cacheTarget}`);
+	hasher.update(cacheTarget);
+
+	// When warming up, loosen the cache key to allow for more cache hits
+	if (core.getInput('cache-base')) {
+		core.debug('Using warmup strategy, not hashing Cargo.lock, GITHUB_WORKFLOW, or GITHUB_JOB');
+		hasher.update('warmup');
+
+		const baseRef = process.env.GITHUB_BASE_REF ?? '';
+
+		if (
+			baseRef === 'master' ||
+			baseRef === 'main' ||
+			baseRef === 'trunk' ||
+			baseRef.startsWith('develop') ||
+			baseRef.startsWith('release')
+		) {
+			core.debug(`Hashing GITHUB_BASE_REF = ${baseRef}`);
+			hasher.update(baseRef);
+		}
+	}
+
+	// Otherwise, these add far too much granularity to the cache key
+	else {
+		const lockHash = await glob.hashFiles('Cargo.lock');
+
+		core.debug(`Hashing Cargo.lock = ${lockHash}`);
+		hasher.update(lockHash);
+
+		const workflow = process.env.GITHUB_WORKFLOW;
+
+		if (workflow) {
+			core.debug(`Hashing GITHUB_WORKFLOW = ${workflow}`);
+			hasher.update(workflow);
+		}
+
+		const job = process.env.GITHUB_JOB;
+
+		if (job) {
+			core.debug(`Hashing GITHUB_JOB = ${job}`);
+			hasher.update(job);
+		}
+	}
+
+	return `${getCachePrefixes()[0]}-${hasher.digest('hex')}`;
+}