perf: improve setup-go cache for build-cache + use improved version of hash dir based on file's meta

action.yml

@@ -17,6 +17,9 @@ inputs:
     default: true
   cache-dependency-path:
     description: 'Used to specify the path to a dependency file - go.sum'
+  cache-key-prefix:
+    description: 'Used to specify a prefix to the cache key - ex: special-cache'
+    default: ''
   architecture:
     description: 'Target architecture for Go to use. Examples: x86, x64. Will use system architecture by default.'
 outputs:

src/cache-restore.ts

@@ -7,6 +7,7 @@ import fs from 'fs';
 import {State, Outputs} from './constants';
 import {PackageManagerInfo} from './package-managers';
 import {getCacheDirectoryPath, getPackageManagerInfo} from './cache-utils';
+import {computeMetaHash} from './hashdir';
 
 export const restoreCache = async (
   versionSpec: string,
@@ -29,14 +30,28 @@ export const restoreCache = async (
     );
   }
 
+  let prefixKey = core.getInput('cache-key-prefix');
+  if (prefixKey) {
+    prefixKey += '-';
+  }
+
   const linuxVersion =
     process.env.RUNNER_OS === 'Linux' ? `${process.env.ImageOS}-` : '';
-  const primaryKey = `setup-go-${platform}-${linuxVersion}go-${versionSpec}-${fileHash}`;
+  const baseKey = `setup-go-${platform}-${linuxVersion}go-${versionSpec}`;
+  const prefixBaseKey = `${prefixKey}${baseKey}`;
+  core.saveState(State.CachePrefixBaseKey, prefixBaseKey);
+
+  const primaryKey = `${prefixBaseKey}-${fileHash}`;
   core.debug(`primary key is ${primaryKey}`);
 
   core.saveState(State.CachePrimaryKey, primaryKey);
 
-  const cacheKey = await cache.restoreCache(cachePaths, primaryKey);
+  const start = Date.now();
+  const cacheKey = await cache.restoreCache(cachePaths, primaryKey, [
+    prefixBaseKey,
+    baseKey
+  ]);
+  core.info(`Time taken to restore cache: ${Date.now() - start}ms`);
   core.setOutput(Outputs.CacheHit, Boolean(cacheKey));
 
   if (!cacheKey) {
@@ -47,6 +62,12 @@ export const restoreCache = async (
 
   core.saveState(State.CacheMatchedKey, cacheKey);
   core.info(`Cache restored from key: ${cacheKey}`);
+
+  if (cachePaths.length > 1) {
+    const buildHash = computeMetaHash([cachePaths[1]]);
+    core.debug(`build hash is ${buildHash}`);
+    core.saveState(State.CacheBuildHash, buildHash);
+  }
 };
 
 const findDependencyFile = (packageManager: PackageManagerInfo) => {

src/cache-save.ts

@@ -3,6 +3,7 @@ import * as cache from '@actions/cache';
 import fs from 'fs';
 import {State} from './constants';
 import {getCacheDirectoryPath, getPackageManagerInfo} from './cache-utils';
+import {computeMetaHash} from './hashdir';
 
 // Catch and log any unhandled exceptions.  These exceptions can leak out of the uploadChunk method in
 // @actions/toolkit when a failed upload closes the file descriptor causing any in-process reads to
@@ -42,6 +43,7 @@ const cachePackages = async () => {
 
   const state = core.getState(State.CacheMatchedKey);
   const primaryKey = core.getState(State.CachePrimaryKey);
+  const prevBuildHash = core.getState(State.CacheBuildHash);
 
   const packageManagerInfo = await getPackageManagerInfo(packageManager);
 
@@ -71,18 +73,23 @@ const cachePackages = async () => {
     return;
   }
 
-  if (primaryKey === state) {
+  const buildHash = computeMetaHash([cachePaths[1]]);
+
+  if (primaryKey === state && buildHash === prevBuildHash) {
     core.info(
-      `Cache hit occurred on the primary key ${primaryKey}, not saving cache.`
+      `Cache hit occurred on the primary key ${primaryKey} and build hash ${buildHash}, not saving cache.`
     );
     return;
   }
 
-  const cacheId = await cache.saveCache(cachePaths, primaryKey);
+  const updatedKey = primaryKey + (buildHash ? `-${buildHash}` : '');
+  const start = Date.now();
+  const cacheId = await cache.saveCache(cachePaths, updatedKey);
+  core.info(`Time taken to save cache: ${Date.now() - start}ms`);
   if (cacheId === -1) {
     return;
   }
-  core.info(`Cache saved with the key: ${primaryKey}`);
+  core.info(`Cache saved with the key: ${updatedKey}`);
 };
 
 function logWarning(message: string): void {

src/constants.ts

@@ -1,5 +1,7 @@
 export enum State {
+  CachePrefixBaseKey = 'CACHE_PREFIX_BASE_KEY',
   CachePrimaryKey = 'CACHE_KEY',
+  CacheBuildHash = 'CACHE_HASH',
   CacheMatchedKey = 'CACHE_RESULT'
 }
 

src/hashdir.ts

@@ -0,0 +1,30 @@
+import {Hash, createHash} from 'node:crypto';
+import {readdirSync, statSync} from 'node:fs';
+import {join} from 'node:path';
+
+/**
+ * Creates hash of given files/folders. Used to conditionally deploy custom
+ * resources depending if source files have changed
+ */
+export function computeMetaHash(paths: string[], inputHash?: Hash) {
+  const hash = inputHash ? inputHash : createHash('sha1');
+  for (const path of paths) {
+    const statInfo = statSync(path);
+    if (statInfo.isDirectory()) {
+      const directoryEntries = readdirSync(path, {withFileTypes: true});
+      const fullPaths = directoryEntries.map(e => join(path, e.name));
+      // recursively walk sub-folders
+      computeMetaHash(fullPaths, hash);
+    } else {
+      const statInfo = statSync(path);
+      // compute hash string name:size:mtime
+      const fileInfo = `${path}:${statInfo.size}:${statInfo.mtimeMs}`;
+      hash.update(fileInfo);
+    }
+  }
+  // if not being called recursively, get the digest and return it as the hash result
+  if (!inputHash) {
+    return hash.digest('hex');
+  }
+  return;
+}