Automatic caching of dependencies

in a best effort manner by default
allowing to specify files to hash for computing the cache key

.github/workflows/dev.yml

@@ -22,10 +22,10 @@ jobs:
       with:
         wrapper-directory: __tests__/data/basic
         build-root-directory: __tests__/data/basic
-        arguments: help
+        arguments: test
     - name: Test dist download
       uses: ./
       with:
         gradle-version: 6.5
         build-root-directory: __tests__/data/basic
-        arguments: help
+        arguments: test

.github/workflows/prod.yml

@@ -21,10 +21,10 @@ jobs:
       with:
         wrapper-directory: __tests__/data/basic
         build-root-directory: __tests__/data/basic
-        arguments: help
+        arguments: test
     - name: Test dist download
       uses: ./
       with:
         gradle-version: 6.5
         build-root-directory: __tests__/data/basic
-        arguments: help
+        arguments: test

__tests__/crypto-utils.test.ts

@@ -0,0 +1,33 @@
+import * as cryptoUtils from '../src/crypto-utils'
+import * as path from 'path'
+
+describe('crypto-utils', () => {
+    describe('can hash', () => {
+        it('a directory', async () => {
+            const hash = await cryptoUtils.hashFiles(
+                path.resolve('__tests__/data/basic/gradle')
+            )
+            expect(hash).toBe(
+                '4ebb65b45e6f6796d5ec6ace96e9471cc6573d294c54f99c4920fe5328e75bab'
+            )
+        })
+        it('a directory with a glob', async () => {
+            const hash = await cryptoUtils.hashFiles(
+                path.resolve('__tests__/data/basic/'),
+                ['gradle/**']
+            )
+            expect(hash).toBe(
+                '4ebb65b45e6f6796d5ec6ace96e9471cc6573d294c54f99c4920fe5328e75bab'
+            )
+        })
+        it('a directory with globs', async () => {
+            const hash = await cryptoUtils.hashFiles(
+                path.resolve('__tests__/data/basic/'),
+                ['**/*.gradle', 'gradle/**']
+            )
+            expect(hash).toBe(
+                '2db1d5291774949ab89e18e9d82ee24748ca0f6cc78de69ea9104357c50ad4a5'
+            )
+        })
+    })
+})

__tests__/data/basic/build.gradle

@@ -1,6 +1,11 @@
-/*
- * This file was generated by the Gradle 'init' task.
- *
- * This is a general purpose Gradle build.
- * Learn how to create Gradle builds at https://guides.gradle.org/creating-new-gradle-builds
- */
+plugins {
+    id 'java'
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testImplementation('junit:junit:4.12')
+}

__tests__/data/basic/src/test/java/basic/BasicTest.java

@@ -0,0 +1,10 @@
+package basic;
+
+import org.junit.Test;
+
+public class BasicTest {
+    @Test
+    public void test() {
+        assert true;
+    }
+}

action.yml

@@ -20,6 +20,9 @@ inputs:
   arguments:
     description: Gradle command line arguments, see gradle --help
     required: false
+  dependencies-cache-key:
+    description: Globs of files to hash in the build root directory, separated by new lines, use best-effort if unset
+    required: false
 
 outputs:
   build-scan-url:

package.json

@@ -24,11 +24,12 @@
   "author": "Paul Merlin <paul@nosphere.org>",
   "license": "MIT",
   "dependencies": {
+    "@actions/cache": "0.2.1",
     "@actions/core": "1.2.4",
     "@actions/exec": "1.0.4",
+    "@actions/glob": "0.1.0",
     "@actions/io": "1.0.2",
     "@actions/tool-cache": "1.5.5",
-    "@actions/cache": "0.2.1",
     "string-argv": "0.3.1",
     "typed-rest-client": "1.7.3",
     "unzipper": "0.10.11"

src/cache-dependencies.ts

@@ -0,0 +1,72 @@
+import * as path from 'path'
+import * as fs from 'fs'
+import * as os from 'os'
+
+import * as core from '@actions/core'
+import * as cache from '@actions/cache'
+
+import * as github from './github-utils'
+import * as crypto from './crypto-utils'
+
+const DEPENDENCIES_CACHE_PATH = 'DEPENDENCIES_CACHE_PATH'
+const DEPENDENCIES_CACHE_KEY = 'DEPENDENCIES_CACHE_KEY'
+const DEPENDENCIES_CACHE_RESULT = 'DEPENDENCIES_CACHE_RESULT'
+
+export async function restoreCachedDependencies(
+    rootDir: string
+): Promise<void> {
+    const cachePath = path.resolve(os.homedir(), '.gradle/caches/modules-2')
+    core.saveState(DEPENDENCIES_CACHE_PATH, cachePath)
+
+    const inputCacheKeyGlobs = github.inputArrayOrNull('dependencies-cache-key')
+    const cacheKeyGlobs = inputCacheKeyGlobs
+        ? inputCacheKeyGlobs
+        : [
+              '**/*.gradle',
+              '**/*.gradle.kts',
+              '**/gradle.properties',
+              'gradle/**'
+          ]
+
+    const hash = await crypto.hashFiles(rootDir, cacheKeyGlobs)
+    const cacheKeyPrefix = 'dependencies-'
+    const cacheKey = `${cacheKeyPrefix}${hash}`
+    core.saveState(DEPENDENCIES_CACHE_KEY, cacheKey)
+
+    const cacheResult = await cache.restoreCache([cachePath], cacheKey, [
+        cacheKeyPrefix
+    ])
+    core.saveState(DEPENDENCIES_CACHE_RESULT, cacheResult)
+}
+
+export async function cacheDependencies(): Promise<void> {
+    const cachePath = core.getState(DEPENDENCIES_CACHE_PATH)
+    const cacheKey = core.getState(DEPENDENCIES_CACHE_KEY)
+    const cacheResult = core.getState(DEPENDENCIES_CACHE_RESULT)
+
+    if (!cachePath || !fs.existsSync(cachePath)) {
+        core.debug('No dependencies to cache.')
+        return
+    }
+
+    if (cacheResult && cacheKey === cacheResult) {
+        core.info(
+            `Dependencies cache hit occurred on the cache key ${cacheKey}, not saving cache.`
+        )
+        return
+    }
+
+    try {
+        await cache.saveCache([cachePath], cacheKey)
+    } catch (error) {
+        if (error.name === cache.ValidationError.name) {
+            throw error
+        } else if (error.name === cache.ReserveCacheError.name) {
+            core.info(error.message)
+        } else {
+            core.info(`[warning] ${error.message}`)
+        }
+    }
+
+    return
+}

src/cache-wrapper.ts

@@ -52,7 +52,7 @@ export async function cacheWrapperDist(): Promise<void> {
     const cachePath = core.getState(WRAPPER_CACHE_PATH)
     const cacheResult = core.getState(WRAPPER_CACHE_RESULT)
 
-    if (!cachePath) {
+    if (!cachePath || !fs.existsSync(cachePath)) {
         core.debug('No wrapper installation to cache.')
         return
     }

src/crypto-utils.ts

@@ -0,0 +1,40 @@
+import * as crypto from 'crypto'
+import * as fs from 'fs'
+import * as path from 'path'
+import * as stream from 'stream'
+import * as util from 'util'
+
+import * as glob from '@actions/glob'
+
+export async function hashFiles(
+    baseDir: string,
+    globs: string[] = ['**'],
+    followSymbolicLinks = false
+): Promise<string | null> {
+    let hasMatch = false
+    const result = crypto.createHash('sha256')
+    for await (const globPattern of globs) {
+        const globMatch = `${baseDir}/${globPattern}`
+        const globber = await glob.create(globMatch, {followSymbolicLinks})
+        for await (const file of globber.globGenerator()) {
+            // console.log(file)
+            if (!file.startsWith(`${baseDir}${path.sep}`)) {
+                // console.log(`Ignore '${file}' since it is not under '${baseDir}'.`)
+                continue
+            }
+            if (fs.statSync(file).isDirectory()) {
+                // console.log(`Skip directory '${file}'.`)
+                continue
+            }
+            const hash = crypto.createHash('sha256')
+            const pipeline = util.promisify(stream.pipeline)
+            await pipeline(fs.createReadStream(file), hash)
+            result.write(hash.digest())
+            if (!hasMatch) {
+                hasMatch = true
+            }
+        }
+    }
+    result.end()
+    return hasMatch ? result.digest('hex') : null
+}

src/execution.ts

@@ -1,10 +1,13 @@
 import * as exec from '@actions/exec'
+import * as cacheDependencies from './cache-dependencies'
 
 export async function execute(
     executable: string,
     root: string,
     argv: string[]
 ): Promise<BuildResult> {
+    await cacheDependencies.restoreCachedDependencies(root)
+
     let publishing = false
     let buildScanUrl: string | undefined
 

src/github-utils.ts

@@ -7,3 +7,12 @@ export function inputOrNull(name: string): string | null {
     }
     return inputString
 }
+
+export function inputArrayOrNull(name: string): string[] | null {
+    const string = inputOrNull(name)
+    if (!string) return null
+    return string
+        .split('\n')
+        .map(s => s.trim())
+        .filter(s => s !== '')
+}

src/post.ts

@@ -1,8 +1,10 @@
 import * as cacheWrapper from './cache-wrapper'
+import * as cacheDependencies from './cache-dependencies'
 
 // Invoked by GitHub Actions
 export async function run(): Promise<void> {
     await cacheWrapper.cacheWrapperDist()
+    await cacheDependencies.cacheDependencies()
 }
 
 run()