Merge pull request #128 from gradle/configuration-caching

Restore/save configuration-cache data in first action step. This will enable the use of the action for caching without managing all gradle invocations.

.github/workflows/integTest-caching-configuration-cache.yml

@@ -26,8 +26,13 @@ jobs:
       with:
         build-root-directory: __tests__/samples/groovy-dsl
         arguments: test --configuration-cache
+    - name: Second build with configuration-cache enabled
+      uses: ./
+      with:
+        build-root-directory: __tests__/samples/kotlin-dsl
+        arguments: test --configuration-cache
 
-  # Test that the project-dot-gradle cache will cache and restore configuration-cache
+  # Test restore configuration-cache
   configuration-cache:
     needs: seed-build
     strategy:
@@ -46,6 +51,25 @@ jobs:
         arguments: test --configuration-cache
         cache-read-only: true
 
+  # Test restore configuration-cache from second build invocation
+  configuration-cache-2:
+    needs: seed-build
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+    - name: Checkout sources
+      uses: actions/checkout@v2
+    - name: Execute Gradle build and verify cached configuration
+      uses: ./
+      env: 
+        VERIFY_CACHED_CONFIGURATION: true
+      with:
+        build-root-directory: __tests__/samples/kotlin-dsl
+        arguments: test --configuration-cache
+        cache-read-only: true
+
   # Check that the build can run when no extracted cache entries are restored
   no-extracted-cache-entries-restored:
     needs: seed-build

__tests__/cache-reporting.test.ts

@@ -1,4 +1,4 @@
-import {CacheEntryListener, CacheListener} from '../src/cache-base'
+import {CacheEntryListener, CacheListener} from '../src/cache-reporting'
 
 describe('caching report', () => {
     describe('reports not fully restored', () => {

__tests__/samples/kotlin-dsl/build.gradle.kts

@@ -16,3 +16,15 @@ dependencies {
 tasks.test {
     useJUnitPlatform()
 }
+
+tasks.named("test").configure {
+    // Use an environment variable to bypass config-cache checks
+    if (System.getenv("VERIFY_CACHED_CONFIGURATION") != null) {
+        throw RuntimeException("Configuration was not cached: unexpected configuration of test task")
+    }
+    doLast {
+        if (System.getProperties().containsKey("verifyCachedBuild")) {
+            throw RuntimeException("Build was not cached: unexpected execution of test task")
+        }
+    }
+}

src/cache-base.ts

@@ -1,10 +1,15 @@
 import * as core from '@actions/core'
 import * as cache from '@actions/cache'
 import * as github from '@actions/github'
-import {isCacheDebuggingEnabled, getCacheKeyPrefix, hashStrings, handleCacheFailure} from './cache-utils'
+import path from 'path'
+import fs from 'fs'
+import {CacheListener} from './cache-reporting'
+import {isCacheDebuggingEnabled, getCacheKeyPrefix, determineJobContext, handleCacheFailure} from './cache-utils'
 
 const CACHE_PROTOCOL_VERSION = 'v5-'
-const JOB_CONTEXT_PARAMETER = 'workflow-job-context'
+
+export const META_FILE_DIR = '.gradle-build-action'
+export const PROJECT_ROOTS_FILE = 'project-roots.txt'
 
 /**
  * Represents a key used to restore a cache entry.
@@ -57,100 +62,17 @@ function generateCacheKey(cacheName: string): CacheKey {
     return new CacheKey(cacheKey, [cacheKeyForJobContext, cacheKeyForJob, cacheKeyForOs])
 }
 
-function determineJobContext(): string {
-    // By default, we hash the full `matrix` data for the run, to uniquely identify this job invocation
-    // The only way we can obtain the `matrix` data is via the `workflow-job-context` parameter in action.yml.
-    const workflowJobContext = core.getInput(JOB_CONTEXT_PARAMETER)
-    return hashStrings([workflowJobContext])
-}
-
-/**
- * Collects information on what entries were saved and restored during the action.
- * This information is used to generate a summary of the cache usage.
- */
-export class CacheListener {
-    cacheEntries: CacheEntryListener[] = []
-
-    get fullyRestored(): boolean {
-        return this.cacheEntries.every(x => !x.wasRequestedButNotRestored())
-    }
-
-    entry(name: string): CacheEntryListener {
-        for (const entry of this.cacheEntries) {
-            if (entry.entryName === name) {
-                return entry
-            }
-        }
-
-        const newEntry = new CacheEntryListener(name)
-        this.cacheEntries.push(newEntry)
-        return newEntry
-    }
-
-    stringify(): string {
-        return JSON.stringify(this)
-    }
-
-    static rehydrate(stringRep: string): CacheListener {
-        const rehydrated: CacheListener = Object.assign(new CacheListener(), JSON.parse(stringRep))
-        const entries = rehydrated.cacheEntries
-        for (let index = 0; index < entries.length; index++) {
-            const rawEntry = entries[index]
-            entries[index] = Object.assign(new CacheEntryListener(rawEntry.entryName), rawEntry)
-        }
-        return rehydrated
-    }
-}
-
-/**
- * Collects information on the state of a single cache entry.
- */
-export class CacheEntryListener {
-    entryName: string
-    requestedKey: string | undefined
-    requestedRestoreKeys: string[] | undefined
-    restoredKey: string | undefined
-    restoredSize: number | undefined
-
-    savedKey: string | undefined
-    savedSize: number | undefined
-
-    constructor(entryName: string) {
-        this.entryName = entryName
-    }
-
-    wasRequestedButNotRestored(): boolean {
-        return this.requestedKey !== undefined && this.restoredKey === undefined
-    }
-
-    markRequested(key: string, restoreKeys: string[] = []): CacheEntryListener {
-        this.requestedKey = key
-        this.requestedRestoreKeys = restoreKeys
-        return this
-    }
-
-    markRestored(key: string, size: number | undefined): CacheEntryListener {
-        this.restoredKey = key
-        this.restoredSize = size
-        return this
-    }
-
-    markSaved(key: string, size: number | undefined): CacheEntryListener {
-        this.savedKey = key
-        this.savedSize = size
-        return this
-    }
-}
-
 export abstract class AbstractCache {
     private cacheName: string
     private cacheDescription: string
     private cacheKeyStateKey: string
     private cacheResultStateKey: string
 
+    protected readonly gradleUserHome: string
     protected readonly cacheDebuggingEnabled: boolean
 
-    constructor(cacheName: string, cacheDescription: string) {
+    constructor(gradleUserHome: string, cacheName: string, cacheDescription: string) {
+        this.gradleUserHome = gradleUserHome
         this.cacheName = cacheName
         this.cacheDescription = cacheDescription
         this.cacheKeyStateKey = `CACHE_KEY_${cacheName}`
@@ -158,23 +80,28 @@ export abstract class AbstractCache {
         this.cacheDebuggingEnabled = isCacheDebuggingEnabled()
     }
 
+    init(): void {
+        const actionCacheDir = path.resolve(this.gradleUserHome, '.gradle-build-action')
+        fs.mkdirSync(actionCacheDir, {recursive: true})
+
+        const initScriptsDir = path.resolve(this.gradleUserHome, 'init.d')
+        fs.mkdirSync(initScriptsDir, {recursive: true})
+
+        this.initializeGradleUserHome(this.gradleUserHome, initScriptsDir)
+    }
+
     /**
      * Restores the cache entry, finding the closest match to the currently running job.
-     * If the target output already exists, caching will be skipped.
      */
     async restore(listener: CacheListener): Promise<void> {
-        if (this.cacheOutputExists()) {
-            core.info(`${this.cacheDescription} already exists. Not restoring from cache.`)
-            return
-        }
         const entryListener = listener.entry(this.cacheDescription)
 
         const cacheKey = this.prepareCacheKey()
 
         this.debug(
             `Requesting ${this.cacheDescription} with
-                key:${cacheKey.key}
+    key:${cacheKey.key}
-                restoreKeys:[${cacheKey.restoreKeys}]`
+    restoreKeys:[${cacheKey.restoreKeys}]`
         )
 
         const cacheResult = await this.restoreCache(this.getCachePath(), cacheKey.key, cacheKey.restoreKeys)
@@ -219,28 +146,17 @@ export abstract class AbstractCache {
     protected async afterRestore(_listener: CacheListener): Promise<void> {}
 
     /**
-     * Saves the cache entry based on the current cache key, unless:
+     * Saves the cache entry based on the current cache key unless the cache was restored with the exact key,
-     * - If the cache output existed before restore, then it is not saved.
+     * in which case we cannot overwrite it.
-     * - If the cache was restored with the exact key, we cannot overwrite it.
      *
      * If the cache entry was restored with a partial match on a restore key, then
      * it is saved with the exact key.
      */
     async save(listener: CacheListener): Promise<void> {
-        if (!this.cacheOutputExists()) {
-            core.info(`No ${this.cacheDescription} to cache.`)
-            return
-        }
-
         // Retrieve the state set in the previous 'restore' step.
         const cacheKeyFromRestore = core.getState(this.cacheKeyStateKey)
         const cacheResultFromRestore = core.getState(this.cacheResultStateKey)
 
-        if (!cacheKeyFromRestore) {
-            core.info(`${this.cacheDescription} existed prior to cache restore. Not saving.`)
-            return
-        }
-
         if (cacheResultFromRestore && cacheKeyFromRestore === cacheResultFromRestore) {
             core.info(`Cache hit occurred on the cache key ${cacheKeyFromRestore}, not saving cache.`)
             return
@@ -283,6 +199,6 @@ export abstract class AbstractCache {
         }
     }
 
-    protected abstract cacheOutputExists(): boolean
     protected abstract getCachePath(): string[]
+    protected abstract initializeGradleUserHome(gradleUserHome: string, initScriptsDir: string): void
 }

src/cache-gradle-user-home.ts

@@ -1,14 +1,13 @@
 import path from 'path'
 import fs from 'fs'
-import os from 'os'
 import * as core from '@actions/core'
 import * as glob from '@actions/glob'
 import * as exec from '@actions/exec'
 
-import {AbstractCache, CacheEntryListener, CacheListener} from './cache-base'
+import {AbstractCache, META_FILE_DIR} from './cache-base'
+import {CacheEntryListener, CacheListener} from './cache-reporting'
 import {getCacheKeyPrefix, hashFileNames, tryDelete} from './cache-utils'
 
-const META_FILE_DIR = '.gradle-build-action'
 const META_FILE = 'cache-metadata.json'
 
 const INCLUDE_PATHS_PARAMETER = 'gradle-home-cache-includes'
@@ -46,16 +45,8 @@ class ExtractedCacheEntryMetadata {
  * for more efficient storage.
  */
 export class GradleUserHomeCache extends AbstractCache {
-    private gradleUserHome: string
+    constructor(gradleUserHome: string) {
-
+        super(gradleUserHome, 'gradle', 'Gradle User Home')
-    constructor(rootDir: string) {
-        super('gradle', 'Gradle User Home')
-        this.gradleUserHome = this.determineGradleUserHome(rootDir)
-    }
-
-    init(): void {
-        this.debug(`Initializing Gradle User Home with properties and init script: ${this.gradleUserHome}`)
-        initializeGradleUserHome(this.gradleUserHome)
     }
 
     /**
@@ -284,21 +275,6 @@ export class GradleUserHomeCache extends AbstractCache {
         fs.writeFileSync(cacheMetadataFile, filedata, 'utf-8')
     }
 
-    protected determineGradleUserHome(rootDir: string): string {
-        const customGradleUserHome = process.env['GRADLE_USER_HOME']
-        if (customGradleUserHome) {
-            return path.resolve(rootDir, customGradleUserHome)
-        }
-
-        return path.resolve(os.homedir(), '.gradle')
-    }
-
-    protected cacheOutputExists(): boolean {
-        // Need to check for 'caches' directory to avoid incorrect detection on MacOS agents
-        const dir = path.resolve(this.gradleUserHome, 'caches')
-        return fs.existsSync(dir)
-    }
-
     /**
      * Determines the paths within Gradle User Home to cache.
      * By default, this is the 'caches' and 'notifications' directories,
@@ -363,21 +339,17 @@ export class GradleUserHomeCache extends AbstractCache {
 
         core.info('-----------------------')
     }
-}
 
-function initializeGradleUserHome(gradleUserHome: string): void {
+    protected initializeGradleUserHome(gradleUserHome: string, initScriptsDir: string): void {
-    fs.mkdirSync(gradleUserHome, {recursive: true})
+        const propertiesFile = path.resolve(gradleUserHome, 'gradle.properties')
+        fs.writeFileSync(propertiesFile, 'org.gradle.daemon=false')
 
-    const propertiesFile = path.resolve(gradleUserHome, 'gradle.properties')
+        const buildScanCapture = path.resolve(initScriptsDir, 'build-scan-capture.init.gradle')
-    fs.writeFileSync(propertiesFile, 'org.gradle.daemon=false')
+        fs.writeFileSync(
+            buildScanCapture,
+            `import org.gradle.util.GradleVersion
 
-    const initScript = path.resolve(gradleUserHome, 'init.gradle')
+// Only run again root build. Do not run against included builds.
-    fs.writeFileSync(
-        initScript,
-        `
-import org.gradle.util.GradleVersion
-
-// Don't run against the included builds (if the main build has any).
 def isTopLevelBuild = gradle.getParent() == null
 if (isTopLevelBuild) {
     def version = GradleVersion.current().baseVersion
@@ -417,7 +389,7 @@ def registerCallbacks(buildScanExtension, rootProjectName) {
             println("::set-output name=build-scan-url::\${buildScan.buildScanUri}")
         }
     }
-}
+}`
-`
+        )
-    )
+    }
 }

src/cache-project-dot-gradle.ts

@@ -1,33 +1,52 @@
+import * as core from '@actions/core'
 import path from 'path'
 import fs from 'fs'
-import {AbstractCache} from './cache-base'
+import {AbstractCache, META_FILE_DIR, PROJECT_ROOTS_FILE} from './cache-base'
-
-// TODO: Maybe allow the user to override / tweak this set
-const PATHS_TO_CACHE = [
-    'configuration-cache' // Only configuration-cache is stored at present
-]
 
 /**
  * A simple cache that saves and restores the '.gradle/configuration-cache' directory in the project root.
  */
 export class ProjectDotGradleCache extends AbstractCache {
-    private rootDir: string
+    constructor(gradleUserHome: string) {
-    constructor(rootDir: string) {
+        super(gradleUserHome, 'project', 'Project configuration cache')
-        super('project', 'Project configuration cache')
-        this.rootDir = rootDir
-    }
-
-    protected cacheOutputExists(): boolean {
-        const dir = this.getProjectDotGradleDir()
-        return fs.existsSync(dir)
     }
 
     protected getCachePath(): string[] {
-        const dir = this.getProjectDotGradleDir()
+        return this.getProjectRoots().map(x => path.resolve(x, '.gradle/configuration-cache'))
-        return PATHS_TO_CACHE.map(x => path.resolve(dir, x))
     }
 
-    private getProjectDotGradleDir(): string {
+    protected initializeGradleUserHome(gradleUserHome: string, initScriptsDir: string): void {
-        return path.resolve(this.rootDir, '.gradle')
+        const projectRootCapture = path.resolve(initScriptsDir, 'project-root-capture.init.gradle')
+        fs.writeFileSync(
+            projectRootCapture,
+            `
+    // Only run again root build. Do not run against included builds.
+    def isTopLevelBuild = gradle.getParent() == null
+    if (isTopLevelBuild) {
+        settingsEvaluated { settings ->
+            def projectRootEntry = settings.rootDir.absolutePath + "\\n"
+            def projectRootList = new File(settings.gradle.gradleUserHomeDir, "${META_FILE_DIR}/${PROJECT_ROOTS_FILE}")
+            println "Adding " + projectRootEntry + " to " + projectRootList
+            if (!projectRootList.exists() || !projectRootList.text.contains(projectRootEntry)) {
+                projectRootList << projectRootEntry
+            }
+        }
+    }`
+        )
+    }
+
+    /**
+     * For every Gradle invocation, we record the project root directory. This method returns the entire
+     * set of project roots, to allow saving of configuration-cache entries for each.
+     */
+    private getProjectRoots(): string[] {
+        const projectList = path.resolve(this.gradleUserHome, META_FILE_DIR, PROJECT_ROOTS_FILE)
+        if (!fs.existsSync(projectList)) {
+            core.info(`Missing project list file ${projectList}`)
+            return []
+        }
+        const projectRoots = fs.readFileSync(projectList, 'utf-8')
+        core.info(`Found project roots '${projectRoots}' in ${projectList}`)
+        return projectRoots.trim().split('\n')
     }
 }

src/cache-reporting.ts

@@ -0,0 +1,123 @@
+import * as core from '@actions/core'
+
+/**
+ * Collects information on what entries were saved and restored during the action.
+ * This information is used to generate a summary of the cache usage.
+ */
+export class CacheListener {
+    cacheEntries: CacheEntryListener[] = []
+
+    get fullyRestored(): boolean {
+        return this.cacheEntries.every(x => !x.wasRequestedButNotRestored())
+    }
+
+    entry(name: string): CacheEntryListener {
+        for (const entry of this.cacheEntries) {
+            if (entry.entryName === name) {
+                return entry
+            }
+        }
+
+        const newEntry = new CacheEntryListener(name)
+        this.cacheEntries.push(newEntry)
+        return newEntry
+    }
+
+    stringify(): string {
+        return JSON.stringify(this)
+    }
+
+    static rehydrate(stringRep: string): CacheListener {
+        const rehydrated: CacheListener = Object.assign(new CacheListener(), JSON.parse(stringRep))
+        const entries = rehydrated.cacheEntries
+        for (let index = 0; index < entries.length; index++) {
+            const rawEntry = entries[index]
+            entries[index] = Object.assign(new CacheEntryListener(rawEntry.entryName), rawEntry)
+        }
+        return rehydrated
+    }
+}
+
+/**
+ * Collects information on the state of a single cache entry.
+ */
+export class CacheEntryListener {
+    entryName: string
+    requestedKey: string | undefined
+    requestedRestoreKeys: string[] | undefined
+    restoredKey: string | undefined
+    restoredSize: number | undefined
+
+    savedKey: string | undefined
+    savedSize: number | undefined
+
+    constructor(entryName: string) {
+        this.entryName = entryName
+    }
+
+    wasRequestedButNotRestored(): boolean {
+        return this.requestedKey !== undefined && this.restoredKey === undefined
+    }
+
+    markRequested(key: string, restoreKeys: string[] = []): CacheEntryListener {
+        this.requestedKey = key
+        this.requestedRestoreKeys = restoreKeys
+        return this
+    }
+
+    markRestored(key: string, size: number | undefined): CacheEntryListener {
+        this.restoredKey = key
+        this.restoredSize = size
+        return this
+    }
+
+    markSaved(key: string, size: number | undefined): CacheEntryListener {
+        this.savedKey = key
+        this.savedSize = size
+        return this
+    }
+}
+
+export function logCachingReport(listener: CacheListener): void {
+    if (listener.cacheEntries.length === 0) {
+        return
+    }
+
+    core.info(`---------- Caching Summary -------------
+Restored Entries Count: ${getCount(listener.cacheEntries, e => e.restoredSize)}
+                  Size: ${getSum(listener.cacheEntries, e => e.restoredSize)}
+Saved Entries    Count: ${getCount(listener.cacheEntries, e => e.savedSize)}
+                  Size: ${getSum(listener.cacheEntries, e => e.savedSize)}`)
+
+    core.startGroup('Cache Entry details')
+    for (const entry of listener.cacheEntries) {
+        core.info(`Entry: ${entry.entryName}
+    Requested Key : ${entry.requestedKey ?? ''}
+    Restored  Key : ${entry.restoredKey ?? ''}
+              Size: ${formatSize(entry.restoredSize)}
+    Saved     Key : ${entry.savedKey ?? ''}
+              Size: ${formatSize(entry.savedSize)}`)
+    }
+    core.endGroup()
+}
+
+function getCount(
+    cacheEntries: CacheEntryListener[],
+    predicate: (value: CacheEntryListener) => number | undefined
+): number {
+    return cacheEntries.filter(e => predicate(e) !== undefined).length
+}
+
+function getSum(
+    cacheEntries: CacheEntryListener[],
+    predicate: (value: CacheEntryListener) => number | undefined
+): string {
+    return formatSize(cacheEntries.map(e => predicate(e) ?? 0).reduce((p, v) => p + v, 0))
+}
+
+function formatSize(bytes: number | undefined): string {
+    if (bytes === undefined || bytes === 0) {
+        return ''
+    }
+    return `${Math.round(bytes / (1024 * 1024))} MB (${bytes} B)`
+}

src/cache-utils.ts

@@ -4,6 +4,7 @@ import * as crypto from 'crypto'
 import * as path from 'path'
 import * as fs from 'fs'
 
+const JOB_CONTEXT_PARAMETER = 'workflow-job-context'
 const CACHE_DISABLED_PARAMETER = 'cache-disabled'
 const CACHE_READONLY_PARAMETER = 'cache-read-only'
 const CACHE_DEBUG_VAR = 'GRADLE_BUILD_ACTION_CACHE_DEBUG_ENABLED'
@@ -26,6 +27,17 @@ export function getCacheKeyPrefix(): string {
     return process.env[CACHE_PREFIX_VAR] || ''
 }
 
+export function determineJobContext(): string {
+    // By default, we hash the full `matrix` data for the run, to uniquely identify this job invocation
+    // The only way we can obtain the `matrix` data is via the `workflow-job-context` parameter in action.yml.
+    const workflowJobContext = core.getInput(JOB_CONTEXT_PARAMETER)
+    return hashStrings([workflowJobContext])
+}
+
+export function hashFileNames(fileNames: string[]): string {
+    return hashStrings(fileNames.map(x => x.replace(new RegExp(`\\${path.sep}`, 'g'), '/')))
+}
+
 export function hashStrings(values: string[]): string {
     const hash = crypto.createHash('md5')
     for (const value of values) {
@@ -34,10 +46,6 @@ export function hashStrings(values: string[]): string {
     return hash.digest('hex')
 }
 
-export function hashFileNames(fileNames: string[]): string {
-    return hashStrings(fileNames.map(x => x.replace(new RegExp(`\\${path.sep}`, 'g'), '/')))
-}
-
 export function handleCacheFailure(error: unknown, message: string): void {
     if (error instanceof cache.ValidationError) {
         // Fail on cache validation errors

src/caches.ts

@@ -1,25 +1,26 @@
+import * as core from '@actions/core'
 import {GradleUserHomeCache} from './cache-gradle-user-home'
 import {ProjectDotGradleCache} from './cache-project-dot-gradle'
-import * as core from '@actions/core'
 import {isCacheDisabled, isCacheReadOnly} from './cache-utils'
-import {CacheEntryListener, CacheListener} from './cache-base'
+import {logCachingReport, CacheListener} from './cache-reporting'
 
-const BUILD_ROOT_DIR = 'BUILD_ROOT_DIR'
+const CACHE_RESTORED_VAR = 'GRADLE_BUILD_ACTION_CACHE_RESTORED'
+const GRADLE_USER_HOME = 'GRADLE_USER_HOME'
 const CACHE_LISTENER = 'CACHE_LISTENER'
 
-export async function restore(buildRootDirectory: string): Promise<void> {
+export async function restore(gradleUserHome: string): Promise<void> {
-    const gradleUserHomeCache = new GradleUserHomeCache(buildRootDirectory)
+    if (!shouldRestoreCaches()) {
-    const projectDotGradleCache = new ProjectDotGradleCache(buildRootDirectory)
-
-    gradleUserHomeCache.init()
-
-    if (isCacheDisabled()) {
-        core.info('Cache is disabled: will not restore state from previous builds.')
         return
     }
 
+    const gradleUserHomeCache = new GradleUserHomeCache(gradleUserHome)
+    gradleUserHomeCache.init()
+
+    const projectDotGradleCache = new ProjectDotGradleCache(gradleUserHome)
+    projectDotGradleCache.init()
+
     await core.group('Restore Gradle state from cache', async () => {
-        core.saveState(BUILD_ROOT_DIR, buildRootDirectory)
+        core.saveState(GRADLE_USER_HOME, gradleUserHome)
 
         const cacheListener = new CacheListener()
         await gradleUserHomeCache.restore(cacheListener)
@@ -38,6 +39,10 @@ export async function restore(buildRootDirectory: string): Promise<void> {
 }
 
 export async function save(): Promise<void> {
+    if (!shouldSaveCaches()) {
+        return
+    }
+
     const cacheListener: CacheListener = CacheListener.rehydrate(core.getState(CACHE_LISTENER))
 
     if (isCacheReadOnly()) {
@@ -47,56 +52,44 @@ export async function save(): Promise<void> {
     }
 
     await core.group('Caching Gradle state', async () => {
-        const buildRootDirectory = core.getState(BUILD_ROOT_DIR)
+        const gradleUserHome = core.getState(GRADLE_USER_HOME)
         return Promise.all([
-            new GradleUserHomeCache(buildRootDirectory).save(cacheListener),
+            new GradleUserHomeCache(gradleUserHome).save(cacheListener),
-            new ProjectDotGradleCache(buildRootDirectory).save(cacheListener)
+            new ProjectDotGradleCache(gradleUserHome).save(cacheListener)
         ])
     })
 
     logCachingReport(cacheListener)
 }
 
-function logCachingReport(listener: CacheListener): void {
+function shouldRestoreCaches(): boolean {
-    if (listener.cacheEntries.length === 0) {
+    if (isCacheDisabled()) {
-        return
+        core.info('Cache is disabled: will not restore state from previous builds.')
+        return false
     }
 
-    core.info(`---------- Caching Summary -------------
+    if (process.env[CACHE_RESTORED_VAR]) {
-Restored Entries Count: ${getCount(listener.cacheEntries, e => e.restoredSize)}
+        core.info('Cache only restored on first action step.')
-                  Size: ${getSum(listener.cacheEntries, e => e.restoredSize)}
+        return false
-Saved Entries    Count: ${getCount(listener.cacheEntries, e => e.savedSize)}
-                  Size: ${getSum(listener.cacheEntries, e => e.savedSize)}`)
-
-    core.startGroup('Cache Entry details')
-    for (const entry of listener.cacheEntries) {
-        core.info(`Entry: ${entry.entryName}
-    Requested Key : ${entry.requestedKey ?? ''}
-    Restored  Key : ${entry.restoredKey ?? ''}
-              Size: ${formatSize(entry.restoredSize)}
-    Saved     Key : ${entry.savedKey ?? ''}
-              Size: ${formatSize(entry.savedSize)}`)
     }
-    core.endGroup()
+
+    // Export var that is detected in all later restore steps
+    core.exportVariable(CACHE_RESTORED_VAR, true)
+    // Export state that is detected in corresponding post-action step
+    core.saveState(CACHE_RESTORED_VAR, true)
+    return true
 }
 
-function getCount(
+function shouldSaveCaches(): boolean {
-    cacheEntries: CacheEntryListener[],
+    if (isCacheDisabled()) {
-    predicate: (value: CacheEntryListener) => number | undefined
+        core.info('Cache is disabled: will not save state for later builds.')
-): number {
+        return false
-    return cacheEntries.filter(e => predicate(e) !== undefined).length
-}
-
-function getSum(
-    cacheEntries: CacheEntryListener[],
-    predicate: (value: CacheEntryListener) => number | undefined
-): string {
-    return formatSize(cacheEntries.map(e => predicate(e) ?? 0).reduce((p, v) => p + v, 0))
-}
-
-function formatSize(bytes: number | undefined): string {
-    if (bytes === undefined || bytes === 0) {
-        return ''
     }
-    return `${Math.round(bytes / (1024 * 1024))} MB (${bytes} B)`
+
+    if (!core.getState(CACHE_RESTORED_VAR)) {
+        core.info('Cache will only be saved in final post-action step.')
+        return false
+    }
+
+    return true
 }

src/main.ts

@@ -1,5 +1,6 @@
 import * as core from '@actions/core'
 import * as path from 'path'
+import * as os from 'os'
 import {parseArgsStringToArgv} from 'string-argv'
 
 import * as caches from './caches'
@@ -14,8 +15,9 @@ export async function run(): Promise<void> {
     try {
         const workspaceDirectory = process.env[`GITHUB_WORKSPACE`] || ''
         const buildRootDirectory = resolveBuildRootDirectory(workspaceDirectory)
+        const gradleUserHome = determineGradleUserHome(buildRootDirectory)
 
-        await caches.restore(buildRootDirectory)
+        await caches.restore(gradleUserHome)
 
         const args: string[] = parseCommandLineArguments()
 
@@ -63,6 +65,15 @@ function resolveBuildRootDirectory(baseDirectory: string): string {
     return resolvedBuildRootDirectory
 }
 
+function determineGradleUserHome(rootDir: string): string {
+    const customGradleUserHome = process.env['GRADLE_USER_HOME']
+    if (customGradleUserHome) {
+        return path.resolve(rootDir, customGradleUserHome)
+    }
+
+    return path.resolve(os.homedir(), '.gradle')
+}
+
 function parseCommandLineArguments(): string[] {
     const input = core.getInput('arguments')
     return parseArgsStringToArgv(input)