Restore/save configuration-cache data in first action

Previously, the action was restoring/saving the configuration-cache data for each
step that applied the action. In order to support Gradle invocations that are _not_
managed by the action, the configuration-cache restore is now performed in the initial
action step, and save is performed in the final post-action step.

The build root directories are recorded for each invocation via an init script.

src/cache-base.ts

@@ -1,11 +1,15 @@
 import * as core from '@actions/core'
 import * as cache from '@actions/cache'
 import * as github from '@actions/github'
+import path from 'path'
+import fs from 'fs'
 import {CacheListener} from './cache-reporting'
-import {isCacheDebuggingEnabled, getCacheKeyPrefix, hashStrings, handleCacheFailure} from './cache-utils'
+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.
@@ -58,22 +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])
-}
-
 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}`
@@ -81,6 +80,16 @@ 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.
      */
@@ -191,4 +200,5 @@ export abstract class AbstractCache {
     }
 
     protected abstract getCachePath(): string[]
+    protected abstract initializeGradleUserHome(gradleUserHome: string, initScriptsDir: string): void
 }

src/cache-gradle-user-home.ts

@@ -1,15 +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} 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'
@@ -47,16 +45,8 @@ class ExtractedCacheEntryMetadata {
  * for more efficient storage.
  */
 export class GradleUserHomeCache extends AbstractCache {
-    private gradleUserHome: string
-
-    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)
+    constructor(gradleUserHome: string) {
+        super(gradleUserHome, 'gradle', 'Gradle User Home')
     }
 
     /**
@@ -285,15 +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')
-    }
-
     /**
      * Determines the paths within Gradle User Home to cache.
      * By default, this is the 'caches' and 'notifications' directories,
@@ -358,21 +339,17 @@ export class GradleUserHomeCache extends AbstractCache {
 
         core.info('-----------------------')
     }
-}
 
-function initializeGradleUserHome(gradleUserHome: string): void {
-    fs.mkdirSync(gradleUserHome, {recursive: true})
+    protected initializeGradleUserHome(gradleUserHome: string, initScriptsDir: string): void {
+        const propertiesFile = path.resolve(gradleUserHome, 'gradle.properties')
+        fs.writeFileSync(propertiesFile, 'org.gradle.daemon=false')
 
-    const propertiesFile = path.resolve(gradleUserHome, 'gradle.properties')
-    fs.writeFileSync(propertiesFile, 'org.gradle.daemon=false')
+        const buildScanCapture = path.resolve(initScriptsDir, 'build-scan-capture.init.gradle')
+        fs.writeFileSync(
+            buildScanCapture,
+            `import org.gradle.util.GradleVersion
 
-    const initScript = path.resolve(gradleUserHome, 'init.gradle')
-    fs.writeFileSync(
-        initScript,
-        `
-import org.gradle.util.GradleVersion
-
-// Don't run against the included builds (if the main build has any).
+// Only run again root build. Do not run against included builds.
 def isTopLevelBuild = gradle.getParent() == null
 if (isTopLevelBuild) {
     def version = GradleVersion.current().baseVersion
@@ -412,7 +389,7 @@ def registerCallbacks(buildScanExtension, rootProjectName) {
             println("::set-output name=build-scan-url::\${buildScan.buildScanUri}")
         }
     }
-}
-`
-    )
+}`
+        )
+    }
 }

src/cache-project-dot-gradle.ts

@@ -1,27 +1,52 @@
+import * as core from '@actions/core'
 import path from 'path'
-import {AbstractCache} 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
-]
+import fs from 'fs'
+import {AbstractCache, META_FILE_DIR, PROJECT_ROOTS_FILE} from './cache-base'
 
 /**
  * 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(rootDir: string) {
-        super('project', 'Project configuration cache')
-        this.rootDir = rootDir
+    constructor(gradleUserHome: string) {
+        super(gradleUserHome, 'project', 'Project configuration cache')
     }
 
     protected getCachePath(): string[] {
-        const dir = this.getProjectDotGradleDir()
-        return PATHS_TO_CACHE.map(x => path.resolve(dir, x))
+        return this.getProjectRoots().map(x => path.resolve(x, '.gradle/configuration-cache'))
     }
 
-    private getProjectDotGradleDir(): string {
-        return path.resolve(this.rootDir, '.gradle')
+    protected initializeGradleUserHome(gradleUserHome: string, initScriptsDir: string): void {
+        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-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

@@ -5,21 +5,22 @@ import {isCacheDisabled, isCacheReadOnly} from './cache-utils'
 import {logCachingReport, CacheListener} from './cache-reporting'
 
 const CACHE_RESTORED_VAR = 'GRADLE_BUILD_ACTION_CACHE_RESTORED'
-const BUILD_ROOT_DIR = 'BUILD_ROOT_DIR'
+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> {
     if (!shouldRestoreCaches()) {
         return
     }
 
-    const gradleUserHomeCache = new GradleUserHomeCache(buildRootDirectory)
-    const projectDotGradleCache = new ProjectDotGradleCache(buildRootDirectory)
-
+    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)
@@ -51,10 +52,10 @@ 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 ProjectDotGradleCache(buildRootDirectory).save(cacheListener)
+            new GradleUserHomeCache(gradleUserHome).save(cacheListener),
+            new ProjectDotGradleCache(gradleUserHome).save(cacheListener)
         ])
     })
 

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)