Truncate Gradle args when constructing cache key (#71)

Cache keys have a hard limit of 512 characters, so we need to ensure that we don't generate a key longer than this.

- Remove excess whitespace
- Truncate to 400 characters

Fixes #70

.github/workflows/prod.yml

@@ -4,9 +4,25 @@ name: prod
 on:
   pull_request:
   push:
+  workflow_dispatch:
 
 jobs:
+  basic-build:
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+    - name: Checkout sources
+      uses: actions/checkout@v2
+    - name: Build using Gradle wrapper
+      uses: ./
+      with:
+        build-root-directory: __tests__/samples/basic
+        arguments: test
+   
   gradle-execution:
+    needs: basic-build
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
@@ -17,11 +33,6 @@ jobs:
     steps:
     - name: Checkout sources
       uses: actions/checkout@v2
-    - name: Test use Gradle wrapper
-      uses: ./
-      with:
-        build-root-directory: __tests__/samples/basic
-        arguments: test
     - name: Test use defined Gradle version
       uses: ./
       with:
@@ -48,6 +59,7 @@ jobs:
         arguments: help
 
   dependencies-cache:
+    needs: basic-build
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
@@ -63,6 +75,7 @@ jobs:
         dependencies-cache-enabled: true
 
   configuration-cache:
+    needs: basic-build
     strategy:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
@@ -79,8 +92,26 @@ jobs:
         dependencies-cache-enabled: true 
         # Configuration cache requires dependencies cache, since it assumes dependencies are already downloaded.
 
+  cache-read-only:
+    needs: basic-build
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+    - name: Checkout sources
+      uses: actions/checkout@v2
+    - name: Test cache-read-only
+      uses: ./
+      with:
+        build-root-directory: __tests__/samples/basic
+        arguments: test --no-daemon
+        dependencies-cache-enabled: true
+        configuration-cache-enabled: true
+        cache-read-only: true
 
   failures: # These build invocations are informational only, and are expected to fail
+    needs: basic-build
     runs-on: ubuntu-latest
     steps:
     - name: Checkout sources

README.md

@@ -144,7 +144,7 @@ The distributions cache is simple and can't be configured further.
 The dependencies and configuration cache will compute a cache key in a best effort manner.
 Keep reading to learn how to better control how they work.
 
-Note that enabling configuration cache without thee dependencies cache is not permitted, since a hit in the configuration cache assumes that dependencies are already present in the local dependencies cache.
+Note that enabling configuration cache without the dependencies cache is not permitted, since a hit in the configuration cache assumes that dependencies are already present in the local dependencies cache.
 
 ### Configuring the dependencies and configuration caches
 
@@ -187,6 +187,18 @@ dependencies-cache-key: gradle/dependency-locks/**
 dependencies-cache-exact: true
 ```
 
+### Using the caches read-only
+
+Cache storage space is limited for GitHub actions, and writing new cache entries can trigger the deletion of exising entries.
+In some circumstances, it makes sense for a Gradle invocation to use any existing cache entries but not to write and changes back.
+For example, you may want to write cache entries for builds on your `main` branch, but not for any PR build invocations.
+
+Use the following configuration to avoid writing cache entries for the action invocation:
+
+```yaml
+cache-read-only: true
+```
+
 ## Build scans
 
 If your build publishes a [build scan](https://gradle.com/build-scans/) the `gradle-build-action` action will emit the link to the published build scan as an output named `build-scan-url`.

__tests__/cache-utils.test.ts

@@ -1,10 +1,10 @@
-import * as cryptoUtils from '../src/crypto-utils'
+import * as cacheUtils from '../src/cache-utils'
 import * as path from 'path'
 
-describe('crypto-utils', () => {
+describe('cacheUtils-utils', () => {
     describe('can hash', () => {
         it('a directory', async () => {
-            const hash = await cryptoUtils.hashFiles(
+            const hash = await cacheUtils.hashFiles(
                 path.resolve('__tests__/data/crypto-utils-test/gradle')
             )
             expect(hash).toBe(
@@ -14,7 +14,7 @@ describe('crypto-utils', () => {
             )
         })
         it('a directory with a glob', async () => {
-            const hash = await cryptoUtils.hashFiles(
+            const hash = await cacheUtils.hashFiles(
                 path.resolve('__tests__/data/crypto-utils-test/'),
                 ['gradle/**']
             )
@@ -25,7 +25,7 @@ describe('crypto-utils', () => {
             )
         })
         it('a directory with globs', async () => {
-            const hash = await cryptoUtils.hashFiles(
+            const hash = await cacheUtils.hashFiles(
                 path.resolve('__tests__/data/crypto-utils-test/'),
                 ['**/*.gradle', 'gradle/**']
             )
@@ -36,4 +36,30 @@ describe('crypto-utils', () => {
             )
         })
     })
+    describe('can truncate args', () => {
+        test('handles zero-length string', () => {
+            expect(cacheUtils.truncateArgs('')).toBe('')
+        })
+        test('leaves short string untouched', () => {
+            expect(
+                cacheUtils.truncateArgs('short string that-should-be-untouched')
+            ).toBe('short string that-should-be-untouched')
+        })
+        test('truncates long string', () => {
+            const longString = 'a'.repeat(500)
+            expect(cacheUtils.truncateArgs(longString)).toBe('a'.repeat(400))
+        })
+        test('trims leading and trailing whitespace', () => {
+            expect(cacheUtils.truncateArgs('    this is an arg      ')).toBe(
+                'this is an arg'
+            )
+        })
+        test('removes repeated whitespace', () => {
+            expect(
+                cacheUtils.truncateArgs(
+                    '   this     one     has long   \t\n\t\r  spaces    '
+                )
+            ).toBe('this one has long spaces')
+        })
+    })
 })

action.yml

@@ -1,5 +1,5 @@
 name: "Gradle Build Action"
-description: 'Execute Gradle Build'
+description: 'Executes a Gradle build, caching useful state in the GitHub actions cache'
 
 # https://help.github.com/en/articles/metadata-syntax-for-github-actions
 
@@ -51,6 +51,10 @@ inputs:
     description: Whether to restore only if exact match, default to 'false'
     required: false
     default: false
+  cache-read-only:
+    description: When 'true', existing entries will be read from the cache but no entries will be written
+    required: false
+    default: false
 
 outputs:
   build-scan-url:

src/cache-configuration.ts

@@ -1,10 +1,10 @@
-import path from 'path'
-import fs from 'fs'
+import * as path from 'path'
+import * as fs from 'fs'
 
 import * as core from '@actions/core'
 import * as cache from '@actions/cache'
 
-import * as crypto from './crypto-utils'
+import * as cacheUtils from './cache-utils'
 
 import {
     inputCacheKeyGlobs,
@@ -32,17 +32,22 @@ export async function restoreCachedConfiguration(
     core.saveState(CONFIGURATION_CACHE_PATH, cachePath)
 
     const inputCacheExact = core.getBooleanInput('configuration-cache-exact')
-    const cacheKeyGlobs = inputCacheKeyGlobs('configuration-cache-key')
+    const cacheKeyPrefix = 'configuration|'
+
+    const args = core.getInput('arguments')
+    const argsKey = cacheUtils.truncateArgs(args)
+    const cacheKeyWithArgs = `${cacheKeyPrefix}${argsKey}|`
+
+    const cacheKeyGlobs = inputCacheKeyGlobs('configuration-cache-key')
+    const hash = await cacheUtils.hashFiles(rootDir, cacheKeyGlobs)
+    const cacheKey = `${cacheKeyWithArgs}${hash}`
 
-    const hash = await crypto.hashFiles(rootDir, cacheKeyGlobs)
-    const cacheKeyPrefix = 'configuration-'
-    const cacheKey = `${cacheKeyPrefix}${hash}`
     core.saveState(CONFIGURATION_CACHE_KEY, cacheKey)
 
     const cacheResult = await cache.restoreCache(
         [cachePath],
         cacheKey,
-        inputCacheExact ? [] : [cacheKeyPrefix]
+        inputCacheExact ? [] : [cacheKeyWithArgs, cacheKeyPrefix]
     )
 
     if (!cacheResult) {
@@ -86,6 +91,8 @@ export async function cacheConfiguration(): Promise<void> {
         return
     }
 
+    core.info(`Will cache configuration with key ${cacheKey}`)
+
     try {
         await cache.saveCache([cachePath], cacheKey)
     } catch (error) {

src/cache-dependencies.ts

@@ -5,7 +5,7 @@ import * as os from 'os'
 import * as core from '@actions/core'
 import * as cache from '@actions/cache'
 
-import * as crypto from './crypto-utils'
+import * as cacheUtils from './cache-utils'
 
 const DEPENDENCIES_CACHE_PATH = 'DEPENDENCIES_CACHE_PATH'
 const DEPENDENCIES_CACHE_KEY = 'DEPENDENCIES_CACHE_KEY'
@@ -21,17 +21,22 @@ export async function restoreCachedDependencies(
     core.saveState(DEPENDENCIES_CACHE_PATH, cachePath)
 
     const inputCacheExact = core.getBooleanInput('dependencies-cache-exact')
-    const cacheKeyGlobs = inputCacheKeyGlobs('dependencies-cache-key')
+    const cacheKeyPrefix = 'dependencies|'
+
+    const args = core.getInput('arguments')
+    const argsKey = cacheUtils.truncateArgs(args)
+    const cacheKeyWithArgs = `${cacheKeyPrefix}${argsKey}|`
+
+    const cacheKeyGlobs = inputCacheKeyGlobs('dependencies-cache-key')
+    const hash = await cacheUtils.hashFiles(rootDir, cacheKeyGlobs)
+    const cacheKey = `${cacheKeyWithArgs}${hash}`
 
-    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,
-        inputCacheExact ? [] : [cacheKeyPrefix]
+        inputCacheExact ? [] : [cacheKeyWithArgs, cacheKeyPrefix]
     )
 
     if (!cacheResult) {
@@ -73,6 +78,8 @@ export async function cacheDependencies(): Promise<void> {
         return
     }
 
+    core.info(`Will cache dependencies with key ${cacheKey}`)
+
     try {
         await cache.saveCache([cachePath], cacheKey)
     } catch (error) {

src/cache-utils.ts

@@ -11,3 +11,7 @@ export async function hashFiles(
         .join('\n')
     return glob.hashFiles(combinedPatterns, {followSymbolicLinks})
 }
+
+export function truncateArgs(args: string): string {
+    return args.trim().replace(/\s+/g, ' ').substr(0, 400)
+}

src/post.ts

@@ -1,12 +1,20 @@
+import * as core from '@actions/core'
+
 import * as cacheWrapper from './cache-wrapper'
 import * as cacheDependencies from './cache-dependencies'
 import * as cacheConfiguration from './cache-configuration'
 
 // Invoked by GitHub Actions
 export async function run(): Promise<void> {
+    if (isCacheReadOnly()) return
+
     await cacheWrapper.cacheWrapperDist()
     await cacheDependencies.cacheDependencies()
     await cacheConfiguration.cacheConfiguration()
 }
 
+function isCacheReadOnly(): boolean {
+    return core.getBooleanInput('cache-read-only')
+}
+
 run()