Use @actions/cache to accelerate the Action

This opt-out feature uses the cache, so that the files are cached the
first time a given artifact from a given buildId is downloaded.
Subsequent attempts to download the same artifact with the same buildId
should become much quicker as a consequence.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

README.md

@@ -66,6 +66,10 @@ Please note that only the `build-installers` and the `full` flavors are availabl
 
 By default, this Action prints a line whenever 250 items were extracted (this does not work for the `full` flavor, where this Action is silent by default). It can be overridden by setting the input parameter `verbose`; setting it to a number will show updates whenever that many items were extracted. Setting it to `false` will suppress progress updates. Setting it to `true` will print every extracted file (this also works for the `full` flavor).
 
+### Caching
+
+To accelerate this Action, artifacts are cached once downloaded. This can be turned off by setting the input parameter `cache` to `false`.
+
 ## Developing _this_ Action
 
 > First, you'll need to have a reasonably modern version of `node` handy, such as Node 12.

__tests__/main.test.ts

@@ -50,7 +50,8 @@ if (process.env.RUN_NETWORK_TESTS !== 'true') {
           INPUT_FLAVOR: 'minimal',
           INPUT_ARCHITECTURE: 'x86_64',
           INPUT_PATH: outputDirectory,
-          INPUT_VERBOSE: '250'
+          INPUT_VERBOSE: '250',
+          INPUT_CACHE: 'true'
         }
       })
     ).toEqual(0)

action.yml

@@ -18,6 +18,10 @@ inputs:
     required: false
     description: 'Whether to log files as they are extracted'
     default: '250'
+  cache:
+    required: false
+    description: 'Use @actions/cache to accelerate this Action'
+    default: 'true'
 runs:
   using: 'node12'
   main: 'dist/index.js'

main.ts

@@ -1,6 +1,7 @@
 import * as core from '@actions/core'
 import process from 'process'
 import {get} from './src/downloader'
+import {restoreCache, saveCache} from '@actions/cache'
 
 async function run(): Promise<void> {
   try {
@@ -14,15 +15,30 @@ async function run(): Promise<void> {
     const architecture = core.getInput('architecture')
     const verbose = core.getInput('verbose')
 
-    const {artifactName, download} = await get(flavor, architecture)
+    const {artifactName, download, id} = await get(flavor, architecture)
     const outputDirectory = core.getInput('path') || `C:/${artifactName}`
+    let useCache = core.getInput('cache') === 'true'
+
+    try {
+      if (useCache && (await restoreCache([outputDirectory], id))) {
+        core.info(`Cached ${id} was successfully restored`)
+        return
+      }
+    } catch (e) {
+      core.warning(`Cannot use @actions/cache (${e})`)
+      useCache = false
+    }
 
     core.info(`Downloading ${artifactName}`)
     await download(
       outputDirectory,
       verbose.match(/^\d+$/) ? parseInt(verbose) : verbose === 'true'
     )
 
+    if (useCache && !(await saveCache([outputDirectory], id))) {
+      core.warning(`Failed to cache ${id}`)
+    }
+
     // Set up PATH so that Git for Windows' SDK's `bash.exe` is found
     core.addPath(`${outputDirectory}/usr/bin`)
     core.exportVariable(