feat: add support for saving / restoring rtx cache (#64)

* feat: add support for saving / restoring rtx cache

* fix: add support for .rtx.toml to file hash

src/cache-save.ts

@@ -0,0 +1,36 @@
+import * as cache from '@actions/cache'
+import * as core from '@actions/core'
+import * as fs from 'fs'
+import {rtxDir} from './utils'
+
+export async function run(): Promise<void> {
+  try {
+    await cacheRTXTools()
+  } catch (error) {
+    if (error instanceof Error) core.setFailed(error.message)
+  }
+}
+
+async function cacheRTXTools(): Promise<void> {
+  const state = core.getState('CACHE_KEY')
+  const primaryKey = core.getState('PRIMARY_KEY')
+  const cachePath = rtxDir()
+
+  if (!fs.existsSync(cachePath)) {
+    throw new Error(`Cache folder path does not exist on disk: ${cachePath}`)
+  }
+
+  if (primaryKey === state) {
+    core.info(
+      `Cache hit occurred on the primary key ${primaryKey}, not saving cache.`
+    )
+    return
+  }
+
+  const cacheId = await cache.saveCache([cachePath], primaryKey)
+  if (cacheId === -1) return
+
+  core.info(`Cache saved with the primary key: ${primaryKey}`)
+}
+
+run()

src/main.ts

@@ -1,17 +1,40 @@
+import * as cache from '@actions/cache'
 import * as core from '@actions/core'
 import * as exec from '@actions/exec'
+import * as glob from '@actions/glob'
 import * as fs from 'fs'
 import * as os from 'os'
 import * as path from 'path'
+import {rtxDir} from './utils'
 
 async function run(): Promise<void> {
+  await setToolVersions()
+  await restoreRTXCache()
   await setupRTX()
   await exec.exec('rtx', ['--version'])
-  await setToolVersions()
   await exec.exec('rtx', ['install'])
   await setPaths()
 }
 
+async function restoreRTXCache(): Promise<void> {
+  const cachePath = rtxDir()
+  const fileHash = await glob.hashFiles(`**/.tool-versions\n**/.rtx.toml`)
+  const primaryKey = `rtx-tools-${getOS()}-${os.arch()}-${fileHash}`
+
+  core.saveState('PRIMARY_KEY', primaryKey)
+
+  const cacheKey = await cache.restoreCache([cachePath], primaryKey)
+  core.setOutput('cache-hit', Boolean(cacheKey))
+
+  if (!cacheKey) {
+    core.info(`rtx cache not found for ${getOS()}-${os.arch()} tool versions`)
+    return
+  }
+
+  core.saveState('CACHE_KEY', cacheKey)
+  core.info(`rtx cache restored from key: ${cacheKey}`)
+}
+
 async function setupRTX(): Promise<void> {
   const rtxBinDir = path.join(rtxDir(), 'bin')
   const url = `https://rtx.pub/rtx-latest-${getOS()}-${os.arch()}`
@@ -53,16 +76,6 @@ async function getBinPaths(): Promise<string[]> {
   return output.stdout.split('\n')
 }
 
-function rtxDir(): string {
-  if (process.env.RTX_DATA_HOME) {
-    return process.env.RTX_DATA_HOME
-  }
-  if (process.env.XDG_DATA_HOME) {
-    return path.join(process.env.XDG_DATA_HOME, 'rtx')
-  }
-  return path.join(os.homedir(), '.local/share/rtx')
-}
-
 if (require.main === module) {
   try {
     run()

src/utils.ts

@@ -0,0 +1,12 @@
+import * as os from 'os'
+import * as path from 'path'
+
+export function rtxDir(): string {
+  if (process.env.RTX_DATA_HOME) {
+    return process.env.RTX_DATA_HOME
+  }
+  if (process.env.XDG_DATA_HOME) {
+    return path.join(process.env.XDG_DATA_HOME, 'rtx')
+  }
+  return path.join(os.homedir(), '.local/share/rtx')
+}