Cache artifacts directory by default

src/caching.ts

@@ -0,0 +1,25 @@
+import * as cache from '@actions/cache'
+import * as glob from '@actions/glob'
+
+import * as path from 'path'
+
+// TODO: Change to hashFiles once https://github.com/actions/toolkit/issues/472 has been resolved
+import * as md5File from 'md5-file'
+
+const JULIA_HOME = path.join(`${process.env.HOME}`, '.julia')
+
+/**
+ * Cache the ~/.julia/artifacts directory.
+ */
+export async function cacheArtifacts(): Promise<number> {
+    const projectFiles = await (await glob.create('**/Project.toml')).glob()
+    let projectsHash = ''
+    projectFiles.forEach((f) => {
+        projectsHash.concat('-', md5File.sync(f))
+    })
+
+    const paths = [path.join(JULIA_HOME, 'artifacts')]
+    const key = `artifacts-${process.env.RUNNER_OS}-${projectsHash}`
+
+    return cache.saveCache(paths, key)
+}

src/setup-julia.ts

@@ -5,6 +5,7 @@ import * as tc from '@actions/tool-cache'
 import * as path from 'path'
 
 import * as installer from './installer'
+import * as jlcache from './caching'
 
 async function run() {
     try {
@@ -39,6 +40,13 @@ async function run() {
         if (core.getInput('show-versioninfo') == 'true') {
             exec.exec('julia', ['-e', 'using InteractiveUtils; versioninfo()'])
         }
+
+        // Create caches
+        if (core.getInput('cache-artifacts') == 'true') {
+            core.debug('caching artifacts directory...')
+            const cacheId = await jlcache.cacheArtifacts()
+            core.setOutput('artifacts-cache-id', cacheId.toString())
+        }
     } catch (error) {
         core.setFailed(error.message)
     }