Download import.sh script inside Builder (#23)

Rather than downloading `import.sh` per-build, it'll be downloaded
at Builder build-time and published in the npm package. This will make
the Builder faster and more reliable.

Author: TooTallNate

build.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+set -euo pipefail
+
+rm -rf dist
+tsc --project src/tsconfig.json
+cp src/bootstrap src/build.sh src/runtime.sh dist
+curl -sfLS "https://import.sh" > dist/import.sh
+chmod +x dist/import.sh

package.json

@@ -15,9 +15,7 @@
     "dist"
   ],
   "scripts": {
-    "prebuild": "rm -rf dist",
-    "build": "tsc --project src/tsconfig.json",
-    "postbuild": "cp src/bootstrap src/build.sh src/runtime.sh dist",
+    "build": "./build.sh",
     "now-build": "next build",
     "prepublishOnly": "npm run build"
   },

src/build.sh

@@ -4,17 +4,9 @@ set -euo pipefail
 # `import` debug logs are always enabled during build
 export IMPORT_DEBUG=1
 
-# Install `import`
-IMPORT_BIN="$IMPORT_CACHE/bin/import"
-echo "Installing \`import\` to \"$IMPORT_BIN\"…"
-mkdir -p "$(dirname "$IMPORT_BIN")"
-curl -sfLS "https://import.sh" > "$IMPORT_BIN"
-chmod +x "$IMPORT_BIN"
-echo "Done installing \`import\`"
-
 # Cache runtime and user dependencies
 echo "Caching imports in \"$ENTRYPOINT\"…"
-. "$IMPORT_BIN"
+. "$BUILDER_DIST/import.sh"
 . "$WORK_PATH/$ENTRYPOINT"
 echo "Done caching imports"
 

src/index.ts

@@ -23,6 +23,7 @@ const TMP = tmpdir();
 // `chmod()` is required for usage with `vercel-dev-runtime`
 // since file mode is not preserved in Vercel CLI deployments.
 fs.chmodSync(join(__dirname, 'build.sh'), 0o755);
+fs.chmodSync(join(__dirname, 'import.sh'), 0o755);
 fs.chmodSync(join(__dirname, 'bootstrap'), 0o755);
 
 const bootstrapPromise = FileFsRef.fromFsPath({
@@ -31,6 +32,9 @@ const bootstrapPromise = FileFsRef.fromFsPath({
 const runtimePromise = FileFsRef.fromFsPath({
 	fsPath: join(__dirname, 'runtime.sh'),
 });
+const importPromise = FileFsRef.fromFsPath({
+	fsPath: join(__dirname, 'import.sh'),
+});
 const curlPromise = fetch(
 	'https://github.com/dtschan/curl-static/releases/download/v7.63.0/curl'
 ).then(async (res) => {
@@ -100,6 +104,7 @@ export const build: BuildV3 = async ({
 		IMPORT_TRACE,
 		WORK_PATH: workPath,
 		ENTRYPOINT: entrypoint,
+		BUILDER_DIST: __dirname,
 	};
 
 	const buildDir = await getWriteableDirectory();
@@ -123,6 +128,7 @@ export const build: BuildV3 = async ({
 		)),
 		bootstrap: await bootstrapPromise,
 		'.import-cache/runtime.sh': await runtimePromise,
+		'.import-cache/bin/import': await importPromise,
 		'.import-cache/bin/curl': await curlPromise,
 		'.import-cache/bin/jq': await jqPromise,
 		// For now only the entrypoint file is copied into the lambda
@@ -157,19 +163,24 @@ export const build: BuildV3 = async ({
 	//  - if symlink, then include if it points to a traced files
 	//  - if not symlink, then always include in output
 	const binDir = join(importCacheDir, 'bin');
-	const bins = await fs.readdir(binDir);
+	let bins: string[] = [];
+	try {
+		bins = await fs.readdir(binDir);
+	} catch (err: any) {
+		if (err.code !== 'ENOENT') throw err;
+	}
 	for (const bin of bins) {
 		const binPath = join(binDir, bin);
 		const target = await fs.readlink(binPath).catch((err) => {
-			if (err.code !== "EINVAL") throw err;
+			if (err.code !== 'EINVAL') throw err;
 		});
 		if (target) {
 			const rel = relative(importCacheDir, join(binDir, target));
-			if (!lambdaFiles[join(".import-cache", rel)]) {
+			if (!lambdaFiles[join('.import-cache', rel)]) {
 				continue;
 			}
 		}
-		lambdaFiles[join(".import-cache/bin", bin)] =
+		lambdaFiles[join('.import-cache/bin', bin)] =
 			await FileFsRef.fromFsPath({
 				fsPath: binPath,
 			});