Publish

- @now/build-utils@0.5.6
 - @now/go@0.5.1
 - @now/lambda@0.5.4
 - @now/layer-node@0.0.2
 - @now/layer-npm@0.0.2
 - @now/layer-yarn@0.0.2
 - @now/next@0.4.1
 - @now/node-bridge@1.1.4
 - @now/node-server@0.7.4
 - @now/node@0.7.4
 - @now/optipng@0.6.2
 - @now/php-bridge@0.5.3
 - @now/php@0.5.5
 - @now/python@0.2.5
 - @now/rust@0.2.5
 - @now/static-build@0.5.8
 - @now/wordpress@0.5.3

.circleci/build.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+set -euo pipefail
+
+circleci_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+needs_build="$(grep -rn '"build"' packages/*/package.json | cut -d: -f1)"
+
+for pkg in $needs_build; do
+  dir="$(dirname "$pkg")"
+  cd "$circleci_dir/../$dir"
+  echo "Building \`$dir\`"
+  yarn build
+done

.circleci/config.yml

@@ -20,23 +20,17 @@ jobs:
       - run:
           name: Bootstrapping
           command: yarn bootstrap
+      - run:
+          name: Building
+          command: ./.circleci/build.sh
       - run:
           name: Linting
           command: yarn lint
       - run:
-          name: Tests
-          command: yarn test
-      - run:
-          name: Potentially save npm token
-          command: "([[ ! -z $NPM_TOKEN ]] && echo \"//registry.npmjs.org/:_authToken=$NPM_TOKEN\" >> ~/.npmrc) || echo \"Did not write npm token\""
-      - run:
-          name: Potentially publish canary release
-          command: "if ls ~/.npmrc >/dev/null 2>&1 && [[ $(git describe --exact-match 2> /dev/null || :) =~ -canary ]]; then yarn run lerna publish from-git --npm-tag canary --yes; else  echo \"Did not publish\"; fi"
-      - run:
-          name: Potentially publish stable release
-          command: "if ls ~/.npmrc >/dev/null 2>&1 && [[ ! $(git describe --exact-match 2> /dev/null || :) =~ -canary ]]; then yarn run lerna publish from-git --yes; else  echo \"Did not publish\"; fi"
+          name: Tests and Coverage
+          command: yarn test-coverage
 workflows:
   version: 2
-  build-and-deploy:
+  build-and-test:
     jobs:
       - build

.circleci/publish.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+set -euo pipefail
+
+if [ -z "$NPM_TOKEN" ]; then
+  echo "NPM_TOKEN not found. Did you forget to assign the GitHub Action secret?"
+  exit 1
+fi
+
+echo "//registry.npmjs.org/:_authToken=$NPM_TOKEN" >> ~/.npmrc
+
+if [ ! -e ~/.npmrc ]; then
+  echo "~/.npmrc file does not exist, skipping publish"
+  exit 0
+fi
+
+npm_tag=""
+tag="$(git describe --tags --exact-match 2> /dev/null || :)"
+
+if [ -z "$tag" ]; then
+  echo "Not a tagged commit, skipping publish"
+  exit 0
+fi
+
+if [[ "$tag" =~ -canary ]]; then
+  echo "Publishing canary release"
+  npm_tag="--npm-tag canary"
+else
+  echo "Publishing stable release"
+fi
+
+yarn run lerna publish from-git $npm_tag --yes

.editorconfig

@@ -0,0 +1,43 @@
+root = true
+
+[*]
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[{*.json,*.json.example,*.gyp,*.yml,*.yaml,*.workflow}]
+indent_style = space
+indent_size = 2
+
+[{*.py,*.asm}]
+indent_style = space
+
+[*.py]
+indent_size = 4
+
+[*.asm]
+indent_size = 8
+
+[*.md]
+trim_trailing_whitespace = false
+indent_style = space
+indent_size = 2
+
+# Ideal settings - some plugins might support these
+[*.js,*.jsx,*.ts,*.tsx]
+quote_type = single
+indent_style = space
+indent_size = 2
+
+[{*.c,*.cc,*.h,*.hh,*.cpp,*.hpp,*.m,*.mm,*.mpp,*.java,*.go,*.rs,*.php,*.ng,*.d,*.cs,*.swift}]
+indent_style = tab
+indent_size = 4
+tab_width = 4
+
+[{*.c,*.cc,*.h,*.hh,*.cpp,*.hpp,*.m,*.mm,*.mpp,*.js,*.java,*.go,*.rs,*.php,*.ng,*.jsx,*.ts,*.tsx,*.d,*.cs,*.swift}]
+curly_bracket_next_line = false
+spaces_around_operators = true
+spaces_around_brackets = outside
+# close enough to 1TB
+indent_brace_style = K&R

.eslintignore

@@ -1,3 +1,17 @@
 /tmp/*
 /node_modules/*
 /**/node_modules/*
+/packages/now-go/go/*
+/packages/now-build-utils/dist/*
+/packages/now-build-utils/src/*.js
+/packages/now-build-utils/src/fs/*.js
+/packages/now-node/dist/*
+/packages/now-layer-node/dist/*
+/packages/now-layer-npm/dist/*
+/packages/now-layer-yarn/dist/*
+/packages/now-next/dist/*
+/packages/now-node-bridge/*
+/packages/now-python/dist/*
+/packages/now-optipng/dist/*
+/packages/now-go/*
+/packages/now-rust/dist/*

.eslintrc

@@ -8,7 +8,7 @@
   },
   "overrides": [
     {
-      "files": ["test/**"],
+      "files": ["**/test/**"],
       "rules": {
         "import/no-extraneous-dependencies": 0
       },

.github/CODEOWNERS

@@ -0,0 +1,9 @@
+# Documentation
+# https://help.github.com/en/articles/about-code-owners
+
+*                       @styfle
+/packages/now-node      @styfle @tootallnate
+/packages/now-next      @timer  @dav-is
+/packages/now-go        @styfle @sophearak
+/packages/now-python    @styfle @sophearak
+/packages/now-rust      @styfle @mike-engel @anmonteiro

.github/main.workflow

@@ -0,0 +1,76 @@
+workflow "Canary publish" {
+  on = "push"
+  resolves = ["3. Canary yarn run publish"]
+}
+
+action "0. Canary filter" {
+  uses = "actions/bin/filter@3c0b4f0e63ea54ea5df2914b4fabf383368cd0da"
+  args = "branch canary"
+}
+
+action "0. Canary PR not deleted" {
+  uses = "actions/bin/filter@3c0b4f0e63ea54ea5df2914b4fabf383368cd0da"
+  needs = ["0. Canary filter"]
+  args = "not deleted"
+}
+
+action "1. Canary yarn install" {
+  uses = "actions/npm@59b64a598378f31e49cb76f27d6f3312b582f680"
+  needs = ["0. Canary PR not deleted"]
+  runs = "yarn"
+  args = "install"
+}
+
+action "2. Canary yarn run build" {
+  uses = "actions/npm@59b64a598378f31e49cb76f27d6f3312b582f680"
+  needs = ["1. Canary yarn install"]
+  runs = "yarn"
+  args = "run build"
+}
+
+action "3. Canary yarn run publish" {
+  uses = "actions/npm@59b64a598378f31e49cb76f27d6f3312b582f680"
+  needs = ["2. Canary yarn run build"]
+  runs = "yarn"
+  args = "run publish-from-github"
+  secrets = ["NPM_TOKEN"]
+}
+
+
+workflow "Master publish" {
+  on = "push"
+  resolves = ["3. Master yarn run publish"]
+}
+
+action "0. Master filter" {
+  uses = "actions/bin/filter@3c0b4f0e63ea54ea5df2914b4fabf383368cd0da"
+  args = "branch master"
+}
+
+action "0. Master PR not deleted" {
+  uses = "actions/bin/filter@3c0b4f0e63ea54ea5df2914b4fabf383368cd0da"
+  needs = ["0. Master filter"]
+  args = "not deleted"
+}
+
+action "1. Master yarn install" {
+  uses = "actions/npm@59b64a598378f31e49cb76f27d6f3312b582f680"
+  needs = ["0. Master PR not deleted"]
+  runs = "yarn"
+  args = "install"
+}
+
+action "2. Master yarn run build" {
+  uses = "actions/npm@59b64a598378f31e49cb76f27d6f3312b582f680"
+  needs = ["1. Master yarn install"]
+  runs = "yarn"
+  args = "run build"
+}
+
+action "3. Master yarn run publish" {
+  uses = "actions/npm@59b64a598378f31e49cb76f27d6f3312b582f680"
+  needs = ["2. Master yarn run build"]
+  runs = "yarn"
+  args = "run publish-from-github"
+  secrets = ["NPM_TOKEN"]
+}

.gitignore

@@ -1,2 +1,6 @@
 node_modules
 tmp
+target/
+.next
+coverage
+*.tgz

.vscode/settings.json

@@ -0,0 +1,3 @@
+{
+  "eslint.enable": false
+}

.yarnrc

@@ -0,0 +1 @@
+save-prefix ""

CODE_OF_CONDUCT.md

@@ -0,0 +1,74 @@
+## Code of Conduct
+
+### Our Pledge
+
+In the interest of fostering an open and welcoming environment, we as
+contributors and maintainers pledge to making participation in our project and
+our community a harassment-free experience for everyone, regardless of age, body
+size, disability, ethnicity, gender identity and expression, level of experience,
+nationality, personal appearance, race, religion, or sexual identity and
+orientation.
+
+### Our Standards
+
+Examples of behavior that contributes to creating a positive environment
+include:
+
+- Using welcoming and inclusive language
+- Being respectful of differing viewpoints and experiences
+- Gracefully accepting constructive criticism
+- Focusing on what is best for the community
+- Showing empathy towards other community members
+
+Examples of unacceptable behavior by participants include:
+
+- The use of sexualized language or imagery and unwelcome sexual attention or
+  advances
+- Trolling, insulting/derogatory comments, and personal or political attacks
+- Public or private harassment
+- Publishing others' private information, such as a physical or electronic
+  address, without explicit permission
+- Other conduct which could reasonably be considered inappropriate in a
+  professional setting
+
+### Our Responsibilities
+
+Project maintainers are responsible for clarifying the standards of acceptable
+behavior and are expected to take appropriate and fair corrective action in
+response to any instances of unacceptable behavior.
+
+Project maintainers have the right and responsibility to remove, edit, or
+reject comments, commits, code, wiki edits, issues, and other contributions
+that are not aligned to this Code of Conduct, or to ban temporarily or
+permanently any contributor for other behaviors that they deem inappropriate,
+threatening, offensive, or harmful.
+
+### Scope
+
+This Code of Conduct applies both within project spaces and in public spaces
+when an individual is representing the project or its community. Examples of
+representing a project or community include using an official project e-mail
+address, posting via an official social media account, or acting as an appointed
+representative at an online or offline event. Representation of a project may be
+further defined and clarified by project maintainers.
+
+### Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be
+reported by contacting the project team at [abuse@zeit.co](mailto:abuse@zeit.co). All
+complaints will be reviewed and investigated and will result in a response that
+is deemed necessary and appropriate to the circumstances. The project team is
+obligated to maintain confidentiality with regard to the reporter of an incident.
+Further details of specific enforcement policies may be posted separately.
+
+Project maintainers who do not follow or enforce the Code of Conduct in good
+faith may face temporary or permanent repercussions as determined by other
+members of the project's leadership.
+
+### Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
+available at [http://contributor-covenant.org/version/1/4][version]
+
+[homepage]: http://contributor-covenant.org
+[version]: http://contributor-covenant.org/version/1/4/

README.md

@@ -1,8 +1,11 @@
 # now-builders
 
-This is the full list of official Builders provided by the ZEIT team.
+This is a monorepo containing the [Official Builders](https://zeit.co/docs/v2/deployments/builders/overview) provided by the ZEIT team.
 
-More details here: http://zeit.co/docs
+There are two branches:
+
+- canary - published to npm as `canary` dist-tag, eg `@now/node@canary`
+- master - published to npm as `latest` dist-tag, eg `@now/node@latest`
 
 ### Publishing to npm
 
@@ -20,8 +23,8 @@ For the canary channel use:
 yarn publish-canary
 ```
 
-CircleCI will take care of publishing the updated packages to npm from there.
+GitHub Actions will take care of publishing the updated packages to npm from there.
 
-If for some reason CircleCI fails to publish the npm package, you may do so
+If for some reason GitHub Actions fails to publish the npm package, you may do so
 manually by running `npm publish` from the package directory. Make sure to
-include the `--tag canary` parameter if you are publishing a canary release!
+use `npm publish --tag canary` if you are publishing a canary release!

errors/now-next-legacy-mode.md

@@ -0,0 +1,72 @@
+# `@now/next` Legacy Mode
+
+#### Why This Warning Occurred
+
+`@now/next` has two modes: `legacy` and `serverless`. You will always want to use the `serverless` mode. `legacy` is to provide backwards compatibility with previous `@now/next` versions.
+
+The differences:
+
+Legacy:
+
+- Minimal lambda size of `2.2Mb` (approximately)
+- Forces `next@v7.0.2-canary.49` and `next-server@v7.0.2-canary.49`
+- Forces all `dependencies` to be `devDependencies`
+- Loads `next.config.js` on bootup, breaking sometimes when users didn't use `phases` to load files
+- Used `next-server` which is the full Next.js server with routing etc.
+- Runs `npm install`
+- Runs `npm run now-build`
+- Runs `npm install --production` after build
+
+Serverless:
+
+- Minimal lambda size of `49Kb` (approximately)
+- Uses Next.js build targets (`target: 'serverless'`) in `next.config.js`. [documentation](https://github.com/zeit/next.js#summary)
+- Does not make changes to your application dependencies
+- Does not load `next.config.js` ([as per the serverless target documentation](https://github.com/zeit/next.js#summary))
+- Runs `npm install`
+- Runs `npm run now-build`
+- Does not run `npm install --production` as the output from the build is all that's needed to bundle lambdas.
+- No runtime dependencies, meaning smaller lambda functions
+- Optimized for fast [cold start](https://zeit.co/blog/serverless-ssr#cold-start)
+
+#### Possible Ways to Fix It
+
+In order to create the smallest possible lambdas Next.js has to be configured to build for the `serverless` target.
+
+1. Serverless Next.js requires Next.js 8 or later, to upgrade you can install the `latest` version:
+
+```
+npm install next --save
+```
+
+2. Add the `now-build` script to your `package.json`
+
+```json
+{
+  "scripts": {
+    "now-build": "next build"
+  }
+}
+```
+
+3. Add `target: 'serverless'` to `next.config.js`
+
+```js
+module.exports = {
+  target: 'serverless',
+  // Other options are still valid
+};
+```
+
+4. Optionally make sure the `"src"` in `"builds"` points to your application `package.json`
+
+```js
+{
+  "version": 2,
+  "builds": [{ "src": "package.json", "use": "@now/next" }]
+}
+```
+
+### Useful Links
+
+- [Serverless target implementation](https://github.com/zeit/now-builders/pull/150)

errors/now-next-no-serverless-pages-built.md

@@ -0,0 +1,45 @@
+# `@now/next` No Serverless Pages Built
+
+#### Why This Error Occurred
+
+This error occurs when you have your application is not configured for Serverless Next.js build output.
+
+#### Possible Ways to Fix It
+
+In order to create the smallest possible lambdas Next.js has to be configured to build for the `serverless` target.
+
+1. Serverless Next.js requires Next.js 8 or later, to upgrade you can install the `latest` version:
+
+```
+npm install next --save
+```
+
+2. Add the `now-build` script to your `package.json`
+
+```json
+{
+  "scripts": {
+    "now-build": "next build"
+  }
+}
+```
+
+3. Add `target: 'serverless'` to `next.config.js`
+
+```js
+module.exports = {
+  target: 'serverless',
+  // Other options
+};
+```
+
+4. Remove `distDir` from `next.config.js` as `@now/next` can't parse this file and expects your build output at `/.next`
+
+5. Optionally make sure the `"src"` in `"builds"` points to your application `package.json`
+
+```js
+{
+  "version": 2,
+  "builds": [{ "src": "package.json", "use": "@now/next" }]
+}
+```

errors/now-static-build-failed-to-detect-a-server.md

@@ -0,0 +1,38 @@
+# `@now/static-build` Failed to detect a server running
+
+#### Why This Warning Occurred
+
+When running `now dev`, the `@now/static-build` builder proxies relevant HTTP
+requests to the server that is created by the `now-dev` script in the
+`package.json` file.
+
+In order for `now dev` to know which port the server is running on, the builder
+is provided a `$PORT` environment variable that the server _must_ bind to. The
+error "Failed to detect a server running on port" is printed if the builder fails
+to detect a server listening on that specific port within five minutes.
+
+#### Possible Ways to Fix It
+
+Please ensure that your `now-dev` script binds the spawned development server on
+the provided `$PORT` that the builder expects the server to bind to.
+
+For example, if you are using Gatsby, your `now-dev` script must use the `-p`
+(port) option to bind to the `$PORT` specified from the builder:
+
+```
+{
+  ...
+  "scripts": {
+    ...
+    "now-dev": "gatsby develop -p $PORT"
+  }
+}
+```
+
+Consult your static builder program's `--help` or documentation to figure out what
+the command line flag to bind to a specific port is (in many cases, it is one of:
+`-p` / `-P` / `--port`).
+
+### Useful Links
+
+- [`@now/static-build` Local Development Documentation](https://zeit.co/docs/v2/deployments/official-builders/static-build-now-static-build#local-development)

jest.config.js

@@ -1,4 +1,40 @@
+const childProcess = require('child_process');
+const path = require('path');
+
+const command = 'git diff HEAD~1 --name-only';
+const diff = childProcess.execSync(command).toString();
+
+const changed = diff
+  .split('\n')
+  .filter(item => Boolean(item) && item.includes('packages/'))
+  .map(item => path.relative('packages', item).split('/')[0]);
+
+const matches = [];
+
+if (changed.length > 0) {
+  console.log('The following packages have changed:');
+
+  changed.map((item) => {
+    matches.push(item);
+    console.log(item);
+
+    return null;
+  });
+} else {
+  matches.push('now-node');
+  console.log(`No packages changed, defaulting to ${matches[0]}`);
+}
+
+const testMatch = Array.from(new Set(matches)).map(
+  item => `**/${item}/**/?(*.)+(spec|test).[jt]s?(x)`,
+);
+
 module.exports = {
   testEnvironment: 'node',
-  collectCoverageFrom: ['packages/**/*.{js,jsx}', '!**/node_modules/**'],
+  testMatch,
+  collectCoverageFrom: [
+    'packages/(!test)/**/*.{js,jsx}',
+    '!**/node_modules/**',
+    '!**/test/**',
+  ],
 };

lerna.json

@@ -1,26 +1,7 @@
 {
   "npmClient": "yarn",
   "useWorkspaces": true,
-  "packages": [
-    "packages/now-build-utils",
-    "packages/now-node-bridge",
-    "packages/now-php-bridge",
-    "packages/now-bash",
-    "packages/now-cgi",
-    "packages/now-go",
-    "packages/now-html-minifier",
-    "packages/now-lambda",
-    "packages/now-md",
-    "packages/now-mdx-deck",
-    "packages/now-next",
-    "packages/now-node",
-    "packages/now-node-server",
-    "packages/now-optipng",
-    "packages/now-php",
-    "packages/now-python",
-    "packages/now-static-build",
-    "packages/now-wordpress"
-  ],
+  "packages": ["packages/*"],
   "command": {
     "publish": {
       "npmClient": "npm",

package.json

@@ -12,18 +12,26 @@
   "scripts": {
     "lerna": "lerna",
     "bootstrap": "lerna bootstrap",
-    "publish-stable": "lerna version",
-    "publish-canary": "lerna version prerelease --preid canary",
-    "lint": "tsc && eslint .",
-    "test": "jest --runInBand",
+    "publish-stable": "git checkout master && git pull && lerna version",
+    "publish-canary": "git checkout canary && git pull && lerna version prerelease --preid canary",
+    "publish-from-github": "./.circleci/publish.sh",
+    "build": "./.circleci/build.sh",
+    "lint": "eslint .",
+    "codecov": "codecov",
+    "test": "jest --runInBand --verbose",
+    "test-coverage": "jest --runInBand --verbose --coverage --globals \"{\\\"coverage\\\":true}\" && codecov",
     "lint-staged": "lint-staged"
   },
   "pre-commit": "lint-staged",
   "lint-staged": {
     "*.js": [
-      "prettier --write --single-quote",
+      "prettier --write",
       "eslint --fix",
       "git add"
+    ],
+    "*.ts": [
+      "prettier --write",
+      "git add"
     ]
   },
   "devDependencies": {
@@ -33,6 +41,7 @@
     "@types/node": "^10.12.8",
     "async-retry": "1.2.3",
     "buffer-replace": "^1.0.0",
+    "codecov": "^3.2.0",
     "eslint": "^5.9.0",
     "eslint-config-airbnb-base": "^13.1.0",
     "eslint-config-prettier": "^3.1.0",
@@ -43,7 +52,10 @@
     "lint-staged": "^8.0.4",
     "node-fetch": "^2.3.0",
     "pre-commit": "^1.2.2",
-    "prettier": "^1.15.2",
-    "typescript": "^3.1.6"
+    "prettier": "1.17.1"
+  },
+  "prettier": {
+    "singleQuote": true,
+    "trailingComma": "es5"
   }
 }

packages/now-bash/bootstrap

@@ -7,7 +7,9 @@ export IMPORT_CACHE="$LAMBDA_TASK_ROOT/.import-cache"
 export PATH="$IMPORT_CACHE/bin:$PATH"
 
 # Load `import` and runtime
+# shellcheck disable=SC1090
 . "$(which import)"
+# shellcheck disable=SC1090
 . "$IMPORT_CACHE/runtime.sh"
 
 # Load user code and process events in a loop forever

packages/now-bash/index.js

@@ -1,10 +1,13 @@
 const execa = require('execa');
 const { join } = require('path');
 const snakeCase = require('snake-case');
-const glob = require('@now/build-utils/fs/glob');
-const download = require('@now/build-utils/fs/download');
-const { createLambda } = require('@now/build-utils/lambda');
-const getWritableDirectory = require('@now/build-utils/fs/get-writable-directory');
+const {
+  glob,
+  download,
+  createLambda,
+  getWriteableDirectory,
+  shouldServe,
+} = require('@now/build-utils'); // eslint-disable-line import/no-extraneous-dependencies
 
 exports.config = {
   maxLambdaSize: '10mb',
@@ -12,9 +15,10 @@ exports.config = {
 
 exports.analyze = ({ files, entrypoint }) => files[entrypoint].digest;
 
-exports.build = async ({ files, entrypoint, config }) => {
-  const srcDir = await getWritableDirectory();
-  const workDir = await getWritableDirectory();
+exports.build = async ({
+  workPath, files, entrypoint, config,
+}) => {
+  const srcDir = await getWriteableDirectory();
 
   console.log('downloading files...');
   await download(files, srcDir);
@@ -24,7 +28,7 @@ exports.build = async ({ files, entrypoint, config }) => {
     return o;
   }, {});
 
-  const IMPORT_CACHE = `${workDir}/.import-cache`;
+  const IMPORT_CACHE = `${workPath}/.import-cache`;
   const env = Object.assign({}, process.env, configEnv, {
     PATH: `${IMPORT_CACHE}/bin:${process.env.PATH}`,
     IMPORT_CACHE,
@@ -37,12 +41,12 @@ exports.build = async ({ files, entrypoint, config }) => {
 
   await execa(builderPath, [entrypoint], {
     env,
-    cwd: workDir,
+    cwd: workPath,
     stdio: 'inherit',
   });
 
   const lambda = await createLambda({
-    files: await glob('**', workDir),
+    files: await glob('**', workPath),
     handler: entrypoint, // not actually used in `bootstrap`
     runtime: 'provided',
     environment: Object.assign({}, configEnv, {
@@ -54,3 +58,5 @@ exports.build = async ({ files, entrypoint, config }) => {
     [entrypoint]: lambda,
   };
 };
+
+exports.shouldServe = shouldServe;

packages/now-bash/package.json

@@ -1,10 +1,15 @@
 {
   "name": "@now/bash",
-  "version": "0.1.1",
+  "version": "0.2.3",
   "description": "Now 2.0 builder for HTTP endpoints written in Bash",
   "main": "index.js",
   "author": "Nathan Rajlich <nate@zeit.co>",
   "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/zeit/now-builders.git",
+    "directory": "packages/now-bash"
+  },
   "files": [
     "builder.sh",
     "runtime.sh",
@@ -15,8 +20,5 @@
   "dependencies": {
     "execa": "^1.0.0",
     "snake-case": "^2.1.0"
-  },
-  "peerDependencies": {
-    "@now/build-utils": ">=0.0.1"
   }
 }

packages/now-bash/runtime.sh

@@ -1,3 +1,4 @@
+#!/bin/bash
 import "static-binaries@1.0.0"
 static_binaries jq
 
@@ -13,12 +14,14 @@ _lambda_runtime_api() {
 
 _lambda_runtime_init() {
 	# Initialize user code
+	# shellcheck disable=SC1090
 	. "$SCRIPT_FILENAME" || {
 		local exit_code="$?"
-		local error
-		error='{"exitCode":'"$exit_code"'}'
+		local error_message="Initialization failed for '$SCRIPT_FILENAME' (exit code $exit_code)"
+		echo "$error_message" >&2
+		local error='{"errorMessage":"'"$error_message"'"}'
 		_lambda_runtime_api "init/error" -X POST -d "$error"
-		exit "$EXIT_CODE"
+		exit "$exit_code"
 	}
 
 	# Process events
@@ -45,18 +48,17 @@ _lambda_runtime_next() {
 	local body
 	body="$(mktemp)"
 
-	local exit_code=0
-	REQUEST="$event"
-
 	# Stdin of the `handler` function is the HTTP request body.
 	# Need to use a fifo here instead of bash <() because Lambda
 	# errors with "/dev/fd/63 not found" for some reason :/
 	local stdin
-	stdin="$(mktemp --dry-run)"
+	stdin="$(mktemp -u)"
 	mkfifo "$stdin"
-	_lambda_runtime_body "$event" > "$stdin" &
+	_lambda_runtime_body < "$event" > "$stdin" &
 
+	local exit_code=0
 	handler "$event" < "$stdin" > "$body" || exit_code="$?"
+
 	rm -f "$event" "$stdin"
 
 	if [ "$exit_code" -eq 0 ]; then
@@ -68,18 +70,21 @@ _lambda_runtime_next() {
 			| _lambda_runtime_api "invocation/$request_id/response" -X POST -d @- > /dev/null
 		rm -f "$body" "$_HEADERS"
 	else
-		echo "\`handler\` function return code: $exit_code"
-		_lambda_runtime_api "invocation/$request_id/error" -X POST -d @- > /dev/null <<< '{"exitCode":'"$exit_code"'}'
+		local error_message="Invocation failed for 'handler' function in '$SCRIPT_FILENAME' (exit code $exit_code)"
+		echo "$error_message" >&2
+		_lambda_runtime_api "invocation/$request_id/error" -X POST -d '{"errorMessage":"'"$error_message"'"}' > /dev/null
 	fi
 }
 
 _lambda_runtime_body() {
-	if [ "$(jq --raw-output '.body | type' < "$1")" = "string" ]; then
-		if [ "$(jq --raw-output '.encoding' < "$1")" = "base64" ]; then
-			jq --raw-output '.body' < "$1" | base64 -d
+	local event
+	event="$(cat)"
+	if [ "$(jq --raw-output '.body | type' <<< "$event")" = "string" ]; then
+		if [ "$(jq --raw-output '.encoding' <<< "$event")" = "base64" ]; then
+			jq --raw-output '.body' <<< "$event" | base64 --decode
 		else
 			# assume plain-text body
-			jq --raw-output '.body' < "$1"
+			jq --raw-output '.body' <<< "$event"
 		fi
 	fi
 }
@@ -97,7 +102,10 @@ http_response_header() {
 	local value="$2"
 	local tmp
 	tmp="$(mktemp)"
-	jq --arg name "$name" --arg value "$value" '.[$name] = $value' < "$_HEADERS" > "$tmp"
+	jq \
+		--arg name "$name" \
+		--arg value "$value" \
+		'.[$name] = $value' < "$_HEADERS" > "$tmp"
 	mv -f "$tmp" "$_HEADERS"
 }
 

packages/now-build-utils/.gitignore

@@ -0,0 +1,3 @@
+dist
+test/symlinks-out
+test/symlinks.zip

packages/now-build-utils/.npmignore

@@ -1 +1,3 @@
+/src
 /test
+tmp

packages/now-build-utils/file-blob.js

@@ -1,33 +1 @@
-const assert = require('assert');
-const intoStream = require('into-stream');
-
-class FileBlob {
-  constructor({ mode = 0o100644, data }) {
-    assert(typeof mode === 'number');
-    assert(typeof data === 'string' || Buffer.isBuffer(data));
-    this.type = 'FileBlob';
-    this.mode = mode;
-    this.data = data;
-  }
-
-  static async fromStream({ mode = 0o100644, stream }) {
-    assert(typeof mode === 'number');
-    assert(typeof stream.pipe === 'function'); // is-stream
-    const chunks = [];
-
-    await new Promise((resolve, reject) => {
-      stream.on('data', chunk => chunks.push(Buffer.from(chunk)));
-      stream.on('error', error => reject(error));
-      stream.on('end', () => resolve());
-    });
-
-    const data = Buffer.concat(chunks);
-    return new FileBlob({ mode, data });
-  }
-
-  toStream() {
-    return intoStream(this.data);
-  }
-}
-
-module.exports = FileBlob;
+module.exports = require('./dist/index').FileBlob;

packages/now-build-utils/file-fs-ref.js

@@ -1,88 +1 @@
-const assert = require('assert');
-const fs = require('fs-extra');
-const multiStream = require('multistream');
-const path = require('path');
-const Sema = require('async-sema');
-
-/** @typedef {{[filePath: string]: FileFsRef}} FsFiles */
-
-const semaToPreventEMFILE = new Sema(30);
-
-/**
- * @constructor
- * @argument {Object} options
- * @argument {number} [options.mode=0o100644]
- * @argument {string} options.fsPath
- */
-class FileFsRef {
-  constructor({ mode = 0o100644, fsPath }) {
-    assert(typeof mode === 'number');
-    assert(typeof fsPath === 'string');
-    /** @type {string} */
-    this.type = 'FileFsRef';
-    /** @type {number} */
-    this.mode = mode;
-    /** @type {string} */
-    this.fsPath = fsPath;
-  }
-
-  /**
-   * @argument {Object} options
-   * @argument {number} [options.mode=0o100644]
-   * @argument {NodeJS.ReadableStream} options.stream
-   * @argument {string} options.fsPath
-   * @returns {Promise<FileFsRef>}
-   */
-  static async fromStream({ mode = 0o100644, stream, fsPath }) {
-    assert(typeof mode === 'number');
-    assert(typeof stream.pipe === 'function'); // is-stream
-    assert(typeof fsPath === 'string');
-    await fs.mkdirp(path.dirname(fsPath));
-
-    await new Promise((resolve, reject) => {
-      const dest = fs.createWriteStream(fsPath);
-      stream.pipe(dest);
-      stream.on('error', reject);
-      dest.on('finish', resolve);
-      dest.on('error', reject);
-    });
-
-    await fs.chmod(fsPath, mode.toString(8).slice(-3));
-    return new FileFsRef({ mode, fsPath });
-  }
-
-  /**
-   * @returns {Promise<NodeJS.ReadableStream>}
-   */
-  async toStreamAsync() {
-    await semaToPreventEMFILE.acquire();
-    const release = () => semaToPreventEMFILE.release();
-    const stream = fs.createReadStream(this.fsPath);
-    stream.on('close', release);
-    stream.on('error', release);
-    return stream;
-  }
-
-  /**
-   * @returns {NodeJS.ReadableStream}
-   */
-  toStream() {
-    let flag;
-
-    // eslint-disable-next-line consistent-return
-    return multiStream((cb) => {
-      if (flag) return cb(null, null);
-      flag = true;
-
-      this.toStreamAsync()
-        .then((stream) => {
-          cb(null, stream);
-        })
-        .catch((error) => {
-          cb(error, null);
-        });
-    });
-  }
-}
-
-module.exports = FileFsRef;
+module.exports = require('./dist/index').FileFsRef;

packages/now-build-utils/file-ref.js

@@ -1,96 +1 @@
-const assert = require('assert');
-const fetch = require('node-fetch');
-const multiStream = require('multistream');
-const retry = require('async-retry');
-const Sema = require('async-sema');
-
-/** @typedef {{[filePath: string]: FileRef}} Files */
-
-const semaToDownloadFromS3 = new Sema(10);
-
-class BailableError extends Error {
-  constructor(...args) {
-    super(...args);
-    /** @type {boolean} */
-    this.bail = false;
-  }
-}
-
-/**
- * @constructor
- * @argument {Object} options
- * @argument {number} [options.mode=0o100644]
- * @argument {string} options.digest
- */
-class FileRef {
-  constructor({ mode = 0o100644, digest }) {
-    assert(typeof mode === 'number');
-    assert(typeof digest === 'string');
-    /** @type {string} */
-    this.type = 'FileRef';
-    /** @type {number} */
-    this.mode = mode;
-    /** @type {string} */
-    this.digest = digest;
-  }
-
-  /**
-   * @returns {Promise<NodeJS.ReadableStream>}
-   */
-  async toStreamAsync() {
-    let url;
-    // sha:24be087eef9fac01d61b30a725c1a10d7b45a256
-    const digestParts = this.digest.split(':');
-    if (digestParts[0] === 'sha') {
-      // url = `https://s3.amazonaws.com/now-files/${digestParts[1]}`;
-      url = `https://dmmcy0pwk6bqi.cloudfront.net/${digestParts[1]}`;
-    }
-
-    assert(url);
-
-    await semaToDownloadFromS3.acquire();
-    console.time(`downloading ${url}`);
-    try {
-      return await retry(
-        async () => {
-          const resp = await fetch(url);
-          if (!resp.ok) {
-            const error = new BailableError(
-              `download: ${resp.status} ${resp.statusText} for ${url}`,
-            );
-            if (resp.status === 403) error.bail = true;
-            throw error;
-          }
-          return resp.body;
-        },
-        { factor: 1, retries: 3 },
-      );
-    } finally {
-      console.timeEnd(`downloading ${url}`);
-      semaToDownloadFromS3.release();
-    }
-  }
-
-  /**
-   * @returns {NodeJS.ReadableStream}
-   */
-  toStream() {
-    let flag;
-
-    // eslint-disable-next-line consistent-return
-    return multiStream((cb) => {
-      if (flag) return cb(null, null);
-      flag = true;
-
-      this.toStreamAsync()
-        .then((stream) => {
-          cb(null, stream);
-        })
-        .catch((error) => {
-          cb(error, null);
-        });
-    });
-  }
-}
-
-module.exports = FileRef;
+module.exports = require('./dist/index').FileRef;

packages/now-build-utils/fs/bootstrap-yarn.js

@@ -1,94 +0,0 @@
-const MemoryFileSystem = require('memory-fs');
-const fs = require('fs');
-const path = require('path');
-const { spawnSync } = require('child_process');
-
-const yarnPath = spawnSync('which', ['yarn'])
-  .stdout.toString()
-  .trim();
-
-const cachePath = spawnSync(yarnPath, ['cache', 'dir'])
-  .stdout.toString()
-  .trim();
-
-spawnSync(yarnPath, ['cache', 'clean']);
-const vfs = new MemoryFileSystem();
-
-function isInsideCachePath(filename) {
-  const relative = path.relative(cachePath, filename);
-  return !relative.startsWith('..');
-}
-
-const saveCreateWriteStream = fs.createWriteStream;
-fs.createWriteStream = (...args) => {
-  const filename = args[0];
-  if (!isInsideCachePath(filename)) {
-    return saveCreateWriteStream.call(fs, ...args);
-  }
-
-  vfs.mkdirpSync(path.dirname(filename));
-  fs.writeFileSync(filename, Buffer.alloc(0));
-  const stream = vfs.createWriteStream(...args);
-
-  stream.on('finish', () => {
-    setTimeout(() => {
-      stream.emit('close');
-    });
-  });
-
-  return stream;
-};
-
-const saveReadFile = fs.readFile;
-fs.readFile = (...args) => {
-  const filename = args[0];
-  if (!isInsideCachePath(filename)) {
-    return saveReadFile.call(fs, ...args);
-  }
-
-  const callback = args[args.length - 1];
-  return vfs.readFile(...args.slice(0, -1), (error, result) => {
-    if (error) {
-      saveReadFile.call(fs, ...args);
-      return;
-    }
-
-    callback(error, result);
-  });
-};
-
-const saveCopyFile = fs.copyFile;
-fs.copyFile = (...args) => {
-  const src = args[0];
-  const dest = args[1];
-  const callback = args[args.length - 1];
-
-  if (isInsideCachePath(src) && !isInsideCachePath(dest)) {
-    const buffer = vfs.readFileSync(src);
-    return fs.writeFile(dest, buffer, callback);
-  }
-
-  if (!isInsideCachePath(src) && isInsideCachePath(dest)) {
-    const buffer = fs.readFileSync(src);
-
-    vfs.mkdirpSync(path.dirname(dest));
-    fs.writeFileSync(dest, Buffer.alloc(0));
-    return vfs.writeFile(dest, buffer, callback);
-  }
-
-  return saveCopyFile.call(fs, ...args);
-};
-
-const saveWriteFile = fs.writeFile;
-fs.writeFile = (...args) => {
-  const filename = args[0];
-  if (!isInsideCachePath(filename)) {
-    return saveWriteFile.call(fs, ...args);
-  }
-
-  vfs.mkdirpSync(path.dirname(filename));
-  fs.writeFileSync(filename, Buffer.alloc(0));
-  return vfs.writeFile(...args);
-};
-
-require(yarnPath);

packages/now-build-utils/fs/download.js

@@ -1,38 +1 @@
-const path = require('path');
-const FileFsRef = require('../file-fs-ref.js');
-
-/** @typedef {import('../file-ref')} FileRef */
-/** @typedef {import('../file-fs-ref')} FileFsRef */
-/** @typedef {{[filePath: string]: FileRef|FileFsRef}} Files */
-/** @typedef {{[filePath: string]: FileFsRef}|{}} DownloadedFiles */
-
-/**
- * @param {FileRef|FileFsRef} file
- * @param {string} fsPath
- * @returns {Promise<FileFsRef>}
- */
-async function downloadFile(file, fsPath) {
-  const { mode } = file;
-  const stream = file.toStream();
-  return FileFsRef.fromStream({ mode, stream, fsPath });
-}
-
-/**
- * Download files to disk
- * @argument {Files} files
- * @argument {string} basePath
- * @returns {Promise<DownloadedFiles>}
- */
-module.exports = async function download(files, basePath) {
-  const files2 = {};
-
-  await Promise.all(
-    Object.keys(files).map(async (name) => {
-      const file = files[name];
-      const fsPath = path.join(basePath, name);
-      files2[name] = await downloadFile(file, fsPath);
-    }),
-  );
-
-  return files2;
-};
+module.exports = require('../dist/fs/download').default;

packages/now-build-utils/fs/get-writable-directory.js

@@ -1,12 +1 @@
-const path = require('path');
-const fs = require('fs-extra');
-
-const prod = process.env.AWS_EXECUTION_ENV || process.env.X_GOOGLE_CODE_LOCATION;
-const TMP_PATH = prod ? '/tmp' : path.join(__dirname, 'tmp');
-
-module.exports = async function getWritableDirectory() {
-  const name = Math.floor(Math.random() * 0x7fffffff).toString(16);
-  const directory = path.join(TMP_PATH, name);
-  await fs.mkdirp(directory);
-  return directory;
-};
+module.exports = require('../dist/fs/get-writable-directory').default;

packages/now-build-utils/fs/glob.js

@@ -1,67 +1 @@
-const assert = require('assert');
-const path = require('path');
-const vanillaGlob = require('glob');
-const FileFsRef = require('../file-fs-ref.js');
-
-/** @typedef {import('fs').Stats} Stats */
-/** @typedef {import('glob').IOptions} GlobOptions */
-/** @typedef {import('../file-fs-ref').FsFiles|{}} GlobFiles */
-
-/**
- * @argument {string} pattern
- * @argument {GlobOptions|string} opts
- * @argument {string} [mountpoint]
- * @returns {Promise<GlobFiles>}
- */
-module.exports = function glob(pattern, opts = {}, mountpoint) {
-  return new Promise((resolve, reject) => {
-    /** @type {GlobOptions} */
-    let options;
-    if (typeof opts === 'string') {
-      options = { cwd: opts };
-    } else {
-      options = opts;
-    }
-
-    if (!options.cwd) {
-      throw new Error(
-        'Second argument (basePath) must be specified for names of resulting files',
-      );
-    }
-
-    if (!path.isAbsolute(options.cwd)) {
-      throw new Error(`basePath/cwd must be an absolute path (${options.cwd})`);
-    }
-
-    options.statCache = {};
-    options.stat = true;
-    options.dot = true;
-
-    // eslint-disable-next-line consistent-return
-    vanillaGlob(pattern, options, (error, files) => {
-      if (error) return reject(error);
-
-      resolve(
-        files.reduce((files2, relativePath) => {
-          const fsPath = path.join(options.cwd, relativePath);
-          /** @type {Stats|any} */
-          const stat = options.statCache[fsPath];
-          assert(
-            stat,
-            `statCache does not contain value for ${relativePath} (resolved to ${fsPath})`,
-          );
-          if (stat && stat.isFile()) {
-            let finalPath = relativePath;
-            if (mountpoint) finalPath = path.join(mountpoint, finalPath);
-            return {
-              ...files2,
-              [finalPath]: new FileFsRef({ mode: stat.mode, fsPath }),
-            };
-          }
-
-          return files2;
-        }, {}),
-      );
-    });
-  });
-};
+module.exports = require('../dist/fs/glob').default;

packages/now-build-utils/fs/rename.js

@@ -1,25 +1 @@
-/** @typedef { import('@now/build-utils/file-ref') } FileRef */
-/** @typedef { import('@now/build-utils/file-fs-ref') } FileFsRef */
-/** @typedef {{[filePath: string]: FileRef|FileFsRef}} Files */
-
-/**
- * @callback delegate
- * @argument {string} name
- * @returns {string}
- */
-
-/**
- * Rename files using delegate function
- * @argument {Files} files
- * @argument {delegate} delegate
- * @returns {Files}
- */
-module.exports = function rename(files, delegate) {
-  return Object.keys(files).reduce(
-    (newFiles, name) => ({
-      ...newFiles,
-      [delegate(name)]: files[name],
-    }),
-    {},
-  );
-};
+module.exports = require('../dist/fs/rename').default;

packages/now-build-utils/fs/run-user-scripts.js

@@ -1,108 +1 @@
-const assert = require('assert');
-const fs = require('fs-extra');
-const path = require('path');
-const { spawn } = require('child_process');
-
-const prod = process.env.AWS_EXECUTION_ENV
-  || process.env.X_GOOGLE_CODE_LOCATION;
-
-function spawnAsync(command, args, cwd) {
-  return new Promise((resolve, reject) => {
-    const child = spawn(command, args, { stdio: 'inherit', cwd });
-    child.on('error', reject);
-    child.on('close', (code, signal) => (code !== 0
-      ? reject(new Error(`Exited with ${code || signal}`))
-      : resolve()));
-  });
-}
-
-async function runShellScript(fsPath) {
-  assert(path.isAbsolute(fsPath));
-  const destPath = path.dirname(fsPath);
-  await spawnAsync(`./${path.basename(fsPath)}`, [], destPath);
-  return true;
-}
-
-async function scanParentDirs(destPath, scriptName) {
-  assert(path.isAbsolute(destPath));
-
-  let hasScript = false;
-  let hasPackageLockJson = false;
-  let currentDestPath = destPath;
-
-  // eslint-disable-next-line no-constant-condition
-  while (true) {
-    const packageJsonPath = path.join(currentDestPath, 'package.json');
-    // eslint-disable-next-line no-await-in-loop
-    if (await fs.exists(packageJsonPath)) {
-      // eslint-disable-next-line no-await-in-loop
-      const packageJson = JSON.parse(await fs.readFile(packageJsonPath));
-      hasScript = Boolean(
-        packageJson.scripts && scriptName && packageJson.scripts[scriptName],
-      );
-      // eslint-disable-next-line no-await-in-loop
-      hasPackageLockJson = await fs.exists(
-        path.join(currentDestPath, 'package-lock.json'),
-      );
-      break;
-    }
-
-    const newDestPath = path.dirname(currentDestPath);
-    if (currentDestPath === newDestPath) break;
-    currentDestPath = newDestPath;
-  }
-
-  return { hasScript, hasPackageLockJson };
-}
-
-async function installDependencies(destPath, args = []) {
-  assert(path.isAbsolute(destPath));
-
-  let commandArgs = args;
-  console.log(`installing to ${destPath}`);
-  const { hasPackageLockJson } = await scanParentDirs(destPath);
-
-  if (hasPackageLockJson) {
-    commandArgs = args.filter(a => a !== '--prefer-offline');
-    await spawnAsync('npm', ['install'].concat(commandArgs), destPath);
-    await spawnAsync('npm', ['cache', 'clean', '--force'], destPath);
-  } else if (prod) {
-    console.log('using memory-fs for yarn cache');
-    await spawnAsync(
-      'node',
-      [path.join(__dirname, 'bootstrap-yarn.js'), '--cwd', destPath].concat(
-        commandArgs,
-      ),
-      destPath,
-    );
-  } else {
-    await spawnAsync('yarn', ['--cwd', destPath].concat(commandArgs), destPath);
-    await spawnAsync('yarn', ['cache', 'clean'], destPath);
-  }
-}
-
-async function runPackageJsonScript(destPath, scriptName) {
-  assert(path.isAbsolute(destPath));
-  const { hasScript, hasPackageLockJson } = await scanParentDirs(
-    destPath,
-    scriptName,
-  );
-  if (!hasScript) return false;
-
-  if (hasPackageLockJson) {
-    console.log(`running "npm run ${scriptName}"`);
-    await spawnAsync('npm', ['run', scriptName], destPath);
-  } else {
-    console.log(`running "yarn run ${scriptName}"`);
-    await spawnAsync('yarn', ['--cwd', destPath, 'run', scriptName], destPath);
-  }
-
-  return true;
-}
-
-module.exports = {
-  runShellScript,
-  installDependencies,
-  runNpmInstall: installDependencies,
-  runPackageJsonScript,
-};
+module.exports = require('../dist/fs/run-user-scripts');

packages/now-build-utils/fs/stream-to-buffer.js

@@ -1,4 +1 @@
-const fastStreamToBuffer = require('fast-stream-to-buffer');
-const { promisify } = require('util');
-
-module.exports = promisify(fastStreamToBuffer);
+module.exports = require('../dist/fs/stream-to-buffer').default;

packages/now-build-utils/lambda.js

@@ -1,60 +1 @@
-const assert = require('assert');
-const Sema = require('async-sema');
-const { ZipFile } = require('yazl');
-const streamToBuffer = require('./fs/stream-to-buffer.js');
-
-class Lambda {
-  constructor({
-    zipBuffer, handler, runtime, environment,
-  }) {
-    this.type = 'Lambda';
-    this.zipBuffer = zipBuffer;
-    this.handler = handler;
-    this.runtime = runtime;
-    this.environment = environment;
-  }
-}
-
-const sema = new Sema(10);
-const mtime = new Date(1540000000000);
-
-async function createLambda({
-  files, handler, runtime, environment = {},
-}) {
-  assert(typeof files === 'object', '"files" must be an object');
-  assert(typeof handler === 'string', '"handler" is not a string');
-  assert(typeof runtime === 'string', '"runtime" is not a string');
-  assert(typeof environment === 'object', '"environment" is not an object');
-
-  await sema.acquire();
-  try {
-    const zipFile = new ZipFile();
-    const zipBuffer = await new Promise((resolve, reject) => {
-      Object.keys(files)
-        .sort()
-        .forEach((name) => {
-          const file = files[name];
-          const stream = file.toStream();
-          stream.on('error', reject);
-          zipFile.addReadStream(stream, name, { mode: file.mode, mtime });
-        });
-
-      zipFile.end();
-      streamToBuffer(zipFile.outputStream).then(resolve).catch(reject);
-    });
-
-    return new Lambda({
-      zipBuffer,
-      handler,
-      runtime,
-      environment,
-    });
-  } finally {
-    sema.release();
-  }
-}
-
-module.exports = {
-  Lambda,
-  createLambda,
-};
+module.exports = require('./dist/index');

packages/now-build-utils/package.json

@@ -1,20 +1,41 @@
 {
   "name": "@now/build-utils",
-  "version": "0.4.32",
+  "version": "0.5.6",
   "license": "MIT",
+  "main": "./dist/index.js",
+  "types": "./dist/index.d.js",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/zeit/now-builders.git",
+    "directory": "packages/now-build-utils"
+  },
   "dependencies": {
+    "@types/cross-spawn": "6.0.0",
     "async-retry": "1.2.3",
     "async-sema": "2.1.4",
-    "fast-stream-to-buffer": "1.0.0",
+    "cross-spawn": "6.0.5",
+    "end-of-stream": "1.4.1",
     "fs-extra": "7.0.0",
     "glob": "7.1.3",
-    "into-stream": "4.0.0",
+    "into-stream": "5.0.0",
     "memory-fs": "0.4.1",
     "multistream": "2.1.1",
     "node-fetch": "2.2.0",
     "yazl": "2.4.3"
   },
   "scripts": {
-    "test": "jest"
+    "build": "tsc",
+    "test": "tsc && jest",
+    "prepublish": "tsc"
+  },
+  "devDependencies": {
+    "@types/async-retry": "^1.2.1",
+    "@types/end-of-stream": "^1.4.0",
+    "@types/fs-extra": "^5.0.5",
+    "@types/glob": "^7.1.1",
+    "@types/node-fetch": "^2.1.6",
+    "@types/yazl": "^2.4.1",
+    "execa": "^1.0.0",
+    "typescript": "3.3.4000"
   }
 }

packages/now-build-utils/src/file-blob.ts

@@ -0,0 +1,46 @@
+import assert from 'assert';
+import intoStream from 'into-stream';
+import { File } from './types';
+
+interface FileBlobOptions {
+  mode?: number;
+  data: string | Buffer;
+}
+
+interface FromStreamOptions {
+  mode?: number;
+  stream: NodeJS.ReadableStream;
+}
+
+export default class FileBlob implements File {
+  public type: 'FileBlob';
+  public mode: number;
+  public data: string | Buffer;
+
+  constructor({ mode = 0o100644, data }: FileBlobOptions) {
+    assert(typeof mode === 'number');
+    assert(typeof data === 'string' || Buffer.isBuffer(data));
+    this.type = 'FileBlob';
+    this.mode = mode;
+    this.data = data;
+  }
+
+  static async fromStream({ mode = 0o100644, stream }: FromStreamOptions) {
+    assert(typeof mode === 'number');
+    assert(typeof stream.pipe === 'function'); // is-stream
+    const chunks: Buffer[] = [];
+
+    await new Promise<void>((resolve, reject) => {
+      stream.on('data', chunk => chunks.push(Buffer.from(chunk)));
+      stream.on('error', error => reject(error));
+      stream.on('end', () => resolve());
+    });
+
+    const data = Buffer.concat(chunks);
+    return new FileBlob({ mode, data });
+  }
+
+  toStream(): NodeJS.ReadableStream {
+    return intoStream(this.data);
+  }
+}

packages/now-build-utils/src/file-fs-ref.ts

@@ -0,0 +1,97 @@
+import assert from 'assert';
+import fs from 'fs-extra';
+import multiStream from 'multistream';
+import path from 'path';
+import Sema from 'async-sema';
+import { File } from './types';
+
+const semaToPreventEMFILE = new Sema(20);
+
+interface FileFsRefOptions {
+  mode?: number;
+  fsPath: string;
+}
+
+interface FromStreamOptions {
+  mode: number;
+  stream: NodeJS.ReadableStream;
+  fsPath: string;
+}
+
+class FileFsRef implements File {
+  public type: 'FileFsRef';
+  public mode: number;
+  public fsPath: string;
+
+  constructor({ mode = 0o100644, fsPath }: FileFsRefOptions) {
+    assert(typeof mode === 'number');
+    assert(typeof fsPath === 'string');
+    this.type = 'FileFsRef';
+    this.mode = mode;
+    this.fsPath = fsPath;
+  }
+
+  static async fromFsPath({
+    mode,
+    fsPath,
+  }: FileFsRefOptions): Promise<FileFsRef> {
+    let m = mode;
+    if (!m) {
+      const stat = await fs.lstat(fsPath);
+      m = stat.mode;
+    }
+    return new FileFsRef({ mode: m, fsPath });
+  }
+
+  static async fromStream({
+    mode = 0o100644,
+    stream,
+    fsPath,
+  }: FromStreamOptions): Promise<FileFsRef> {
+    assert(typeof mode === 'number');
+    assert(typeof stream.pipe === 'function'); // is-stream
+    assert(typeof fsPath === 'string');
+    await fs.mkdirp(path.dirname(fsPath));
+
+    await new Promise<void>((resolve, reject) => {
+      const dest = fs.createWriteStream(fsPath, {
+        mode: mode & 0o777,
+      });
+      stream.pipe(dest);
+      stream.on('error', reject);
+      dest.on('finish', resolve);
+      dest.on('error', reject);
+    });
+
+    return new FileFsRef({ mode, fsPath });
+  }
+
+  async toStreamAsync(): Promise<NodeJS.ReadableStream> {
+    await semaToPreventEMFILE.acquire();
+    const release = () => semaToPreventEMFILE.release();
+    const stream = fs.createReadStream(this.fsPath);
+    stream.on('close', release);
+    stream.on('error', release);
+    return stream;
+  }
+
+  toStream(): NodeJS.ReadableStream {
+    let flag = false;
+
+    // eslint-disable-next-line consistent-return
+    return multiStream(cb => {
+      if (flag) return cb(null, null);
+      flag = true;
+
+      this.toStreamAsync()
+        .then(stream => {
+          cb(null, stream);
+        })
+        .catch(error => {
+          cb(error, null);
+        });
+    });
+  }
+}
+
+export = FileFsRef;

packages/now-build-utils/src/file-ref.ts

@@ -0,0 +1,95 @@
+import assert from 'assert';
+import fetch from 'node-fetch';
+import multiStream from 'multistream';
+import retry from 'async-retry';
+import Sema from 'async-sema';
+import { File } from './types';
+
+interface FileRefOptions {
+  mode?: number;
+  digest: string;
+}
+
+const semaToDownloadFromS3 = new Sema(5);
+
+class BailableError extends Error {
+  public bail: boolean;
+
+  constructor(...args: string[]) {
+    super(...args);
+    this.bail = false;
+  }
+}
+
+export default class FileRef implements File {
+  public type: 'FileRef';
+  public mode: number;
+  public digest: string;
+
+  constructor({ mode = 0o100644, digest }: FileRefOptions) {
+    assert(typeof mode === 'number');
+    assert(typeof digest === 'string');
+    this.type = 'FileRef';
+    this.mode = mode;
+    this.digest = digest;
+  }
+
+  async toStreamAsync(): Promise<NodeJS.ReadableStream> {
+    let url = '';
+    // sha:24be087eef9fac01d61b30a725c1a10d7b45a256
+    const [digestType, digestHash] = this.digest.split(':');
+    if (digestType === 'sha') {
+      // This CloudFront URL edge caches the `now-files` S3 bucket to prevent
+      // overloading it
+      // `https://now-files.s3.amazonaws.com/${digestHash}`
+      url = `https://dmmcy0pwk6bqi.cloudfront.net/${digestHash}`;
+    } else if (digestType === 'sha+ephemeral') {
+      // This URL is currently only used for cache files that constantly
+      // change. We shouldn't cache it on CloudFront because it'd always be a
+      // MISS.
+      url = `https://now-ephemeral-files.s3.amazonaws.com/${digestHash}`;
+    } else {
+      throw new Error('Expected digest to be sha');
+    }
+
+    await semaToDownloadFromS3.acquire();
+    // console.time(`downloading ${url}`);
+    try {
+      return await retry(
+        async () => {
+          const resp = await fetch(url);
+          if (!resp.ok) {
+            const error = new BailableError(
+              `download: ${resp.status} ${resp.statusText} for ${url}`
+            );
+            if (resp.status === 403) error.bail = true;
+            throw error;
+          }
+          return resp.body;
+        },
+        { factor: 1, retries: 3 }
+      );
+    } finally {
+      // console.timeEnd(`downloading ${url}`);
+      semaToDownloadFromS3.release();
+    }
+  }
+
+  toStream(): NodeJS.ReadableStream {
+    let flag = false;
+
+    // eslint-disable-next-line consistent-return
+    return multiStream(cb => {
+      if (flag) return cb(null, null);
+      flag = true;
+
+      this.toStreamAsync()
+        .then(stream => {
+          cb(null, stream);
+        })
+        .catch(error => {
+          cb(error, null);
+        });
+    });
+  }
+}

packages/now-build-utils/src/fs/download.ts

@@ -0,0 +1,75 @@
+import path from 'path';
+import FileFsRef from '../file-fs-ref';
+import { File, Files, Meta } from '../types';
+import { remove, mkdirp, readlink, symlink } from 'fs-extra';
+
+export interface DownloadedFiles {
+  [filePath: string]: FileFsRef;
+}
+
+const S_IFMT = 61440; /* 0170000 type of file */
+const S_IFLNK = 40960; /* 0120000 symbolic link */
+
+export function isSymbolicLink(mode: number): boolean {
+  return (mode & S_IFMT) === S_IFLNK;
+}
+
+async function downloadFile(file: File, fsPath: string): Promise<FileFsRef> {
+  const { mode } = file;
+  if (mode && isSymbolicLink(mode) && file.type === 'FileFsRef') {
+    const [target] = await Promise.all([
+      readlink((file as FileFsRef).fsPath),
+      mkdirp(path.dirname(fsPath)),
+    ]);
+    await symlink(target, fsPath);
+    return FileFsRef.fromFsPath({ mode, fsPath });
+  } else {
+    const stream = file.toStream();
+    return FileFsRef.fromStream({ mode, stream, fsPath });
+  }
+}
+
+async function removeFile(basePath: string, fileMatched: string) {
+  const file = path.join(basePath, fileMatched);
+  await remove(file);
+}
+
+export default async function download(
+  files: Files,
+  basePath: string,
+  meta?: Meta
+): Promise<DownloadedFiles> {
+  const { isDev = false, filesChanged = null, filesRemoved = null } =
+    meta || {};
+
+  if (isDev) {
+    // In `now dev`, the `download()` function is a no-op because
+    // the `basePath` matches the `cwd` of the dev server, so the
+    // source files are already available.
+    return files as DownloadedFiles;
+  }
+
+  const files2: DownloadedFiles = {};
+
+  await Promise.all(
+    Object.keys(files).map(async name => {
+      // If the file does not exist anymore, remove it.
+      if (Array.isArray(filesRemoved) && filesRemoved.includes(name)) {
+        await removeFile(basePath, name);
+        return;
+      }
+
+      // If a file didn't change, do not re-download it.
+      if (Array.isArray(filesChanged) && !filesChanged.includes(name)) {
+        return;
+      }
+
+      const file = files[name];
+      const fsPath = path.join(basePath, name);
+
+      files2[name] = await downloadFile(file, fsPath);
+    })
+  );
+
+  return files2;
+}

packages/now-build-utils/src/fs/get-writable-directory.ts

@@ -0,0 +1,10 @@
+import { join } from 'path';
+import { tmpdir } from 'os';
+import { mkdirp } from 'fs-extra';
+
+export default async function getWritableDirectory() {
+  const name = Math.floor(Math.random() * 0x7fffffff).toString(16);
+  const directory = join(tmpdir(), name);
+  await mkdirp(directory);
+  return directory;
+}

packages/now-build-utils/src/fs/glob.ts

@@ -0,0 +1,70 @@
+import path from 'path';
+import assert from 'assert';
+import vanillaGlob_ from 'glob';
+import { promisify } from 'util';
+import { lstat, Stats } from 'fs-extra';
+import FileFsRef from '../file-fs-ref';
+
+type GlobOptions = vanillaGlob_.IOptions;
+
+interface FsFiles {
+  [filePath: string]: FileFsRef;
+}
+
+const vanillaGlob = promisify(vanillaGlob_);
+
+export default async function glob(
+  pattern: string,
+  opts: GlobOptions | string,
+  mountpoint?: string
+): Promise<FsFiles> {
+  let options: GlobOptions;
+  if (typeof opts === 'string') {
+    options = { cwd: opts };
+  } else {
+    options = opts;
+  }
+
+  if (!options.cwd) {
+    throw new Error(
+      'Second argument (basePath) must be specified for names of resulting files'
+    );
+  }
+
+  if (!path.isAbsolute(options.cwd)) {
+    throw new Error(`basePath/cwd must be an absolute path (${options.cwd})`);
+  }
+
+  const results: FsFiles = {};
+
+  options.symlinks = {};
+  options.statCache = {};
+  options.stat = true;
+  options.dot = true;
+
+  const files = await vanillaGlob(pattern, options);
+
+  for (const relativePath of files) {
+    const fsPath = path.join(options.cwd!, relativePath).replace(/\\/g, '/');
+    let stat: Stats = options.statCache![fsPath] as Stats;
+    assert(
+      stat,
+      `statCache does not contain value for ${relativePath} (resolved to ${fsPath})`
+    );
+    if (stat.isFile()) {
+      const isSymlink = options.symlinks![fsPath];
+      if (isSymlink) {
+        stat = await lstat(fsPath);
+      }
+
+      let finalPath = relativePath;
+      if (mountpoint) {
+        finalPath = path.join(mountpoint, finalPath);
+      }
+
+      results[finalPath] = new FileFsRef({ mode: stat.mode, fsPath });
+    }
+  }
+
+  return results;
+}

packages/now-build-utils/src/fs/rename.ts

@@ -0,0 +1,12 @@
+import { Files } from '../types';
+type Delegate = (name: string) => string;
+
+export default function rename(files: Files, delegate: Delegate): Files {
+  return Object.keys(files).reduce(
+    (newFiles, name) => ({
+      ...newFiles,
+      [delegate(name)]: files[name],
+    }),
+    {}
+  );
+}

packages/now-build-utils/src/fs/run-user-scripts.ts

@@ -0,0 +1,154 @@
+import assert from 'assert';
+import fs from 'fs-extra';
+import path from 'path';
+import spawn from 'cross-spawn';
+import { SpawnOptions } from 'child_process';
+
+function spawnAsync(
+  command: string,
+  args: string[],
+  cwd: string,
+  opts: SpawnOptions = {}
+) {
+  return new Promise<void>((resolve, reject) => {
+    const stderrLogs: Buffer[] = [];
+    opts = { stdio: 'inherit', cwd, ...opts };
+    const child = spawn(command, args, opts);
+
+    if (opts.stdio === 'pipe') {
+      child.stderr.on('data', data => stderrLogs.push(data));
+    }
+
+    child.on('error', reject);
+    child.on('close', (code, signal) => {
+      if (code === 0) {
+        return resolve();
+      }
+
+      const errorLogs = stderrLogs.map(line => line.toString()).join('');
+      if (opts.stdio !== 'inherit') {
+        reject(new Error(`Exited with ${code || signal}\n${errorLogs}`));
+      } else {
+        reject(new Error(`Exited with ${code || signal}`));
+      }
+    });
+  });
+}
+
+async function chmodPlusX(fsPath: string) {
+  const s = await fs.stat(fsPath);
+  const newMode = s.mode | 64 | 8 | 1; // eslint-disable-line no-bitwise
+  if (s.mode === newMode) return;
+  const base8 = newMode.toString(8).slice(-3);
+  await fs.chmod(fsPath, base8);
+}
+
+export async function runShellScript(fsPath: string) {
+  assert(path.isAbsolute(fsPath));
+  const destPath = path.dirname(fsPath);
+  await chmodPlusX(fsPath);
+  await spawnAsync(`./${path.basename(fsPath)}`, [], destPath);
+  return true;
+}
+
+async function scanParentDirs(destPath: string, scriptName?: string) {
+  assert(path.isAbsolute(destPath));
+
+  let hasScript = false;
+  let hasPackageLockJson = false;
+  let currentDestPath = destPath;
+
+  // eslint-disable-next-line no-constant-condition
+  while (true) {
+    const packageJsonPath = path.join(currentDestPath, 'package.json');
+    // eslint-disable-next-line no-await-in-loop
+    if (await fs.pathExists(packageJsonPath)) {
+      // eslint-disable-next-line no-await-in-loop
+      const packageJson = JSON.parse(
+        await fs.readFile(packageJsonPath, 'utf8')
+      );
+      hasScript = Boolean(
+        packageJson.scripts && scriptName && packageJson.scripts[scriptName]
+      );
+      // eslint-disable-next-line no-await-in-loop
+      hasPackageLockJson = await fs.pathExists(
+        path.join(currentDestPath, 'package-lock.json')
+      );
+      break;
+    }
+
+    const newDestPath = path.dirname(currentDestPath);
+    if (currentDestPath === newDestPath) break;
+    currentDestPath = newDestPath;
+  }
+
+  return { hasScript, hasPackageLockJson };
+}
+
+export async function installDependencies(
+  destPath: string,
+  args: string[] = []
+) {
+  assert(path.isAbsolute(destPath));
+
+  let commandArgs = args;
+  console.log(`installing to ${destPath}`);
+  const { hasPackageLockJson } = await scanParentDirs(destPath);
+
+  const opts = {
+    env: {
+      ...process.env,
+      // This is a little hack to force `node-gyp` to build for the
+      // Node.js version that `@now/node` and `@now/node-server` use
+      npm_config_target: '8.10.0',
+    },
+    stdio: 'pipe',
+  };
+
+  if (hasPackageLockJson) {
+    commandArgs = args.filter(a => a !== '--prefer-offline');
+    await spawnAsync(
+      'npm',
+      ['install', '--unsafe-perm'].concat(commandArgs),
+      destPath,
+      opts as SpawnOptions
+    );
+  } else {
+    await spawnAsync(
+      'yarn',
+      ['--ignore-engines', '--cwd', destPath].concat(commandArgs),
+      destPath,
+      opts as SpawnOptions
+    );
+  }
+}
+
+export async function runPackageJsonScript(
+  destPath: string,
+  scriptName: string,
+  opts?: SpawnOptions
+) {
+  assert(path.isAbsolute(destPath));
+  const { hasScript, hasPackageLockJson } = await scanParentDirs(
+    destPath,
+    scriptName
+  );
+  if (!hasScript) return false;
+
+  if (hasPackageLockJson) {
+    console.log(`running "npm run ${scriptName}"`);
+    await spawnAsync('npm', ['run', scriptName], destPath, opts);
+  } else {
+    console.log(`running "yarn run ${scriptName}"`);
+    await spawnAsync(
+      'yarn',
+      ['--cwd', destPath, 'run', scriptName],
+      destPath,
+      opts
+    );
+  }
+
+  return true;
+}
+
+export const runNpmInstall = installDependencies;

packages/now-build-utils/src/fs/stream-to-buffer.ts

@@ -0,0 +1,28 @@
+import eos from 'end-of-stream';
+
+export default function streamToBuffer(
+  stream: NodeJS.ReadableStream
+): Promise<Buffer> {
+  return new Promise<Buffer>((resolve, reject) => {
+    const buffers: Buffer[] = [];
+
+    stream.on('data', buffers.push.bind(buffers));
+
+    eos(stream, err => {
+      if (err) {
+        reject(err);
+        return;
+      }
+      switch (buffers.length) {
+        case 0:
+          resolve(Buffer.allocUnsafe(0));
+          break;
+        case 1:
+          resolve(buffers[0]);
+          break;
+        default:
+          resolve(Buffer.concat(buffers));
+      }
+    });
+  });
+}

packages/now-build-utils/src/index.ts

@@ -0,0 +1,51 @@
+import FileBlob from './file-blob';
+import FileFsRef from './file-fs-ref';
+import FileRef from './file-ref';
+import {
+  File,
+  Files,
+  AnalyzeOptions,
+  BuildOptions,
+  PrepareCacheOptions,
+  ShouldServeOptions,
+  Meta,
+} from './types';
+import { Lambda, createLambda } from './lambda';
+import download, { DownloadedFiles } from './fs/download';
+import getWriteableDirectory from './fs/get-writable-directory';
+import glob from './fs/glob';
+import rename from './fs/rename';
+import {
+  installDependencies,
+  runPackageJsonScript,
+  runNpmInstall,
+  runShellScript,
+} from './fs/run-user-scripts';
+import streamToBuffer from './fs/stream-to-buffer';
+import shouldServe from './should-serve';
+
+export {
+  FileBlob,
+  FileFsRef,
+  FileRef,
+  Files,
+  File,
+  Meta,
+  Lambda,
+  createLambda,
+  download,
+  DownloadedFiles,
+  getWriteableDirectory,
+  glob,
+  rename,
+  installDependencies,
+  runPackageJsonScript,
+  runNpmInstall,
+  runShellScript,
+  streamToBuffer,
+  AnalyzeOptions,
+  BuildOptions,
+  PrepareCacheOptions,
+  ShouldServeOptions,
+  shouldServe,
+};

packages/now-build-utils/src/lambda.ts

@@ -0,0 +1,107 @@
+import assert from 'assert';
+import Sema from 'async-sema';
+import { ZipFile } from 'yazl';
+import { readlink } from 'fs-extra';
+import { Files } from './types';
+import FileFsRef from './file-fs-ref';
+import { isSymbolicLink } from './fs/download';
+import streamToBuffer from './fs/stream-to-buffer';
+
+interface Environment {
+  [key: string]: string;
+}
+
+interface LambdaOptions {
+  zipBuffer: Buffer;
+  handler: string;
+  runtime: string;
+  environment: Environment;
+}
+
+interface CreateLambdaOptions {
+  files: Files;
+  handler: string;
+  runtime: string;
+  environment?: Environment;
+}
+
+export class Lambda {
+  public type: 'Lambda';
+  public zipBuffer: Buffer;
+  public handler: string;
+  public runtime: string;
+  public environment: Environment;
+
+  constructor({ zipBuffer, handler, runtime, environment }: LambdaOptions) {
+    this.type = 'Lambda';
+    this.zipBuffer = zipBuffer;
+    this.handler = handler;
+    this.runtime = runtime;
+    this.environment = environment;
+  }
+}
+
+const sema = new Sema(10);
+const mtime = new Date(1540000000000);
+
+export async function createLambda({
+  files,
+  handler,
+  runtime,
+  environment = {},
+}: CreateLambdaOptions): Promise<Lambda> {
+  assert(typeof files === 'object', '"files" must be an object');
+  assert(typeof handler === 'string', '"handler" is not a string');
+  assert(typeof runtime === 'string', '"runtime" is not a string');
+  assert(typeof environment === 'object', '"environment" is not an object');
+
+  await sema.acquire();
+
+  try {
+    const zipBuffer = await createZip(files);
+    return new Lambda({
+      zipBuffer,
+      handler,
+      runtime,
+      environment,
+    });
+  } finally {
+    sema.release();
+  }
+}
+
+export async function createZip(files: Files): Promise<Buffer> {
+  const names = Object.keys(files).sort();
+
+  const symlinkTargets = new Map<string, string>();
+  for (const name of names) {
+    const file = files[name];
+    if (file.mode && isSymbolicLink(file.mode) && file.type === 'FileFsRef') {
+      const symlinkTarget = await readlink((file as FileFsRef).fsPath);
+      symlinkTargets.set(name, symlinkTarget);
+    }
+  }
+
+  const zipFile = new ZipFile();
+  const zipBuffer = await new Promise<Buffer>((resolve, reject) => {
+    for (const name of names) {
+      const file = files[name];
+      const opts = { mode: file.mode, mtime };
+      const symlinkTarget = symlinkTargets.get(name);
+      if (typeof symlinkTarget === 'string') {
+        zipFile.addBuffer(Buffer.from(symlinkTarget, 'utf8'), name, opts);
+      } else {
+        const stream = file.toStream() as import('stream').Readable;
+        stream.on('error', reject);
+        zipFile.addReadStream(stream, name, opts);
+      }
+    }
+
+    zipFile.end();
+    streamToBuffer(zipFile.outputStream)
+      .then(resolve)
+      .catch(reject);
+  });
+
+  return zipBuffer;
+}

packages/now-build-utils/src/should-serve.ts

@@ -0,0 +1,27 @@
+import { parse } from 'path';
+import { ShouldServeOptions } from './types';
+import FileFsRef from './file-fs-ref';
+
+export default function shouldServe({
+  entrypoint,
+  files,
+  requestPath,
+}: ShouldServeOptions): boolean {
+  requestPath = requestPath.replace(/\/$/, ''); // sanitize trailing '/'
+  entrypoint = entrypoint.replace(/\\/, '/'); // windows compatibility
+
+  if (entrypoint === requestPath && hasProp(files, entrypoint)) {
+    return true;
+  }
+
+  const { dir, name } = parse(entrypoint);
+  if (name === 'index' && dir === requestPath && hasProp(files, entrypoint)) {
+    return true;
+  }
+
+  return false;
+}
+
+function hasProp(obj: { [path: string]: FileFsRef }, key: string): boolean {
+  return Object.hasOwnProperty.call(obj, key);
+}

packages/now-build-utils/src/types.ts

@@ -0,0 +1,157 @@
+import FileRef from './file-ref';
+import FileFsRef from './file-fs-ref';
+
+export interface File {
+  type: string;
+  mode: number;
+  toStream: () => NodeJS.ReadableStream;
+  /**
+   * The absolute path to the file in the filesystem
+   */
+  fsPath?: string;
+}
+
+export interface Files {
+  [filePath: string]: File;
+}
+
+export interface Config {
+  [key: string]: string;
+}
+
+export interface Meta {
+  isDev?: boolean;
+  requestPath?: string;
+  filesChanged?: string[];
+  filesRemoved?: string[];
+}
+
+export interface AnalyzeOptions {
+  /**
+   * All source files of the project
+   */
+  files: {
+    [filePath: string]: FileRef;
+  };
+
+  /**
+   * Name of entrypoint file for this particular build job. Value
+   * `files[entrypoint]` is guaranteed to exist and be a valid File reference.
+   * `entrypoint` is always a discrete file and never a glob, since globs are
+   * expanded into separate builds at deployment time.
+   */
+  entrypoint: string;
+
+  /**
+   * A writable temporary directory where you are encouraged to perform your
+   * build process. This directory will be populated with the restored cache.
+   */
+  workPath: string;
+
+  /**
+   * An arbitrary object passed by the user in the build definition defined
+   * in `now.json`.
+   */
+  config: Config;
+}
+
+export interface BuildOptions {
+  /**
+   * All source files of the project
+   */
+  files: Files;
+
+  /**
+   * Name of entrypoint file for this particular build job. Value
+   * `files[entrypoint]` is guaranteed to exist and be a valid File reference.
+   * `entrypoint` is always a discrete file and never a glob, since globs are
+   * expanded into separate builds at deployment time.
+   */
+  entrypoint: string;
+
+  /**
+   * A writable temporary directory where you are encouraged to perform your
+   * build process. This directory will be populated with the restored cache.
+   */
+  workPath: string;
+
+  /**
+   * An arbitrary object passed by the user in the build definition defined
+   * in `now.json`.
+   */
+  config: Config;
+
+  /**
+   * Metadata related to the invoker of the builder, used by `now dev`.
+   * Builders may use the properties on this object to change behavior based
+   * on the build environment.
+   */
+  meta?: Meta;
+}
+
+export interface PrepareCacheOptions {
+  /**
+   * All source files of the project
+   */
+  files: Files;
+
+  /**
+   * Name of entrypoint file for this particular build job. Value
+   * `files[entrypoint]` is guaranteed to exist and be a valid File reference.
+   * `entrypoint` is always a discrete file and never a glob, since globs are
+   * expanded into separate builds at deployment time.
+   */
+  entrypoint: string;
+
+  /**
+   * A writable temporary directory where you are encouraged to perform your
+   * build process.
+   */
+  workPath: string;
+
+  /**
+   * A writable temporary directory where you can build a cache to use for
+   * the next run.
+   */
+  cachePath: string;
+
+  /**
+   * An arbitrary object passed by the user in the build definition defined
+   * in `now.json`.
+   */
+  config: Config;
+}
+
+export interface ShouldServeOptions {
+  /**
+   * A path string from a request.
+   */
+  requestPath: string;
+
+  /**
+   * Name of entrypoint file for this particular build job. Value
+   * `files[entrypoint]` is guaranteed to exist and be a valid File reference.
+   * `entrypoint` is always a discrete file and never a glob, since globs are
+   * expanded into separate builds at deployment time.
+   */
+  entrypoint: string;
+
+  /**
+   * All source files of the project
+   */
+  files: {
+    [path: string]: FileFsRef;
+  };
+
+  /**
+   * A writable temporary directory where you are encouraged to perform your
+   * build process. This directory will be populated with the restored cache.
+   */
+  workPath: string;
+
+  /**
+   * An arbitrary object passed by the user in the build definition defined
+   * in `now.json`.
+   */
+  config: Config;
+}

packages/now-build-utils/test/fixtures/07-cross-install/now.json

@@ -1,9 +1,10 @@
 {
   "version": 2,
-  "builds": [
-    { "src": "api/index.js", "use": "@now/node" }
-  ],
+  "builds": [{ "src": "api/index.js", "use": "@now/node" }],
   "probes": [
-    { "path": "/api/index.js", "mustContain": "cross-cow:RANDOMNESS_PLACEHOLDER" }
+    {
+      "path": "/api/index.js",
+      "mustContain": "cross-cow:RANDOMNESS_PLACEHOLDER"
+    }
   ]
 }

packages/now-build-utils/test/fixtures/15-yarn-ignore-engines/index.js

@@ -0,0 +1,9 @@
+const scheduler = require('@google-cloud/scheduler');
+
+module.exports = (_, res) => {
+  if (scheduler) {
+    res.end('found:RANDOMNESS_PLACEHOLDER');
+  } else {
+    res.end('nope:RANDOMNESS_PLACEHOLDER');
+  }
+};

packages/now-build-utils/test/fixtures/15-yarn-ignore-engines/now.json

@@ -0,0 +1,11 @@
+{
+  "version": 2,
+  "builds": [
+    {
+      "src": "index.js",
+      "use": "@now/node",
+      "config": { "maxLambdaSize": "15mb" }
+    }
+  ],
+  "probes": [{ "path": "/", "mustContain": "found:RANDOMNESS_PLACEHOLDER" }]
+}

packages/now-build-utils/test/fixtures/15-yarn-ignore-engines/package.json

@@ -0,0 +1,8 @@
+{
+  "name": "15-yarn-ignore-engines",
+  "version": "1.0.0",
+  "main": "index.js",
+  "dependencies": {
+    "@google-cloud/scheduler": "0.3.0"
+  }
+}

packages/now-build-utils/test/symlinks/a.txt

@@ -0,0 +1 @@
+contents

packages/now-build-utils/test/symlinks/link.txt

@@ -0,0 +1 @@
+./a.txt

packages/now-build-utils/test/test.js

@@ -1,13 +1,18 @@
 /* global beforeAll, expect, it, jest */
-const fs = require('fs');
 const path = require('path');
+const fs = require('fs-extra');
+// eslint-disable-next-line import/no-extraneous-dependencies
+const execa = require('execa');
+const assert = require('assert');
+const { glob, download } = require('../');
+const { createZip } = require('../dist/lambda');
 
 const {
   packAndDeploy,
   testDeployment,
 } = require('../../../test/lib/deployment/test-deployment.js');
 
-jest.setTimeout(2 * 60 * 1000);
+jest.setTimeout(4 * 60 * 1000);
 const builderUrl = '@canary';
 let buildUtilsUrl;
 
@@ -17,6 +22,48 @@ beforeAll(async () => {
   console.log('buildUtilsUrl', buildUtilsUrl);
 });
 
+// unit tests
+
+it('should re-create symlinks properly', async () => {
+  const files = await glob('**', path.join(__dirname, 'symlinks'));
+  assert.equal(Object.keys(files).length, 2);
+
+  const outDir = path.join(__dirname, 'symlinks-out');
+  await fs.remove(outDir);
+
+  const files2 = await download(files, outDir);
+  assert.equal(Object.keys(files2).length, 2);
+
+  const [linkStat, aStat] = await Promise.all([
+    fs.lstat(path.join(outDir, 'link.txt')),
+    fs.lstat(path.join(outDir, 'a.txt')),
+  ]);
+  assert(linkStat.isSymbolicLink());
+  assert(aStat.isFile());
+});
+
+it('should create zip files with symlinks properly', async () => {
+  const files = await glob('**', path.join(__dirname, 'symlinks'));
+  assert.equal(Object.keys(files).length, 2);
+
+  const outFile = path.join(__dirname, 'symlinks.zip');
+  await fs.remove(outFile);
+
+  const outDir = path.join(__dirname, 'symlinks-out');
+  await fs.remove(outDir);
+  await fs.mkdirp(outDir);
+
+  await fs.writeFile(outFile, await createZip(files));
+  await execa('unzip', [outFile], { cwd: outDir });
+
+  const [linkStat, aStat] = await Promise.all([
+    fs.lstat(path.join(outDir, 'link.txt')),
+    fs.lstat(path.join(outDir, 'a.txt')),
+  ]);
+  assert(linkStat.isSymbolicLink());
+  assert(aStat.isFile());
+});
+
 // own fixtures
 
 const fixturesPath = path.resolve(__dirname, 'fixtures');

packages/now-build-utils/tsconfig.json

@@ -0,0 +1,20 @@
+{
+  "compilerOptions": {
+    "declaration": true,
+    "esModuleInterop": true,
+    "lib": ["esnext"],
+    "module": "commonjs",
+    "moduleResolution": "node",
+    "noEmitOnError": true,
+    "noFallthroughCasesInSwitch": true,
+    "noImplicitReturns": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "outDir": "./dist",
+    "types": ["node"],
+    "strict": true,
+    "target": "esnext"
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules"]
+}

packages/now-cgi/index.js

@@ -1,19 +1,21 @@
 const path = require('path');
 const { mkdirp, copyFile } = require('fs-extra');
 
-const glob = require('@now/build-utils/fs/glob');
-const download = require('@now/build-utils/fs/download');
-const { createLambda } = require('@now/build-utils/lambda');
-const getWritableDirectory = require('@now/build-utils/fs/get-writable-directory');
+const glob = require('@now/build-utils/fs/glob'); // eslint-disable-line import/no-extraneous-dependencies
+const download = require('@now/build-utils/fs/download'); // eslint-disable-line import/no-extraneous-dependencies
+const { createLambda } = require('@now/build-utils/lambda'); // eslint-disable-line import/no-extraneous-dependencies
+const getWritableDirectory = require('@now/build-utils/fs/get-writable-directory'); // eslint-disable-line import/no-extraneous-dependencies
+const { shouldServe } = require('@now/build-utils'); // eslint-disable-line import/no-extraneous-dependencies
 
 exports.analyze = ({ files, entrypoint }) => files[entrypoint].digest;
 
-exports.build = async ({ files, entrypoint }) => {
+exports.build = async ({
+  workPath, files, entrypoint, meta,
+}) => {
   console.log('downloading files...');
-  const srcDir = await getWritableDirectory();
   const outDir = await getWritableDirectory();
 
-  await download(files, srcDir);
+  await download(files, workPath, meta);
 
   const handlerPath = path.join(__dirname, 'handler');
   await copyFile(handlerPath, path.join(outDir, 'handler'));
@@ -23,7 +25,7 @@ exports.build = async ({ files, entrypoint }) => {
 
   // For now only the entrypoint file is copied into the lambda
   await copyFile(
-    path.join(srcDir, entrypoint),
+    path.join(workPath, entrypoint),
     path.join(outDir, entrypoint),
   );
 
@@ -40,3 +42,5 @@ exports.build = async ({ files, entrypoint }) => {
     [entrypoint]: lambda,
   };
 };
+
+exports.shouldServe = shouldServe;

packages/now-cgi/package.json

@@ -1,7 +1,12 @@
 {
   "name": "@now/cgi",
-  "version": "0.0.15",
+  "version": "0.1.4",
   "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/zeit/now-builders.git",
+    "directory": "packages/now-cgi"
+  },
   "scripts": {
     "test": "best -I test/*.js",
     "prepublish": "./build.sh"
@@ -16,8 +21,5 @@
   "devDependencies": {
     "@zeit/best": "0.4.3",
     "rmfr": "2.0.0"
-  },
-  "peerDependencies": {
-    "@now/build-utils": ">=0.0.1"
   }
 }

packages/now-go/.gitignore

@@ -1,4 +1,6 @@
 node_modules
 *.log
-launcher
-bin
+/go
+/analyze
+*.js
+!util/install.js

packages/now-go/.npmignore

@@ -0,0 +1,5 @@
+*.ts
+test
+tsconfig.json
+package-lock.json
+yarn.lock

packages/now-go/build.sh

@@ -1,7 +0,0 @@
-#!/usr/bin/env bash
-
-mkdir -p bin
-cd util
-GOOS=linux GOARCH=amd64 go build get-exported-function-name.go
-mv get-exported-function-name ../bin/
-

packages/now-go/download-go-bin.js

@@ -1,23 +0,0 @@
-const path = require('path');
-
-const fetch = require('node-fetch');
-const tar = require('tar');
-const getWritableDirectory = require('@now/build-utils/fs/get-writable-directory.js');
-
-const url = 'https://dl.google.com/go/go1.11.1.linux-amd64.tar.gz';
-
-module.exports = async () => {
-  const res = await fetch(url);
-  const dir = await getWritableDirectory();
-
-  if (!res.ok) {
-    throw new Error(`Failed to download: ${url}`);
-  }
-
-  return new Promise((resolve, reject) => {
-    res.body
-      .on('error', reject)
-      .pipe(tar.extract({ cwd: dir, strip: 1 }))
-      .on('finish', () => resolve(path.join(dir, 'bin', 'go')));
-  });
-};

packages/now-go/go-helpers.ts

@@ -0,0 +1,170 @@
+import tar from 'tar';
+import execa from 'execa';
+import fetch from 'node-fetch';
+import { mkdirp, pathExists } from 'fs-extra';
+import { dirname, join } from 'path';
+import { homedir } from 'os';
+import Debug from 'debug';
+
+const debug = Debug('@now/go:go-helpers');
+const archMap = new Map([['x64', 'amd64'], ['x86', '386']]);
+const platformMap = new Map([['win32', 'windows']]);
+
+// Location where the `go` binary will be installed after `postinstall`
+const GO_DIR = join(__dirname, 'go');
+const GO_BIN = join(GO_DIR, 'bin/go');
+
+const getPlatform = (p: string) => platformMap.get(p) || p;
+const getArch = (a: string) => archMap.get(a) || a;
+const getGoUrl = (version: string, platform: string, arch: string) => {
+  const goArch = getArch(arch);
+  const goPlatform = getPlatform(platform);
+  const ext = platform === 'win32' ? 'zip' : 'tar.gz';
+  return `https://dl.google.com/go/go${version}.${goPlatform}-${goArch}.${ext}`;
+};
+
+export async function getAnalyzedEntrypoint(filePath: string, modulePath = '') {
+  debug('Analyzing entrypoint %o', filePath);
+  const bin = join(__dirname, 'analyze');
+
+  const isAnalyzeExist = await pathExists(bin);
+  if (!isAnalyzeExist) {
+    const src = join(__dirname, 'util', 'analyze.go');
+    const dest = join(__dirname, 'analyze');
+    const go = await downloadGo();
+    await go.build(src, dest);
+  }
+
+  const args = [`-modpath=${modulePath}`, filePath];
+
+  const analyzed = await execa.stdout(bin, args);
+  debug('Analyzed entrypoint %o', analyzed);
+  return analyzed;
+}
+
+// Creates a `$GOPATH` directory tree, as per `go help gopath` instructions.
+// Without this, `go` won't recognize the `$GOPATH`.
+function createGoPathTree(goPath: string, platform: string, arch: string) {
+  const tuple = `${getPlatform(platform)}_${getArch(arch)}`;
+  debug('Creating GOPATH directory structure for %o (%s)', goPath, tuple);
+  return Promise.all([
+    mkdirp(join(goPath, 'bin')),
+    mkdirp(join(goPath, 'pkg', tuple)),
+  ]);
+}
+
+class GoWrapper {
+  private env: { [key: string]: string };
+  private opts: execa.Options;
+
+  constructor(env: { [key: string]: string }, opts: execa.Options = {}) {
+    if (!opts.cwd) {
+      opts.cwd = process.cwd();
+    }
+    this.env = env;
+    this.opts = opts;
+  }
+
+  private execute(...args: string[]) {
+    const { opts, env } = this;
+    debug('Exec %o', `go ${args.join(' ')}`);
+    return execa('go', args, { stdio: 'inherit', ...opts, env });
+  }
+
+  mod() {
+    return this.execute('mod', 'tidy');
+  }
+
+  get(src?: string) {
+    const args = ['get'];
+    if (src) {
+      debug('Fetching `go` dependencies for file %o', src);
+      args.push(src);
+    } else {
+      debug('Fetching `go` dependencies for cwd %o', this.opts.cwd);
+    }
+    return this.execute(...args);
+  }
+
+  build(src: string | string[], dest: string, ldsflags = '-s -w') {
+    debug('Building optimized `go` binary %o -> %o', src, dest);
+    const sources = Array.isArray(src) ? src : [src];
+    return this.execute('build', '-ldflags', ldsflags, '-o', dest, ...sources);
+  }
+}
+
+export async function createGo(
+  goPath: string,
+  platform = process.platform,
+  arch = process.arch,
+  opts: execa.Options = {},
+  goMod = false
+) {
+  const path = `${dirname(GO_BIN)}:${process.env.PATH}`;
+  const env: { [key: string]: string } = {
+    ...process.env,
+    PATH: path,
+    GOPATH: goPath,
+    ...opts.env,
+  };
+  if (goMod) {
+    env.GO111MODULE = 'on';
+  }
+  await createGoPathTree(goPath, platform, arch);
+  return new GoWrapper(env, opts);
+}
+
+export async function downloadGo(
+  dir = GO_DIR,
+  version = '1.12',
+  platform = process.platform,
+  arch = process.arch
+) {
+  // Check default `Go` in user machine
+  const isUserGo = await pathExists(join(homedir(), 'go'));
+
+  // If we found GOPATH in ENV, or default `Go` path exists
+  // asssume that user have `Go` installed
+  if (isUserGo || process.env.GOPATH !== undefined) {
+    const { stdout } = await execa('go', ['version']);
+
+    if (parseInt(stdout.split('.')[1]) >= 11) {
+      return createGo(dir, platform, arch);
+    }
+
+    throw new Error(
+      `Your current ${stdout} doesn't support Go Modules. Please update.`
+    );
+  } else {
+    // Check `Go` bin in builder CWD
+    const isGoExist = await pathExists(join(dir, 'bin'));
+    if (!isGoExist) {
+      debug(
+        'Installing `go` v%s to %o for %s %s',
+        version,
+        dir,
+        platform,
+        arch
+      );
+      const url = getGoUrl(version, platform, arch);
+      debug('Downloading `go` URL: %o', url);
+      console.log('Downloading Go ...');
+      const res = await fetch(url);
+
+      if (!res.ok) {
+        throw new Error(`Failed to download: ${url} (${res.status})`);
+      }
+
+      // TODO: use a zip extractor when `ext === "zip"`
+      await mkdirp(dir);
+      await new Promise((resolve, reject) => {
+        res.body
+          .on('error', reject)
+          .pipe(tar.extract({ cwd: dir, strip: 1 }))
+          .on('error', reject)
+          .on('finish', resolve);
+      });
+    }
+    return createGo(dir, platform, arch);
+  }
+}

packages/now-go/index.js

@@ -1,136 +0,0 @@
-const path = require('path');
-const { mkdirp, readFile, writeFile } = require('fs-extra');
-
-const execa = require('execa');
-const { createLambda } = require('@now/build-utils/lambda.js');
-const getWritableDirectory = require('@now/build-utils/fs/get-writable-directory.js');
-const download = require('@now/build-utils/fs/download.js');
-const downloadGit = require('lambda-git');
-const glob = require('@now/build-utils/fs/glob.js');
-const downloadGoBin = require('./download-go-bin');
-
-// creates a `$GOPATH` directory tree, as per
-// `go help gopath`'s instructions.
-// without this, Go won't recognize the `$GOPATH`
-async function createGoPathTree(goPath) {
-  await mkdirp(path.join(goPath, 'bin'));
-  await mkdirp(path.join(goPath, 'pkg', 'linux_amd64'));
-}
-
-exports.config = {
-  maxLambdaSize: '10mb',
-};
-
-exports.build = async ({ files, entrypoint }) => {
-  console.log('downloading files...');
-
-  const gitPath = await getWritableDirectory();
-  const goPath = await getWritableDirectory();
-  const srcPath = path.join(goPath, 'src', 'lambda');
-  const outDir = await getWritableDirectory();
-
-  await createGoPathTree(goPath);
-
-  const downloadedFiles = await download(files, srcPath);
-
-  console.log('downloading go binary...');
-  const goBin = await downloadGoBin();
-
-  console.log('downloading git binary...');
-  // downloads a git binary that works on Amazon Linux and sets
-  // `process.env.GIT_EXEC_PATH` so `go(1)` can see it
-  await downloadGit({ targetDirectory: gitPath });
-
-  const goEnv = {
-    ...process.env,
-    GOOS: 'linux',
-    GOARCH: 'amd64',
-    GOPATH: goPath,
-  };
-
-  console.log(`parsing AST for "${entrypoint}"`);
-  let handlerFunctionName = '';
-  try {
-    handlerFunctionName = await execa.stdout(
-      path.join(__dirname, 'bin', 'get-exported-function-name'),
-      [downloadedFiles[entrypoint].fsPath],
-    );
-  } catch (err) {
-    console.log(`failed to parse AST for "${entrypoint}"`);
-    throw err;
-  }
-
-  if (handlerFunctionName === '') {
-    const e = new Error(
-      `Could not find an exported function on "${entrypoint}"`,
-    );
-    console.log(e.message);
-    throw e;
-  }
-
-  console.log(
-    `Found exported function "${handlerFunctionName}" on "${entrypoint}"`,
-  );
-
-  const origianlMainGoContents = await readFile(
-    path.join(__dirname, 'main.go'),
-    'utf8',
-  );
-  const mainGoContents = origianlMainGoContents.replace(
-    '__NOW_HANDLER_FUNC_NAME',
-    handlerFunctionName,
-  );
-  // in order to allow the user to have `main.go`, we need our `main.go` to be called something else
-  const mainGoFileName = 'main__now__go__.go';
-
-  // we need `main.go` in the same dir as the entrypoint,
-  // otherwise `go build` will refuse to build
-  const entrypointDirname = path.dirname(downloadedFiles[entrypoint].fsPath);
-
-  // Go doesn't like to build files in different directories,
-  // so now we place `main.go` together with the user code
-  await writeFile(path.join(entrypointDirname, mainGoFileName), mainGoContents);
-
-  console.log('installing dependencies');
-  // `go get` will look at `*.go` (note we set `cwd`), parse
-  // the `import`s and download any packages that aren't part of the stdlib
-  try {
-    await execa(goBin, ['get'], {
-      env: goEnv,
-      cwd: entrypointDirname,
-      stdio: 'inherit',
-    });
-  } catch (err) {
-    console.log('failed to `go get`');
-    throw err;
-  }
-
-  console.log('running go build...');
-  try {
-    await execa(
-      goBin,
-      [
-        'build',
-        '-o',
-        path.join(outDir, 'handler'),
-        path.join(entrypointDirname, mainGoFileName),
-        downloadedFiles[entrypoint].fsPath,
-      ],
-      { env: goEnv, cwd: entrypointDirname, stdio: 'inherit' },
-    );
-  } catch (err) {
-    console.log('failed to `go build`');
-    throw err;
-  }
-
-  const lambda = await createLambda({
-    files: await glob('**', outDir),
-    handler: 'handler',
-    runtime: 'go1.x',
-    environment: {},
-  });
-
-  return {
-    [entrypoint]: lambda,
-  };
-};

packages/now-go/index.ts

@@ -0,0 +1,388 @@
+import { join, sep, dirname, basename } from 'path';
+import { readFile, writeFile, pathExists, move } from 'fs-extra';
+import { homedir } from 'os';
+import execa from 'execa';
+
+import {
+  glob,
+  download,
+  createLambda,
+  getWriteableDirectory,
+  BuildOptions,
+  shouldServe,
+  Files,
+} from '@now/build-utils';
+
+import { createGo, getAnalyzedEntrypoint } from './go-helpers';
+
+interface Analyzed {
+  found?: boolean;
+  packageName: string;
+  functionName: string;
+  watch: string[];
+}
+interface BuildParamsMeta {
+  isDev: boolean | undefined;
+}
+interface BuildParamsType extends BuildOptions {
+  files: Files;
+  entrypoint: string;
+  workPath: string;
+  meta: BuildParamsMeta;
+}
+
+// Initialize private git repo for Go Modules
+async function initPrivateGit(credentials: string) {
+  await execa('git', [
+    'config',
+    '--global',
+    'credential.helper',
+    `store --file ${join(homedir(), '.git-credentials')}`,
+  ]);
+
+  await writeFile(join(homedir(), '.git-credentials'), credentials);
+}
+
+export const version = 2;
+
+export const config = {
+  maxLambdaSize: '10mb',
+};
+
+export async function build({
+  files,
+  entrypoint,
+  config,
+  workPath,
+  meta = {} as BuildParamsMeta,
+}: BuildParamsType) {
+  if (process.env.GIT_CREDENTIALS && !meta.isDev) {
+    console.log('Initialize Git credentials...');
+    await initPrivateGit(process.env.GIT_CREDENTIALS);
+  }
+
+  console.log('Downloading user files...');
+  const entrypointArr = entrypoint.split(sep);
+
+  let [goPath, outDir] = await Promise.all([
+    getWriteableDirectory(),
+    getWriteableDirectory(),
+  ]);
+
+  const srcPath = join(goPath, 'src', 'lambda');
+  let downloadedFiles;
+  if (meta.isDev) {
+    downloadedFiles = await download(files, workPath, meta);
+  } else {
+    downloadedFiles = await download(files, srcPath);
+  }
+
+  console.log(`Parsing AST for "${entrypoint}"`);
+  let analyzed: string;
+  try {
+    let goModAbsPathDir = '';
+    for (const file of Object.keys(downloadedFiles)) {
+      if (file === 'go.mod') {
+        goModAbsPathDir = dirname(downloadedFiles[file].fsPath);
+      }
+    }
+    analyzed = await getAnalyzedEntrypoint(
+      downloadedFiles[entrypoint].fsPath,
+      goModAbsPathDir
+    );
+  } catch (err) {
+    console.log(`Failed to parse AST for "${entrypoint}"`);
+    throw err;
+  }
+
+  if (!analyzed) {
+    const err = new Error(
+      `Could not find an exported function in "${entrypoint}"
+Learn more: https://zeit.co/docs/v2/deployments/official-builders/go-now-go/#entrypoint
+      `
+    );
+    console.log(err.message);
+    throw err;
+  }
+
+  const parsedAnalyzed = JSON.parse(analyzed) as Analyzed;
+
+  if (meta.isDev) {
+    const base = dirname(downloadedFiles['now.json'].fsPath);
+    const destNow = join(
+      base,
+      '.now',
+      'cache',
+      basename(entrypoint, '.go'),
+      'src',
+      'lambda'
+    );
+    // this will ensure Go rebuilt fast
+    goPath = join(base, '.now', 'cache', basename(entrypoint, '.go'));
+    await download(downloadedFiles, destNow);
+
+    downloadedFiles = await glob('**', destNow);
+  }
+
+  // find `go.mod` in downloadedFiles
+  const entrypointDirname = dirname(downloadedFiles[entrypoint].fsPath);
+  let isGoModExist = false;
+  let goModPath = '';
+  let goModPathArr: string[] = [];
+  for (const file of Object.keys(downloadedFiles)) {
+    const fileDirname = dirname(downloadedFiles[file].fsPath);
+    if (file === 'go.mod') {
+      isGoModExist = true;
+      goModPath = fileDirname;
+      goModPathArr = goModPath.split(sep);
+    } else if (file.includes('go.mod')) {
+      isGoModExist = true;
+      if (entrypointDirname === fileDirname) {
+        goModPath = fileDirname;
+        goModPathArr = goModPath.split(sep);
+      }
+    }
+  }
+
+  const input = entrypointDirname;
+  var includedFiles: Files = {};
+
+  if (config && config.includeFiles) {
+    for (const pattern of config.includeFiles) {
+      const files = await glob(pattern, input);
+      for (const assetName of Object.keys(files)) {
+        includedFiles[assetName] = files[assetName];
+      }
+    }
+  }
+
+  const handlerFunctionName = parsedAnalyzed.functionName;
+  console.log(
+    `Found exported function "${handlerFunctionName}" in "${entrypoint}"`
+  );
+
+  // check if package name other than main
+  // using `go.mod` way building the handler
+  const packageName = parsedAnalyzed.packageName;
+
+  if (isGoModExist && packageName === 'main') {
+    throw new Error('Please change `package main` to `package handler`');
+  }
+
+  if (packageName !== 'main') {
+    const go = await createGo(
+      goPath,
+      process.platform,
+      process.arch,
+      {
+        cwd: entrypointDirname,
+      },
+      true
+    );
+    if (!isGoModExist) {
+      try {
+        const defaultGoModContent = `module ${packageName}`;
+
+        await writeFile(join(entrypointDirname, 'go.mod'), defaultGoModContent);
+      } catch (err) {
+        console.log(`failed to create default go.mod for ${packageName}`);
+        throw err;
+      }
+    }
+
+    const mainModGoFileName = 'main__mod__.go';
+    const modMainGoContents = await readFile(
+      join(__dirname, mainModGoFileName),
+      'utf8'
+    );
+
+    let goPackageName = `${packageName}/${packageName}`;
+    const goFuncName = `${packageName}.${handlerFunctionName}`;
+
+    if (isGoModExist) {
+      const goModContents = await readFile(join(goModPath, 'go.mod'), 'utf8');
+      const usrModName = goModContents.split('\n')[0].split(' ')[1];
+      goPackageName = `${usrModName}/${packageName}`;
+    }
+
+    const mainModGoContents = modMainGoContents
+      .replace('__NOW_HANDLER_PACKAGE_NAME', goPackageName)
+      .replace('__NOW_HANDLER_FUNC_NAME', goFuncName);
+
+    if (goModPathArr.length > 1) {
+      // using `go.mod` path to write main__mod__.go
+      await writeFile(join(goModPath, mainModGoFileName), mainModGoContents);
+    } else {
+      // using `entrypointDirname` to write main__mod__.go
+      await writeFile(
+        join(entrypointDirname, mainModGoFileName),
+        mainModGoContents
+      );
+    }
+
+    // move user go file to folder
+    try {
+      // default path
+      let finalDestination = join(entrypointDirname, packageName, entrypoint);
+      let forceMove = false;
+
+      if (meta.isDev) {
+        forceMove = true;
+      }
+
+      // if `entrypoint` include folder, only use filename
+      if (entrypointArr.length > 1) {
+        finalDestination = join(
+          entrypointDirname,
+          packageName,
+          entrypointArr[entrypointArr.length - 1]
+        );
+      }
+
+      if (
+        dirname(downloadedFiles[entrypoint].fsPath) === goModPath ||
+        !isGoModExist
+      ) {
+        await move(downloadedFiles[entrypoint].fsPath, finalDestination, {
+          overwrite: forceMove,
+        });
+      }
+    } catch (err) {
+      console.log('failed to move entry to package folder');
+      throw err;
+    }
+
+    if (meta.isDev) {
+      let entrypointDir = entrypointDirname;
+      if (goModPathArr.length > 1) {
+        entrypointDir = goModPath;
+      }
+      const isGoModBk = await pathExists(join(entrypointDir, 'go.mod.bk'));
+      if (isGoModBk) {
+        await move(
+          join(entrypointDir, 'go.mod.bk'),
+          join(entrypointDir, 'go.mod'),
+          { overwrite: true }
+        );
+        await move(
+          join(entrypointDir, 'go.sum.bk'),
+          join(entrypointDir, 'go.sum'),
+          { overwrite: true }
+        );
+      }
+    }
+
+    console.log('Tidy `go.mod` file...');
+    try {
+      // ensure go.mod up-to-date
+      await go.mod();
+    } catch (err) {
+      console.log('failed to `go mod tidy`');
+      throw err;
+    }
+
+    console.log('Running `go build`...');
+    const destPath = join(outDir, 'handler');
+    const isGoModInRootDir = goModPathArr.length === 1;
+    const baseGoModPath = isGoModInRootDir ? entrypointDirname : goModPath;
+    try {
+      let src = [join(baseGoModPath, mainModGoFileName)];
+
+      await go.build(src, destPath, config.ldsflags);
+    } catch (err) {
+      console.log('failed to `go build`');
+      throw err;
+    }
+    if (meta.isDev) {
+      // caching for `now dev`
+      await move(
+        join(baseGoModPath, 'go.mod'),
+        join(baseGoModPath, 'go.mod.bk'),
+        { overwrite: true }
+      );
+      await move(
+        join(baseGoModPath, 'go.sum'),
+        join(baseGoModPath, 'go.sum.bk'),
+        { overwrite: true }
+      );
+    }
+  } else {
+    // legacy mode
+    // we need `main.go` in the same dir as the entrypoint,
+    // otherwise `go build` will refuse to build
+    const go = await createGo(
+      goPath,
+      process.platform,
+      process.arch,
+      {
+        cwd: entrypointDirname,
+      },
+      false
+    );
+    const origianlMainGoContents = await readFile(
+      join(__dirname, 'main.go'),
+      'utf8'
+    );
+    const mainGoContents = origianlMainGoContents.replace(
+      '__NOW_HANDLER_FUNC_NAME',
+      handlerFunctionName
+    );
+
+    // in order to allow the user to have `main.go`,
+    // we need our `main.go` to be called something else
+    const mainGoFileName = 'main__now__go__.go';
+
+    // Go doesn't like to build files in different directories,
+    // so now we place `main.go` together with the user code
+    await writeFile(join(entrypointDirname, mainGoFileName), mainGoContents);
+
+    // `go get` will look at `*.go` (note we set `cwd`), parse the `import`s
+    // and download any packages that aren't part of the stdlib
+    console.log('Running `go get`...');
+    try {
+      await go.get();
+    } catch (err) {
+      console.log('failed to `go get`');
+      throw err;
+    }
+
+    console.log('Running `go build`...');
+    const destPath = join(outDir, 'handler');
+    try {
+      const src = [
+        join(entrypointDirname, mainGoFileName),
+        downloadedFiles[entrypoint].fsPath,
+      ];
+      await go.build(src, destPath);
+    } catch (err) {
+      console.log('failed to `go build`');
+      throw err;
+    }
+  }
+
+  const lambda = await createLambda({
+    files: { ...(await glob('**', outDir)), ...includedFiles },
+    handler: 'handler',
+    runtime: 'go1.x',
+    environment: {},
+  });
+  const output = {
+    [entrypoint]: lambda,
+  };
+
+  let watch = parsedAnalyzed.watch;
+  let watchSub: string[] = [];
+  // if `entrypoint` located in subdirectory
+  // we will need to concat it with return watch array
+  if (entrypointArr.length > 1) {
+    entrypointArr.pop();
+    watchSub = parsedAnalyzed.watch.map(file => join(...entrypointArr, file));
+  }
+
+  return {
+    output,
+    watch: watch.concat(watchSub),
+  };
+}
+
+export { shouldServe };

packages/now-go/main.go

@@ -1,8 +1,8 @@
 package main
 
 import (
-	now "../../utils/go/bridge"
 	"net/http"
+	now "github.com/zeit/now-builders/utils/go/bridge"
 )
 
 func main() {

packages/now-go/main__mod__.go

@@ -0,0 +1,12 @@
+package main
+
+import (
+  "net/http"
+  "__NOW_HANDLER_PACKAGE_NAME"
+
+  now "github.com/zeit/now-builders/utils/go/bridge"
+)
+
+func main() {
+  now.Start(http.HandlerFunc(__NOW_HANDLER_FUNC_NAME))
+}

packages/now-go/package.json

@@ -1,30 +1,36 @@
 {
   "name": "@now/go",
-  "version": "0.2.12",
+  "version": "0.5.1",
   "license": "MIT",
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/zeit/now-builders.git",
+    "directory": "packages/now-go"
+  },
   "scripts": {
-    "test": "best -I test/*.js",
-    "prepublish": "./build.sh"
+    "build": "tsc",
+    "test": "tsc && jest",
+    "prepublish": "tsc"
   },
   "files": [
-    "bin",
-    "download-go-bin.js",
-    "index.js",
-    "main.go"
+    "*.js",
+    "main.go",
+    "main__mod__.go",
+    "util"
   ],
   "dependencies": {
+    "debug": "^4.1.1",
     "execa": "^1.0.0",
     "fs-extra": "^7.0.0",
-    "lambda-git": "^0.1.2",
-    "mkdirp-promise": "5.0.1",
     "node-fetch": "^2.2.1",
     "tar": "4.4.6"
   },
   "devDependencies": {
-    "@zeit/best": "0.4.3",
-    "rmfr": "2.0.0"
-  },
-  "peerDependencies": {
-    "@now/build-utils": ">=0.0.1"
+    "@types/debug": "^4.1.3",
+    "@types/execa": "^0.9.0",
+    "@types/fs-extra": "^5.0.5",
+    "@types/node-fetch": "^2.3.0",
+    "@types/tar": "^4.0.0",
+    "typescript": "^3.4.2"
   }
 }

packages/now-go/test/fixtures/01-cowsay/index.go

@@ -0,0 +1,13 @@
+package cowsay
+
+import (
+	"fmt"
+	"net/http"
+
+	say "github.com/dhruvbird/go-cowsay"
+)
+
+// Handler function
+func Handler(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintf(w, say.Format("cow:RANDOMNESS_PLACEHOLDER"))
+}

packages/now-go/test/fixtures/01-cowsay/now.json

@@ -0,0 +1,11 @@
+{
+  "version": 2,
+  "builds": [
+    { "src": "index.go", "use": "@now/go" },
+    { "src": "subdirectory/index.go", "use": "@now/go" }
+  ],
+  "probes": [
+    { "path": "/", "mustContain": "cow:RANDOMNESS_PLACEHOLDER" },
+    { "path": "/subdirectory", "mustContain": "subcow:RANDOMNESS_PLACEHOLDER" }
+  ]
+}

packages/now-go/test/fixtures/01-cowsay/subdirectory/index.go

@@ -0,0 +1,13 @@
+package subcow
+
+import (
+	"fmt"
+	"net/http"
+
+	say "github.com/dhruvbird/go-cowsay"
+)
+
+// Handler function
+func Handler(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintf(w, say.Format("subcow:RANDOMNESS_PLACEHOLDER"))
+}

packages/now-go/test/fixtures/03-env-vars/build-env/go.mod

@@ -0,0 +1 @@
+module build-env

packages/now-go/test/fixtures/03-env-vars/build-env/index.go

@@ -0,0 +1,17 @@
+package buildenv
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+)
+
+// Handler function
+func Handler(w http.ResponseWriter, r *http.Request) {
+	rdm := os.Getenv("RANDOMNESS_BUILD_ENV")
+	if rdm == "" {
+		fmt.Println("No build env received")
+	}
+
+	fmt.Fprintf(w, rdm+":build-env")
+}

packages/now-go/test/fixtures/03-env-vars/env/go.mod

@@ -0,0 +1 @@
+module env

packages/now-go/test/fixtures/03-env-vars/env/index.go

@@ -0,0 +1,17 @@
+package env
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+)
+
+// Handler function
+func Handler(w http.ResponseWriter, r *http.Request) {
+	rdm := os.Getenv("RANDOMNESS_ENV")
+	if rdm == "" {
+		fmt.Println("No env received")
+	}
+
+	fmt.Fprintf(w, rdm)
+}

packages/now-go/test/fixtures/03-env-vars/now.json

@@ -0,0 +1,18 @@
+{
+  "version": 2,
+  "builds": [
+    {
+      "src": "env/index.go",
+      "use": "@now/go"
+    }
+  ],
+  "env": {
+    "RANDOMNESS_ENV": "RANDOMNESS_PLACEHOLDER"
+  },
+  "probes": [
+    {
+      "path": "/env",
+      "mustContain": "RANDOMNESS_PLACEHOLDER"
+    }
+  ]
+}

packages/now-go/test/fixtures/06-content-type/index.go

@@ -0,0 +1,11 @@
+package function
+
+import (
+	"fmt"
+	"net/http"
+)
+
+// Handler function
+func Handler(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintf(w, "RANDOMNESS_PLACEHOLDER")
+}

packages/now-go/test/fixtures/06-content-type/now.json

@@ -0,0 +1,4 @@
+{
+  "version": 2,
+  "builds": [{ "src": "index.go", "use": "@now/go" }]
+}

packages/now-go/test/fixtures/07-content-length/now.json

@@ -0,0 +1,7 @@
+{
+  "version": 2,
+  "builds": [{ "src": "*.go", "use": "@now/go" }],
+  "env": {
+    "RANDOMNESS_ENV_VAR": "RANDOMNESS_PLACEHOLDER"
+  }
+}

packages/now-go/test/fixtures/07-content-length/test1.go

@@ -0,0 +1,16 @@
+package function
+
+import (
+	"net/http"
+	"os"
+	"strconv"
+)
+
+// HandlerTest1 function
+func HandlerTest1(w http.ResponseWriter, r *http.Request) {
+	rdm := os.Getenv("RANDOMNESS_ENV_VAR")
+
+	w.WriteHeader(401)
+	w.Header().Set("content-length", strconv.Itoa(len(rdm+":content-length")))
+	w.Write([]byte(rdm + ":content-length"))
+}

packages/now-go/test/fixtures/07-content-length/test2.go

@@ -0,0 +1,12 @@
+package function
+
+import (
+	"net/http"
+)
+
+// HandlerTest2 function
+func HandlerTest2(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Content-Length", "2")
+	w.WriteHeader(401)
+	w.Write([]byte(""))
+}

packages/now-go/test/fixtures/07-content-length/test3.go

@@ -0,0 +1,13 @@
+package function
+
+import (
+	"net/http"
+	"os"
+)
+
+// HandlerTest3 function
+func HandlerTest3(w http.ResponseWriter, r *http.Request) {
+	rev := os.Getenv("RANDOMNESS_ENV_VAR")
+	w.WriteHeader(401)
+	w.Write([]byte(rev + ":content-length"))
+}

packages/now-go/test/fixtures/08-include-files/index.go

@@ -0,0 +1,16 @@
+package cowsay
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net/http"
+)
+
+// Handler function
+func Handler(w http.ResponseWriter, r *http.Request) {
+	bts, err := ioutil.ReadFile("templates/foo.txt")
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+	}
+	fmt.Fprintf(w, string(bts))
+}

packages/now-go/test/fixtures/08-include-files/now.json

@@ -0,0 +1,18 @@
+{
+  "version": 2,
+  "builds": [
+    {
+      "src": "index.go",
+      "use": "@now/go",
+      "config": {
+        "includeFiles": ["templates/**"]
+      }
+    }
+  ],
+  "probes": [
+    {
+      "path": "/",
+      "mustContain": "foobar from file"
+    }
+  ]
+}

packages/now-go/test/fixtures/08-include-files/templates/foo.txt

@@ -0,0 +1 @@
+foobar from file

packages/now-go/test/fixtures/09-exported-function/index.go

@@ -0,0 +1,22 @@
+package function
+
+import (
+	"fmt"
+	"net/http"
+)
+
+// Person struct
+type Person struct {
+	name string
+	age  int
+}
+
+// NewPerson struct method
+func NewPerson(name string, age int) *Person {
+	return &Person{name: name, age: age}
+}
+
+// H func
+func H(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintf(w, "RANDOMNESS_PLACEHOLDER")
+}

packages/now-go/test/fixtures/09-exported-function/now.json

@@ -0,0 +1,5 @@
+{
+  "version": 2,
+  "builds": [{ "src": "index.go", "use": "@now/go" }],
+  "probes": [{ "path": "/", "mustContain": "RANDOMNESS_PLACEHOLDER" }]
+}

packages/now-go/test/fixtures/10-go-mod/go.mod

@@ -0,0 +1,3 @@
+module go-mod
+
+go 1.12

packages/now-go/test/fixtures/10-go-mod/index.go

@@ -0,0 +1,11 @@
+package handler
+
+import (
+	"fmt"
+	"net/http"
+)
+
+// Handler func
+func Handler(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintf(w, "RANDOMNESS_PLACEHOLDER")
+}

packages/now-go/test/fixtures/10-go-mod/now.json

@@ -0,0 +1,5 @@
+{
+  "version": 2,
+  "builds": [{ "src": "index.go", "use": "@now/go" }],
+  "probes": [{ "path": "/", "mustContain": "RANDOMNESS_PLACEHOLDER" }]
+}

packages/now-go/test/fixtures/11-go-mod-shared/api/index.go

@@ -0,0 +1,12 @@
+package api
+
+import (
+	"fmt"
+	"net/http"
+	"with-shared/shared"
+)
+
+// Handler func
+func Handler(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintf(w, shared.Say("RANDOMNESS_PLACEHOLDER"))
+}

packages/now-go/test/fixtures/11-go-mod-shared/go.mod

@@ -0,0 +1,3 @@
+module with-shared
+
+go 1.12

packages/now-go/test/fixtures/11-go-mod-shared/now.json

@@ -0,0 +1,5 @@
+{
+  "version": 2,
+  "builds": [{ "src": "api/*.go", "use": "@now/go" }],
+  "probes": [{ "path": "/api", "mustContain": "RANDOMNESS_PLACEHOLDER" }]
+}

packages/now-go/test/fixtures/11-go-mod-shared/shared/shared.go

@@ -0,0 +1,6 @@
+package shared
+
+// Say func
+func Say(text string) string {
+	return text
+}

packages/now-go/test/fixtures/12-go-mod-subs/now.json

@@ -0,0 +1,8 @@
+{
+  "version": 2,
+  "builds": [{ "src": "**/*.go", "use": "@now/go" }],
+  "probes": [
+    { "path": "/sub-1", "mustContain": "RANDOMNESS_PLACEHOLDER" },
+    { "path": "/sub-2", "mustContain": "RANDOMNESS_PLACEHOLDER" }
+  ]
+}

packages/now-go/test/fixtures/12-go-mod-subs/sub-1/go.mod

@@ -0,0 +1,3 @@
+module sub-1
+
+go 1.12

packages/now-go/test/fixtures/12-go-mod-subs/sub-1/index.go

@@ -0,0 +1,11 @@
+package sub1
+
+import (
+	"fmt"
+	"net/http"
+)
+
+// Handler func
+func Handler(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintf(w, "RANDOMNESS_PLACEHOLDER")
+}

packages/now-go/test/fixtures/12-go-mod-subs/sub-2/go.mod

@@ -0,0 +1,3 @@
+module sub-2
+
+go 1.12