feat: support disabling of Netlify function generation (#240)

* feat: support disabling of Netlify function generation

* chore: cleanup functions if they are disabled

* fix: correct test name

* chore: test timeout

* chore: re-word

Author: ascorbic

README.md

@@ -83,6 +83,18 @@ See
 [the gatsby-plugin-netlify docs](https://github.com/netlify/gatsby-plugin-netlify/)
 for more information, including optional plugin configuration.
 
+### Disabling Netlify functions
+
+In order to support Gatsby Functions and DSG and SSR render modes, this plugin
+generates three Netlify Functions called `__api`, `__ssr` and `__dsg`. If you
+are not using any of these modes, then you can disable the creation of these
+functions. If you are using the latest version of `gatsby-plugin-netlify` then
+this will be handled automatically, disabling functions if the site has no
+Gatsby Functions, or DSG/SSR pages. Otherwise, you can do this manually by
+setting the environment variable `NETLIFY_SKIP_GATSBY_FUNCTIONS` to `true`. Be
+aware that if you do this, any DSG or SSR pages will not work, and nor will any
+Gatsby Functions.
+
 ### Caveats
 
 Currently you cannot use `StaticImage` or `gatsby-transformer-sharp` in SSR or

plugin/src/helpers/config.ts

@@ -2,7 +2,8 @@ import { EOL } from 'os'
 import path from 'path'
 import process from 'process'
 
-import fs from 'fs-extra'
+import { stripIndent } from 'common-tags'
+import fs, { existsSync } from 'fs-extra'
 import type { GatsbyConfig, PluginRef } from 'gatsby'
 
 export async function spliceConfig({
@@ -39,8 +40,7 @@ export async function spliceConfig({
 
 function loadGatsbyConfig(utils): GatsbyConfig | never {
   const gatsbyConfigFile = path.resolve(process.cwd(), 'gatsby-config.js')
-  // eslint-disable-next-line node/no-sync
-  if (!fs.existsSync(gatsbyConfigFile)) {
+  if (!existsSync(gatsbyConfigFile)) {
     return {}
   }
 
@@ -96,7 +96,7 @@ export function checkGatsbyConfig({ utils, netlifyConfig }): void {
 export function mutateConfig({
   netlifyConfig,
   compiledFunctionsDir,
-  CACHE_DIR,
+  cacheDir,
 }): void {
   /* eslint-disable no-underscore-dangle, no-param-reassign */
   netlifyConfig.functions.__api = {
@@ -108,9 +108,9 @@ export function mutateConfig({
     included_files: [
       'public/404.html',
       'public/500.html',
-      path.posix.join(CACHE_DIR, 'data', '**'),
-      path.posix.join(CACHE_DIR, 'query-engine', '**'),
-      path.posix.join(CACHE_DIR, 'page-ssr', '**'),
+      path.posix.join(cacheDir, 'data', '**'),
+      path.posix.join(cacheDir, 'query-engine', '**'),
+      path.posix.join(cacheDir, 'page-ssr', '**'),
       '!**/*.js.map',
     ],
     external_node_modules: ['msgpackr-extract'],
@@ -120,3 +120,35 @@ export function mutateConfig({
   netlifyConfig.functions.__ssr = { ...netlifyConfig.functions.__dsg }
   /* eslint-enable no-underscore-dangle, no-param-reassign */
 }
+
+export function shouldSkipFunctions(cacheDir: string): boolean {
+  if (
+    process.env.NETLIFY_SKIP_GATSBY_FUNCTIONS === 'true' ||
+    process.env.NETLIFY_SKIP_GATSBY_FUNCTIONS === '1'
+  ) {
+    console.log(
+      'Skipping Gatsby Functions and SSR/DSG support because the environment variable NETLIFY_SKIP_GATSBY_FUNCTIONS is set to true',
+    )
+    return true
+  }
+
+  if (!existsSync(path.join(cacheDir, 'functions'))) {
+    console.log(
+      `Skipping Gatsby Functions and SSR/DSG support because the site's Gatsby version does not support them`,
+    )
+    return true
+  }
+
+  const skipFile = path.join(cacheDir, '.nf-skip-gatsby-functions')
+
+  if (existsSync(skipFile)) {
+    console.log(
+      stripIndent`
+      Skipping Gatsby Functions and SSR/DSG support because gatsby-plugin-netlify reported that this site does not use them. 
+      If this is incorrect, remove the file "${skipFile}" and try again.`,
+    )
+    return true
+  }
+
+  return false
+}

plugin/src/helpers/functions.ts

@@ -1,7 +1,7 @@
 import process from 'process'
 
 import { NetlifyPluginConstants } from '@netlify/build'
-import { copy, copyFile, ensureDir, writeFile } from 'fs-extra'
+import { copy, copyFile, ensureDir, existsSync, rm, writeFile } from 'fs-extra'
 import { resolve, join, relative } from 'pathe'
 
 import { makeHandler } from '../templates/handlers'
@@ -48,3 +48,14 @@ export const writeFunctions = async ({
     functionDir,
   )
 }
+
+export const deleteFunctions = async ({
+  INTERNAL_FUNCTIONS_SRC,
+}: NetlifyPluginConstants): Promise<void> => {
+  for (const func of ['__api', '__ssr', '__dsg']) {
+    const funcDir = join(process.cwd(), INTERNAL_FUNCTIONS_SRC, func)
+    if (existsSync(funcDir)) {
+      await rm(funcDir, { recursive: true, force: true })
+    }
+  }
+}

plugin/src/index.ts

@@ -1,28 +1,36 @@
 import path, { dirname, join } from 'path'
 import process from 'process'
 
-import fs from 'fs-extra'
+import { NetlifyPluginOptions } from '@netlify/build'
+import { stripIndent } from 'common-tags'
+import { existsSync, readFile, writeFile } from 'fs-extra'
 
 import { normalizedCacheDir, restoreCache, saveCache } from './helpers/cache'
-import { checkGatsbyConfig, mutateConfig, spliceConfig } from './helpers/config'
-import { writeFunctions } from './helpers/functions'
+import {
+  checkGatsbyConfig,
+  mutateConfig,
+  shouldSkipFunctions,
+  spliceConfig,
+} from './helpers/config'
+import { deleteFunctions, writeFunctions } from './helpers/functions'
 import { checkZipSize } from './helpers/verification'
 
-// eslint-disable-next-line no-template-curly-in-string
-const lmdbCacheString = 'process.cwd(), `.cache/${cacheDbFile}`'
-// eslint-disable-next-line no-template-curly-in-string
-const replacement = "require('os').tmpdir(), 'gatsby', `.cache/${cacheDbFile}`"
-
+/**
+ * This horrible thing is required because Gatsby tries to use a cache file in location that is readonly when deployed to a lambda
+ */
 async function patchFile(baseDir): Promise<void> {
+  /* eslint-disable no-template-curly-in-string */
+  const lmdbCacheString = 'process.cwd(), `.cache/${cacheDbFile}`'
+  const replacement =
+    "require('os').tmpdir(), 'gatsby', `.cache/${cacheDbFile}`"
+  /* eslint-enable no-template-curly-in-string */
+
   const bundleFile = join(baseDir, '.cache', 'query-engine', 'index.js')
-  // eslint-disable-next-line node/no-sync
-  if (!fs.existsSync(bundleFile)) {
+  if (!existsSync(bundleFile)) {
     return
   }
-  const bundle = await fs.readFile(bundleFile, 'utf8')
-
-  //  I'm so, so sorry
-  await fs.writeFile(bundleFile, bundle.replace(lmdbCacheString, replacement))
+  const bundle = await readFile(bundleFile, 'utf8')
+  await writeFile(bundleFile, bundle.replace(lmdbCacheString, replacement))
 }
 
 const DEFAULT_FUNCTIONS_SRC = 'netlify/functions'
@@ -32,64 +40,54 @@ export async function onPreBuild({
   utils,
   netlifyConfig,
 }): Promise<void> {
-  // print a helpful message if the publish dir is misconfigured
+  // Print a helpful message if the publish dir is misconfigured
   if (!PUBLISH_DIR || process.cwd() === PUBLISH_DIR) {
     utils.build.failBuild(
-      `Gatsby sites must publish the public directory, but your site’s publish directory is set to “${PUBLISH_DIR}”. Please set your publish directory to your Gatsby site’s public directory.`,
+      `Gatsby sites must publish the "public" directory, but your site’s publish directory is set to “${PUBLISH_DIR}”. Please set your publish directory to your Gatsby site’s "public" directory.`,
     )
   }
   await restoreCache({ utils, publish: PUBLISH_DIR })
-  const CACHE_DIR = normalizedCacheDir(PUBLISH_DIR)
-
-  // Work around Gatsby bug https://github.com/gatsbyjs/gatsby/issues/33262
-  await fs.ensureDir(join(CACHE_DIR, 'json'))
 
   checkGatsbyConfig({ utils, netlifyConfig })
 }
 
-export async function onBuild({ constants, netlifyConfig }): Promise<void> {
+export async function onBuild({
+  constants,
+  netlifyConfig,
+}: NetlifyPluginOptions): Promise<void> {
   const {
     PUBLISH_DIR,
     FUNCTIONS_SRC = DEFAULT_FUNCTIONS_SRC,
     INTERNAL_FUNCTIONS_SRC,
   } = constants
-  const CACHE_DIR = normalizedCacheDir(PUBLISH_DIR)
-  const compiledFunctionsDir = path.join(CACHE_DIR, '/functions')
-  // eslint-disable-next-line node/no-sync
-  if (!fs.existsSync(compiledFunctionsDir)) {
-    return
-  }
-
-  await writeFunctions(constants)
-
-  // copying Netlify wrapper function into functions directory
+  const cacheDir = normalizedCacheDir(PUBLISH_DIR)
 
   if (
     INTERNAL_FUNCTIONS_SRC &&
-    // eslint-disable-next-line node/no-sync
-    fs.existsSync(path.join(FUNCTIONS_SRC, 'gatsby'))
+    existsSync(path.join(FUNCTIONS_SRC, 'gatsby'))
   ) {
-    console.log(`
-Detected the function "${path.join(
+    console.log(stripIndent`
+    Detected the function "${path.join(
       FUNCTIONS_SRC,
       'gatsby',
     )}" that seem to have been generated by an old version of the Essential Gatsby plugin. 
 The plugin no longer uses this and it should be deleted to avoid conflicts.\n`)
   }
 
-  mutateConfig({ netlifyConfig, CACHE_DIR, compiledFunctionsDir })
+  if (shouldSkipFunctions(cacheDir)) {
+    await deleteFunctions(constants)
+    return
+  }
+  const compiledFunctionsDir = path.join(cacheDir, '/functions')
 
-  await spliceConfig({
-    startMarker: '# @netlify/plugin-gatsby start',
-    endMarker: '# @netlify/plugin-gatsby end',
-    contents: `GATSBY_PRECOMPILE_DEVELOP_FUNCTIONS=true`,
-    fileName: join(PUBLISH_DIR, '..', '.env.development'),
-  })
+  await writeFunctions(constants)
+
+  mutateConfig({ netlifyConfig, cacheDir, compiledFunctionsDir })
 
   const root = dirname(netlifyConfig.build.publish)
   await patchFile(root)
 
-  // Editing _redirects to it works with ntl dev
+  // Editing _redirects so it works with ntl dev
   spliceConfig({
     startMarker: '# @netlify/plugin-gatsby redirects start',
     endMarker: '# @netlify/plugin-gatsby redirects end',

plugin/src/templates/handlers.ts

@@ -135,7 +135,7 @@ export const makeHandler = (appDir: string, renderMode: RenderMode): string =>
     const { getPagePathFromPageDataPath, getGraphQLEngine, prepareFilesystem, getErrorResponse } = require('./utils')
     const { join, resolve } = require("path");
     const etag = require('etag');
-    const pageRoot = resolve(join(__dirname, "${appDir}"));
+    const pageRoot = resolve(__dirname, "${appDir}");
     exports.handler = ${
       renderMode === 'DSG'
         ? `builder((${getHandler.toString()})("${renderMode}", pageRoot))`

plugin/test/fixtures/with-no-gatsby-config/e2e-tests/build.test.js

@@ -2,7 +2,7 @@
 const { buildSite } = require('../../../helpers')
 
 jest.setTimeout(120_000)
-describe('A site with no functions', () => {
+describe('A site with no Gatsby config', () => {
   it('successfully builds', async () => {
     const { success } = await buildSite()
     expect(success).toBeTruthy()

plugin/test/fixtures/with-no-plugins/e2e-tests/build.test.js

@@ -2,7 +2,7 @@
 const { buildSite } = require('../../../helpers')
 
 jest.setTimeout(120_000)
-describe('A site with no functions', () => {
+describe('A site with no plugins', () => {
   it('successfully builds', async () => {
     const { success } = await buildSite()
     expect(success).toBeTruthy()