feat: support configuring the browser download path (#6014)

By adding support for an environment variable `PUPPETEER_DOWNLOAD_PATH` it is possible to support downloading the browser binaries into a folder outside the `node_modules` folder. This makes it possible to preserve previously downloaded binaries in order to skip downloading them again.

docs/api.md

@@ -411,6 +411,7 @@ If Puppeteer doesn't find them in the environment during the installation step,
 - `HTTP_PROXY`, `HTTPS_PROXY`, `NO_PROXY` - defines HTTP proxy settings that are used to download and run Chromium.
 - `PUPPETEER_SKIP_CHROMIUM_DOWNLOAD` - do not download bundled Chromium during installation step.
 - `PUPPETEER_DOWNLOAD_HOST` - overwrite URL prefix that is used to download Chromium. Note: this includes protocol and might even include path prefix. Defaults to `https://storage.googleapis.com`.
+- `PUPPETEER_DOWNLOAD_PATH` - overwrite the path for the downloads folder. Defaults to `<root>/.local-chromium`, where `<root>` is puppeteer's package root.
 - `PUPPETEER_CHROMIUM_REVISION` - specify a certain version of Chromium you'd like Puppeteer to use. See [puppeteer.launch([options])](#puppeteerlaunchoptions) on how executable path is inferred. **BEWARE**: Puppeteer is only [guaranteed to work](https://github.com/puppeteer/puppeteer/#q-why-doesnt-puppeteer-vxxx-work-with-chromium-vyyy) with the bundled Chromium, use at your own risk.
 - `PUPPETEER_EXECUTABLE_PATH` - specify an executable path to be used in `puppeteer.launch`. See [puppeteer.launch([options])](#puppeteerlaunchoptions) on how the executable path is inferred. **BEWARE**: Puppeteer is only [guaranteed to work](https://github.com/puppeteer/puppeteer/#q-why-doesnt-puppeteer-vxxx-work-with-chromium-vyyy) with the bundled Chromium, use at your own risk.
 - `PUPPETEER_PRODUCT` - specify which browser you'd like Puppeteer to use. Must be one of `chrome` or `firefox`. This can also be used during installation to fetch the recommended browser binary. Setting `product` programmatically in [puppeteer.launch([options])](#puppeteerlaunchoptions) supersedes this environment variable. The product is exposed in [`puppeteer.product`](#puppeteerproduct)

experimental/puppeteer-firefox/install.js

@@ -20,9 +20,10 @@ if (require('./package.json').name === 'puppeteer-core')
   return;
 
 const downloadHost = process.env.PUPPETEER_DOWNLOAD_HOST || process.env.npm_config_puppeteer_download_host || process.env.npm_package_config_puppeteer_download_host;
+const downloadPath = process.env.PUPPETEER_DOWNLOAD_PATH || process.env.npm_config_puppeteer_download_path || process.env.npm_package_config_puppeteer_download_path;
 
 const puppeteer = require('./index');
-const browserFetcher = puppeteer.createBrowserFetcher({ host: downloadHost, product: 'firefox' });
+const browserFetcher = puppeteer.createBrowserFetcher({ host: downloadHost, product: 'firefox', path: downloadPath });
 
 const revision = require('./package.json').puppeteer.firefox_revision;
 

experimental/puppeteer-firefox/lib/Launcher.js

@@ -231,7 +231,10 @@ class Launcher {
   }
 
   _resolveExecutablePath() {
-    const browserFetcher = new BrowserFetcher(this._projectRoot, { product: 'firefox' });
+    const downloadPath = process.env.PUPPETEER_DOWNLOAD_PATH ||
+      process.env.npm_config_puppeteer_download_path ||
+      process.env.npm_package_config_puppeteer_download_path;
+    const browserFetcher = new BrowserFetcher(this._projectRoot, { product: 'firefox', path: downloadPath });
     const revisionInfo = browserFetcher.revisionInfo(this._preferredRevision);
     const missingText = !revisionInfo.local ? `Firefox revision is not downloaded. Run "npm install" or "yarn install"` : null;
     return {executablePath: revisionInfo.executablePath, missingText};

src/install.ts

@@ -35,9 +35,14 @@ export async function downloadBrowser() {
     process.env.npm_config_puppeteer_product ||
     process.env.npm_package_config_puppeteer_product ||
     'chrome';
+  const downloadPath =
+    process.env.PUPPETEER_DOWNLOAD_PATH ||
+    process.env.npm_config_puppeteer_download_path ||
+    process.env.npm_package_config_puppeteer_download_path;
   const browserFetcher = puppeteer.createBrowserFetcher({
     product,
     host: downloadHost,
+    path: downloadPath,
   });
   const revision = await getRevision();
   await fetchBinary(revision);

src/node/Launcher.ts

@@ -744,6 +744,7 @@ function getWSEndpoint(browserURL: string): Promise<string> {
 function resolveExecutablePath(
   launcher: ChromeLauncher | FirefoxLauncher
 ): { executablePath: string; missingText?: string } {
+  let downloadPath: string;
   // puppeteer-core doesn't take into account PUPPETEER_* env variables.
   if (!launcher._isPuppeteerCore) {
     const executablePath =
@@ -757,9 +758,14 @@ function resolveExecutablePath(
         : null;
       return { executablePath, missingText };
     }
+    downloadPath =
+      process.env.PUPPETEER_DOWNLOAD_PATH ||
+      process.env.npm_config_puppeteer_download_path ||
+      process.env.npm_package_config_puppeteer_download_path;
   }
   const browserFetcher = new BrowserFetcher(launcher._projectRoot, {
     product: launcher.product,
+    path: downloadPath,
   });
   if (!launcher._isPuppeteerCore && launcher.product === 'chrome') {
     const revision = process.env['PUPPETEER_CHROMIUM_REVISION'];