feat: introduce PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD env variable (#1892)

Author: aslushnikov

docs/api.md

@@ -4148,6 +4148,7 @@ If Playwright doesn't find them in the environment, a lowercased variant of thes
 
 - `PLAYWRIGHT_DOWNLOAD_HOST` - overwrite URL prefix that is used to download browsers. Note: this includes protocol and might even include path prefix. By default, Playwright uses `https://storage.googleapis.com` to download Chromium and `https://playwright.azureedge.net` to download Webkit & Firefox.
 - `PLAYWRIGHT_BROWSERS_PATH` - specify a shared folder that playwright will use to download browsers and to look for browsers when launching browser instances.
+- `PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD` - set to non-empty value to skip browser downloads altogether.
 
 ```sh
 # Install browsers to the shared location.

download-browser.js

@@ -37,6 +37,7 @@ function downloadOptionsFromENV(packagePath, browserName) {
       path.join(packagePath, '.local-browsers', browserName);
   return {
     downloadPath,
+    skipBrowserDownload: getFromENV('PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD'),
     progressBarBrowserName: `${browserName} for playwright v${packageJSON.version}`,
     revision: packageJSON.playwright[`${browserName}_revision`],
     browser: browserName,
@@ -46,6 +47,10 @@ function downloadOptionsFromENV(packagePath, browserName) {
 }
 
 async function downloadBrowserWithProgressBar(options) {
+  if (options.skipBrowserDownload) {
+    logPolitely('Skipping browsers download because `PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD` env variable is set');
+    return;
+  }
   let progressBar = null;
   let lastDownloadedBytes = 0;
   function progress(downloadedBytes, totalBytes) {

test/installation-tests/installation-tests.sh

@@ -30,6 +30,7 @@ SANITY_JS="$(pwd -P)/../sanity.js"
 TEST_ROOT="$(pwd -P)"
 
 function run_tests {
+  test_skip_browser_download
   test_playwright_global_installation_subsequent_installs
   test_playwright_should_work
   test_playwright_chromium_should_work
@@ -74,6 +75,22 @@ function test_playwright_global_installation_subsequent_installs {
   PLAYWRIGHT_BROWSERS_PATH="${BROWSERS}" node --unhandled-rejections=strict node_modules/playwright/install.js
 }
 
+function test_skip_browser_download {
+  initialize_test "${FUNCNAME[0]}"
+
+  npm install ${PLAYWRIGHT_CORE_TGZ}
+  OUTPUT=$(PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD=1 npm install ${PLAYWRIGHT_TGZ})
+  if [[ "${OUTPUT}" != *"Skipping browsers download because"* ]]; then
+    echo "missing log message that browsers download is skipped"
+    exit 1
+  fi
+
+  if [[ -d ./node_modules/playwright/.local-browsers ]]; then
+    echo "local browsers folder should be empty"
+    exit 1
+  fi
+}
+
 function test_playwright_should_work {
   initialize_test "${FUNCNAME[0]}"