build(bazel): consolidate windows chromium path workaround

Add the hack to a central location so that it's easier to fix later.

aio/BUILD.bazel

@@ -145,6 +145,7 @@ TEST_DEPS = APPLICATION_DEPS + [
     "@aio_npm//karma-coverage",
     "@aio_npm//karma-jasmine",
     "@aio_npm//karma-jasmine-html-reporter",
+    "//aio/tools:windows-chromium-path",
 ]
 
 # All sources, specs, and config files required to serve the app
@@ -159,6 +160,7 @@ E2E_DEPS = APPLICATION_DEPS + [
     "@aio_npm//jasmine-spec-reporter",
     "@aio_npm//protractor",
     "@aio_npm//ts-node",
+    "//aio/tools:windows-chromium-path",
 ]
 
 # Stamp npm_link targets for all dependencies that correspond to a

aio/content/examples/examples.bzl

@@ -191,6 +191,7 @@ def docs_example(name, test = True, test_tags = [], test_exec_properties = {}):
                 YARN_LABEL,
                 "@aio_npm//@angular/build-tooling/bazel/browsers/chromium",
                 "//aio/tools/examples:run-example-e2e",
+                "//aio/tools:windows-chromium-path",
                 # We install the whole node modules for runtime deps of e2e tests
                 "@{workspace}//:node_modules_files".format(workspace = EXAMPLE_DEPS_WORKSPACE_NAME),
             ] + select({

aio/karma.conf.js

@@ -1,28 +1,9 @@
 // Karma configuration file, see link for more information
 // https://karma-runner.github.io/1.0/config/configuration-file.html
 
-const os = require('os');
+const {getAdjustedChromeBinPathForWindows} = require('./tools/windows-chromium-path');
 
-if (os.platform() === 'win32') {
-  /*
-    For some unknown reason, the symlinked copy of chromium under runfiles won't run under
-    karma on Windows. Instead, modify the CHROME_BIN env var to point to the chrome binary
-    under external/ in the execroot.
-
-    CHROME_BIN is set to the make var $(CHROMIUM) in aio/BUILD.bazel, which points to chrome
-    under runfiles and thus starts with ../. Because we run architect with a chdir into aio,
-    $(CHROMIUM) additionally has a second ../.
-
-    First, back out of
-        bazel-out/x64_windows-fastbuild/bin/aio/test.bat.runfiles/angular/aio
-    Then go into
-        external/
-    and then into
-        org_chromium_chromium_windows/chrome-win
-    to cancel out the leading ../../
-  */
-  process.env.CHROME_BIN = `../../../../../../../external/org_chromium_chromium_windows/chrome-win/${process.env.CHROME_BIN}`;
-}
+process.env.CHROME_BIN = getAdjustedChromeBinPathForWindows();
 
 module.exports = function (config) {
   config.set({

aio/scripts/BUILD.bazel

@@ -39,6 +39,7 @@ nodejs_binary(
     name = "audit-web-app",
     testonly = True,
     data = [
+        "//aio/tools:windows-chromium-path",
         "@aio_npm//@angular/build-tooling/bazel/browsers/chromium",
         "@aio_npm//lighthouse",
         "@aio_npm//lighthouse-logger",

aio/scripts/audit-web-app.mjs

@@ -27,17 +27,17 @@
 import lighthouse from 'lighthouse';
 import * as printer from 'lighthouse/lighthouse-cli/printer.js';
 import logger from 'lighthouse-logger';
-import os from 'os';
 import puppeteer from 'puppeteer-core';
 import path from 'path';
+import {getAdjustedChromeBinPathForWindows} from '../tools/windows-chromium-path.js';
 
 // Constants
 const AUDIT_CATEGORIES = ['accessibility', 'best-practices', 'performance', 'pwa', 'seo'];
 const LIGHTHOUSE_FLAGS = {logLevel: process.env.CI ? 'error' : 'info'};  // Be less verbose on CI.
 const VIEWER_URL = 'https://googlechrome.github.io/lighthouse/viewer';
 const WAIT_FOR_SW_DELAY = 5000;
 
-process.env.CHROME_BIN = adjustChromeBinPathForWindows();
+process.env.CHROME_BIN = getAdjustedChromeBinPathForWindows();
 
 // Run
 _main(process.argv.slice(2));
@@ -169,30 +169,3 @@ async function runLighthouse(browser, url, flags, config) {
     await browser.close();
   }
 }
-
-// TODO: this is a hack; the root cause should be found and fixed
-function adjustChromeBinPathForWindows() {
-  if (os.platform() === 'win32') {
-    /*
-      For some unknown reason, the symlinked copy of chromium under runfiles won't run under
-      karma on Windows. Instead, modify the CHROME_BIN env var to point to the chrome binary
-      under external/ in the execroot.
-
-      CHROME_BIN is equal to the make var $(CHROMIUM), which points to chrome relative
-      to the runfiles root.
-
-      The org_chromium_chromium_windows/ in the path below is needed to cancel out the
-      leading ../ in CHROME_BIN.
-
-      First, back out of
-          bazel-out/x64_windows-fastbuild/bin/aio/scripts/audit-web-app.bat.runfiles/angular
-      Then go into`
-          external/
-      and then into
-          org_chromium_chromium_windows/
-      to cancel out the leading ../ in CHROME_BIN
-    */
-   return path.resolve(`../../../../../../external/org_chromium_chromium_windows/${process.env.CHROME_BIN}`);
-  }
-  return process.env.CHROME_BIN;
-}

aio/tests/e2e/protractor.conf.js

@@ -4,28 +4,9 @@
 
 const { SpecReporter, StacktraceOption } = require('jasmine-spec-reporter');
 const path = require('path')
-const os = require('os');
+const {getAdjustedChromeBinPathForWindows} = require('../../tools/windows-chromium-path');
 
-if (os.platform() === 'win32') {
-  /*
-    For some unknown reason, the symlinked copy of chromium under runfiles won't run under
-    karma on Windows. Instead, modify the CHROME_BIN env var to point to the chrome binary
-    under external/ in the execroot.
-
-    CHROME_BIN is set to the make var $(CHROMIUM) in aio/BUILD.bazel, which points to chrome
-    under runfiles and thus starts with ../. Because we run architect with a chdir into aio,
-    $(CHROMIUM) additionally has a second ../.
-
-    First, back out of
-        bazel-out/x64_windows-fastbuild/bin/aio/e2e.bat.runfiles/angular/aio
-    Then go into
-        external/
-    and then into
-        org_chromium_chromium_windows/chrome-win
-    to cancel out the leading ../../
-  */
-  process.env.CHROME_BIN = `../../../../../../../external/org_chromium_chromium_windows/chrome-win/${process.env.CHROME_BIN}`;
-}
+process.env.CHROME_BIN = getAdjustedChromeBinPathForWindows();
 
 /**
  * @type { import("protractor").Config }

aio/tools/BUILD.bazel

@@ -0,0 +1,10 @@
+load("@build_bazel_rules_nodejs//:index.bzl", "js_library")
+
+package(default_visibility = ["//aio:__subpackages__"])
+
+js_library(
+    name = "windows-chromium-path",
+    srcs = [
+        "windows-chromium-path.js",
+    ],
+)

aio/tools/examples/run-example-e2e.mjs

@@ -9,10 +9,11 @@ import yargs from 'yargs';
 import {hideBin} from 'yargs/helpers'
 import getPort from 'get-port';
 import {constructExampleSandbox} from "./example-sandbox.mjs";
+import { getAdjustedChromeBinPathForWindows } from '../windows-chromium-path.js';
 
 shelljs.set('-e');
 
-process.env.CHROME_BIN = adjustChromeBinPathForWindows();
+process.env.CHROME_BIN = getAdjustedChromeBinPathForWindows();
 
 // Resolve CHROME_BIN and CHROMEDRIVER_BIN from relative paths to absolute paths within the
 // runfiles tree so that subprocesses spawned in a different working directory can still find them.
@@ -329,31 +330,4 @@ function loadExampleConfig(exampleFolder) {
   return config;
 }
 
-// TODO: this is a hack; the root cause should be found and fixed
-function adjustChromeBinPathForWindows() {
-  if (os.platform() === 'win32') {
-    /*
-      For some unknown reason, the symlinked copy of chromium under runfiles won't run under
-      karma on Windows. Instead, modify the CHROME_BIN env var to point to the chrome binary
-      under external/ in the execroot.
-
-      CHROME_BIN is equal to the make var $(CHROMIUM), which points to chrome relative
-      to the runfiles root.
-
-      The org_chromium_chromium_windows/ in the path below is needed to cancel out the
-      leading ../ in CHROME_BIN.
-
-      First, back out of
-          bazel-out/x64_windows-fastbuild/bin/aio/content/examples/{EXAMPLE}/e2e.bat.runfiles/angular
-      Then go into
-          external/
-      and then into
-          org_chromium_chromium_windows/
-      to cancel out the leading ../ in CHROME_BIN
-    */
-   return path.join(`../../../../../../../../../external/org_chromium_chromium_windows/${process.env.CHROME_BIN}`);
-  }
-  return process.env.CHROME_BIN;
-}
-
 runE2e(EXAMPLE_PATH);

aio/tools/windows-chromium-path.js

@@ -0,0 +1,41 @@
+const os = require('os');
+const path = require('path');
+
+/*
+  TODO: this is a hack; the root cause should be found and fixed.
+
+  For some unknown reason, the symlinked copy of chromium under runfiles won't run under
+  karma on Windows. To work around this, use chromium under the execroot in the external
+  folder and point to that instead.
+
+  Return:
+    The adjusted absolute chromium path to use on Windows. On other platforms this is a
+    noop and returns the existing process.env.CHROME_BIN.
+*/
+exports.getAdjustedChromeBinPathForWindows = function() {
+    if (os.platform() === 'win32') {
+        const runfilesWorkspaceRoot = path.join(process.env.RUNFILES, 'angular');
+
+        // Get the path to chromium from the runfiles base folder. By default, the Bazel make var
+        // $(CHROMIUM) (which CHROME_BIN is set to) has a preceeding '../' to escape the workspace
+        // root within runfiles. Additional '../' may have been prepended to cancel out any chdirs.
+        const chromiumPath = process.env.CHROME_BIN.replace(/^(\.\.\/)*/, '');
+
+        // Escape from runfiles to the exec root
+        const execRootSlashWorkspace = 'execroot' + path.sep + 'angular';
+        const index = runfilesWorkspaceRoot.indexOf(execRootSlashWorkspace);
+        const execRootPath = runfilesWorkspaceRoot.substring(0, index + execRootSlashWorkspace.length);
+        const runfilesToExecRoot = path.relative(runfilesWorkspaceRoot, execRootPath);
+
+        // Resolve the path to chromium under the execroot
+        const chromiumExecRootPath = path.resolve(
+            runfilesWorkspaceRoot,
+            runfilesToExecRoot,
+            'external',
+            chromiumPath
+        );
+
+        return chromiumExecRootPath;
+    }
+    return process.env.CHROME_BIN;
+}