Merge branch '65698-monitor-webpack-dev-server-memory' into 'master'

Add webpack memory test to CI

Closes #65698

See merge request gitlab-org/gitlab-ce!31537

.gitlab/ci/frontend.gitlab-ci.yml

@@ -232,3 +232,17 @@ qa-frontend-node:latest:
   extends: .qa-frontend-node
   image: node:latest
   allow_failure: true
+
+webpack-dev-server:
+  extends:
+    - .default-tags
+    - .default-retry
+    - .default-cache
+    - .except-docs-qa
+  dependencies: ["compile-assets", "compile-assets pull-cache", "setup-test-env"]
+  variables:
+    SETUP_DB: "false"
+    WEBPACK_MEMORY_TEST: "true"
+  script:
+    - node --version
+    - node --expose-gc node_modules/.bin/webpack-dev-server --config config/webpack.config.js

config/webpack.config.js

@@ -17,6 +17,7 @@ const DEV_SERVER_HOST = process.env.DEV_SERVER_HOST || 'localhost';
 const DEV_SERVER_PORT = parseInt(process.env.DEV_SERVER_PORT, 10) || 3808;
 const DEV_SERVER_LIVERELOAD = IS_DEV_SERVER && process.env.DEV_SERVER_LIVERELOAD !== 'false';
 const WEBPACK_REPORT = process.env.WEBPACK_REPORT;
+const WEBPACK_MEMORY_TEST = process.env.WEBPACK_MEMORY_TEST;
 const NO_COMPRESSION = process.env.NO_COMPRESSION;
 const NO_SOURCEMAPS = process.env.NO_SOURCEMAPS;
@@ -337,6 +338,30 @@ module.exports = {
       },
     },
+    // output the in-memory heap size upon compilation and exit
+    WEBPACK_MEMORY_TEST && {
+      apply(compiler) {
+        compiler.hooks.emit.tapAsync('ReportMemoryConsumptionPlugin', (compilation, callback) => {
+          console.log('Assets compiled...');
+          if (global.gc) {
+            console.log('Running garbage collection...');
+            global.gc();
+          } else {
+            console.error(
+              "WARNING: you must use the --expose-gc node option to accurately measure webpack's heap size",
+            );
+          }
+          const memoryUsage = process.memoryUsage().heapUsed;
+          const toMB = bytes => Math.floor(bytes / 1024 / 1024);
+
+          console.log(`Webpack heap size: ${toMB(memoryUsage)} MB`);
+
+          // exit in case we're running webpack-dev-server
+          IS_DEV_SERVER && process.exit();
+        });
+      },
+    },
+
     // enable HMR only in webpack-dev-server
     DEV_SERVER_LIVERELOAD && new webpack.HotModuleReplacementPlugin(),