Add latest changes from gitlab-org/gitlab@13-9-stable-eev13.9.0-rc42

1 files changed, 128 insertions, 0 deletions

diff --git a/config/helpers/incremental_webpack_compiler.js b/config/helpers/incremental_webpack_compiler.js
new file mode 100644
index 00000000000..786bb6071fa
--- /dev/null
+++ b/config/helpers/incremental_webpack_compiler.js
@@ -0,0 +1,128 @@
+const fs = require('fs');
+const path = require('path');
+
+const log = (msg, ...rest) => console.log(`IncrementalWebpackCompiler: ${msg}`, ...rest);
+
+// If we force a recompile immediately, the page reload doesn't seem to work.
+// Five seconds seem to work fine and the user can read the message
+const TIMEOUT = 5000;
+
+class NoopCompiler {
+  constructor() {
+    this.enabled = false;
+  }
+
+  filterEntryPoints(entryPoints) {
+    return entryPoints;
+  }
+
+  logStatus() {}
+
+  setupMiddleware() {}
+}
+
+class IncrementalWebpackCompiler {
+  constructor(historyFilePath) {
+    this.enabled = true;
+    this.history = {};
+    this.compiledEntryPoints = new Set([
+      // Login page
+      'pages.sessions.new',
+      // Explore page
+      'pages.root',
+    ]);
+    this.historyFilePath = historyFilePath;
+    this._loadFromHistory();
+  }
+
+  filterEntryPoints(entrypoints) {
+    return Object.fromEntries(
+      Object.entries(entrypoints).map(([key, val]) => {
+        if (this.compiledEntryPoints.has(key)) {
+          return [key, val];
+        }
+        return [key, ['./webpack_non_compiled_placeholder.js']];
+      }),
+    );
+  }
+
+  logStatus(totalCount) {
+    const current = this.compiledEntryPoints.size;
+    log(`Currently compiling route entrypoints: ${current} of ${totalCount}`);
+  }
+
+  setupMiddleware(app, server) {
+    app.use((req, res, next) => {
+      const fileName = path.basename(req.url);
+
+      /**
+       * We are only interested in files that have a name like `pages.foo.bar.chunk.js`
+       * because those are the ones corresponding to our entry points.
+       *
+       * This filters out hot update files that are for example named "pages.foo.bar.[hash].hot-update.js"
+       */
+      if (fileName.startsWith('pages.') && fileName.endsWith('.chunk.js')) {
+        const chunk = fileName.replace(/\.chunk\.js$/, '');
+
+        this._addToHistory(chunk);
+
+        if (!this.compiledEntryPoints.has(chunk)) {
+          log(`First time we are seeing ${chunk}. Adding to compilation.`);
+
+          this.compiledEntryPoints.add(chunk);
+
+          setTimeout(() => {
+            server.middleware.invalidate(() => {
+              if (server.sockets) {
+                server.sockWrite(server.sockets, 'content-changed');
+              }
+            });
+          }, TIMEOUT);
+        }
+      }
+
+      next();
+    });
+  }
+
+  // private methods
+
+  _addToHistory(chunk) {
+    if (!this.history[chunk]) {
+      this.history[chunk] = { lastVisit: null, count: 0 };
+    }
+    this.history[chunk].lastVisit = Date.now();
+    this.history[chunk].count += 1;
+
+    try {
+      fs.writeFileSync(this.historyFilePath, JSON.stringify(this.history), 'utf8');
+    } catch (e) {
+      log('Warning – Could not write to history', e.message);
+    }
+  }
+
+  _loadFromHistory() {
+    try {
+      this.history = JSON.parse(fs.readFileSync(this.historyFilePath, 'utf8'));
+      const entryPoints = Object.keys(this.history);
+      log(`Successfully loaded history containing ${entryPoints.length} entry points`);
+      /*
+      TODO: Let's ask a few folks to give us their history file after a milestone of usage
+            Then we can make smarter decisions on when to throw out rather than rendering everything
+            Something like top 20/30/40 entries visited in the last 7/10/15 days might be sufficient
+       */
+      this.compiledEntryPoints = new Set([...this.compiledEntryPoints, ...entryPoints]);
+    } catch (e) {
+      log(`No history found...`);
+    }
+  }
+}
+
+module.exports = (enabled, historyFilePath) => {
+  log(`Status – ${enabled ? 'enabled' : 'disabled'}`);
+
+  if (enabled) {
+    return new IncrementalWebpackCompiler(historyFilePath);
+  }
+  return new NoopCompiler();
+};