ui: add gae internal server code

infra/gae-internal/.gcloudignore

@@ -0,0 +1,19 @@
+# This file specifies files that are *not* uploaded to Google Cloud
+# using gcloud. It follows the same syntax as .gitignore, with the addition of
+# "#!include" directives (which insert the entries of the given .gitignore-style
+# file at that point).
+#
+# For more information, run:
+#   $ gcloud topic gcloudignore
+#
+.gcloudignore
+# If you would like to upload your .git directory, .gitignore file or files
+# from your .gitignore file, remove the corresponding line
+# below:
+.git
+.gitignore
+
+# Python pycache:
+__pycache__/
+# Ignored by the build system
+/setup.cfg

infra/gae-internal/app.yaml

@@ -0,0 +1,8 @@
+runtime: python312
+
+entrypoint: gunicorn -b :$PORT main:app
+
+instance_class: F1
+
+automatic_scaling:
+  max_instances: 2

infra/gae-internal/deploy

@@ -0,0 +1,3 @@
+#!/bin/bash
+gcloud app deploy app.yaml --project google.com:perfetto-gae-internal
+

infra/gae-internal/main.py

@@ -0,0 +1,41 @@
+import posixpath
+
+from flask import Flask, Response, abort
+from flask_cors import CORS
+from google.cloud import storage
+
+app = Flask(__name__)
+CORS(
+    app,
+    origins=["https://ui.perfetto.dev", "http://localhost:10000"],
+    supports_credentials=True)
+
+BUCKET_NAME = "perfetto-ui-internal"
+BASE_PREFIX = "extension-server-v1"
+
+gcs_client = storage.Client()
+bucket = gcs_client.bucket(BUCKET_NAME)
+
+
+@app.route("/", defaults={"path": ""})
+@app.route("/<path:path>")
+def serve(path):
+  # Normalize and reject any path traversal attempts.
+  normalized = posixpath.normpath(path) if path else ""
+  if normalized.startswith(
+      "..") or "/../" in normalized or normalized.startswith("/"):
+    abort(403)
+
+  blob_path = f"{BASE_PREFIX}/{normalized}" if normalized else BASE_PREFIX + "/"
+
+  blob = bucket.blob(blob_path)
+  if not blob.exists():
+    abort(404)
+
+  data = blob.download_as_bytes()
+  content_type = blob.content_type or "application/octet-stream"
+  return Response(data, content_type=content_type)
+
+
+if __name__ == "__main__":
+  app.run(host="127.0.0.1", port=8080)

infra/gae-internal/requirements.txt

@@ -0,0 +1,4 @@
+Flask==3.0.0
+Flask-Cors==4.0.0
+google-cloud-storage==2.14.0
+gunicorn==21.2.0