scripts: Add ui.sh

This script runs your local checkout of the UI.

scripts/ui.sh

@@ -0,0 +1,34 @@
+#!/bin/bash
+#
+# This script opens your local checkout of the UI in your browser.
+#
+# Note you need to have run `scripts/ui_assets.sh download` at least
+# once prior to running this script.
+#
+# Usage example:
+#
+#     ./scripts/ui.sh
+
+set -eu
+
+# Change dir to project root
+cd "$(git rev-parse --show-toplevel)"
+
+# Quick sanity check
+if [[ ! -d ./ui/static ]]; then
+  echo >&2 "Error: you haven't run scripts/ui_assets.sh yet"
+  exit 1
+fi
+
+# Need to run a local webserver to avoid CORS violations
+python -m http.server -d ./ui -b localhost 8080 &> /dev/null &
+pid=$!
+trap 'kill ${pid}' EXIT
+
+# Best effort in case someone is on OSX or SSH forwarding
+if ! xdg-open http://localhost:8080/status.html &> /dev/null; then
+  echo "UI is available at http://localhost:8080/status.html"
+fi
+
+echo "Press Enter to stop serving and exit..."
+read -r -p ""