demo.py

import os.path as op

from flask import Flask
from flask.helpers import locked_cached_property

from jinja2 import FileSystemLoader


class BubbleApp(Flask):
    def __init__(self):
        super(BubbleApp, self).__init__(__name__)

    # Custom template loader with support for plugins
    @locked_cached_property
    def jinja_loader(self):
        paths = []

        plugin_path = op.join(op.dirname(op.abspath(__file__)), 'customizations', 'templates')
        if op.exists(plugin_path):
            paths.append(plugin_path)

        paths.append(op.join(self.root_path, self.template_folder))

        return FileSystemLoader(paths)