Elastic Beanstalk没有安装requirements.txt文件

Question

我当前的目录结构是这样，

/site
 - .elasticbeanstalk
 - static
 - templates
 - views
 - application.py
 - requirements.txt

要创建我的网站，请使用已安装的flask。将项目上传到Elastic Beanstalk时，出现以下错误：

[Wed Aug 01 17:56:30.174032 2018] [:error] [pid 313] [remote 172.31.19.50:124] Traceback (most recent call last):
[Wed Aug 01 17:56:30.174051 2018] [:error] [pid 313] [remote 172.31.19.50:124] File "/opt/python/current/app/application.py", line 1, in <module>
[Wed Aug 01 17:56:30.174055 2018] [:error] [pid 313] [remote 172.31.19.50:124] from flask import Flask
[Wed Aug 01 17:56:30.174068 2018] [:error] [pid 313] [remote 172.31.19.50:124] ModuleNotFoundError: No module named 'flask'

我的requirements.txt位于根目录中，但由于某些原因未安装flask。

requirements.txt文件的内容为：

click==6.7
Flask==1.0.2
itsdangerous==0.24
Jinja2==2.10
MarkupSafe==1.0
Werkzeug==0.14.1

有什么建议吗？