嘗試創建python web應用程序時出現流言錯誤

Question

我正在通過使用Vagrant和Ansbile（https://github.com/nickhs/flask_skeleton）部署Flask應用程序的指南，但不斷遇到一個我不知道如何解決的錯誤。

我運行下面... $無業遊民了分貝

...這將經歷一個錯誤，我才找不到任何答案，一個公平的幾個步驟。

這些都是完成的步驟...

（分貝）運行預配：ansible ...

PLAY [dbservers] ************************************************************** 

GATHERING FACTS *************************************************************** 

TASK: [update apt] ************************************************************ 
changed: [192.168.100.20] 

TASK: [install base packages] ************************************************* 
changed: [192.168.100.20] => (item=libpq-dev,python-dev,python-setuptools,git,libevent-dev,python-psycopg2) 

TASK: [install pip] *********************************************************** 
changed: [192.168.100.20] 

TASK: [add env variables] ***************************************************** 
changed: [192.168.100.20] 

TASK: [install db server packages] ******************************************** 
changed: [192.168.100.20] => (item=postgresql,postgresql-contrib) 

TASK: [update postgres db configuration] ************************************** 
changed: [192.168.100.20] 

TASK: [update postgres client configuration] ********************************** 
changed: [192.168.100.20] 

TASK: [link /vagrant to /srv/flask_skeleton] ********************************** 
changed: [192.168.100.20] 

TASK: [install dependencies] ************************************************** 
changed: [192.168.100.20] 

NOTIFIED: [source env variables] ********************************************** 
ok: [192.168.100.20] 

NOTIFIED: [restart postgresql] ************************************************ 

PLAY [dbservers] ************************************************************** 
TASK: [create database user] ************************************************** 
TASK: [create database] ******************************************************* 

NOTIFIED: [build database] **************************************************** 
failed: [192.168.100.20] => {"item": "", "rc": 1} 
stdout: Traceback (most recent call last): 
    File "/srv/flask_skeleton/createdb.py", line 1, in <module> 
    from app import db 
ImportError: cannot import name db 


PLAY RECAP ******************************************************************** 
      to retry, use: --limit @/var/tmp/ansible/vagrant-dbserver.retry 

192.168.100.20    : ok=14 changed=12 unreachable=0 failed=1 

任何人都可以點我在正確的方向？

Answer 1

綜觀app.py行：

app.config['SQLALCHEMY_DATABASE_URI'] = os.environ.get('DATABASE_URL') 

if app.config['SQLALCHEMY_DATABASE_URI']: 
    db = SQLAlchemy(app) 

如果沒有DATABASE_URL定義，那麼就不會有「DB」創建變量，然後不能在createdb.py進口模塊。你能檢查你是否確實有os.environ.get（'DATABASE_URL'）的值嗎？