python – ImportError：安装后没有名为psycopg2的模块

这是我正在尝试运行的代码：

from flask import Flask
from flask.ext.sqlalchemy import SQLAlchemy

app = Flask(__name__)
app.config['SQLALCHEMY_DATABASE_URI'] = "postgresql://USERNAME:PASSWORD@localhost/mydb"
db = SQLAlchemy(app)
app.debug = True

class User(db.Model):
    __tablename__ = 'users'
    id = db.Column(db.Integer,primary_key = True)
    name = db.Column(db.String(100))

@app.route('/users/',methods = ['GET'])
def users():
    query = "SELECT id,name FROM users"

    results = User.query.from_statement(query).all()

    json_results = []
    for result in results:
        d = {'id' : result.id,'name' : result.name}
        json_results.append(d)

    res = jsonify(items=json_results)
    res.headers['Access-Control-Allow-Origin'] = '*'
    return res

但是,当用这个文件运行uWSGI时：uwsgi –socket 127.0.0.1:8080 –wsgi-file my_app.py –callable app –processes 4 –threads 2 –stats 127.0.0.1：9191,和使用SERVER_URL / users /调用它,我收到以下错误：

Traceback (most recent call last):
  File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/flask/app.py",line 1836,in __call__
    return self.wsgi_app(environ,start_response)
  File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/flask/app.py",line 1820,in wsgi_app
    response = self.make_response(self.handle_exception(e))
  File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/flask/app.py",line 1403,in handle_exception
    reraise(exc_type,exc_value,tb)
  File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/flask/app.py",line 1817,in wsgi_app
    response = self.full_dispatch_request()
  File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/flask/app.py",line 1477,in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/flask/app.py",line 1381,in handle_user_exception
    reraise(exc_type,line 1475,in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/flask/app.py",line 1461,in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "my_app.py",line 18,in users
    results = User.query.from_statement(query).all()
  File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/flask_sqlalchemy/__init__.py",line 428,in __get__
    return type.query_class(mapper,session=self.sa.session())
  File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/sqlalchemy/orm/scoping.py",line 70,in __call__
    return self.registry()
  File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/sqlalchemy/util/_collections.py",line 903,in __call__
    return self.registry.setdefault(key,self.createfunc())
  File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/flask_sqlalchemy/__init__.py",line 139,in __init__
    bind=db.engine,File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/flask_sqlalchemy/__init__.py",line 780,in engine
    return self.get_engine(self.get_app())
  File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/flask_sqlalchemy/__init__.py",line 797,in get_engine
    return connector.get_engine()
  File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/flask_sqlalchemy/__init__.py",line 473,in get_engine
    self._engine = rv = sqlalchemy.create_engine(info,**options)
  File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/sqlalchemy/engine/__init__.py",line 344,in create_engine
    return strategy.create(*args,**kwargs)
  File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/sqlalchemy/engine/strategies.py",line 73,in create
    dbapi = dialect_cls.dbapi(**dbapi_args)
  File "/home/ubuntu/my_app/my_app_venv/local/lib/python2.7/site-packages/sqlalchemy/dialects/postgresql/psycopg2.py",line 401,in dbapi
    import psycopg2
ImportError: No module named psycopg2
[pid: 10902|app: 0|req: 3/3] 74.108.216.27 () {40 vars in 708 bytes} [Sun May 18 01:46:00 2014] GET /users/ => generated 0 bytes in 13 msecs (HTTP/1.1 500) 0 headers in 0 bytes (0 switches on core 0)