我目前在我的 Cherrypy 项目中使用 SQLAlchemy 作为 ORM。当我在我的 Cherrypy 嵌入式网络服务器上时，我没有发生错误，但仅来自我的 Nginx 部署。
在带有 Nginx 1.2.1 的 Debian Wheezy 上，但这并不重要，因为我已经在带有 Nginx 1.2.8 和 1.4 的 Sqeeze 上进行了测试——结果相同！
因此，我使用 Nginx 和 uWsgi 部署我的项目。我的 wsgi_handler.py 与我的 devserver 启动脚本没有什么不同，但无论如何我在开发模式下没有错误。
项目结构：
testproj:
- models.py
- root.py
- tools.py //this is a cherrypy tool that I found to bind sqlalchemy session to cherrypy requests
- devserver.py
//the production mode files
- wsgi_handler.py
- uwsgi.ini
这是满足我的应用程序要求的 Web 项目的最小配置：
模型.py：
# -*- coding: utf-8 -*-
import logging
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column
from sqlalchemy.types import String, Integer
logging.basicConfig()
logging.getLogger('sqlalchemy.engine').setLevel(logging.CRITICAL)
Base = declarative_base()
class User(Base):
__tablename__ = 'user'
id = Column(Integer, primary_key=True)
firstname = Column(String)
lastname = Column(String)
def __init__(self, firstname, lastname):
self.firstname = firstname
self.lastname = lastname
工具.py：
# -*- coding: utf-8 -*-
import os
import cherrypy
from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker
from models import *
class SAEnginePlugin(cherrypy.process.plugins.SimplePlugin):
def __init__(self, bus, dburi):
"""
The plugin is registered to the CherryPy engine and therefore
is part of the bus (the engine *is* a bus) registery.
We use this plugin to create the SA engine. At the same time,
when the plugin starts we create the tables into the database
using the mapped class of the global metadata.
Finally we create a new 'bind' channel that the SA tool
will use to map a session to the SA engine at request time.
"""
cherrypy.process.plugins.SimplePlugin.__init__(self, bus)
self.sa_engine = None
self.bus.subscribe("bind", self.bind)
self.dburi = dburi
def start(self):
db_path = os.path.abspath(os.path.join(os.curdir, self.dburi))
self.sa_engine = create_engine('sqlite:///%s' % db_path, echo=True)
Base.metadata.create_all(self.sa_engine)
def stop(self):
if self.sa_engine:
self.sa_engine.dispose()
self.sa_engine = None
def bind(self, session):
session.configure(bind=self.sa_engine)
class SATool(cherrypy.Tool):
def __init__(self):
"""
The SA tool is responsible for associating a SA session
to the SA engine and attaching it to the current request.
Since we are running in a multithreaded application,
we use the scoped_session that will create a session
on a per thread basis so that you don't worry about
concurrency on the session object itself.
This tools binds a session to the engine each time
a requests starts and commits/rollbacks whenever
the request terminates.
"""
cherrypy.Tool.__init__(self, 'on_start_resource', self.bind_session, priority=20)
self.session = scoped_session(sessionmaker(autoflush=True, autocommit=False))
def _setup(self):
cherrypy.Tool._setup(self)
cherrypy.request.hooks.attach('on_end_resource', self.commit_transaction, priority=80)
def bind_session(self):
cherrypy.engine.publish('bind', self.session)
cherrypy.request.db = self.session
def commit_transaction(self):
cherrypy.request.db = None
try:
self.session.commit()
except:
self.session.rollback()
raise
finally:
self.session.remove()
根.py：
# -*- coding: utf-8 -*-
import cherrypy
from models import User
class Root(object):
def index(self):
"""
List users from the DB & add new if no users
"""
user = cherrypy.request.db.query(User).filter_by(firstname='John').first()
if user is None:
user = User('John', 'Doe')
cherrypy.request.db.add(user)
return 'Created user: %s %s' % (user.firstname, user.lastname)
return 'Found user: %s %s' % (user.firstname, user.lastname)
index.exposed = True
这是有趣的部分，我的 devserver.py 与我的 wsgi_handler.py 没有太大区别
开发服务器.py：
# -*- coding: utf-8 -*-
import os, cherrypy
from tools import SAEnginePlugin, SATool
from root import Root
basedir = os.path.abspath(os.path.dirname(__file__))
config = {
'DEFAULT': {
basedir : basedir,
},
'global': {
'server.socket_port' : 8000,
'server.socket_host' : "127.0.0.1",
'tools.encode.on' : True,
'tools.encode.encoding' : 'utf-8',
'request.show_tracebacks' : True,
},
'/': {
'tools.db.on' : True,
},
}
if __name__ == "__main__":
SAEnginePlugin(cherrypy.engine, '/tmp/data.db3').subscribe()
cherrypy.tools.db = SATool()
cherrypy.quickstart(Root(), config=config)
wsgi_handler.py：
# -*- coding: utf-8 -*-
import os, cherrypy
from tools import SAEnginePlugin, SATool
from root import Root
basedir = os.path.abspath(os.path.dirname(__file__))
config = {
'DEFAULT': {
basedir : basedir,
},
'global': {
'server.socket_port' : 80,
'server.socket_host' : "127.0.0.1",
'tools.encode.on' : True,
'tools.encode.encoding' : 'utf-8',
'request.show_tracebacks' : True,
},
'/': {
'tools.db.on' : True,
},
}
def application(environ, start_response):
SAEnginePlugin(cherrypy.engine, '/tmp/data.db3').subscribe()
cherrypy.tools.db = SATool()
cherrypy.tree.mount(Root(), script_name='/', config=config)
return cherrypy.tree(environ, start_response)
uwsgi.ini：
[uwsgi]
thread=3
master=1
uid = www-data
gid = www-data
wsgi-file = /var/www/testproj/wsgi_handler.py
chdir = /var/www/testproj
socket = /tmp/uwsgi.sock
logto = /var/log/uwsgi.log
安装应用程序堆栈
sudo apt-get install python-dev python-setuptools nginx
sudo easy_install pip
sudo pip install CherryPy==3.2.2 SQLAlchemy==0.7.10 uWSGI==1.9.11
启动开发服务器
python devserver.py
localhost:8000 gives me the first & the last name of the registered user in my database. If it does not exist, I create it & display it.
使用 python uWsgi 在 Nginx 上部署项目：
sudo mkdir -p /var/www
sudo cp -r testproj /var/www/
sudo chown -R www-data:www-data /var/www/testproj
创建 nginx 配置文件：
/etc/nginx/sites-available/默认：
server {
server_name 127.0.0.1;
listen 80;
charset UTF-8;
access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log;
location / {
uwsgi_pass unix:///tmp/uwsgi.sock;
include uwsgi_params;
}
}
重启 Nginx 并启动一个 uwsgi 守护进程：
sudo service nginx restart
uwsgi --enable-threads --ini /var/www/testproj/uwsgi.ini
这就是区别。
On localhost:8000 I get the expected output:
Found user: John Doe
并且在
127.0.0.1/
我得到：
UnboundExecutionError: 找不到映射器映射器上配置的绑定|用户|用户、SQL 表达式或此会话
我不明白为什么在开发模式下会话边界应该如此！