sandbox for python

遇到一台机器上部署多个不同的python程序，管理其之间import不同的libs而麻烦

http://virtualenv.openplans.org/

virtualenv通过隔离包目录和系统环境参数来实现多个相对独立的虚拟环境。
这样可避免过多的第三方库因版本依赖造成问题。
同时每个独立的虚拟环境只需通过打包即可分发，方便了系统部署。

1. 安装

[root@CT53-64-BASE ~]# pip install -U virtualenv
Downloading/unpacking virtualenv
  Downloading virtualenv-1.5.1.tar.gz (1.4Mb): 1.4Mb downloaded
  Running setup.py egg_info for package virtualenv
    warning: no previously-included files matching '*.*' found under directory 'docs/_templates'
Installing collected packages: virtualenv
  Found existing installation: virtualenv 1.5.1
    Uninstalling virtualenv:
      Successfully uninstalled virtualenv
  Running setup.py install for virtualenv
    warning: no previously-included files matching '*.*' found under directory 'docs/_templates'
    Installing virtualenv script to /usr/bin
Successfully installed virtualenv
Cleaning up...
[root@CT53-64-BASE ~]#

2. 创建虚拟环境

[root@CT53-64-BASE ~]# virtualenv env_1
New python executable in env_1/bin/python
Installing setuptools............done.
[root@CT53-64-BASE ~]# ls env_1/
bin  include  lib  lib64
[root@CT53-64-BASE ~]#

建议使用 virtualenv --no-site-packages env_1 来创建虚拟环境，限制virtualenv 继承全局的site-packages，从而达到完全虚拟环境

完全的新的虚拟python环境

[root@CT53-64-BASE env_1]# cd include/python2.4/
abstract.h       codecs.h         errcode.h        grammar.h        marshal.h        objimpl.h        pyconfig-64.h    pymem.h          setobject.h      token.h
bitset.h         compile.h        eval.h           import.h         metagrammar.h    opcode.h         pyconfig.h       pyport.h         sliceobject.h    traceback.h
boolobject.h     complexobject.h  fileobject.h     intobject.h      methodobject.h   osdefs.h         py_curses.h      pystate.h        stringobject.h   tupleobject.h
bufferobject.h   cStringIO.h      floatobject.h    intrcheck.h      modsupport.h     parsetok.h       pydebug.h        pystrtod.h       structmember.h   ucnhash.h
cellobject.h     datetime.h       frameobject.h    iterobject.h     moduleobject.h   patchlevel.h     pyerrors.h       Python.h         structseq.h      unicodeobject.h
ceval.h          descrobject.h    funcobject.h     listobject.h     node.h           pgen.h           pyfpe.h          pythonrun.h      symtable.h       weakrefobject.h
classobject.h    dictobject.h     genobject.h      longintrepr.h    Numeric/         pgenheaders.h    pygetopt.h       pythread.h       sysmodule.h
cobject.h        enumobject.h     graminit.h       longobject.h     object.h         pyconfig-32.h    pymactoolbox.h   rangeobject.h    timefuncs.h

[root@CT53-64-BASE env_1]# python
Python 2.4.3 (#1, Sep  3 2009, 15:37:37)
[GCC 4.1.2 20080704 (Red Hat 4.1.2-46)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> for i in sys.path:
...     print i
...

/usr/lib/python2.4/site-packages/setuptools-0.6c11-py2.4.egg
/usr/lib/python2.4/site-packages/celery-2.0.3-py2.4.egg
/usr/lib/python2.4/site-packages/uuid-1.30-py2.4.egg
/usr/lib/python2.4/site-packages/multiprocessing-2.6.2.1-py2.4-linux-x86_64.egg
/usr/lib/python2.4/site-packages/pyparsing-1.5.5-py2.4.egg
/usr/lib/python2.4/site-packages/carrot-0.10.6-py2.4.egg
/usr/lib/python2.4/site-packages/anyjson-0.2.5-py2.4.egg
/usr/lib/python2.4/site-packages/SQLAlchemy-0.6.4-py2.4.egg
/usr/lib/python2.4/site-packages/python_dateutil-1.5-py2.4.egg
/usr/lib/python2.4/site-packages/importlib-1.0.2-py2.4.egg
/usr/lib/python2.4/site-packages/amqplib-0.6.1-py2.4.egg
/usr/lib/python2.4/site-packages/pip-0.8.1-py2.4.egg
/usr/lib64/python24.zip
/usr/lib64/python2.4
/usr/lib64/python2.4/plat-linux2
/usr/lib64/python2.4/lib-tk
/usr/lib64/python2.4/lib-dynload
/usr/lib64/python2.4/site-packages
/usr/lib64/python2.4/site-packages/Numeric
/usr/lib64/python2.4/site-packages/PIL
/usr/lib64/python2.4/site-packages/gst-0.10
/usr/lib64/python2.4/site-packages/gtk-2.0
/usr/lib/python2.4/site-packages
>>>

3. 激活这个虚拟python环境，其实主要是为了得到专属的虚拟site-packages

[root@CT53-64-BASE env_1]# source bin/activate
[color=red](env_1)[/color][root@CT53-64-BASE env_1]#

主要是注意shell前面的提示符变成 (env_1) 这个意味着，你再使用python的 ez_install or pip 安装第三方包到 site-packages 是你这个虚拟python环境的，不会影响到全局的系统python环境

4. 我们可以用 "deactivate" 命令退出虚拟环境

(env_1)[root@CT53-64-BASE env_1]# deactivate
[root@CT53-64-BASE env_1]#