今天Heroku宣布支持Python，原本一直眼馋Ruby的同学有Heroku这个云主机平台，终于等到支持Python，立刻尝鲜一把。
安装Heroku环境
虽然系统是Ubuntu 10.04，但因为不想增加apt-get-repository，我没有使用官方推荐的apt-get方式。采用tarball方式，下载解压运行，提示没有ruby环境，那就安装吧：
sudo apt-get install ruby rubygems libreadline-ruby libopenssl-ruby
然后手动把解压出来的heroku-client文件夹加到PATH路径里。
配置Heroku环境
此处借用Heroku的文档，配置Heroku登录凭据与公私钥
$ heroku loginEnter your Heroku credentials.Email: adam@example.comPassword: Could not find an existing public key.Would you like to generate one? [Yn] Generating new SSH public key.Uploading ssh public key /Users/adam/.ssh/id_rsa.pub
编写hello world
Heroku文档是介绍使用flask这个web框架，由于习惯使用web.py，所以使用web.py来编写hello world。
编写pip的requirements.txt
$ echo "web.py==0.36" > requirements.txt
创建一个virtualenv
$ virtualenv --no-site-packages .New python executable in ./bin/pythonInstalling setuptools............done.$source bin/activate
这里的activate很重要,在windows下是打Scripts\activate
然后根据requirements.txt安装环境：
$ bin/pip install -r requirements.txtDownloading/unpacking web.py==0.36 (from -r requirements.txt (line 1)) Downloading web.py-0.36.tar.gz (87Kb): 87Kb downloaded Running setup.py egg_info for package web.pyInstalling collected packages: web.py Running setup.py install for web.pySuccessfully installed web.pyCleaning up...
编写.gitignore，将以下内容写到.gitignore文件里
binbuildincludelib.Python*.pyc
编写web.py程序
终于开始写干活的程序，直接上代码：
$ vi hello.py
import webimport os, sysurls = ( '/(.*)', 'hello')app = web.application(urls, globals())class hello: def GET(self, name): if not name: name = 'World' return 'Hello, ' + name + '!'if __name__ == "__main__": port = os.environ.get("PORT", "5000") sys.argv[1] = port app.run()由于Heroku会提供PORT环境变量来指定应用程序的端口，而web.py默认使用命令行第一个参数作为端口，因此直接获取环境变量PORT，放到sys.argv[1]里，注意web.py从命令行参数读端口参数，端口参数是字符串。
使用Foreman作为启动脚本
Heroku是ruby系的产品，使用Foreman作为启动脚本
使用rubygems即可安装foreman
$ gem install foreman
在ubuntu 10.04上安装foreman，会遇到错误：
ERROR: Error installing foreman: thor requires RubyGems version >= 1.3.6
而ubuntu 10.04的默认源里的rubygems是1.3.5的，参考stackoverflow一篇文章，找到解决方法：
sudo gem install rubygems-updatecd /var/lib/gems/1.8/binsudo ./update_rubygems
然后编写Procfile，这个Procfile是Foreman所读取的启动项
echo "web: python hello.py 5000" > Procfile
然后就可以启动来看下
$ foreman start13:20:59 web.1 | started with pid 2565613:21:00 web.1 | http://0.0.0.0:5000/
正常。
部署到Heroku
Heroku使用git push的部署方式，当代码push到远端，Heroku会自动更新代码并重启应用，使用过git的同学应该不会陌生。
$ heroku create --stack cedarCreating simple-mountain-9034... done, stack is cedarhttp://simple-mountain-9034.herokuapp.com/ | git@heroku.com:simple-mountain-9034.gitGit remote heroku added
然后推送到远端：
$ git push heroku masterCounting objects: 6, done.Delta compression using up to 4 threads.Compressing objects: 100% (3/3), done.Writing objects: 100% (6/6), 592 bytes, done.Total 6 (delta 0), reused 0 (delta 0)-----> Heroku receiving push-----> Python app detected-----> Preparing virtualenv version 1.6.1 New python executable in ./bin/python2.7 Also creating executable in ./bin/python Installing setuptools............done. Installing pip...............done.-----> Installing dependencies using pip version 1.0.1 Downloading/unpacking web.py==0.36 (from -r requirements.txt (line 1)) Creating supposed download cache at /app/tmp/repo.git/.cache/pip_downloads Storing download in cache at /app/tmp/repo.git/.cache/pip_downloads/http%3A%2F%2Fpypi.python.org%2Fpackages%2Fsource%2Fw%2Fweb.py%2Fweb.py-0.36.tar.gz Running setup.py egg_info for package web.py Installing collected packages: web.py Running setup.py install for web.py Successfully installed web.py Cleaning up...-----> Discovering process types Procfile declares types -> web-----> Compiled slug size is 2.6MB-----> Launching... done, v3 http://simple-mountain-9034.herokuapp.com deployed to HerokuTo git@heroku.com:simple-mountain-9034.git * [new branch] master -> master
这里注意要修改web的进程数：
$ heroku scale web=1Scaling web processes... done, now running 1
然后可以查看进程的状态：
$ heroku psProcess State Command------------ ------------------ ------------------------------web.1 up for 5s python hello.py 5000
