在Heroku上部署web.py应用

Posted in python, web On 2011-09-29 13:33:10 , tagged with , , , .

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 login
Enter your Heroku credentials.
Email: adam@example.com
Password: 
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/python
Installing setuptools............done.

$source bin/activate

然后根据requirements.txt安装环境：

$ bin/pip install -r requirements.txt
Downloading/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.py
Installing collected packages: web.py
  Running setup.py install for web.py
Successfully installed web.py
Cleaning up...

编写.gitignore，将以下内容写到.gitignore文件里

bin
build
include
lib
.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 web
import os, sys

urls = (
    '/(.*)', '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-update
cd /var/lib/gems/1.8/bin
sudo ./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 start
13:20:59 web.1     | started with pid 25656
13:21:00 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 cedar
Creating simple-mountain-9034... done, stack is cedar
http://simple-mountain-9034.herokuapp.com/ | git@heroku.com:simple-mountain-9034.git
Git remote heroku added

然后推送到远端：

$ git push heroku master
Counting 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 Heroku

To 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=1
Scaling web processes... done, now running 1

然后可以查看进程的状态：

$ heroku ps
Process       State               Command
------------  ------------------  ------------------------------
web.1         up for 5s           python hello.py 5000

访问自己的Heroku应用地址，例如我的是http://simple-mountain-9034.herokuapp.com/abcdefg，成功！

参考资料：