Ruby On Rails 环境搭建
作者: 洛桑扎巴 | 个人学习记录，内容来自网络，如果有相关版权问题请联系我，我会删除。
网址: http://notes.11ten.net/ruby-on-rails.html
网址: http://notes.11ten.net/ruby-on-rails.html
##前言
Ruby On Rails是最流行和体验最好的敏捷开发WEB框架（没有之一），介绍性的内容这里就不赘述了。本文介绍下Ruby On Rails环境的搭建流程。
环境如下：
- 操作系统采用Ubuntu 12.04.1 LTS (Precise Pangolin) Server Editon
- Ruby版本为1.9.3-p0
- Rails为3.2.8
默认情况下Ubuntu有很多库和软件没有安装，我们首先安装一下所需要的库：
$ sudo apt-get upgrade
$ sudo apt-get install build-essential libssl-dev libreadline-gplv2-dev \
lib64readline-gplv2-dev zlib1g zlib1g-dev libyaml-dev libsqlite3-dev
##安装Ruby
由于系统自带的Ruby版本较低，所以这里我们先安装Ruby：
$ wget http://ftp.ruby-lang.org/pub/ruby/1.9/ruby-1.9.3-p0.tar.gz
$ tar xzvf ruby-1.9.3-p0.tar.gz
$ cd ruby-1.9.3-p0
$ ./configure
$ make
$ sudo make install
安装完成之后，查看下Ruby信息：
$ ruby -v
ruby 1.9.3p0 (2011-10-30 revision 33570) [i686-linux]
##安装Gem
Rails需要通过Gem来安装，下面安装Gem：
$ wget http://production.cf.rubygems.org/rubygems/rubygems-1.8.24.tgz
$ tar -zxvf rubygems-1.8.24.tgz
$ cd rubygems-1.8.24
$ ruby setup.rb
RubyGems 1.8.24 installed
== 1.8.24 / 2012-04-27
* 1 bug fix:
* Install the .pem files properly. Fixes #320
* Remove OpenSSL dependency from the http code path
---------------------------------------------------------------------
RubyGems installed the following executables:
/usr/local/bin/gem
更新Gem：
$ gem update --system
Latest version currently installed. Aborting.
##安装Rails
接下来安装Rails:
$ sudo gem install rails
Successfully installed i18n-0.6.1
Successfully installed multi_json-1.3.6
Successfully installed activesupport-3.2.8
Successfully installed builder-3.0.3
...
...
Successfully installed rack-ssl-1.3.2
Successfully installed thor-0.16.0
Successfully installed railties-3.2.8
Successfully installed bundler-1.2.1
Successfully installed rails-3.2.8
28 gems installed
如果出现以下的错误信息：
ERROR: Loading command: update (LoadError)
no such file to load -- zlib
ERROR: While executing gem ... (NameError)
uninitialized constant Gem::Commands::UpdateCommand
这是因为Ruby的zlib模块没有安装，安装zlib模块：
sudo apt-get install zlib1g-dev
cd /ruby-source-files/ext/zlib
ruby extconf.rb
make
sudo make install
如果出现以下错误信息：
Installing ri documentation for rails-3.2.8...
file 'lib' not found
Installing RDoc documentation for rails-3.2.8...
file 'lib' not found
是因为rdoc没有安装，安装rdoc：
sudo gem install rdoc
$ wget -O ~/.rails.bash https://raw.github.com/jweslley/rails_completion/master/rails.bash
$ echo source ~/.rails.bash >> ~/.bashrc
$ source ~/.bashrc
##第一个应用
Rails安装完成之后，你可以创建自己的Rails应用了：
$ cd /srv
$ rails new myapp
create
create README.rdoc
create Rakefile
create config.ru
create .gitignore
create Gemfile
…
…
Using rails (3.2.8)
Using sass (3.2.1)
Using sass-rails (3.2.5)
Using sqlite3 (1.3.6)
Installing uglifier (1.3.0)
Your bundle is complete! Use bundle show [gemname] to see where a
bundled gem is installed.
Rails应用创建成功之后，你可以测试下这个应用是否可以运行：
$ cd myapp
$ rails server
rails server
=> Booting WEBrick
=> Rails 3.2.8 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
[2012-09-23 15:02:22] INFO WEBrick 1.3.1
[2012-09-23 15:02:22] INFO ruby 1.9.3 (2012-04-20) [x86_64-darwin12.0.0]
[2012-09-23 15:02:22] INFO WEBrick::HTTPServer#start: pid=9907 port=3000
执行以上的操作后，系统会启动WEBrick服务器，你可以通过http://127.0.0.1:3000来访问应用的内容了。不过WEBrick只可以作为测试用，
不能应用在大规模的生产环境中，所以我们需要一个高性能的服务器，这就是下面将要介绍的Unicorn。
##安装Unicorn
Unicorn（独角兽）是一个高性能的Rack HTTP server，更多介绍参见Github的介绍。
Unicorn依赖于JavaScript Runtime，首先我们安装Node.js：
$ sudo apt-get install nodejs
接下来我们通过Gem来安装Unicorn：
$ gem install unicorn
Fetching: kgio-2.7.4.gem (100%)
Building native extensions. This could take a while...
Fetching: raindrops-0.10.0.gem (100%)
Building native extensions. This could take a while...
Fetching: unicorn-4.3.1.gem (100%)
Building native extensions. This could take a while...
Successfully installed kgio-2.7.4
Successfully installed raindrops-0.10.0
Successfully installed unicorn-4.3.1
3 gems installed
Installing ri documentation for kgio-2.7.4...
Installing ri documentation for raindrops-0.10.0...
Installing ri documentation for unicorn-4.3.1...
Installing RDoc documentation for kgio-2.7.4...
Installing RDoc documentation for raindrops-0.10.0...
Installing RDoc documentation for unicorn-4.3.1...
安装完成之后，启动Unicorn：
$ cd /srv/myapp
$ unicorn -l 127.0.0.1:8080 -E development
I, [2012-09-23T15:22:39.793852 #12107] INFO -- : listening on addr=0.0.0.0:8080 fd=5
I, [2012-09-23T15:22:39.794149 #12107] INFO -- : worker=0 spawning...
I, [2012-09-23T15:22:39.795973 #12107] INFO -- : master process ready
I, [2012-09-23T15:22:39.797613 #12108] INFO -- : worker=0 spawned pid=12108
I, [2012-09-23T15:22:39.797927 #12108] INFO -- : Refreshing Gem list
I, [2012-09-23T15:22:41.245205 #12108] INFO -- : worker=0 ready
其中-l 127.0.0.1:8080指定Unicorn监听8080端口，-E development指定运行环境为开发环境，更多内容参见unicorn -h。Unicorn启动成功之后，可以通过http://127.0.0.1:8080来访问Rails应用。
##环境配置
以上只是一个快速使用Unicorn的例子，我们还需要进行设置，使其可以自动化的启动。我们采用Nginx作为我们的Web服务器，并使用反向代理的方式对外提供服务：
首先，在myapp下创建配置文件/srv/myapp/config/unicorn.rb，内容如下：
worker_processes 4
working_directory "/srv/myapp" # available in 0.94.0+
listen "/tmp/unicorn.sock", :backlog => 64
listen 8080, :tcp_nopush => true
timeout 30
pid "/srv/myapp/tmp/unicorn.pid"
stderr_path "/srv/myapp/log/unicorn.stderr.log"
stdout_path "/srv/myapp/log/unicorn.stdout.log"
# combine Ruby 2.0.0dev or REE with "preload_app true" for memory savings
# http://rubyenterpriseedition.com/faq.html#adapt_apps_for_cow
preload_app true
GC.respond_to?(:copy_on_write_friendly=) and
GC.copy_on_write_friendly = true
before_fork do |server, worker|
# the following is highly recomended for Rails + "preload_app true"
# as there's no need for the master process to hold a connection
defined?(ActiveRecord::Base) and
ActiveRecord::Base.connection.disconnect!
# The following is only recommended for memory/DB-constrained
# installations. It is not needed if your system can house
# twice as many worker_processes as you have configured.
#
# # This allows a new master process to incrementally
# # phase out the old master process with SIGTTOU to avoid a
# # thundering herd (especially in the "preload_app false" case)
# # when doing a transparent upgrade. The last worker spawned
# # will then kill off the old master process with a SIGQUIT.
# old_pid = "#{server.config[:pid]}.oldbin"
# if old_pid != server.pid
# begin
# sig = (worker.nr + 1) >= server.worker_processes ? :QUIT : :TTOU
# Process.kill(sig, File.read(old_pid).to_i)
# rescue Errno::ENOENT, Errno::ESRCH
# end
# end
#
# Throttle the master from forking too quickly by sleeping. Due
# to the implementation of standard Unix signal handlers, this
# helps (but does not completely) prevent identical, repeated signals
# from being lost when the receiving process is busy.
# sleep 1
end
after_fork do |server, worker|
# per-process listener ports for debugging/admin/migrations
# addr = "127.0.0.1:#{9293 + worker.nr}"
# server.listen(addr, :tries => -1, :delay => 5, :tcp_nopush => true)
# the following is *required* for Rails + "preload_app true",
defined?(ActiveRecord::Base) and
ActiveRecord::Base.establish_connection
# if preload_app is true, then you may also want to check and
# restart any other shared sockets/descriptors such as Memcached,
# and Redis. TokyoCabinet file handles are safe to reuse
# between any number of forked children (assuming your kernel
# correctly implements pread()/pwrite() system calls)
end
然后，在Nginx中添加如下配置：
upstream app_server {
# fail_timeout=0 means we always retry an upstream even if it failed
# to return a good HTTP response (in case the Unicorn master nukes a
# single worker for timing out).
# for UNIX domain socket setups:
server unix:/tmp/unicorn.sock fail_timeout=0;
}
server {
listen 8888;
server_name _;
#access_log logs/host.access.log main;
location / {
# an HTTP header important enough to have its own Wikipedia entry:
# http://en.wikipedia.org/wiki/X-Forwarded-For
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
# enable this if you forward HTTPS traffic to unicorn,
# this helps Rack set the proper URL scheme for doing redirects:
# proxy_set_header X-Forwarded-Proto $scheme;
# pass the Host: header from the client right along so redirects
# can be set properly within the Rack application
proxy_set_header Host $http_host;
# we don't want nginx trying to do something clever with
# redirects, we set the Host: header above already.
proxy_redirect off;
# set "proxy_buffering off" *only* for Rainbows! when doing
# Comet/long-poll/streaming. It's also safe to set if you're using
# only serving fast clients with Unicorn + nginx, but not slow
# clients. You normally want nginx to buffer responses to slow
# clients, even with Rails 3.1 streaming because otherwise a slow
# client can become a bottleneck of Unicorn.
#
# The Rack application may also set "X-Accel-Buffering (yes|no)"
# in the response headers do disable/enable buffering on a
# per-response basis.
# proxy_buffering off;
proxy_pass http://app_server;
}
}
之后，添加配置文件/etc/unicorn/myapp.conf，内容如下：
RAILS_ENV=development #environment
RAILS_ROOT=/srv/myapp #
UNICORN=/usr/local/bin/unicorn
最后，创建启动脚本：
$ wget -O unicornd https://raw.github.com/gist/3769241/293df374dd7946ac44ac5575feccbfe80f6aa18d/unicornd
$ sudo cp unicornd /etc/init.d/
$ sudo chmod +x /etc/init.d/unicornd
$ echo /etc/init.d/unicornd start >> /etc/rc.local
$ sudo /etc/init.d/unicornd start
##参考
https://github.com/blog/517-unicorn
(完)
23 Sep 2012
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