• 用tsuru部署Ruby应用
  • 概述
  • 在tsuru中创建应用
  • 应用代码
  • . 创建项目 (rails new blog)
  • . 为Post生成脚手架(rails generate scaffold Post title:string body:text)
  • 通过Git部署
  • 列出依赖
  • 运行应用
  • 使用服务
  • 部署钩子
  • 进一步探索

    用tsuru部署Ruby应用

    概述

    本文档是在tsuru中部署一个简单的Ruby应用的实战指南。例子应用是一个关联MySQL服务的简单Rails项目。

    在tsuru中创建应用

    使用app-create命令创建应用：

    2.     $ tsuru app-create <app-name> <app-platform>

    对于Ruby来说，应用平台是，你猜，ruby！让我们脑洞打开，开发一个从未有人做过的教学应用：一个博客，而且它的名字也应该是很有创意，让我们叫它blog：

    1.     $ tsuru app-create blog ruby

    使用platform-list命令列出所有的可用的平台。使用app-list查看你所有的应用。

    1.     $ tsuru app-list
    2.     +-------------+-------------------------+-------------+
    3.     | Application | Units State Summary     | Address     |
    4.     +-------------+-------------------------+-------------+
    5.     | blog        | 0 of 0 units in-service |             |
    6.     +-------------+-------------------------+-------------+

    应用代码

    本文档不会专注于介绍如何用Rails实现博客，你可以从GitHub clone整个源代码：https://github.com/tsuru/tsuru-ruby-sample。 下面是我们在项目中所做的事情：

    . 创建项目 (rails new blog)

    . 为Post生成脚手架(rails generate scaffold Post title:string body:text)

    通过Git部署

    在创建新的应用时，tsuru会显示应该使用的Git远程分支。用app-info命令可以获得其信息：

    1.     $ tsuru app-info --app blog
    2.     Application: blog
    3.     Repository: git@192.168.50.4.nip.io:blog.git
    4.     Platform: ruby
    5.     Teams: admin
    6.     Address: blog.192.168.50.4.nip.io
    7.     Owner: admin@example.com
    8.     Team owner: admin
    9.     Deploys: 0
    10.     Pool: theonepool
    12.     App Plan:
    13.     +---------------+--------+------+-----------+--------+---------+
    14.     | Name          | Memory | Swap | Cpu Share | Router | Default |
    15.     +---------------+--------+------+-----------+--------+---------+
    16.     | autogenerated | 0 MB   | 0 MB | 100       |        | false   |
    17.     +---------------+--------+------+-----------+--------+---------+

    Git远程分支被用来通过Git部署应用。当修改被推送到tsuru远程分支时，项目同时也被部署：

    1.     $ git push git@192.168.50.4.nip.io:blog.git master
    2.     Counting objects: 86, done.
    3.     Delta compression using up to 4 threads.
    4.     Compressing objects: 100% (75/75), done.
    5.     Writing objects: 100% (86/86), 29.75 KiB, done.
    6.     Total 86 (delta 2), reused 0 (delta 0)
    7.     remote: Cloning into '/home/application/current'...
    8.     remote: requirements.apt not found.
    9.     remote: Skipping...
    10.     remote: /home/application/current /
    11.     remote: Fetching gem metadata from https://rubygems.org/.........
    12.     remote: Fetching gem metadata from https://rubygems.org/..
    13.     #####################################
    14.     #          OMIT (see below)         #
    15.     #####################################
    16.     remote:  ---> App will be restarted, please check its log for more details...
    17.     remote:
    18.     To git@192.168.50.4.nip.io:blog.git
    19.      * [new branch]      master -> master

    如果遇到"Permission denied (publickey)."的错误，请确保你是团队一员并把公钥加到tsuru中。用key-add命令添加公钥：

    1.     $ tsuru key-add mykey ~/.ssh/id_rsa.pub

    使用git remote add命令来避免每次push代码时都要输入整个远程仓库的链接：

    1.     $ git remote add tsuru git@192.168.50.4.nip.io:blog.git

    然后运行：

    1.     $ git push tsuru master
    2.     Everything up-to-date

    从此之后就可以省略掉—app标记:

    1.     $ tsuru app-info
    2.     Application: blog
    3.     Repository: git@192.168.50.4.nip.io:blog.git
    4.     Platform: ruby
    5.     Teams: admin
    6.     Address: blog.192.168.50.4.nip.io
    7.     Owner: admin@example.com
    8.     Team owner: admin
    9.     Deploys: 0
    10.     Pool: theonepool
    11.     Units: 1
    12.     +------------+---------+
    13.     | Unit       | State   |
    14.     +------------+---------+
    15.     | eab5151eff | started |
    16.     +------------+---------+
    18.     App Plan:
    19.     +---------------+--------+------+-----------+--------+---------+
    20.     | Name          | Memory | Swap | Cpu Share | Router | Default |
    21.     +---------------+--------+------+-----------+--------+---------+
    22.     | autogenerated | 0 MB   | 0 MB | 100       |        | false   |
    23.     +---------------+--------+------+-----------+--------+---------+

    列出依赖

    在上一个部分我们忽略了部署过程的依赖。在tsuru中，一个应用可以有两种依赖：

    • 操作系统级别的依赖, 以底层操作系统使用的包管理器为代表（比如: yum和apt-get）;
    • 平台依赖, 以平台/语言依赖的包管理工具为代表（在Ruby中是bundler）。
      所有的apt-get依赖必须在requirements.apt文件中指定，放在应用的根目录，同理，ruby的依赖也必须放在应用根目录名为Gemfile的文件中。因为要用Rails连接MySQL，我们需要用gem安装mysql，这个包依赖于：libmysqlclient-dev，因此requirements.apt内容如下：
    1.     libmysqlclient-dev

    下面是Gemfile的内容:

    2.     source 'https://rubygems.org'
    4.     gem 'rails', '3.2.13'
    5.     gem 'mysql'
    6.     gem 'sass-rails',   '~> 3.2.3'
    7.     gem 'coffee-rails', '~> 3.2.1'
    8.     gem 'therubyracer', platforms: 'ruby'
    9.     gem 'uglifier', '>= 1.0.3'
    10.     gem 'jquery-rails'

    下面是安装这些依赖的完整输出：

    1.     $ git push tsuru master
    2.     #####################################
    3.     #                OMIT               #
    4.     #####################################
    5.     remote: Reading package lists...
    6.     remote: Building dependency tree...
    7.     remote: Reading state information...
    8.     remote: The following extra packages will be installed:
    9.     remote:   libmysqlclient18 mysql-common
    10.     remote: The following NEW packages will be installed:
    11.     remote:   libmysqlclient-dev libmysqlclient18 mysql-common
    12.     remote: 0 upgraded, 3 newly installed, 0 to remove and 0 not upgraded.
    13.     remote: Need to get 2360 kB of archives.
    14.     remote: After this operation, 9289 kB of additional disk space will be used.
    15.     remote: Get:1 http://archive.ubuntu.com/ubuntu/ quantal/main mysql-common all 5.5.27-0ubuntu2 [13.7 kB]
    16.     remote: Get:2 http://archive.ubuntu.com/ubuntu/ quantal/main libmysqlclient18 amd64 5.5.27-0ubuntu2 [949 kB]
    17.     remote: Get:3 http://archive.ubuntu.com/ubuntu/ quantal/main libmysqlclient-dev amd64 5.5.27-0ubuntu2 [1398 kB]
    18.     remote: Fetched 2360 kB in 2s (1112 kB/s)
    19.     remote: Selecting previously unselected package mysql-common.
    20.     remote: (Reading database ... 41063 files and directories currently installed.)
    21.     remote: Unpacking mysql-common (from .../mysql-common_5.5.27-0ubuntu2_all.deb) ...
    22.     remote: Selecting previously unselected package libmysqlclient18:amd64.
    23.     remote: Unpacking libmysqlclient18:amd64 (from .../libmysqlclient18_5.5.27-0ubuntu2_amd64.deb) ...
    24.     remote: Selecting previously unselected package libmysqlclient-dev.
    25.     remote: Unpacking libmysqlclient-dev (from .../libmysqlclient-dev_5.5.27-0ubuntu2_amd64.deb) ...
    26.     remote: Setting up mysql-common (5.5.27-0ubuntu2) ...
    27.     remote: Setting up libmysqlclient18:amd64 (5.5.27-0ubuntu2) ...
    28.     remote: Setting up libmysqlclient-dev (5.5.27-0ubuntu2) ...
    29.     remote: Processing triggers for libc-bin ...
    30.     remote: ldconfig deferred processing now taking place
    31.     remote: /home/application/current /
    32.     remote: Fetching gem metadata from https://rubygems.org/..........
    33.     remote: Fetching gem metadata from https://rubygems.org/..
    34.     remote: Using rake (10.1.0)
    35.     remote: Using i18n (0.6.1)
    36.     remote: Using multi_json (1.7.8)
    37.     remote: Using activesupport (3.2.13)
    38.     remote: Using builder (3.0.4)
    39.     remote: Using activemodel (3.2.13)
    40.     remote: Using erubis (2.7.0)
    41.     remote: Using journey (1.0.4)
    42.     remote: Using rack (1.4.5)
    43.     remote: Using rack-cache (1.2)
    44.     remote: Using rack-test (0.6.2)
    45.     remote: Using hike (1.2.3)
    46.     remote: Using tilt (1.4.1)
    47.     remote: Using sprockets (2.2.2)
    48.     remote: Using actionpack (3.2.13)
    49.     remote: Using mime-types (1.23)
    50.     remote: Using polyglot (0.3.3)
    51.     remote: Using treetop (1.4.14)
    52.     remote: Using mail (2.5.4)
    53.     remote: Using actionmailer (3.2.13)
    54.     remote: Using arel (3.0.2)
    55.     remote: Using tzinfo (0.3.37)
    56.     remote: Using activerecord (3.2.13)
    57.     remote: Using activeresource (3.2.13)
    58.     remote: Using coffee-script-source (1.6.3)
    59.     remote: Using execjs (1.4.0)
    60.     remote: Using coffee-script (2.2.0)
    61.     remote: Using rack-ssl (1.3.3)
    62.     remote: Using json (1.8.0)
    63.     remote: Using rdoc (3.12.2)
    64.     remote: Using thor (0.18.1)
    65.     remote: Using railties (3.2.13)
    66.     remote: Using coffee-rails (3.2.2)
    67.     remote: Using jquery-rails (3.0.4)
    68.     remote: Installing libv8 (3.11.8.17)
    69.     remote: Installing mysql (2.9.1)
    70.     remote: Using bundler (1.3.5)
    71.     remote: Using rails (3.2.13)
    72.     remote: Installing ref (1.0.5)
    73.     remote: Using sass (3.2.10)
    74.     remote: Using sass-rails (3.2.6)
    75.     remote: Installing therubyracer (0.11.4)
    76.     remote: Installing uglifier (2.1.2)
    77.     remote: Your bundle is complete!
    78.     remote: Gems in the groups test and development were not installed.
    79.     remote: It was installed into ./vendor/bundle
    80.     #####################################
    81.     #                OMIT               #
    82.     #####################################
    83.     To git@192.168.50.4.nip.io:blog.git
    84.        9515685..d67c3cd  master -> master

    运行应用

    如你所见，部署的输出信息中有一个步骤叫做"重启你的应用"。在这个步骤中，如果应用在运行，tsuru会重启它，如果没有运行，tsuru会启动它。但是tsuru是如何启动一个应用呢？非常简单，它使用了一个Procfile（从Foreman中偷学的概念）。这个Procfile用来描述应用如何被启动。如下是Procfile的内容：

    1.     web: bundle exec rails server -p $PORT -e production

    现在我们提交文件并将其推送到tsuru的git服务器，再运行一次部署任务：

    1.     $ git add Procfile
    2.     $ git commit -m "Procfile: added file"
    3.     $ git push tsuru master
    4.     #####################################
    5.     #                OMIT               #
    6.     #####################################
    7.     remote:  ---> App will be restarted, please check its log for more details...
    8.     remote:
    9.     To git@192.168.50.4.nip.io:blog.git
    10.        d67c3cd..f2a5d2d  master -> master

    应用部署成功，可以通过app-list命令获得IP或者主机名，然后用浏览器去访问。比如，在下面的列表中：

    2.     $ tsuru app-list
    3.     +-------------+-------------------------+---------------------+
    4.     | Application | Units State Summary     | Address             |
    5.     +-------------+-------------------------+---------------------+
    6.     | blog        | 1 of 1 units in-service | blog.cloud.tsuru.io |
    7.     +-------------+-------------------------+---------------------+

    使用服务

    应用没有成功运行，原因在于rails不能连接到MySQL服务器，而我们在rails应用和MySQL实例之间添加了关联关系。要实现这点，必须使用一个服务.服务的工作流分为下面两步：

    . 创建一个服务的实例. 将服务的实例绑定到应用

    但是如何知道哪些服务是可用的呢？这很简单，运行service-list命令：

    1.     $ tsuru service-list
    2.     +----------------+-----------+
    3.     | Services       | Instances |
    4.     +----------------+-----------+
    5.     | elastic-search |           |
    6.     | mysql          |           |
    7.     +----------------+-----------+

    上面service-list的输出说明有两个可用的服务："elastic-search"和"mysql"，并且没有实例。通过service-add命令可以创建MySQL实例：

    1.     $ tsuru service-add mysql blogsql
    2.     Service successfully added.

    现在，如果再次运行service-list命令，可以从输出中看到新的服务实例：

    1.     $ tsuru service-list
    2.     +----------------+-----------+
    3.     | Services       | Instances |
    4.     +----------------+-----------+
    5.     | elastic-search |           |
    6.     | mysql          | blogsql   |
    7.     +----------------+-----------+

    使用service-bind命令将服务实例绑定到应用：

    1.     $ tsuru service-bind mysql blogsql
    2.     Instance blogsql is now bound to the app blog.
    4.     The following environment variables are now available for use in your app:
    6.     - MYSQL_PORT
    7.     - MYSQL_PASSWORD
    8.     - MYSQL_USER
    9.     - MYSQL_HOST
    10.     - MYSQL_DATABASE_NAME
    12.     For more details, please check the documentation for the service, using service-doc command.

    从绑定的输出中我们看出，可以通过环境变量来连接MySQL服务器。下一步就是更新conf/database.yml去使用这些环境变量去连接数据库：

    2.     production:
    3.       adapter: mysql
    4.       encoding: utf8
    5.       database: <%= ENV["MYSQL_DATABASE_NAME"] %>
    6.       pool: 5
    7.       username: <%= ENV["MYSQL_USER"] %>
    8.       password: <%= ENV["MYSQL_PASSWORD"] %>
    9.       host: <%= ENV["MYSQL_HOST"] %>

    现在提交修改，再次运行部署：

    1.     $ git add conf/database.yml
    2.     $ git commit -m "database.yml: using environment variables to connect to MySQL"
    3.     $ git push tsuru master
    4.     Counting objects: 7, done.
    5.     Delta compression using up to 4 threads.
    6.     Compressing objects: 100% (4/4), done.
    7.     Writing objects: 100% (4/4), 535 bytes, done.
    8.     Total 4 (delta 3), reused 0 (delta 0)
    9.     remote:
    10.     remote:  ---> tsuru receiving push
    11.     remote:
    12.     remote:  ---> Installing dependencies
    13.     #####################################
    14.     #               OMIT                #
    15.     #####################################
    16.     remote:
    17.     remote:  ---> Restarting your app
    18.     remote:
    19.     remote:  ---> Deploy done!
    20.     remote:
    21.     To git@192.168.50.4.nip.io:blog.git
    22.        ab4e706..a780de9  master -> master

    如果现在尝试访问admin页面，会得到另外一个错误："Table 'blogsql.django_session' doesn't exist"。这意味着绑定成功，可以访问数据库服务器，但是数据库还没有建立。需要在远程服务器运行rake db:migrate。我们可以使用app-run在机器上执行命令，所以对于运行rake db:migrate，可以这么写：

    1.     $ tsuru app-run -- RAILS_ENV=production bundle exec rake db:migrate
    2.     ==  CreatePosts: migrating ====================================================
    3.     -- create_table(:posts)
    4.        -> 0.1126s
    5.     ==  CreatePosts: migrated (0.1128s) ===========================================

    部署钩子

    每次部署后手动运行rake db:migrate会很烦人。所以我们可以配置一个自动的钩子，在每次应用重启前或者重启后运行。tsuru会解析一个名为tsuru.yaml的文件，运行重启的钩子。如扩展所建议的那样，这是一个YAML文件，包含了一系列在重启前后要运行的命令。下面是一个tsuru.yaml文件的例子：

    1.     hooks:
    2.       restart:
    3.         before-each:
    4.           - RAILS_ENV=production bundle exec rake db:migrate

    更多内容，请查看tsuru.yaml中的钩子文档部分。tsuru会在项目的根目录查找这个文件。让我们提交并且部署它：

    1.     $ git add tsuru.yaml
    2.     $ git commit -m "tsuru.yaml: added file"
    3.     $ git push tsuru master
    4.     #####################################
    5.     #                OMIT               #
    6.     #####################################
    7.     To git@192.168.50.4.nip.io:blog.git
    8.        a780de9..1b675b8  master -> master

    在应用重启前，有必要编译资源文件。可以用rake assets:precompile命令实现。让我们把这个命令加入tsuru.yaml文件中：

    1.     hooks:
    2.       build:
    3.         - RAILS_ENV=production bundle exec rake assets:precompile
    1.     $ git add tsuru.yaml
    2.     $ git commit -m "tsuru.yaml: added file"
    3.     $ git push tsuru master
    4.     #####################################
    5.     #                OMIT               #
    6.     #####################################
    7.     To git@192.168.50.4.nip.io:blog.git
    8.        a780de9..1b675b8  master -> master

    顺利完成！现在我们有了一个部署在tsuru上，使用MySQL服务的Rails项目，现在我们可以访问app-info返回的blog app的URL了。

    进一步探索

    更多信息，可以查看tsuru文档，或者阅读tsuru命令完全使用指南。

    原文: http://doc.oschina.net/tsuru-paas?t=52818