Capistrano::Parcel

Distributed building tool, originally inspired by Python's Parcel, just written in Ruby and with many improvements. Parcel is taking advantage of Capistrano 3, SSHkit and FPM.

The idea is simple:

• we want to deploy native packages packed with all dependencies
• support multiple releases/distribution
• fast and reliable deployment
• updating N production servers with git pull + package dependencies doesn't scale well
• package should be tested before going to production

Project structure looks like this:

├── lib
├── config
│   ├── deploy
│   │   ├── build.rb
│   │   ├── production.rb
│   │   └── staging.rb
│   └── deploy.rb
├── Capfile
├── Gemfile
├── Gemfile.lock

In Capfile we specify which plugins should be used during package making process.

Capfile: (note: we're not using standard Capistrano deploy task)

# Load DSL and Setup Up Stages
require 'capistrano/setup'
require 'capistrano/parcel'
# build package with fpm
require 'capistrano/parcel/fpm'

Basic scenario expects few categories of servers:

• build - for each distribution you can have one
• staging
• production

For each category you can you different settings (ssh keys, user account, etc.)

This will build package on remote server and transfer package back to your machnine (over scp)

$ cap build parcel

Build process

Each phase is a separate Rake task. You can use before and after hooks to execute any code before/after.

1. starting
2. updating
3. compiling
4. packaging
5. finishing

Rsync

Rsync is used for copying files to build server. This way we can easily copy a git repository with submodules.

You can control which files will be packaged with

set :rsync_exclude, [ '.git', 'some-other-dir' ]

Plugins

Plugins are usually simple tasks that are executed in several steps during building process. Plugins can't rely on each other, rather use variables, that are accessible with set(:var) and for reading fetch(:var).

Each plugin can be enabled in Capfile:

require 'capistrano/parcel/plugin_name'

fpm

Used for packaging whole directory as a deb package. Could be used also for RPM or other packages.

uwsgi

Simple application server configuration.

Enable with:

require 'capistrano/parcel/uwsgi'

nginx

Currently allows only intialization of nginx scripts.

Enable with:

require 'capistrano/parcel/nginx'

supervisor

(experimental)

virtualenv

(experimental)

Package metadata

Meta information about package is fetched from a package.yml file which must be located on local filesystem (in directory where is cap command executed).

version: '0.0.1'
arch: 'all'
license: 'MIT'
category: 'misc'
maintainer: 'john.doe@example.com'
vendor: 'Jon Doe et al.'
description: 'Package description'
url: 'http://example.com'

Installation

requirements:

• some version of Ruby (> 1.8.7 is recommended)
• Bundler (gem install bundler)

Create a Gemfile with following content:

source 'https://rubygems.org'

gem 'capistrano-parcel', github: 'deric/capistrano-parcel'

and run bundle install