Omnibus

[][gem]

Umbrella Project: Chef Foundation

Project State: Active

Issues Response Time Maximum: 14 days

Pull Request Response Time Maximum: 14 days

Easily create full-stack installers for your project across a variety of platforms.

Seth Chisamore and Christopher Maier of CHEF gave an introductory talk on Omnibus at ChefConf 2013, entitled Eat the Whole Bowl: Building a Full-Stack Installer with Omnibus:

• Slides

This project is managed by the CHEF Release Engineering team. For more information on the Release Engineering team's contribution, triage, and release process, please consult the CHEF Release Engineering OSS Management Guide.

Prerequisites

Omnibus is designed to run with a minimal set of prerequisites. You will need the following:

• Ruby 2.6+

Get Started

Omnibus provides both a DSL for defining Omnibus projects for your software, as well as a command-line tool for generating installer artifacts from that definition.

To get started, install Omnibus locally on your workstation.

$ gem install omnibus

You can now create an Omnibus project in your current directory by using the project generator feature.

$ omnibus new $MY_PROJECT_NAME

This will generate a complete project skeleton in the directory omnibus-$MY_PROJECT_NAME

By default this will make a directory called omnibus-$MY_PROJECT_NAME assuming you're keeping your omnibus config separate from the repo. However, keeping it in your repo is a common practice, so feel to rename this directory to omnibus and place it in the top level of your projects source repo.

$ cd omnibus-$MY_PROJECT_NAME
$ bundle install --binstubs

More details can be found in the generated project's README file.

Omnibus determines the platform for which to build an installer based on the platform it is currently running on. That is, you can only generate a .deb file on a Debian-based system. To alleviate this caveat, the generated project includes a Test Kitchen setup suitable for generating a series of Omnibus projects.

More documentation

• Building on Debian
• Building on OSX
• Building on RHEL
• Building on Windows
• Build Cache

Configuration DSL

Though the template project will build, it will not do anything exciting. For that, you need to use the Omnibus DSL to define the specifics of your application.

Config

If present, Omnibus will use a top-level configuration file named omnibus.rb at the root of your repository. This file is loaded at runtime and includes a number of configuration tunables. Here is an example:

# Build locally (instead of /var)
# -------------------------------
base_dir './local'

# Disable git caching
# ------------------------------
use_git_caching false

# Enable S3 asset caching
# ------------------------------
use_s3_caching true
s3_bucket      ENV['S3_BUCKET']

# There are three ways to authenticate to the S3 bucket

# 1. set `s3_access_key` and `s3_secret_key`
s3_access_key  ENV['S3_ACCESS_KEY']
s3_secret_key  ENV['S3_SECRET_KEY']

# 2. set `s3_profile` to use an AWS profile in the Shared Credentials files
#s3_profile    ENV['S3_PROFILE']

# 3. set `s3_iam_role_arn` to use an AWS IAM role
#s3_iam_role_arn    ENV['S3_IAM_ROLE_ARN']

For more information, please see the Config documentation.

You can tell Omnibus to load a different configuration file by passing the --config option to any command:

$ bin/omnibus --config /path/to/config.rb

Finally, you can override a specific configuration option at the command line using the --override flag. This takes ultimate precedence over any configuration file values:

$ bin/omnibus --override use_git_caching:false

Projects

A Project DSL file defines your actual application; this is the thing you are creating a full-stack installer for in the first place. It provides a means to define the dependencies of the project (again, as specified in Software DSL definition files), as well as ways to set installer package metadata.

All project definitions must be in the config/projects directory of your Omnibus repository.

name            "chef-full"
maintainer      "YOUR NAME"
homepage        "http://yoursite.com"

install_dir     "/opt/chef"
build_version   "0.10.8"
build_iteration 4

dependency "chef"

Some DSL methods available include:

DSL Method | Description :---------------- | ---------------------------------------------------------------- name | The name of the project install_dir | The desired install location of the package build_version | The package version build_iteration | The package iteration number dependency | An Omnibus software-defined component to include in this package package | Invoke a packager-specific DSL compress | Invoke a compressor-specific DSL

By default a timestamp is appended to the build_version. You can turn this behavior off by setting append_timestamp to false in your omnibus.rb or using --override append_timestamp:false at the command line.

For more information, please see the Project documentation.

Software

Omnibus "software" files define individual software components that go into making your overall package. They are the building blocks of your application. The Software DSL provides a way to define where to retrieve the software sources, how to build them, and what dependencies they have. These dependencies are also defined in their own Software DSL files, thus forming the basis for a dependency-aware build ordering.

All Software definitions should go in the config/software directory of your Omnibus project repository.

Here is an example:

name "ruby"
default_version "1.9.2-p290"
source url: "http://ftp.ruby-lang.org/pub/ruby/1.9/ruby-#{version}.tar.gz",
       md5: "604da71839a6ae02b5b5b5e1b792d5eb"

dependency "zlib"
dependency "ncurses"
dependency "openssl"

relative_path "ruby-#{version}"

build do
  command "./configure"
  command "make"
  command "make install"
end

Some of the DSL methods available include:

DSL Method | Description :---------------- | ------------------------------------------------------------------- name | The name of the software component (this should come first) default_version | The version of the software component source | Directions to the location of the source dependency | An Omnibus software-defined component that this software depends on relative_path | The relative path of the extracted tarball build | The build instructions

For more DSL methods, please consult the Software documentation.

Additionally, there are a number of DSL methods available inside the build block:

DSL Method | Description :------------------ | ------------------------------------------------------------- command | Execute a single shell command make | Run make (with or without args), using gmake when appropriate patch | Apply a patch from disk workers | The maximum number of builders windows_safe_path | Format the path to be safe for shelling out on Windows go | Execute the code as the embedded Go ruby | Execute the code as the embedded Ruby gem | Execute the code as the embedded Rubygems bundle | Execute the code as the embedded Bundler rake | Execute the code as the embedded Rake gem block | Execute Ruby block at build time erb | Render the given ERB template mkdir | Create the given directory touch | Create the given empty file delete | Remove the given file or directory strip | Strip symbols from binaries on a given file or directory copy | Copy a to b move | Move a to b link | Link a to b sync | Copy all files from a to b, removing any union files

For more DSL methods, please consult the Builder documentation.

You can support building multiple versions of the same software in the same software definition file using the version method and giving a block:

name "ruby"
default_version "1.9.2-p290"

version "1.9.2-p290" do
  source url: "http://ftp.ruby-lang.org/pub/ruby/1.9/ruby-#{version}.tar.gz",
         md5: "604da71839a6ae02b5b5b5e1b792d5eb"
end

version "2.1.1" do
  source url: "http://ftp.ruby-lang.org/pub/ruby/2.1/ruby-#{version}.tar.gz",
         md5: "e57fdbb8ed56e70c43f39c79da1654b2"
end

Since the software definitions are simply ruby code, you can conditionally execute anything