Elixir Release Manager DEB generator

Adds simple Debian Package (DEB) generation to the exrm package manager.

Functionality list

1. Able to build debian packages:
   1. With changelog
   2. With control file
2. Ability to add in pre/post install/remove scripts
3. Validates configuration before completing the build
4. Add ability for you to replace file templates with your own
5. Distillery support
6. Automatically builds init scripts:
   1. Upstart
   2. Systemd
   3. SysV
7. Handle functionality for Hot Upgrades
8. Merge debian to-be-deployed files with your own structure

External dependencies

Before using exrm-deb, you'll need the following commands installed and in your path:

• tar (or gtar if you're on a mac - you can brew install gnu-tar if you don't already have it)
• ar
• uname

Configuration

Exrm-deb relies on the following data in the mix.exs file being set:

defmodule Testapp.Mixfile do
   use Mix.Project

   def project do
      [app: :testapp,
      version: "0.0.1",
      elixir: "~> 1.0",
+     description: "Create a deb for your elixir release with ease",
      build_embedded: Mix.env == :prod,
      start_permanent: Mix.env == :prod,
-     deps: deps]
+     deps: deps,
+     package: package]
   end

The package function must be set as per the hex guidelines, but with some extra lines:

def package do
   [
+     external_dependencies: [],
+     codename: lsb_release(),
+     license_file: "LICENSE",
      files: [ "lib", "mix.exs", "README*", "LICENSE"],
+     config_files: ["/etc/init/api.conf"],
      maintainers: ["John Hamelink <[email protected]>"],
      licenses: ["MIT"],
      vendor: "John Hamelink",
      links:  %{
        "GitHub" => "https://github.com/johnhamelink/testapp",
        "Docs" => "hexdocs.pm/testapp",
+       "Homepage" => "https://github.com/johnhamelink/testapp"
      }
   ]
end

def lsb_release do
  {release, _} = System.cmd("lsb_release", ["-c", "-s"])
  String.replace(release, "\n", "")
end

A list of configuration options you can add to package/0:

• config_file
  • Array of Strings
  • Should contain the absolute path of the config file to be overwritten.
• licenses
  • Array of Strings
  • Can be something like ["Copyright <date> <company_name>"] if you are building private packages.
• maintainers
  • Array of Strings
  • Should be in the format name <email>
• external_dependencies
  • Array of Strings
  • Should be in the format of package-name (operator version_number) where operator is either <<, <=, =, >=, or >> - read more about this here.
• maintainer_scripts
  • A keyword list of Strings
  • The keyword should be one of: :pre_install, :post_install, :pre_uninstall, or :post_uninstall
  • The keyword should point to the path of a script you want to run at the moment in question.
• vendor
  • String
  • The distribution vendor that's creating the debian package. I normally just put my name or company name.
• owner
  • A keyword list of Strings
  • If set, requires both user and group keys to be set.
  • This is used when building the archive to set the correct user and group
  • Defaults to root for user & group.
• codename
  • String
  • Should contain the distribution codename to be chained to version number.

Additional details about codename

This configuration can be very useful in case you want to package the same version of the app for different distributions dynamically, without modifying the version in Distillery configuration.

A typical use case can be an environment where you have different Docker containers, and a different OS: each container compiles and packages the application in the running OS, in order to avoid startup problems in production.

With codename, at the end of the process, you obtain a package in the form myapp-1.2.1~xenial_amd64.deb. Also the control script in the deb file is packaged with the correct version like 1.2.1~xenial. At this point, it's easier to manage the packages loaded in a repository, because they are versioned also by distribution.

Usage

Building Deb file

Distillery

You can build a deb by adding plugin ExrmDeb.Distillery to your rel/config.exs file. With distillery, the name and version is taken from the rel/config.exs file as opposed to the mix.exs file.

Exrm

You can build a deb at the same time as building a release by adding the --deb option to release.

mix release --deb

This task first constructs the release using exrm, then generates a deb file for the release. The deb is built from scratch, retrieving default values such as the name, version, etc using the mix.exs file.

The _build/deb directory tree, along with the rest of the release can be removed with mix release.clean

Please visit exrm for additional information.

Customising deb config files

You can customise the debs that are being built by copying the template files used and modifying them:

mix release.deb.generate_templates

When you next run mix release --deb, your custom templates will be used instead of the defaults inside the plugin.

Installation

The package can be installed as:

1. Add exrm_deb to your list of dependencies in mix.exs:

   def deps do [{:exrm_deb, "~> 0.0.1"}] end

2. Ensure exrm_deb is started before your application:

   def application do [applications: [:exrm_deb]] end