Error compiling Ejabberd dependency of a Phoenix application with Mix: could not compile dependency :ejabberd, "mix compile" failed

Question

I have been trying to embed Ejabberd into a Phoenix web application. To do this, I tried to follow this tutorial. The steps were the following:

• Installed a ubuntu/xenial64 Vagrant box.

• Installed Elixir according to the official guide.

• Installed Phoenix according to the official guide.

• Installed some packages to successfully compile the Phoenix' seed app dependencies: sudo apt install build-essential libssl-dev libyaml-cpp-dev libyaml-dev libpython2.7-dev

• I've added the ejabberd dependency to the mix.exs file:

  defmodule PhoenixEjabberd.Mixfile do
    use Mix.Project
  
    def project do
      [app: :phoenix_ejabberd,
       version: "0.0.1",
       elixir: "~> 1.2",
       elixirc_paths: elixirc_paths(Mix.env),
       compilers: [:phoenix, :gettext] ++ Mix.compilers,
       build_embedded: Mix.env == :prod,
       start_permanent: Mix.env == :prod,
       aliases: aliases(),
       deps: deps()]
    end
  
    # Configuration for the OTP application.
    #
    # Type `mix help compile.app` for more information.
    def application do
      [mod: {PhoenixEjabberd, []},
       applications: [:phoenix, :phoenix_pubsub, :phoenix_html, :cowboy, 
                      :logger, :ejabberd, :gettext,
                      :phoenix_ecto, :postgrex]]
    end
  
    # Specifies which paths to compile per environment.
    defp elixirc_paths(:test), do: ["lib", "web", "test/support"]
    defp elixirc_paths(_),     do: ["lib", "web"]
  
    # Specifies your project dependencies.
    #
    # Type `mix help deps` for examples and options.
    defp deps do
      [{:phoenix, "~> 1.2.1"},
       {:phoenix_pubsub, "~> 1.0"},
       {:phoenix_ecto, "~> 3.0"},
       {:postgrex, ">= 0.0.0"},
       {:phoenix_html, "~> 2.6"},
       {:phoenix_live_reload, "~> 1.0", only: :dev},
       {:gettext, "~> 0.11"},
       {:cowboy, "~> 1.0"},
       {:ejabberd, "~> 16.12", github: "processone/ejabberd"}
     ]
    end
  
    # Aliases are shortcuts or tasks specific to the current project.
    # For example, to create, migrate and run the seeds file at once:
    #
    #     $ mix ecto.setup
    #
    # See the documentation for `Mix` for more info on aliases.
    defp aliases do
      ["ecto.setup": ["ecto.create", "ecto.migrate", "run priv/repo/seeds.exs"],
       "ecto.reset": ["ecto.drop", "ecto.setup"],
       "test": ["ecto.create --quiet", "ecto.migrate", "test"]]
    end
  end
  

• Executed mix do deps.get, compile

• Got a very large amount of errors, mostly of undefined functions and variables. I put the full log on this Gist.

Why are those errors occurring? Did anyone succeed in compiling the ejabberd dependency? How? Thank you for your time :).

Answer 1

For unknown reason ejabberd fails to compile from the root project folder. To compile it, I did the following:

mix deps.get # to retrieve ejabberd 
cd deps/ejabberd
mix do deps.get, compile
cd - # to the project root
mix compile # now the project would compile