ejabberd can be embedded in an Elixir application

.gitignore

@@ -28,7 +28,7 @@
 /ebin/
 /ejabberd.init
 /ejabberdctl.example
-/include/XmppAddr.hrl
+XmppAddr.hrl
 /rel/ejabberd/
 /src/XmppAddr.asn1db
 /src/XmppAddr.erl

lib/mix/tasks/compile.asn1.ex

@@ -0,0 +1,53 @@
+defmodule Mix.Tasks.Compile.Asn1 do
+  use Mix.Task
+  alias Mix.Compilers.Erlang
+
+  @recursive true
+  @manifest ".compile.asn1"
+
+  @moduledoc """
+  Compile ASN.1 source files.
+  When this task runs, it will check the modification time of every file, and
+  if it has changed, the file will be compiled. Files will be
+  compiled in the source directory with a .erl extension and generate a .hrl file.
+  You can force compilation regardless of modification times by passing
+  the `--force` option.
+  ## Command line options
+    * `--force` - forces compilation regardless of modification times
+  ## Configuration
+    * `:asn1_paths` - directories to find asn1 files. Defaults to `["asn1"]`.
+  """
+
+  @doc """
+  Runs this task.
+  """
+  @spec run(OptionParser.argv) :: :ok | :noop
+  def run(args) do
+    {opts, _, _} = OptionParser.parse(args, switches: [force: :boolean])
+
+    project      = Mix.Project.config
+    source_paths = project[:asn1_paths] || ["asn1"]
+    dest_paths    = project[:erlc_paths]
+    mappings     = Enum.zip(source_paths, dest_paths)
+    options      = project[:asn1_options] || []
+
+    Erlang.compile(manifest(), mappings, :asn1, :erl, opts[:force], fn
+      input, output ->
+        options = options ++ [:noobj, outdir: Erlang.to_erl_file(Path.dirname(output))]
+        :asn1ct.compile(Erlang.to_erl_file(input), options)
+    end)
+  end
+
+  @doc """
+  Returns ASN.1 manifests.
+  """
+  def manifests, do: [manifest]
+  defp manifest, do: Path.join(Mix.Project.manifest_path, @manifest)
+
+  @doc """
+  Cleans up compilation artifacts.
+  """
+  def clean do
+    Erlang.clean(manifest())
+  end
+end

mix.exs

@@ -0,0 +1,44 @@
+defmodule Ejabberd.Mixfile do
+  use Mix.Project
+
+  def project do
+    [app: :ejabberd,
+     version: "15.03.0",
+     elixir: "~> 1.0",
+     elixirc_paths: ["lib"],
+     compile_path: ".",
+     compilers: Mix.compilers,
+     erlc_options: erlc_options,
+     deps: deps]
+  end
+
+  def application do
+    [mod: {:ejabberd_app, []},
+     applications: [:kernel, :stdlib]]
+  end
+
+  defp erlc_options do
+    includes = Path.wildcard(Path.join("..", "/*/include"))
+    [:debug_info, {:d, :NO_EXT_LIB}] ++ Enum.map(includes, fn(path) -> {:i, path} end)
+  end
+
+  defp deps do
+    [
+        {:p1_xml, github: "processone/xml"},
+        {:p1_logger, github: "processone/p1_logger"},
+        {:p1_yaml, github: "processone/p1_yaml"},
+        {:p1_tls, github: "processone/tls"},
+        {:p1_stringprep, github: "processone/stringprep"},
+        {:p1_zlib, github: "processone/zlib"},
+        {:p1_cache_tab, github: "processone/cache_tab"},
+        {:p1_utils, github: "processone/p1_utils"},
+        {:p1_iconv, github: "processone/eiconv"},
+	      {:esip, github: "processone/p1_sip"},
+	      {:p1_stun, github: "processone/stun"},
+        {:ehyperloglog, github: "vaxelfel/eHyperLogLog"},
+        {:p1_mysql, github: "processone/mysql"},
+        {:p1_pgsql, github: "processone/pgsql"},
+		    {:eredis, github: "wooga/eredis"}
+     ]
+  end
+end

src/ejabberd_config.erl

@@ -84,7 +84,7 @@ start() ->
 %% If not specified, the default value 'ejabberd.yml' is assumed.
 %% @spec () -> string()
 get_ejabberd_config_path() ->
-    case application:get_env(config) of
+    case get_env_config() of
 	{ok, Path} -> Path;
 	undefined ->
 	    case os:getenv("EJABBERD_CONFIG_PATH") of
@@ -95,6 +95,18 @@ get_ejabberd_config_path() ->
 	    end
     end.
 
+-spec get_env_config() -> {ok, string()} | undefined.
+get_env_config() ->
+    %% First case: the filename can be specified with: erl -config "/path/to/ejabberd.yml".
+    case application:get_env(config) of
+	R = {ok, _Path} -> R;
+	undefined ->
+            %% Second case for embbeding ejabberd in another app, for example for Elixir:
+            %% config :ejabberd,
+            %%   file: "config/ejabberd.yml"
+            application:get_env(ejabberd, file)
+    end.
+
 %% @doc Read the ejabberd configuration file.
 %% It also includes additional configuration files and replaces macros.
 %% This function will crash if finds some error in the configuration file.
@@ -679,7 +691,10 @@ is_file_readable(Path) ->
     end.
 
 get_version() ->
-    list_to_binary(element(2, application:get_key(ejabberd, vsn))).
+    case application:get_key(ejabberd, vsn) of
+        undefined -> "";
+        {ok, Vsn} -> list_to_binary(Vsn)
+    end.
 
 -spec get_myhosts() -> [binary()].