Rebar3/Mix: If dev profile/environment, enable tools automatically

mix.exs

@@ -187,10 +187,14 @@ defmodule Ejabberd.MixProject do
       {:ok, path} ->
         path
     end
-    case :file.consult(filepath) do
+    config2 = case :file.consult(filepath) do
       {:ok,config} -> config
       _ -> [stun: true, zlib: true]
     end
+    case Mix.env() do
+      :dev -> List.keystore(config2, :tools, 0, {:tools, true})
+      _ -> config2
+    end
   end
 
   defp config(key) do

src/ejabberd.app.src.script

@@ -6,10 +6,22 @@
             {elixir, true} -> [elixir, iex, logger, mix];
             _ -> []
         end,
-        Tools = case lists:keyfind(tools, 1, Terms) of
+
-            {tools, true} -> [observer]; % for `ejabberdctl etop`
+        ProfileEnvironmentVariable = os:getenv("REBAR_PROFILE"),
+        AsProfiles = case lists:dropwhile(fun("as") -> false; (_) -> true end,
+                                               init:get_plain_arguments()) of
+                              ["as", Profiles | _] -> string:split(Profiles, ",");
                               _ -> []
                           end,
+        Terms2 = case lists:member("dev", [ProfileEnvironmentVariable | AsProfiles]) of
+            true -> lists:keystore(tools, 1, Terms, {tools, true});
+            false -> Terms
+        end,
+        Tools = case lists:keyfind(tools, 1, Terms2) of
+            {tools, true} -> [observer];
+            _ -> []
+        end,
+
         {[lists:keyfind(description, 1, Terms),
          lists:keyfind(vsn, 1, Terms),
          {env, [{enabled_backends, EBs}]}