Provide a new config directive that allows per-app module exclusion

By introducing a new entry in the config file allow excluding
specific modules from a given app, they will not be copied
onto the final release and their reference removed from
the .app file. The new entry takes on the following form:
{exclude_modules, [
  {App :: atom(), [Module :: atom()]}
]}

3 files changed, 85 insertions, 33 deletions

diff --git a/src/rlx_config.erl b/src/rlx_config.erl
index 1dbfa13..dfcb511 100644
--- a/src/rlx_config.erl
+++ b/src/rlx_config.erl
@@ -173,6 +173,8 @@ load_terms({skip_apps, SkipApps0}, {ok, State0}) ->
     {ok, rlx_state:skip_apps(State0, SkipApps0)};
 load_terms({exclude_apps, ExcludeApps0}, {ok, State0}) ->
     {ok, rlx_state:exclude_apps(State0, ExcludeApps0)};
+load_terms({exclude_modules, ExcludeModules0}, {ok, State0}) ->
+    {ok, rlx_state:exclude_modules(State0, ExcludeModules0)};
 load_terms({debug_info, DebugInfo}, {ok, State0}) ->
     {ok, rlx_state:debug_info(State0, DebugInfo)};
 load_terms({overrides, Overrides0}, {ok, State0}) ->
diff --git a/src/rlx_prv_assembler.erl b/src/rlx_prv_assembler.erl
index 7ff1d61..3829c82 100644
--- a/src/rlx_prv_assembler.erl
+++ b/src/rlx_prv_assembler.erl
@@ -162,7 +162,7 @@ copy_app_directories_to_output(State, Release, OutputDir) ->
                                   false
                           end,
                          lists:flatten(ec_plists:map(fun(App) ->
-                                                             copy_app(LibDir, App, IncludeSrc, IncludeErts)
+                                                             copy_app(State, LibDir, App, IncludeSrc, IncludeErts)
                                                      end, Apps))),
     case Result of
         [E | _] ->
@@ -179,7 +179,7 @@ prepare_applications(State, Apps) ->
             Apps
     end.
 
-copy_app(LibDir, App, IncludeSrc, IncludeErts) ->
+copy_app(State, LibDir, App, IncludeSrc, IncludeErts) ->
     AppName = erlang:atom_to_list(rlx_app_info:name(App)),
     AppVsn = rlx_app_info:original_vsn(App),
     AppDir = rlx_app_info:dir(App),
@@ -196,52 +196,67 @@ copy_app(LibDir, App, IncludeSrc, IncludeErts) ->
                         true ->
                             [];
                         false ->
-                            copy_app_(App, AppDir, TargetDir, IncludeSrc)
+                            copy_app_(State, App, AppDir, TargetDir, IncludeSrc)
                     end;
                 _ ->
-                    copy_app_(App, AppDir, TargetDir, IncludeSrc)
+                    copy_app_(State, App, AppDir, TargetDir, IncludeSrc)
             end
     end.
 
 is_erts_lib(Dir) ->
     lists:prefix(filename:split(list_to_binary(code:lib_dir())), filename:split(Dir)).
 
-copy_app_(App, AppDir, TargetDir, IncludeSrc) ->
+copy_app_(State, App, AppDir, TargetDir, IncludeSrc) ->
     remove_symlink_or_directory(TargetDir),
     case rlx_app_info:link(App) of
         true ->
             link_directory(AppDir, TargetDir),
-            rewrite_app_file(App, AppDir);
+            rewrite_app_file(State, App, AppDir);
         false ->
-            copy_directory(AppDir, TargetDir, IncludeSrc),
-            rewrite_app_file(App, TargetDir)
+            copy_directory(State, App, AppDir, TargetDir, IncludeSrc),
+            rewrite_app_file(State, App, TargetDir)
     end.
 
 %% If excluded apps exist in this App's applications list we must write a new .app
-rewrite_app_file(App, TargetDir) ->
+rewrite_app_file(State, App, TargetDir) ->
     Name = rlx_app_info:name(App),
     ActiveDeps = rlx_app_info:active_deps(App),
     IncludedDeps = rlx_app_info:library_deps(App),
     AppFile = filename:join([TargetDir, "ebin", ec_cnv:to_list(Name) ++ ".app"]),
-    {ok, [{application, AppName, AppData}]} = file:consult(AppFile),
-    OldActiveDeps = proplists:get_value(applications, AppData, []),
-    OldIncludedDeps = proplists:get_value(included_applications, AppData, []),
-
-    case {OldActiveDeps, OldIncludedDeps} of
-        {ActiveDeps, IncludedDeps} ->
-            ok;
-        _ ->
-            AppData1 = lists:keyreplace(applications
-                                       ,1
-                                       ,AppData
-                                       ,{applications, ActiveDeps}),
-            AppData2 = lists:keyreplace(included_applications
-                                       ,1
-                                       ,AppData1
-                                       ,{included_applications, IncludedDeps}),
-            Spec = io_lib:format("~p.\n", [{application, AppName, AppData2}]),
-            write_file_if_contents_differ(AppFile, Spec)
-    end.
+    {ok, [{application, AppName, AppData0}]} = file:consult(AppFile),
+    OldActiveDeps = proplists:get_value(applications, AppData0, []),
+    OldIncludedDeps = proplists:get_value(included_applications, AppData0, []),
+    OldModules = proplists:get_value(modules, AppData0, []),
+    ExcludedModules = proplists:get_value(Name,
+                                          rlx_state:exclude_modules(State), []),
+
+    %% maybe replace excluded apps
+    AppData2 =
+        case {OldActiveDeps, OldIncludedDeps} of
+            {ActiveDeps, IncludedDeps} ->
+                AppData0;
+            _ ->
+                AppData1 = lists:keyreplace(applications
+                                           ,1
+                                           ,AppData0
+                                           ,{applications, ActiveDeps}),
+                lists:keyreplace(included_applications
+                                 ,1
+                                 ,AppData1
+                                 ,{included_applications, IncludedDeps})
+        end,
+    %% maybe replace excluded modules
+    AppData3 =
+        case ExcludedModules of
+            [] -> AppData2;
+            _ ->
+                lists:keyreplace(modules
+                                 ,1
+                                 ,AppData2
+                                 ,{modules, OldModules -- ExcludedModules})
+        end,
+    Spec = io_lib:format("~p.\n", [{application, AppName, AppData3}]),
+    write_file_if_contents_differ(AppFile, Spec).
 
 write_file_if_contents_differ(Filename, Bytes) ->
     ToWrite = iolist_to_binary(Bytes),
@@ -275,8 +290,8 @@ link_directory(AppDir, TargetDir) ->
             ok
     end.
 
-copy_directory(AppDir, TargetDir, IncludeSrc) ->
-    [copy_dir(AppDir, TargetDir, SubDir)
+copy_directory(State, App, AppDir, TargetDir, IncludeSrc) ->
+    [copy_dir(State, App, AppDir, TargetDir, SubDir)
     || SubDir <- ["ebin",
                   "include",
                   "priv",
@@ -289,13 +304,20 @@ copy_directory(AppDir, TargetDir, IncludeSrc) ->
                           []
                   end]].
 
-copy_dir(AppDir, TargetDir, SubDir) ->
+copy_dir(State, App, AppDir, TargetDir, SubDir) ->
     SubSource = filename:join(AppDir, SubDir),
     SubTarget = filename:join(TargetDir, SubDir),
     case ec_file:is_dir(SubSource) of
         true ->
             ok = rlx_util:mkdir_p(SubTarget),
-            case ec_file:copy(SubSource, SubTarget, [recursive]) of
+            %% get a list of the modules to be excluded from this app
+            AppName = rlx_app_info:name(App),
+            ExcludedModules = proplists:get_value(AppName, rlx_state:exclude_modules(State),
+                                                  []),
+            ExcludedFiles = [filename:join([binary_to_list(SubSource), 
+                                            atom_to_list(M) ++ ".beam"]) ||
+                                M <- ExcludedModules],
+            case copy_dir(SubSource, SubTarget, ExcludedFiles) of
                 {error, E} ->
                     ?RLX_ERROR({ec_file_error, AppDir, SubTarget, E});
                 ok ->
@@ -305,6 +327,22 @@ copy_dir(AppDir, TargetDir, SubDir) ->
             ok
     end.
 
+%% no files are excluded, just copy the whole dir
+copy_dir(SourceDir, TargetDir, []) ->
+     case ec_file:copy(SourceDir, TargetDir, [recursive]) of
+        {error, E} -> {error, E};
+        ok ->
+            ok
+    end;
+copy_dir(SourceDir, TargetDir, ExcludeFiles) ->
+    SourceFiles = filelib:wildcard(
+                    filename:join([binary_to_list(SourceDir), "*"])),
+    lists:foreach(fun(F) ->
+                    ok = ec_file:copy(F,
+                                      filename:join([TargetDir,
+                                                     filename:basename(F)]))
+                  end, SourceFiles -- ExcludeFiles).
+
 create_release_info(State0, Release0, OutputDir) ->
     RelName = atom_to_list(rlx_release:name(Release0)),
     ReleaseDir = rlx_util:release_output_dir(State0, Release0),
diff --git a/src/rlx_state.erl b/src/rlx_state.erl
index 6974d52..75a5cba 100644
--- a/src/rlx_state.erl
+++ b/src/rlx_state.erl
@@ -82,7 +82,9 @@
          upfrom/1,
          upfrom/2,
          format/1,
-         format/2]).
+         format/2,
+         exclude_modules/1,
+         exclude_modules/2]).
 
 
 -export_type([t/0,
@@ -107,6 +109,7 @@
                   overrides=[] :: [{AppName::atom(), Directory::file:filename()}],
                   skip_apps=[] :: [AppName::atom()],
                   exclude_apps=[] :: [AppName::atom()],
+                  exclude_modules=[] :: [{App::atom(), [Module::atom()]}],
                   debug_info=keep :: keep | strip,
                   configured_releases :: releases(),
                   realized_releases :: releases(),
@@ -200,6 +203,15 @@ exclude_apps(#state_t{exclude_apps=Apps}) ->
 exclude_apps(State, SkipApps) ->
     State#state_t{exclude_apps=SkipApps}.
 
+-spec exclude_modules(t()) -> [{App::atom(), [Module::atom()]}].
+exclude_modules(#state_t{exclude_modules=Modules}) ->
+    Modules.
+
+%% @doc modules to be excluded from the release 
+-spec exclude_modules(t(), [{App::atom(), [Module::atom()]}]) -> t().
+exclude_modules(State, SkipModules) ->
+    State#state_t{exclude_modules=SkipModules}.
+
 -spec debug_info(t()) -> keep | strip.
 debug_info(#state_t{debug_info=DebugInfo}) ->
     DebugInfo.