add config script funcionality

similar to rebar's config script, append a .script
suffix to the provided relx config that is evaluated
and can possibly change values in the original config

2 files changed, 96 insertions, 17 deletions

diff --git a/src/rlx_config.erl b/src/rlx_config.erl
index dd416ee..045bf33 100644
--- a/src/rlx_config.erl
+++ b/src/rlx_config.erl
@@ -97,25 +97,50 @@ parent_dir([_H], Acc) ->
 parent_dir([H | T], Acc) ->
     parent_dir(T, [H | Acc]).
 
+-spec config_script_file(file:filename(), rlx_state:t()) -> file:filename().
+config_script_file(ConfigFile, _State) ->
+    ConfigFile ++ ".script".
+
+bs(Vars) ->
+    lists:foldl(fun({K,V}, Bs) ->
+                        erl_eval:add_binding(K, V, Bs)
+                end, erl_eval:new_bindings(), Vars).
+
+-spec apply_config_script(proplists:proplist(), file:filename()) ->
+                                proplists:proplist().
+apply_config_script(ConfigData, ConfigScriptFile) ->
+    {ok, Config} = file:script(ConfigScriptFile, bs([{'CONFIG', ConfigData},
+                                                     {'SCRIPT', ConfigScriptFile}])),
+    Config.
+
 -spec load_config(file:filename() | proplists:proplist(), rlx_state:t()) ->
                          {ok, rlx_state:t()} | relx:error().
 load_config(ConfigFile, State) ->
     {ok, CurrentCwd} = file:get_cwd(),
-    case filelib:is_regular(ConfigFile) of
-        true ->
-            ok = file:set_cwd(filename:dirname(ConfigFile)),
-            Result = case file:consult(ConfigFile) of
-                         {error, Reason} ->
-                             ?RLX_ERROR({consult, ConfigFile, Reason});
-                         {ok, Terms} ->
-                             CliTerms = rlx_state:cli_args(State),
-                             lists:foldl(fun load_terms/2, {ok, State}, merge_configs(CliTerms, Terms))
-                     end,
-            ok = file:set_cwd(CurrentCwd),
-            Result;
-        false ->
-            CliTerms = rlx_state:cli_args(State),
-            lists:foldl(fun load_terms/2, {ok, State}, merge_configs(CliTerms, ConfigFile))
+    CliTerms = rlx_state:cli_args(State),
+    Config0 = case filelib:is_regular(ConfigFile) of
+                true ->
+                    ok = file:set_cwd(filename:dirname(ConfigFile)),
+                    Result = case file:consult(ConfigFile) of
+                                {error, Reason} ->
+                                    ?RLX_ERROR({consult, ConfigFile, Reason});
+                                {ok, Terms} -> merge_configs(CliTerms, Terms)
+                             end,
+                    ok = file:set_cwd(CurrentCwd),
+                    Result;
+                false -> merge_configs(CliTerms, ConfigFile)
+              end,
+    % we now take the merged config and try to apply a config script to it,
+    % get a new config as a result
+    case Config0 of
+        {error, _} = Error -> Error;
+        _ ->
+            ConfigScriptFile = config_script_file(ConfigFile, State),
+            Config1 = case filelib:is_regular(ConfigScriptFile) of
+                        false -> Config0;
+                        true -> apply_config_script(Config0, ConfigScriptFile)
+                      end,
+            lists:foldl(fun load_terms/2, {ok, State}, Config1)
     end.
 
 -spec load_terms(term(), {ok, rlx_state:t()} | relx:error()) ->
diff --git a/test/rlx_release_SUITE.erl b/test/rlx_release_SUITE.erl
index ce7d5de..f123e79 100644
--- a/test/rlx_release_SUITE.erl
+++ b/test/rlx_release_SUITE.erl
@@ -40,7 +40,8 @@
          make_relup_release/1,
          make_relup_release2/1,
          make_one_app_top_level_release/1,
-         make_dev_mode_release/1]).
+         make_dev_mode_release/1,
+         make_config_script_release/1]).
 
 -include_lib("common_test/include/ct.hrl").
 -include_lib("eunit/include/eunit.hrl").
@@ -71,7 +72,8 @@ all() ->
      make_implicit_config_release, make_rerun_overridden_release,
      overlay_release, make_goalless_release, make_depfree_release,
      make_invalid_config_release, make_relup_release, make_relup_release2,
-     make_one_app_top_level_release, make_dev_mode_release].
+     make_one_app_top_level_release, make_dev_mode_release,
+     make_config_script_release].
 
 make_release(Config) ->
     LibDir1 = proplists:get_value(lib1, Config),
@@ -935,6 +937,58 @@ make_dev_mode_release(Config) ->
     ?assert(ec_file:is_symlink(filename:join([OutputDir, "foo", "releases", "0.0.1",
                                               "vm.args"]))).
 
+make_config_script_release(Config) ->
+    LibDir1 = proplists:get_value(lib1, Config),
+    FooRoot = filename:join([LibDir1, "foodir1", "foodir2"]),
+    filelib:ensure_dir(filename:join([FooRoot, "tmp"])),
+    [(fun({Name, Vsn}) ->
+              rlx_test_utils:create_app(LibDir1, Name, Vsn, [kernel, stdlib], [])
+      end)(App)
+     ||
+        App <-
+            [{rlx_test_utils:create_random_name("lib_app1_"), rlx_test_utils:create_random_vsn()}
+             || _ <- lists:seq(1, 100)]],
+
+    rlx_test_utils:create_app(LibDir1, "goal_app_1", "0.0.1", [stdlib,kernel,non_goal_1], []),
+    rlx_test_utils:create_app(LibDir1, "lib_dep_1", "0.0.1", [stdlib,kernel], []),
+    rlx_test_utils:create_app(LibDir1, "goal_app_2", "0.0.1", [stdlib,kernel,goal_app_1,non_goal_2], []),
+    rlx_test_utils:create_app(LibDir1, "non_goal_1", "0.0.1", [stdlib,kernel], [lib_dep_1]),
+    rlx_test_utils:create_app(LibDir1, "non_goal_2", "0.0.1", [stdlib,kernel], []),
+
+    ConfigFile = filename:join([LibDir1, "relx.config"]),
+    rlx_test_utils:write_config(ConfigFile,
+                 [{release, {foo, "0.0.1"},
+                   [goal_app_1,
+                    goal_app_2]}]),
+    ConfigScriptFile = filename:join([LibDir1, "relx.config.script"]),
+    ok = file:write_file(ConfigScriptFile,
+            "case os:getenv(\"RELX_TEST\") of\n"
+            "   \"true\" ->\n"
+            "       {release, {RelName, Version}, Apps} = lists:keyfind(release, 1, CONFIG),\n"
+            "       lists:keyreplace(release, 1, CONFIG, {release, {RelName, \"0.0.2\"}, Apps});\n"
+            "    _ -> CONFIG % env var not defined or anything other than true\n"
+            "end.\n"),
+
+    OutputDir = filename:join([proplists:get_value(data_dir, Config),
+                               rlx_test_utils:create_random_name("relx-output")]),
+    ok = file:set_cwd(FooRoot),
+    {ok, FooRoot} = file:get_cwd(),
+
+    % set the env var that will cause relx.config to be altered by the config script
+    os:putenv("RELX_TEST", "true"),
+
+    {ok, State} = relx:do(undefined, undefined, [], [LibDir1], 3,
+                             OutputDir, undefined),
+    [{{foo, "0.0.2"}, Release}] = ec_dictionary:to_list(rlx_state:realized_releases(State)),
+    ?assert(ec_file:exists(OutputDir)),
+    AppSpecs = rlx_release:applications(Release),
+    ?assert(lists:keymember(stdlib, 1, AppSpecs)),
+    ?assert(lists:keymember(kernel, 1, AppSpecs)),
+    ?assert(lists:member({non_goal_1, "0.0.1"}, AppSpecs)),
+    ?assert(lists:member({non_goal_2, "0.0.1"}, AppSpecs)),
+    ?assert(lists:member({goal_app_1, "0.0.1"}, AppSpecs)),
+    ?assert(lists:member({goal_app_2, "0.0.1"}, AppSpecs)),
+    ?assert(lists:member({lib_dep_1, "0.0.1", load}, AppSpecs)).
 
 %%%===================================================================
 %%% Helper Functions