support for OTP21's sys.config.src file in releases (#647)

* support for OTP21's sys.config.src file in releases

* always replace os vars in .src files if found

* support vm_args_src to be consistent with sys_config_src

* add newlines after warning logs

* improve sys and vm src config tests

3 files changed, 99 insertions, 24 deletions

diff --git a/src/rlx_config.erl b/src/rlx_config.erl
index 57aac71..ee58db5 100644
--- a/src/rlx_config.erl
+++ b/src/rlx_config.erl
@@ -256,10 +256,14 @@ load_terms({vm_args, false}, {ok, State}) ->
     {ok, rlx_state:vm_args(State, false)};
 load_terms({vm_args, VmArgs}, {ok, State}) ->
     {ok, rlx_state:vm_args(State, filename:absname(VmArgs))};
+load_terms({vm_args_src, VmArgs}, {ok, State}) ->
+    {ok, rlx_state:vm_args_src(State, filename:absname(VmArgs))};
 load_terms({sys_config, false}, {ok, State}) ->
     {ok, rlx_state:sys_config(State, false)};
 load_terms({sys_config, SysConfig}, {ok, State}) ->
     {ok, rlx_state:sys_config(State, filename:absname(SysConfig))};
+load_terms({sys_config_src, SysConfigSrc}, {ok, State}) ->
+    {ok, rlx_state:sys_config_src(State, filename:absname(SysConfigSrc))};
 load_terms({root_dir, Root}, {ok, State}) ->
     {ok, rlx_state:root_dir(State, filename:absname(Root))};
 load_terms({output_dir, OutputDir}, {ok, State}) ->
diff --git a/src/rlx_prv_assembler.erl b/src/rlx_prv_assembler.erl
index 65975e5..705e51a 100644
--- a/src/rlx_prv_assembler.erl
+++ b/src/rlx_prv_assembler.erl
@@ -86,8 +86,17 @@ format_error({unresolved_release, RelName, RelVsn}) ->
 format_error({ec_file_error, AppDir, TargetDir, E}) ->
     io_lib:format("Unable to copy OTP App from ~s to ~s due to ~p",
                   [AppDir, TargetDir, E]);
+format_error({vmargs_does_not_exist, Path}) ->
+    io_lib:format("The vm.args file specified for this release (~s) does not exist!",
+                  [Path]);
+format_error({vmargs_src_does_not_exist, Path}) ->
+    io_lib:format("The vm.args.src file specified for this release (~s) does not exist!",
+                  [Path]);
 format_error({config_does_not_exist, Path}) ->
-    io_lib:format("The config file specified for this release (~s) does not exist!",
+    io_lib:format("The sys.config file specified for this release (~s) does not exist!",
+                  [Path]);
+format_error({config_src_does_not_exist, Path}) ->
+    io_lib:format("The sys.config.src file specified for this release (~s) does not exist!",
                   [Path]);
 format_error({sys_config_parse_error, ConfigPath, Reason}) ->
     io_lib:format("The config file (~s) specified for this release could not be opened or parsed: ~s",
@@ -557,18 +566,38 @@ generate_start_erl_data_file(Release, ReleasesDir) ->
 
 copy_or_generate_vmargs_file(State, Release, RelDir) ->
     RelVmargsPath = filename:join([RelDir, "vm.args"]),
-    case rlx_state:vm_args(State) of
-        false ->
-            ok;
+    RelVmargsSrcPath = filename:join([RelDir, "vm.args.src"]),
+    case rlx_state:vm_args_src(State) of
         undefined ->
-            RelName = erlang:atom_to_list(rlx_release:name(Release)),
-            unless_exists_write_default(RelVmargsPath, vm_args_file(RelName));
-        ArgsPath ->
-            case filelib:is_regular(ArgsPath) of
+            case rlx_state:vm_args(State) of
+                false ->
+                    ok;
+                undefined ->
+                    RelName = erlang:atom_to_list(rlx_release:name(Release)),
+                    unless_exists_write_default(RelVmargsPath, vm_args_file(RelName));
+                ArgsPath ->
+                    case filelib:is_regular(ArgsPath) of
+                        false ->
+                            ?RLX_ERROR({vmargs_does_not_exist, ArgsPath});
+                        true ->
+                            copy_or_symlink_config_file(State, ArgsPath, RelVmargsPath)
+                    end
+            end;
+        ArgsSrcPath ->
+            %% print a warning if vm_args is also set
+            case rlx_state:vm_args(State) of
+                undefined ->
+                    ok;
+                _->
+                    ec_cmd_log:warn(rlx_state:log(State),
+                                    "Both vm_args_src and vm_args are set, vm_args will be ignored~n", [])
+            end,
+
+            case filelib:is_regular(ArgsSrcPath) of
                 false ->
-                    ?RLX_ERROR({vmargs_does_not_exist, ArgsPath});
+                    ?RLX_ERROR({vmargs_src_does_not_exist, ArgsSrcPath});
                 true ->
-                    copy_or_symlink_config_file(State, ArgsPath, RelVmargsPath)
+                    copy_or_symlink_config_file(State, ArgsSrcPath, RelVmargsSrcPath)
             end
     end.
 
@@ -577,23 +606,43 @@ copy_or_generate_vmargs_file(State, Release, RelDir) ->
                                               {ok, rlx_state:t()} | relx:error().
 copy_or_generate_sys_config_file(State, RelDir) ->
     RelSysConfPath = filename:join([RelDir, "sys.config"]),
-    case rlx_state:sys_config(State) of
-        false ->
-            ok;
+    RelSysConfSrcPath = filename:join([RelDir, "sys.config.src"]),
+    case rlx_state:sys_config_src(State) of
         undefined ->
-            unless_exists_write_default(RelSysConfPath, sys_config_file());
-        ConfigPath ->
-            case filelib:is_regular(ConfigPath) of
+            case rlx_state:sys_config(State) of
                 false ->
-                    ?RLX_ERROR({config_does_not_exist, ConfigPath});
-                true ->
-                    %% validate sys.config is valid Erlang terms
-                    case file:consult(ConfigPath) of
-                        {ok, _} ->
-                            copy_or_symlink_config_file(State, ConfigPath, RelSysConfPath);
-                        {error, Reason} ->
-                            ?RLX_ERROR({sys_config_parse_error, ConfigPath, Reason})
+                    ok;
+                undefined ->
+                    unless_exists_write_default(RelSysConfPath, sys_config_file());
+                ConfigPath ->
+                    case filelib:is_regular(ConfigPath) of
+                        false ->
+                            ?RLX_ERROR({config_does_not_exist, ConfigPath});
+                        true ->
+                            %% validate sys.config is valid Erlang terms
+                            case file:consult(ConfigPath) of
+                                {ok, _} ->
+                                    copy_or_symlink_config_file(State, ConfigPath, RelSysConfPath);
+                                {error, Reason} ->
+                                    ?RLX_ERROR({sys_config_parse_error, ConfigPath, Reason})
+                            end
                     end
+            end;
+        ConfigSrcPath ->
+            %% print a warning if sys_config is also set
+            case rlx_state:sys_config(State) of
+                P when P =:= false orelse P =:= undefined ->
+                    ok;
+                _->
+                    ec_cmd_log:warn(rlx_state:log(State),
+                                    "Both sys_config_src and sys_config are set, sys_config will be ignored~n", [])
+            end,
+
+            case filelib:is_regular(ConfigSrcPath) of
+                false ->
+                    ?RLX_ERROR({config_src_does_not_exist, ConfigSrcPath});
+                true ->
+                    copy_or_symlink_config_file(State, ConfigSrcPath, RelSysConfSrcPath)
             end
     end.
 
diff --git a/src/rlx_state.erl b/src/rlx_state.erl
index 5032628..5488a41 100644
--- a/src/rlx_state.erl
+++ b/src/rlx_state.erl
@@ -54,8 +54,12 @@
          hooks/2,
          vm_args/1,
          vm_args/2,
+         vm_args_src/1,
+         vm_args_src/2,
          sys_config/1,
          sys_config/2,
+         sys_config_src/1,
+         sys_config_src/2,
          root_dir/1,
          root_dir/2,
          add_configured_release/2,
@@ -106,7 +110,9 @@
                   available_apps=[] :: [rlx_app_info:t()],
                   default_configured_release :: {rlx_release:name() | undefined, rlx_release:vsn() |undefined} | undefined,
                   vm_args :: file:filename() | false | undefined,
+                  vm_args_src :: file:filename() | undefined,
                   sys_config :: file:filename() | false | undefined,
+                  sys_config_src :: file:filename() | undefined,
                   overrides=[] :: [{AppName::atom(), Directory::file:filename()}],
                   skip_apps=[] :: [AppName::atom()],
                   exclude_apps=[] :: [AppName::atom()],
@@ -284,6 +290,14 @@ vm_args(#state_t{vm_args=VmArgs}) ->
 vm_args(State, VmArgs) ->
     State#state_t{vm_args=VmArgs}.
 
+-spec vm_args_src(t()) -> file:filename() | undefined.
+vm_args_src(#state_t{vm_args_src=VmArgs}) ->
+    VmArgs.
+
+-spec vm_args_src(t(), undefined | file:filename()) -> t().
+vm_args_src(State, VmArgs) ->
+    State#state_t{vm_args_src=VmArgs}.
+
 -spec sys_config(t()) -> file:filename() | false | undefined.
 sys_config(#state_t{sys_config=SysConfig}) ->
     SysConfig.
@@ -292,6 +306,14 @@ sys_config(#state_t{sys_config=SysConfig}) ->
 sys_config(State, SysConfig) ->
     State#state_t{sys_config=SysConfig}.
 
+-spec sys_config_src(t()) -> file:filename() | undefined.
+sys_config_src(#state_t{sys_config_src=SysConfigSrc}) ->
+    SysConfigSrc.
+
+-spec sys_config_src(t(), file:filename() | undefined) -> t().
+sys_config_src(State, SysConfigSrc) ->
+    State#state_t{sys_config_src=SysConfigSrc}.
+
 -spec root_dir(t()) -> file:filename() | undefined.
 root_dir(#state_t{root_dir=RootDir}) ->
     RootDir.