Make config file parsers pluggable

rebar.config

@@ -3,9 +3,8 @@
 {plugins, [rebar3_hex]}.
 
 {deps, [
-         {zj, {git, "https://gitlab.com/zxq9/zj.git", {tag, "1.1.2"}}}
+         {setup, {git, "https://github.com/uwiger/setup.git", {ref, "9675f9a"}}}
-       , {yamerl, "0.10.0"}
+       %% , {setup, "2.1.2"}
-       , {setup, "2.1.2"}
        ]}.
 
 {profiles, [
@@ -17,5 +16,5 @@
                deprecated_function_calls, deprecated_functions]}.
 
 {dialyzer, [ {warnings, [unknown]}
-           , {base_plt_apps, [erts, kernel, stdlib, yamerl, zj, setup]}
+           , {base_plt_apps, [erts, kernel, stdlib, setup]}
            ]}.

rebar.lock

@@ -1,15 +1,4 @@
-{"1.2.0",
+[{<<"setup">>,
-[{<<"setup">>,{pkg,<<"setup">>,<<"2.1.2">>},0},
+  {git,"https://github.com/uwiger/setup.git",
- {<<"yamerl">>,{pkg,<<"yamerl">>,<<"0.10.0">>},0},
+       {ref,"9675f9a25c2087e676660911987935caeff9fef8"}},
- {<<"zj">>,
+  0}].
-  {git,"https://gitlab.com/zxq9/zj.git",
-       {ref,"090a43d23edc481695664f16763f147a78c45afc"}},
-  0}]}.
-[
-{pkg_hash,[
- {<<"setup">>, <<"43C0BBFE9160DE7925BF2FC2FE4396A99DC4EE1B73F0DC46ACC3F10E27B07A9C">>},
- {<<"yamerl">>, <<"4FF81FEE2F1F6A46F1700C0D880B24D193DDB74BD14EF42CB0BCF46E81EF2F8E">>}]},
-{pkg_hash_ext,[
- {<<"setup">>, <<"596713D48D8241DF31821C08A9F7BAAF3E7CDD042C8396BC956CC7AE056925DC">>},
- {<<"yamerl">>, <<"346ADB2963F1051DC837A2364E4ACF6EB7D80097C0F53CBDC3046EC8EC4B4E6E">>}]}
-].

src/gmconfig.app.src

@@ -7,7 +7,7 @@
    [
      kernel
    , stdlib
-   , zj
+   , setup
    ]},
   {env, []},
   {modules, []},

src/gmconfig.erl

@@ -48,6 +48,7 @@
         , gmconfig_env/1
         , gmconfig_env/2
         , set_gmconfig_env/1
+        , default_gmconfig_env/0
         ]).
 
 -ifdef(TEST).
@@ -62,11 +63,19 @@
 
 -include_lib("kernel/include/logger.hrl").
 
+-type extension() :: string().   %% file extension (without leading dot)
+
+-type decoder_return() :: config_tree()
+                        | {ok, config_tree()}
+                        | {error, any()}.
+-type decoder_fun() :: fun( (binary()) -> decoder_return() ).
+
 -type gmconfig() :: #{ os_env_prefix => string()
                      , config_file_basename => string() | 'undefined'
                      , config_file_os_env => string() | 'undefined'
                      , config_file_search_path => [string() | fun(() -> string())]
-                     , system_suffix => string()
+                     , system_suffix  => string()
+                     , config_formats => #{ extension() => decoder_fun() }
                      , schema => string() | map() | fun(() -> map())}.
 
 -type basic_type() :: number() | binary() | boolean().
@@ -115,7 +124,7 @@ set_gmconfig_env(Env) when is_map(Env) ->
 
 -spec gmconfig_env() -> gmconfig().
 gmconfig_env() ->
-    persistent_term:get({?MODULE, gmconfig_env}, default_gmconfig()).
+    persistent_term:get({?MODULE, gmconfig_env}, default_gmconfig_env()).
 
 -spec gmconfig_env(atom()) -> any().
 gmconfig_env(Key) ->
@@ -142,11 +151,13 @@ search_path(Kind) ->
               end, Path0)
     end.
 
-default_gmconfig() ->
+default_gmconfig_env() ->
     #{ os_env_prefix => "GM"
      , config_file_basename => "gmconfig"
      , config_file_os_env => undefined
      , config_file_search_path => ["."]
+     , config_formats => #{ "json"  => fun json_decode/1
+                          , "eterm" => fun eterm_consult/1 }
      , system_defaults_search_path => [fun setup:data_dir/0]
      , system_suffix => "" }.
 
@@ -552,8 +563,8 @@ coerce_type(Key, Value, Schema) ->
                 <<"integer">> -> to_integer(Value);
                 <<"string">>  -> to_string(Value);
                 <<"boolean">> -> to_bool(Value);
-                <<"array">>   -> json_decode(list_to_binary(Value));
+                <<"array">>   -> json:decode(list_to_binary(Value));
-                <<"object">>  -> json_decode(list_to_binary(Value))
+                <<"object">>  -> json:decode(list_to_binary(Value))
             end;
         _ ->
             error({unknown_key, Key})
@@ -642,10 +653,21 @@ search_default_config() ->
         Basename ->
             Dirs = search_path(),
             SystemSuffix = get_system_suffix(),
-            Fname = Basename ++ SystemSuffix ++ ".{json,yaml}",
+            ExtPattern = extension_pattern(),
+            Fname = Basename ++ SystemSuffix ++ ExtPattern,
             search_for_config_file(Dirs, Fname)
     end.
 
+config_formats() ->
+    gmconfig_env(config_formats).
+
+extension_pattern() ->
+    Exts = maps:keys(config_formats()),
+    lists:flatten([".{", intersperse(Exts),"}"]).
+
+intersperse([H|T]) ->
+    [H | [[",", X] || X <- T]].
+
 search_for_config_file(Dirs, FileWildcard) ->
     lists:foldl(
       fun(D0, undefined) ->
@@ -665,13 +687,16 @@ to_list_string(S) when is_list(S) ->
     binary_to_list(iolist_to_binary(S)).
 
 do_load_user_config(F, Action, Mode) ->
-    case {filename:extension(F), Action} of
+    {Ext, Decoder} = pick_decoder(F),
-        {".json", store} -> store(read_json(F, Mode), Mode);
+    case Action of
-        {".yaml", store} -> store(read_yaml(F, Mode), Mode);
+        store -> store(read_file(F, Ext, Decoder, Mode), Mode);
-        {".json", check} -> check_config_(catch read_json(F, Mode));
+        check -> check_config_(catch read_file(F, Ext, Decoder, Mode))
-        {".yaml", check} -> check_config_(catch read_yaml(F, Mode))
     end.
 
+pick_decoder(F) ->
+    "." ++ Ext = filename:extension(F),
+    {Ext, maps:get(Ext, config_formats())}.
+
 store(Vars, Mode) when is_map(Vars) ->
     case pt_get_config() of
         Map when map_size(Map) == 0 ->
@@ -726,12 +751,15 @@ silent_as_report(silent) -> report;
 silent_as_report(Mode  ) -> Mode.
 
 schema_string(Schema, Mode) ->
-    JSONSchema = json:encode(Schema),
+    JSONSchema = json_encode(Schema),
     case Mode of
         check  -> json:format(JSONSchema, #{indent => 2});
         report -> JSONSchema
     end.
 
+json_encode(J) ->
+    iolist_to_binary(json:encode(J)).
+
 error_format(Fmt, Args, check) ->
     io:format(Fmt, Args);
 error_format(Fmt, Args, report) ->
@@ -906,70 +934,50 @@ update_map(With, Map) when is_map(With), is_map(Map) ->
               end
       end, Map, With).
 
-read_json(F, Mode) ->
+read_file(F, Type, Decoder, Mode) ->
-    validate(
-      try_decode(F, fun(F1) ->
-                            json_consult(F1)
-                    end, "JSON", Mode), F, Mode).
-
-json_consult(F) ->
     case setup_file:read_file(F) of
         {ok, Bin} ->
-            [json_decode(Bin)];
+            validate(
+              try_decode_bin(Bin, Decoder, Type, Mode),
+              F, Mode);
         {error, Reason} ->
             ?LOG_ERROR("Read error ~s - ~p", [F, Reason]),
             error({read_error, F, Reason})
     end.
 
-json_decode(Bin) ->
+json_decode(Str) when is_list(Str) ->
-    case json_decode_(Bin) of
+    json:decode(iolist_to_binary(Str));
-        {ok, Value} ->
+json_decode(Bin) when is_binary(Bin) ->
-            Value;
+    json:decode(Bin).
-        {error, Reason} ->
-            ?LOG_ERROR("CAUGHT: ~p", [Reason]),
-            error(Reason)
-    end.
 
-json_decode_(Bin) ->
+eterm_consult(Bin) ->
-    case zj:binary_decode(Bin) of
+    setup_file:consult_binary(Bin).
-        {ok, _} = Ok ->
-            Ok;
-        {error, _Parsed, Remainder} ->
-            {error, {json_decode_error, string_slice(Remainder)}}
-    end.
 
--define(SliceSz, 80).
+try_decode_bin(Bin, Decoder, Fmt, Mode) ->
-string_slice(B) ->
+    try decode_bin(Bin, Decoder)
-    case size(B) of
-        Sz when Sz > ?SliceSz ->
-            Sl = string:slice(B, 0, ?SliceSz - 4),
-            <<Sl/binary, " ...">>;
-        _ ->
-            B
-    end.
-
-read_yaml(F, Mode) ->
-    validate(
-      try_decode(
-        F,
-        fun(F1) ->
-                yamerl:decode_file(F1, [{str_node_as_binary, true},
-                                        {map_node_format, map}])
-        end, "YAML", Mode),
-      F, Mode).
-
-try_decode(F, DecF, Fmt, Mode) ->
-    try DecF(F)
     catch
         error:E ->
-            error_msg(Mode, "Error reading ~s file: ~s~n", [Fmt, F]),
+            decode_fail(E, Fmt, Mode)
-            erlang:error(E)
     end.
 
-validate(JSON, F, Mode) when is_list(JSON) ->
+decode_bin(Str, Decoder) when is_list(Str) ->
-    check_validation([validate_(J) || J <- JSON], JSON, F, Mode).
+    decode_bin(iolist_to_binary(Str), Decoder);
-%% validate(JSON, F, Mode) when is_map(JSON) ->
+decode_bin(Bin, Decoder) when is_binary(Bin), is_function(Decoder, 1) ->
-%%     validate([JSON], F, Mode).
+    case Decoder(Bin) of
+        {ok, Map} when is_map(Map) ->
+            Map;
+        Map when is_map(Map) ->
+            Map;
+        {error, E} ->
+            error(E)
+    end.
+
+decode_fail(E, Fmt, Mode) ->
+    error_msg(Mode, "Parse error (~p)", [Fmt]),
+    erlang:error(E).
+    
+validate(JSON, F, Mode) when is_map(JSON) ->
+    check_validation([validate_(JSON)], JSON, F, Mode).
 
 vinfo(Mode, Res, F) ->
     case Res of
@@ -1071,7 +1079,8 @@ ensure_schema_loaded() ->
 
 load_schema() ->
     JSON = gmconfig_schema(),
-    Schema = json_decode(JSON),
+    Decode = maps:get("json", config_formats()),
+    Schema = decode_bin(JSON, Decode),
     pt_set_schema(Schema),
     Schema.
 
@@ -1084,3 +1093,13 @@ gmconfig_schema() ->
         F when is_function(F, 0) ->
             F()
     end.
+
+json_consult(F) ->
+    Decode = maps:get("json", config_formats()),
+    case setup_file:read_file(F) of
+        {ok, Bin} ->
+            decode_bin(Bin, Decode);
+        {error, Reason} ->
+            ?LOG_ERROR("Read error ~s - ~p", [F, Reason]),
+            error({read_error, F, Reason})
+    end.