chore: Added jsonlogger module

src/nova_jsonlogger.erl

@@ -0,0 +1,319 @@
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%%% This module is copied from https://github.com/kivra/jsonformat
+%%%
+%%% What is changed is that we don't use jsx but the json library in Nova
+%%%
+%%% @doc Custom formatter for the Erlang OTP logger application which
+%%%      outputs single-line JSON formatted data
+%%% @end
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+
+-module(nova_jsonlogger).
+%%%_* Exports ==========================================================
+-export([format/2,
+         system_time_to_iso8601/1,
+         system_time_to_iso8601_nano/1]).
+
+%%%_* Types ============================================================
+-type config() :: #{
+    new_line => boolean(),
+    new_line_type => nl | crlf | cr | unix | windows | macos9,
+    key_mapping => #{atom() => atom()},
+    format_funs => #{atom() => fun((_) -> _)}
+}.
+
+-export_type([config/0]).
+
+%%%_* Macros ===========================================================
+%%%_* Options ----------------------------------------------------------
+-define(NEW_LINE, false).
+
+%%%_* Code =============================================================
+%%%_ * API -------------------------------------------------------------
+-spec format(logger:log_event(), config()) -> unicode:chardata().
+format(
+    #{msg := {report, #{format := Format, args := Args, label := {error_logger, _}}}} = Map, Config
+) ->
+    Report = #{text => io_lib:format(Format, Args)},
+    format(Map#{msg := {report, Report}}, Config);
+format(#{level := Level, msg := {report, Msg}, meta := Meta}, Config) when is_map(Msg) ->
+    Data0 = merge_meta(Msg, Meta#{level => Level}, Config),
+    Data1 = apply_key_mapping(Data0, Config),
+    Data2 = apply_format_funs(Data1, Config),
+    encode(pre_encode(Data2, Config), Config);
+format(Map = #{msg := {report, KeyVal}}, Config) when is_list(KeyVal) ->
+    format(Map#{msg := {report, maps:from_list(KeyVal)}}, Config);
+format(Map = #{msg := {string, String}}, Config) ->
+    Report = #{text => unicode:characters_to_binary(String)},
+    format(Map#{msg := {report, Report}}, Config);
+format(Map = #{msg := {Format, Terms}}, Config) ->
+    format(Map#{msg := {string, io_lib:format(Format, Terms)}}, Config).
+
+%%% Useful for converting logger:timestamp() to a readable timestamp.
+-spec system_time_to_iso8601(integer()) -> binary().
+system_time_to_iso8601(Epoch) ->
+    system_time_to_iso8601(Epoch, microsecond).
+
+-spec system_time_to_iso8601_nano(integer()) -> binary().
+system_time_to_iso8601_nano(Epoch) ->
+    system_time_to_iso8601(1000 * Epoch, nanosecond).
+
+-spec system_time_to_iso8601(integer(), erlang:time_unit()) -> binary().
+system_time_to_iso8601(Epoch, Unit) ->
+    binary:list_to_bin(calendar:system_time_to_rfc3339(Epoch, [{unit, Unit}, {offset, "Z"}])).
+
+%%%_* Private functions ================================================
+pre_encode(Data, Config) ->
+    maps:fold(
+        fun
+            (K, V, Acc) when is_map(V) ->
+                maps:put(jsonify(K), pre_encode(V, Config), Acc);
+            % assume list of maps
+            (K, Vs, Acc) when is_list(Vs), is_map(hd(Vs)) ->
+                maps:put(jsonify(K), [pre_encode(V, Config) || V <- Vs, is_map(V)], Acc);
+            (K, V, Acc) ->
+                maps:put(jsonify(K), jsonify(V), Acc)
+        end,
+        maps:new(),
+        Data
+    ).
+
+merge_meta(Msg, Meta0, Config) ->
+    Meta1 = meta_without(Meta0, Config),
+    Meta2 = meta_with(Meta1, Config),
+    maps:merge(Msg, Meta2).
+
+encode(Data, Config) ->
+    JsonLib = nova:get_env(json_lib, thoas),
+    Json = JsonLib:encode(Data),
+    case new_line(Config) of
+        true -> [Json, new_line_type(Config)];
+        false -> Json
+    end.
+
+jsonify(A) when is_atom(A) -> A;
+jsonify(B) when is_binary(B) -> B;
+jsonify(I) when is_integer(I) -> I;
+jsonify(F) when is_float(F) -> F;
+jsonify(B) when is_boolean(B) -> B;
+jsonify(P) when is_pid(P) -> jsonify(pid_to_list(P));
+jsonify(P) when is_port(P) -> jsonify(port_to_list(P));
+jsonify(F) when is_function(F) -> jsonify(erlang:fun_to_list(F));
+jsonify(L) when is_list(L) ->
+    try list_to_binary(L) of
+        S -> S
+    catch
+        error:badarg ->
+            unicode:characters_to_binary(io_lib:format("~0p", [L]))
+    end;
+jsonify({M, F, A}) when is_atom(M), is_atom(F), is_integer(A) ->
+    <<(atom_to_binary(M, utf8))/binary, $:, (atom_to_binary(F, utf8))/binary, $/, (integer_to_binary(A))/binary>>;
+jsonify(Any) ->
+    unicode:characters_to_binary(io_lib:format("~0p", [Any])).
+
+apply_format_funs(Data, #{format_funs := Callbacks}) ->
+    maps:fold(
+        fun
+            (K, Fun, Acc) when is_map_key(K, Data) -> maps:update_with(K, Fun, Acc);
+            (_, _, Acc) -> Acc
+        end,
+        Data,
+        Callbacks
+    );
+apply_format_funs(Data, _) ->
+    Data.
+
+apply_key_mapping(Data, #{key_mapping := Mapping}) ->
+    DataOnlyMapped =
+        maps:fold(
+            fun
+                (K, V, Acc) when is_map_key(K, Data) -> Acc#{V => maps:get(K, Data)};
+                (_, _, Acc) -> Acc
+            end,
+            #{},
+            Mapping
+        ),
+    DataNoMapped = maps:without(maps:keys(Mapping), Data),
+    maps:merge(DataNoMapped, DataOnlyMapped);
+apply_key_mapping(Data, _) ->
+    Data.
+
+new_line(Config) -> maps:get(new_line, Config, ?NEW_LINE).
+
+new_line_type(#{new_line_type := nl}) -> <<"\n">>;
+new_line_type(#{new_line_type := unix}) -> <<"\n">>;
+new_line_type(#{new_line_type := crlf}) -> <<"\r\n">>;
+new_line_type(#{new_line_type := windows}) -> <<"\r\n">>;
+new_line_type(#{new_line_type := cr}) -> <<"\r">>;
+new_line_type(#{new_line_type := macos9}) -> <<"\r">>;
+new_line_type(_Default) -> <<"\n">>.
+
+meta_without(Meta, Config) ->
+    maps:without(maps:get(meta_without, Config, [report_cb]), Meta).
+
+meta_with(Meta, #{meta_with := Ks}) ->
+    maps:with(Ks, Meta);
+meta_with(Meta, _ConfigNotPresent) ->
+    Meta.
+
+%%%_* Tests ============================================================
+-ifdef(TEST).
+-include_lib("eunit/include/eunit.hrl").
+
+-define(assertJSONEqual(Expected, Actual),
+    ?assertEqual(thoas:decode(Expected), thoas:decode(Actual))
+).
+
+format_test() ->
+    ?assertJSONEqual(
+        <<"{\"level\":\"alert\",\"text\":\"derp\"}">>,
+        format(#{level => alert, msg => {string, "derp"}, meta => #{}}, #{})
+    ),
+    ?assertJSONEqual(
+        <<"{\"herp\":\"derp\",\"level\":\"alert\"}">>,
+        format(#{level => alert, msg => {report, #{herp => derp}}, meta => #{}}, #{})
+    ).
+
+format_funs_test() ->
+    Config1 = #{
+        format_funs => #{
+            time => fun(Epoch) -> Epoch + 1 end,
+            level => fun(alert) -> info end
+        }
+    },
+    ?assertJSONEqual(
+        <<"{\"level\":\"info\",\"text\":\"derp\",\"time\":2}">>,
+        format(#{level => alert, msg => {string, "derp"}, meta => #{time => 1}}, Config1)
+    ),
+
+    Config2 = #{
+        format_funs => #{
+            time => fun(Epoch) -> Epoch + 1 end,
+            foobar => fun(alert) -> info end
+        }
+    },
+    ?assertJSONEqual(
+        <<"{\"level\":\"alert\",\"text\":\"derp\",\"time\":2}">>,
+        format(#{level => alert, msg => {string, "derp"}, meta => #{time => 1}}, Config2)
+    ).
+
+key_mapping_test() ->
+    Config1 = #{
+        key_mapping => #{
+            level => lvl,
+            text => message
+        }
+    },
+    ?assertJSONEqual(
+        <<"{\"lvl\":\"alert\",\"message\":\"derp\"}">>,
+        format(#{level => alert, msg => {string, "derp"}, meta => #{}}, Config1)
+    ),
+
+    Config2 = #{
+        key_mapping => #{
+            level => lvl,
+            text => level
+        }
+    },
+    ?assertJSONEqual(
+        <<"{\"level\":\"derp\",\"lvl\":\"alert\"}">>,
+        format(#{level => alert, msg => {string, "derp"}, meta => #{}}, Config2)
+    ),
+
+    Config3 = #{
+        key_mapping => #{
+            level => lvl,
+            foobar => level
+        }
+    },
+    ?assertJSONEqual(
+        <<"{\"lvl\":\"alert\",\"text\":\"derp\"}">>,
+        format(#{level => alert, msg => {string, "derp"}, meta => #{}}, Config3)
+    ),
+
+    Config4 = #{
+        key_mapping => #{time => timestamp},
+        format_funs => #{timestamp => fun(T) -> T + 1 end}
+    },
+    ?assertJSONEqual(
+        <<"{\"level\":\"alert\",\"text\":\"derp\",\"timestamp\":2}">>,
+        format(#{level => alert, msg => {string, "derp"}, meta => #{time => 1}}, Config4)
+    ).
+
+list_format_test() ->
+    ErrorReport =
+        #{
+            level => error,
+            meta => #{time => 1},
+            msg => {report, #{report => [{hej, "hopp"}]}}
+        },
+    ?assertJSONEqual(
+        <<"{\"level\":\"error\",\"report\":\"[{hej,\\\"hopp\\\"}]\",\"time\":1}">>,
+        format(ErrorReport, #{})
+    ).
+
+meta_without_test() ->
+    Error = #{
+        level => info,
+        msg => {report, #{answer => 42}},
+        meta => #{secret => xyz}
+    },
+    ?assertEqual(
+        {ok, #{
+            <<"answer">> => 42,
+            <<"level">> => <<"info">>,
+            <<"secret">> => <<"xyz">>
+        }},
+        thoas:decode(format(Error, #{}))
+    ),
+    Config2 = #{meta_without => [secret]},
+    ?assertEqual(
+        {ok, #{
+            <<"answer">> => 42,
+            <<"level">> => <<"info">>
+        }},
+        thoas:decode(format(Error, Config2))
+    ),
+    ok.
+
+meta_with_test() ->
+    Error = #{
+        level => info,
+        msg => {report, #{answer => 42}},
+        meta => #{secret => xyz}
+    },
+    ?assertEqual(
+        {ok, #{
+            <<"answer">> => 42,
+            <<"level">> => <<"info">>,
+            <<"secret">> => <<"xyz">>
+        }},
+        thoas:decode(format(Error, #{}))
+    ),
+    Config2 = #{meta_with => [level]},
+    ?assertEqual(
+        {ok, #{
+            <<"answer">> => 42,
+            <<"level">> => <<"info">>
+        }},
+        thoas:decode(format(Error, Config2))
+    ),
+    ok.
+
+newline_test() ->
+    ConfigDefault = #{new_line => true},
+    ?assertEqual(
+        [<<"{\"level\":\"alert\",\"text\":\"derp\"}">>, <<"\n">>],
+        format(#{level => alert, msg => {string, "derp"}, meta => #{}}, ConfigDefault)
+    ),
+    ConfigCRLF = #{
+        new_line_type => crlf,
+        new_line => true
+    },
+    ?assertEqual(
+        [<<"{\"level\":\"alert\",\"text\":\"derp\"}">>, <<"\r\n">>],
+        format(#{level => alert, msg => {string, "derp"}, meta => #{}}, ConfigCRLF)
+    ).
+
+-endif.