simple file logger

apps/iot/src/iot_logger.erl

@@ -19,14 +19,10 @@
 
 -define(SERVER, ?MODULE).
 
-%% 缓冲区大小
--define(BUFFER_SIZE, 100).
-
 -record(state, {
     file_name :: string(),
     date :: calendar:date(),
-    file,
-    buffer = []
+    file
 }).
 
 %%%===================================================================
@@ -53,11 +49,9 @@ start_link(FileName) when is_list(FileName) ->
     {stop, Reason :: term()} | ignore).
 init([FileName]) ->
     ensure_dir(),
-    FilePath = make_file(FileName),
+    FilePath = make_file(FileName, erlang:date()),
     {ok, File} = file:open(FilePath, [append, binary]),
 
-    erlang:start_timer(5000, self(), flush_ticker),
-
     {ok, #state{file = File, file_name = FileName, date = get_date()}}.
 
 %% @private
@@ -79,14 +73,23 @@ handle_call(_Request, _From, State = #state{}) ->
     {noreply, NewState :: #state{}} |
     {noreply, NewState :: #state{}, timeout() | hibernate} |
     {stop, Reason :: term(), NewState :: #state{}}).
-handle_cast({write, Data}, State = #state{buffer = Buffer}) ->
-    Line = <<(time_prefix())/binary, " ", (format(Data))/binary, $\n>>,
-    NBuffer = [Line|Buffer],
-    case length(NBuffer) >= ?BUFFER_SIZE of
+handle_cast({write, Data}, State = #state{file = OldFile, file_name = FileName, date = Date}) ->
+    Line = iolist_to_binary([time_prefix(), <<" ">>, format(Data), <<$\n>>]),
+    NDate = erlang:date(),
+    case maybe_new_file(Date, NDate) of
         true ->
-            {noreply, flush(State#state{buffer = NBuffer})};
+            file:close(OldFile),
+
+            FilePath = make_file(FileName, NDate),
+            {ok, File} = file:open(FilePath, [append, binary]),
+            ok = file:write(File, Line),
+            %% 清理历史的文件, 日志文件保留一个月的
+            delete_old_files(FileName, 30),
+
+            {noreply, State#state{file = File, date = get_date()}};
         false ->
-            {noreply, State#state{buffer = NBuffer}}
+            ok = file:write(OldFile, Line),
+            {noreply, State}
     end.
 
 %% @private
@@ -95,9 +98,6 @@ handle_cast({write, Data}, State = #state{buffer = Buffer}) ->
     {noreply, NewState :: #state{}} |
     {noreply, NewState :: #state{}, timeout() | hibernate} |
     {stop, Reason :: term(), NewState :: #state{}}).
-handle_info({timeout, _, flush_ticker}, State) ->
-    erlang:start_timer(5000, self(), flush_ticker),
-    {noreply, flush(State)};
 handle_info(_Info, State = #state{}) ->
     {noreply, State}.
 
@@ -123,29 +123,6 @@ code_change(_OldVsn, State = #state{}, _Extra) ->
 %%% Internal functions
 %%%===================================================================
 
--spec flush(State :: #state{}) -> NState :: #state{}.
-flush(State = #state{buffer = []}) ->
-    State;
-flush(State = #state{file = OldFile, file_name = FileName, date = Date, buffer = Buffer}) ->
-    Content = iolist_to_binary(lists:reverse(Buffer)),
-    case maybe_new_file(Date) of
-        true ->
-            file:close(OldFile),
-
-            FilePath = make_file(FileName),
-            {ok, File} = file:open(FilePath, [append, binary]),
-
-            ok = file:write(File, Content),
-
-            %% 清理历史的文件, 日志文件保留一个月的
-            delete_old_files(FileName, 30),
-
-            State#state{file = File, buffer = [], date = get_date()};
-        false ->
-            ok = file:write(OldFile, Content),
-            State#state{buffer = []}
-    end.
-
 format(Data) when is_binary(Data) ->
     iolist_to_binary(Data);
 format(Items) when is_list(Items) ->
@@ -155,11 +132,7 @@ time_prefix() ->
     {{Y, M, D}, {H, I, S}} = calendar:local_time(),
     iolist_to_binary(io_lib:format("[~b-~2..0b-~2..0b ~2..0b:~2..0b:~2..0b]", [Y, M, D, H, I, S])).
 
--spec make_file(LogFile :: string()) -> string().
-make_file(LogFile) when is_list(LogFile) ->
-    Date = erlang:date(),
-    make_file(LogFile, Date).
-
+-spec make_file(LogFile :: string(), {Year :: integer(), Month :: integer(), Day :: integer()}) -> string().
 make_file(LogFile, {Year, Month, Day}) when is_list(LogFile) ->
     Suffix = io_lib:format("~b~2..0b~2..0b", [Year, Month, Day]),
     RootDir = code:root_dir() ++ "/log/",
@@ -171,7 +144,7 @@ ensure_dir() ->
         true ->
             ok;
         false ->
-            file:make_dir(RootDir)
+            ok = file:make_dir(RootDir)
     end.
 
 %% 获取日期信息
@@ -181,9 +154,8 @@ get_date() ->
     Date.
 
 %% 通过日志判断是否需要生成新的日志文件
--spec maybe_new_file(Date :: calendar:date()) -> boolean().
-maybe_new_file({Y, M, D}) ->
-    {{Y0, M0, D0}, _} = calendar:local_time(),
+-spec maybe_new_file(Date :: calendar:date(), Date0 :: calendar:date()) -> boolean().
+maybe_new_file({Y, M, D}, {Y0, M0, D0}) ->
     not (Y =:= Y0 andalso M =:= M0 andalso D =:= D0).
 
 -spec delete_old_files(FileName :: string(), Days :: integer()) -> no_return().
@@ -193,10 +165,5 @@ delete_old_files(FileName, Days) when is_list(FileName), is_integer(Days) ->
     lists:foreach(fun(Day) ->
         {Date, _} = calendar:gregorian_seconds_to_datetime(Seconds - Day * 86400),
         FilePath = make_file(FileName, Date),
-        case filelib:is_file(FilePath) of
-            true ->
-                file:delete(FilePath);
-            false ->
-                ok
-        end
+        filelib:is_file(FilePath) andalso file:delete(FilePath)
                   end, lists:seq(1, 10)).