gen_server for watcher

apps/log_monitor/src/monitor.erl

@@ -54,5 +54,6 @@ isError(Text) ->
     end.
 
 startWatcher(File) ->
-    WatcherPid = spawn_link(watcher, init, [self(), File]),
+    %% WatcherPid = spawn_link(watcher, init, [self(), File]),
+    WatcherPid = watcher:start_link(self(), File),
     {ok, WatcherPid}.

apps/log_monitor/src/watcher.erl

@@ -1,20 +1,35 @@
 -module(watcher).
+-behaviour(gen_server).
 -compile(export_all).
 
-start(MonitorPid, File) ->
+start_link(MonitorPid, File) ->
-    spawn_link(?MODULE, init, [MonitorPid, File]).
+    gen_server:start_link(?MODULE, [MonitorPid, File], []).
 
-init(MonitorPid, File) ->
+init([MonitorPid, File]) ->
+    io:format("Init~n"),
     Cmd = "/usr/bin/tail -n0 --follow=name " ++ File,
     Port = open_port({spawn, Cmd}, [stderr_to_stdout, exit_status, binary]),
-    loop(MonitorPid, Port).
+    {ok, [MonitorPid, Port]}.
 
-loop(MonitorPid, Port) ->
+handle_info(Msg, [MonitorPid, Port]) ->
-    receive
+    case Msg of
-        {Port, {data, {eol, Bin}}} ->
+        {Port, {data, Text}} ->
-            Text = binary_to_list(iolist_to_binary(Bin)),
             MonitorPid ! {log_line, Text},
-            loop(MonitorPid, Port);
+            {noreply, [MonitorPid, Port]};
         {Port, {exit_status, _Status}} ->
-            io:format("Watcher terminated~n")
+            io:format("Watcher terminated~n"),
+            {stop, tail_exit, []}
     end.
+
+handle_cast(_Msg, State) ->
+    {noreply, State}.
+
+handle_call(_Request, _From, State) ->
+    {noreply, State}.
+
+terminate(Reason, _State) ->
+    io:format("Reason: ~s~n", [Reason]),
+    shutdown.
+
+code_change(_OldVsn, State, _Extra) ->
+    {ok, State}.