observer: Add SASL log view for processes

Add a new menu to toggle log view.
Disabled by default.
Disabled if rb_server already started on observed node,
in order not to interfere with somebody else.
If enabled, add a tab in process view where log entries
related to pid process are shown.
Need an observed node with at least a version R16B2,
due to the use of newly capability to rb to write into
a file descriptor (on the observing node).

1 files changed, 110 insertions, 15 deletions

diff --git a/lib/observer/src/observer_wx.erl b/lib/observer/src/observer_wx.erl
index c86f5ea916..54c4092a78 100644
--- a/lib/observer/src/observer_wx.erl
+++ b/lib/observer/src/observer_wx.erl
@@ -37,6 +37,7 @@
 -define(ID_CONNECT, 2).
 -define(ID_NOTEBOOK, 3).
 -define(ID_CDV,      4).
+-define(ID_LOGVIEW, 5).
 
 -define(FIRST_NODES_MENU_ID, 1000).
 -define(LAST_NODES_MENU_ID,  2000).
@@ -60,7 +61,8 @@
 	 active_tab,
 	 node,
 	 nodes,
-	 prev_node=""
+	 prev_node="",
+	 log = false
 	}).
 
 start() ->
@@ -215,14 +217,17 @@ handle_event(#wx{event=#wxNotebook{type=command_notebook_page_changing}},
 	    {noreply, State#state{active_tab=Pid}}
     end;
 
-handle_event(#wx{event = #wxClose{}}, State) ->
-    {stop, normal, State};
-
 handle_event(#wx{id = ?ID_CDV, event = #wxCommand{type = command_menu_selected}}, State) ->
     spawn(crashdump_viewer, start, []),
     {noreply, State};
 
-handle_event(#wx{id = ?wxID_EXIT, event = #wxCommand{type = command_menu_selected}}, State) ->
+handle_event(#wx{event = #wxClose{}}, #state{log=LogOn} = State) ->
+    LogOn andalso rpc:block_call(State#state.node, rb, stop, []),
+    {stop, normal, State};
+
+handle_event(#wx{id = ?wxID_EXIT, event = #wxCommand{type = command_menu_selected}},
+	     #state{log=LogOn} = State) ->
+    LogOn andalso rpc:block_call(State#state.node, rb, stop, []),
     {stop, normal, State};
 
 handle_event(#wx{id = ?wxID_HELP, event = #wxCommand{type = command_menu_selected}}, State) ->
@@ -300,12 +305,42 @@ handle_event(#wx{id = ?ID_PING, event = #wxCommand{type = command_menu_selected}
 	       end,
     {noreply, UpdState};
 
-handle_event(#wx{id = Id, event = #wxCommand{type = command_menu_selected}}, State)
-  when Id > ?FIRST_NODES_MENU_ID, Id < ?LAST_NODES_MENU_ID ->
+handle_event(#wx{id = ?ID_LOGVIEW, event = #wxCommand{type = command_menu_selected}},
+	     #state{frame = Frame, log = PrevLog, node = Node} = State) ->
+    try
+	ok = ensure_sasl_started(Node),
+	ok = ensure_mf_h_handler_used(Node),
+	ok = ensure_rb_mode(Node, PrevLog),
+	case PrevLog of
+	    false ->
+		rpc:block_call(Node, rb, start, []),
+		set_status("Observer - " ++ atom_to_list(Node) ++ " (rb_server started)"),
+		{noreply, State#state{log=true}};
+	    true ->
+		rpc:block_call(Node, rb, stop, []),
+		set_status("Observer - " ++ atom_to_list(Node) ++ " (rb_server stopped)"),
+		{noreply, State#state{log=false}}
+	end
+    catch
+	throw:Reason ->
+	    create_txt_dialog(Frame, Reason, "Log view status", ?wxICON_ERROR),
+	    {noreply, State}
+    end;
 
-    Node = lists:nth(Id - ?FIRST_NODES_MENU_ID, State#state.nodes),
-    UpdState = change_node_view(Node, State),
-    {noreply, UpdState};
+handle_event(#wx{id = Id, event = #wxCommand{type = command_menu_selected}},
+	     #state{nodes= Ns , node = PrevNode, log = PrevLog} = State)
+  when Id > ?FIRST_NODES_MENU_ID, Id < ?LAST_NODES_MENU_ID ->
+    Node = lists:nth(Id - ?FIRST_NODES_MENU_ID, Ns),
+    %% Close rb_server only if another node than current one selected
+    LState = case PrevLog of
+		 true  -> case Node == PrevNode of
+			      false -> rpc:block_call(PrevNode, rb, stop, []),
+				       State#state{log=false} ;
+			      true  -> State
+			  end;
+		 false -> State
+             end,
+    {noreply, change_node_view(Node, LState)};
 
 handle_event(Event, State) ->
     Pid = get_active_pid(State),
@@ -340,6 +375,9 @@ handle_call(stop, _, State = #state{frame = Frame}) ->
     wxFrame:destroy(Frame),
     {stop, normal, ok, State};
 
+handle_call(log_status, _From, State) ->
+    {reply, State#state.log, State};
+
 handle_call(_Msg, _From, State) ->
     {reply, ok, State}.
 
@@ -422,8 +460,7 @@ return_to_localnode(Frame, Node) ->
     end.
 
 create_txt_dialog(Frame, Msg, Title, Style) ->
-    MD = wxMessageDialog:new(Frame, Msg, [{style, Style}]),
-    wxMessageDialog:setTitle(MD, Title),
+    MD = wxMessageDialog:new(Frame, Msg, [{style, Style}, {caption,Title}]),
     wxDialog:showModal(MD),
     wxDialog:destroy(MD).
 
@@ -569,17 +606,19 @@ default_menus(NodesMenuItems) ->
 		   false -> {"Nodes", NodesMenuItems ++
 				 [#create_menu{id = ?ID_CONNECT, text = "Enable distribution"}]}
 	       end,
+    LogMenu =  {"Log", [#create_menu{id = ?ID_LOGVIEW, text = "Toggle log view"}]},
     case os:type() =:= {unix, darwin} of
 	false ->
 	    FileMenu = {"File", [CDV, Quit]},
 	    HelpMenu = {"Help", [About,Help]},
-	    [FileMenu, NodeMenu, HelpMenu];
+	    [FileMenu, NodeMenu, LogMenu, HelpMenu];
 	true ->
 	    %% On Mac quit and about will be moved to the "default' place
 	    %% automagicly, so just add them to a menu that always exist.
 	    %% But not to the help menu for some reason
-	    {Tag, Menus} = FileMenu,
-	    [{Tag, Menus ++ [About]}, NodeMenu, {"&Help", [Help]}]
+
+	    {Tag, Menus} = NodeMenu,
+	    [{Tag, Menus ++ [Quit,About]}, LogMenu, {"&Help", [Help]}]
     end.
 
 clean_menus(Menus, MenuBar) ->
@@ -658,3 +697,59 @@ update_node_list(State = #state{menubar=MenuBar}) ->
 	   end,
     observer_lib:create_menu_item(Dist, NodeMenu, Index),
     State#state{nodes = Nodes}.
+
+ensure_sasl_started(Node) ->
+   %% is sasl started ?
+   Apps = rpc:block_call(Node, application, which_applications, []),
+   case lists:keyfind(sasl, 1, Apps) of
+       false        ->  throw("Error: sasl application not started."),
+                        error;
+       {sasl, _, _} ->  ok
+   end.
+
+ensure_mf_h_handler_used(Node) ->
+   %% is log_mf_h used ?
+   Handlers = rpc:block_call(Node, gen_event, which_handlers, [error_logger]),
+   case lists:any(fun(L)-> L == log_mf_h end, Handlers) of
+       false -> throw("Error: log_mf_h handler not used in sasl."),
+                error;
+       true  -> ok
+   end.
+
+ensure_rb_mode(Node, PrevLog) ->
+    ok = ensure_rb_module_loaded(Node),
+    ok = is_rb_compatible(Node),
+    ok = is_rb_server_running(Node, PrevLog),
+    ok.
+
+
+ensure_rb_module_loaded(Node) ->
+   %% Need to ensure that module is loaded in order to detect exported
+   %% functions on interactive nodes
+   case rpc:block_call(Node, code, ensure_loaded, [rb]) of
+       {badrpc, Reason} ->
+	   throw("Error: badrpc - " ++ io_lib:format("~tp",[Reason]));
+       {error, Reason} ->
+	   throw("Error: rb module load error - " ++ io_lib:format("~tp",[Reason]));
+       {module,rb} ->
+	   ok
+   end.
+
+is_rb_compatible(Node) ->
+   %% Simply test that rb:log_list/0 is exported
+   case rpc:block_call(Node, erlang, function_exported, [rb, log_list, 0]) of
+       false -> throw("Error: Node's Erlang release must be at least R16B02.");
+       true  -> ok
+   end.
+
+is_rb_server_running(Node, LogState) ->
+   %% If already started, somebody else may use it.
+   %% We can not use it too, as far log file would be overriden. Not fair.
+   case rpc:block_call(Node, erlang, whereis, [rb_server]) of
+       Pid when is_pid(Pid), (LogState == false) ->
+	   throw("Error: rb_server is already started and maybe used by someone.");
+       Pid when is_pid(Pid) ->
+	   ok;
+       undefined ->
+	   ok
+   end.