Merge pull request #4430 from esl/report-long-tasks

Report long tasks

Author: chrzaszcz

src/ejabberd_app.erl

@@ -40,7 +40,10 @@
 
 start(normal, _Args) ->
     try
-        do_start()
+        %% We want to print the starting progress if starting is too slow
+        %% (i.e. it would print the current stacktrace each several seconds
+        %%  during the startup)
+        mongoose_task:run_tracked(#{task => start_mongooseim}, fun do_start/0)
     catch Class:Reason:StackTrace ->
         %% Log a stacktrace because while proc_lib:crash_report/4 would report a crash reason,
         %% it would not report the stacktrace

src/ejabberd_sup.erl

@@ -32,6 +32,9 @@
 -export([start_child/1, start_child/2, stop_child/1]).
 -export([create_ets_table/2]).
 
+-export([start_linked_child/2]).
+-ignore_xref([start_linked_child/2]).
+
 -include("mongoose_logger.hrl").
 
 start_link() ->
@@ -121,7 +124,17 @@ worker_spec(Mod) ->
     worker_spec(Mod, []).
 
 worker_spec(Mod, Args) ->
-    {Mod, {Mod, start_link, Args}, permanent, timer:seconds(5), worker, [Mod]}.
+    %% We use `start_linked_child' wrapper to log delays
+    %% in the slow init worker functions.
+    MFA = {?MODULE, start_linked_child, [Mod, Args]},
+    {Mod, MFA, permanent, timer:seconds(5), worker, [Mod]}.
+
+%% In case one of the workers takes long time to start
+%% we want the logging progress (to know which child got stuck).
+%% This could happend on CI during the node restarts.
+start_linked_child(Mod, Args) ->
+    F = fun() -> erlang:apply(Mod, start_link, Args) end,
+    mongoose_task:run_tracked(#{task => start_linked_child, child_module => Mod}, F).
 
 -spec create_ets_table(atom(), list()) -> ok.
 create_ets_table(TableName, TableOpts) ->

src/mongoose_cluster_id.erl

@@ -24,8 +24,9 @@ start() ->
     PersistentBackend = which_persistent_backend_enabled(),
     VolatileBackend = which_volatile_backend_available(),
     maybe_prepare_queries(PersistentBackend),
-    cets_long:run_tracked(#{task => wait_for_any_backend,
-                            backend => PersistentBackend, volatile_backend => VolatileBackend},
+    mongoose_task:run_tracked(#{task => wait_for_any_backend,
+                                backend => PersistentBackend,
+                                volatile_backend => VolatileBackend},
                           fun() -> wait_for_any_backend(PersistentBackend, VolatileBackend) end),
     CachedRes = get_cached_cluster_id(VolatileBackend),
     BackendRes = get_backend_cluster_id(PersistentBackend),
@@ -80,7 +81,8 @@ wait_for_backend_promise(cets, Alias) ->
         end)];
 wait_for_backend_promise(rdbms, Alias) ->
     [spawn(fun() ->
-            cets_long:run_tracked(#{task => wait_for_rdbms}, fun() -> wait_for_rdbms() end),
+            mongoose_task:run_tracked(#{task => wait_for_rdbms},
+                                      fun wait_for_rdbms/0),
             Alias ! {ready, Alias}
         end)];
 wait_for_backend_promise(_, Alias) ->

src/mongoose_start_node_id.erl

@@ -41,6 +41,9 @@ start_link() ->
     gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
 
 init(_) ->
+    mongoose_task:run_tracked(#{task => mongoose_start_node_id_init}, fun do_init/0).
+
+do_init() ->
     net_kernel:monitor_nodes(true),
     StartId = mongoose_bin:gen_from_crypto(),
     persistent_term:put(mongoose_start_node_id, StartId),
@@ -93,8 +96,15 @@ code_change(_OldVsn, State, _Extra) ->
     {ok, State}.
 
 register_on_remote_node(RemoteNode, StartId) ->
+    Info = #{task => register_on_remote_node,
+             remote_node => RemoteNode,
+             start_id => StartId},
+    F = fun() -> do_register_on_remote_node(RemoteNode, StartId) end,
+    mongoose_task:run_tracked(Info, F).
+
+do_register_on_remote_node(RemoteNode, StartId) ->
     Res = rpc:call(RemoteNode, ?MODULE, register_on_remote_node_rpc,
-                   [node(), StartId, self()]),
+                   [node(), StartId, self()], timer:seconds(10)),
     case Res of
         ok ->
             ok;

src/mongoose_task.erl

@@ -0,0 +1,12 @@
+%% @doc Helper module for slow tasks.
+-module(mongoose_task).
+-export([run_tracked/2]).
+
+%% @doc Run a task, log if it takes too long
+-spec run_tracked(Info :: map(), F :: fun(() -> Res)) -> Res
+    when Res :: term().
+run_tracked(Info, F) ->
+    %% Reuse code from CETS.
+    %% `cets_long' module does not use any CETS functionality and
+    %% can be used, even if CETS tables are not used.
+    cets_long:run_tracked(Info, F).

src/wpool/mongoose_wpool_mgr.erl

@@ -71,10 +71,10 @@ start_link(Type) ->
 
 start(Type, Host, Tag, PoolOpts, ConnOpts) ->
     ok = ensure_started(Type),
-    gen_server:call(name(Type), {start_pool, Host, Tag, PoolOpts, ConnOpts}).
+    gen_server:call(name(Type), {start_pool, Host, Tag, PoolOpts, ConnOpts}, timer:seconds(30)).
 
 stop(Type, Host, Tag) ->
-    gen_server:call(name(Type), {stop_pool, Host, Tag}).
+    gen_server:call(name(Type), {stop_pool, Host, Tag}, timer:seconds(30)).
 
 -spec name(mongoose_wpool:pool_type()) -> mongoose_wpool:proc_name().
 name(Type) ->
@@ -93,7 +93,11 @@ handle_call({start_pool, Host, Tag, WpoolOpts, ConnOpts}, _From,
             #state{type = Type, pools = Pools, monitors = Monitors} = State) ->
     ?LOG_INFO(#{what => pool_starting, pool_type => Type, tag => Tag, server => Host,
                 pool_opts => WpoolOpts}),
-    case mongoose_wpool:call_start_callback(Type, [Host, Tag, WpoolOpts, ConnOpts]) of
+    F = fun() ->
+            mongoose_wpool:call_start_callback(Type, [Host, Tag, WpoolOpts, ConnOpts])
+        end,
+    Info = #{task => start_pool, tag => Tag},
+    case mongoose_task:run_tracked(Info, F) of
         {_, Pid} = OkReply when is_pid(Pid) ->
             Ref = erlang:monitor(process, Pid),
             Key = {Type, Host, Tag},