Check process aliveness on remote nodes

Author: dcorbacho

src/rabbit_core_metrics_gc.erl

@@ -103,7 +103,7 @@ gc_process(Table) ->
               end, none, Table).
 
 gc_process(Pid, Table, Key) ->
-    case erlang:is_process_alive(Pid) of
+    case is_process_alive_in_cluster(Pid) of
         true ->
             none;
         false ->
@@ -151,7 +151,7 @@ gc_process_and_entity(Table, GbSet) ->
               end, none, Table).
 
 gc_process_and_entity(Id, Pid, Table, Key, GbSet) ->
-    case erlang:is_process_alive(Pid) orelse gb_sets:is_member(Id, GbSet) of
+    case is_process_alive_in_cluster(Pid) orelse gb_sets:is_member(Id, GbSet) of
         true ->
             none;
         false ->
@@ -166,3 +166,18 @@ gc_process_and_entities(Table, QueueGbSet, ExchangeGbSet) ->
                       gc_entity(Q, Table, Key, QueueGbSet),
                       gc_entity(X, Table, Key, ExchangeGbSet)
               end, none, Table).
+
+is_process_alive_in_cluster(Pid) ->
+    Local = node(),
+    case node(Pid) of
+        Local ->
+            is_process_alive(Pid);
+        Remote ->
+            case rabbit_misc:rpc_call(Remote, erlang, is_process_alive, [Pid]) of
+                Bool when is_boolean(Bool) ->
+                    Bool;
+                {badrpc, _} ->
+                    %% If the node is unreachable, the process might be dead
+                    false
+            end
+    end.