Переделать связь нод в кластере на автоматическое обнаружение #9

src/infra/admin_utils.erl

@@ -30,6 +30,11 @@ get_permissions(superadmin) ->
     <<"manage_calendars">>, <<"manage_reviews">>, <<"manage_reports">>,
     <<"manage_tickets">>, <<"manage_banned_words">>, <<"view_stats">>,
     <<"view_audit">>];
+get_permissions(admin) ->
+  [<<"manage_users">>, <<"manage_events">>,
+    <<"manage_calendars">>, <<"manage_reviews">>, <<"manage_reports">>,
+    <<"manage_tickets">>, <<"manage_banned_words">>, <<"view_stats">>,
+    <<"view_audit">>];
 get_permissions(moderator) ->
   [<<"manage_events">>, <<"manage_calendars">>, <<"manage_reviews">>,
     <<"manage_reports">>, <<"manage_tickets">>, <<"manage_banned_words">>,

src/infra/cluster_discovery.erl

@@ -0,0 +1,36 @@
+-module(cluster_discovery).
+-export([discover/0]).
+
+-define(DNS_ALIAS, "eventhub-node").
+-define(RETRY_INTERVAL, 5000).
+
+discover() ->
+  io:format("Starting cluster DNS discovery via epmd (~s)...~n", [?DNS_ALIAS]),
+  discover_loop().
+
+discover_loop() ->
+  case inet:getaddrs(?DNS_ALIAS, inet) of
+    {ok, IPs} when is_list(IPs) ->
+      lists:foreach(fun(IP) ->
+        IPStr = inet:ntoa(IP),
+%%        io:format("Checking epmd on ~s...~n", [IPStr]),
+        case erl_epmd:names(IP) of
+          {ok, List} ->
+            lists:foreach(fun({Name, _Port}) ->
+              Node = list_to_atom(Name ++ "@" ++ Name),
+%%              io:format("    Trying net_kernel:connect_node(~s)...~n", [Node]),
+              case net_kernel:connect_node(Node) of
+                true  -> ok; %io:format("    *** Connected to ~s ***~n", [Node]);
+                false -> io:format("    *** Failed to connect to ~s ***~n", [Node]);
+                ignored -> ok
+              end
+                          end, List);
+          {error, Reason} ->
+            io:format("  epmd error on ~s: ~p~n", [IPStr, Reason])
+        end
+                    end, IPs);
+    {error, Reason} ->
+      io:format("DNS lookup failed (~p), retrying...~n", [Reason])
+  end,
+  timer:sleep(?RETRY_INTERVAL),
+  discover_loop().