feat: simplify auto cluster configs

src/ekka.app.src

@@ -1,6 +1,6 @@
 {application, ekka,
  [{description, "Autocluster for EMQ X Broker"},
-  {vsn, "0.12.9"},
+  {vsn, "0.13.0"},
   {mod, {ekka_app,[]}},
   {registered,
    [ekka_sup,

src/ekka.appup.src

@@ -1,6 +1,6 @@
 %% -*-: erlang -*-
 
-{<<"0.12.9">>,
+{<<"0.13.0">>,
   [
     {<<".*">>, []}
   ],

src/ekka_cluster_dns.erl

@@ -27,19 +27,22 @@
         ]).
 
 discover(Options) ->
-    Name = proplists:get_value(name, Options),
-    App  = proplists:get_value(app, Options),
+    DomainName = proplists:get_value(name, Options),
+    NodeName = proplists:get_value(app, Options, undefined),
     Type = proplists:get_value(type, Options, a),
-    {ok, [node_name(App, Host) || Host <- resolve_hosts(Name, Type)]}.
+    {ok, [node_name(NodeName, Host) || Host <- resolve_hosts(DomainName, Type)]}.
 
-resolve_hosts(Name, a) ->
-    [inet:ntoa(IP) || IP <- inet_res:lookup(Name, in, a)];
-resolve_hosts(Name, srv) ->
-    Records = inet_res:lookup(Name, in, srv),
+resolve_hosts(DomainName, a) ->
+    [inet:ntoa(IP) || IP <- inet_res:lookup(DomainName, in, a)];
+resolve_hosts(DomainName, srv) ->
+    Records = inet_res:lookup(DomainName, in, srv),
     lists:usort(lists:map(fun({_, _, _, Host}) -> Host end, Records)).
 
-node_name(App, Host) ->
-    list_to_atom(lists:concat([App, "@", Host])).
+node_name(undefined, Host) ->
+    [Name | _] = string:tokens(atom_to_list(node()), "@"),
+    node_name(Name, Host);
+node_name(NodeName, Host) ->
+    list_to_atom(lists:concat([NodeName, "@", Host])).
 
 lock(_Options) ->
     ignore.
@@ -52,4 +55,3 @@ register(_Options) ->
 
 unregister(_Options) ->
     ignore.
-

src/ekka_cluster_k8s.erl

@@ -39,7 +39,7 @@
 discover(Options) ->
     Server = get_value(apiserver, Options),
     Service = get_value(service_name, Options),
-    App = get_value(app_name, Options, "ekka"),
+    App = resolve_name(get_value(app_name, Options, undefined)),
     AddrType = get_value(address_type, Options, ip),
     Namespace = get_value(namespace, Options, "default"),
     Suffix = get_value(suffix, Options, ""),
@@ -51,6 +51,12 @@ discover(Options) ->
             {error, Reason}
     end.
 
+resolve_name(undefined) ->
+    [Name | _] = string:tokens(atom_to_list(node()), "@"),
+    Name;
+resolve_name(Name) ->
+    Name.
+
 node_name(App, Addr, Service, hostname, Namespace, Suffix) when length(Suffix) > 0 ->
     list_to_atom(lists:concat([App, "@", binary_to_list(Addr), ".", Service, ".", Namespace, ".", Suffix]));
 

test/ekka_cluster_dns_SUITE.erl

@@ -55,6 +55,7 @@ end_per_testcase(_, Config) -> Config.
 
 all() -> ekka_ct:all(?MODULE).
 
+%% This test case relies on DNS resolution from localhost to 127.0.0.1
 t_discover(_) ->
     Options1 = [{name, "localhost"}, {app, "ekka"}],
     {ok, ['ekka@127.0.0.1']} = ekka_cluster_dns:discover(Options1),
@@ -64,6 +65,10 @@ t_discover(_) ->
           'ekka@emqx-1.emqx.default.svc.cluster.local',
           'ekka@emqx-2.emqx.default.svc.cluster.local'
          ]} = ekka_cluster_dns:discover(Options2),
+
+    Options3 = [{name, "localhost"}],
+    %% below test relies on rebar3 ct is run with '--name ct@127.0.0.1'
+    {ok, ['ct@127.0.0.1']} = ekka_cluster_dns:discover(Options3),
     ok.
 
 t_lock(_) ->

test/ekka_cluster_k8s_SUITE.erl

@@ -25,7 +25,6 @@
                   {namespace, "default"},
                   {service_name, "ekka"},
                   {address_type, ip},
-                  {app_name, "ekka"},
                   {suffix, ""}
                  ]).
 
@@ -37,7 +36,9 @@ t_discover(_) ->
     ok = meck:expect(httpc, request, fun(get, _Req, _Opts, _) ->
                                              {ok, {{"HTTP/1.1", 200, "OK"}, [], Json}}
                                      end),
-    {ok, ['ekka@192.168.10.10']} = ekka_cluster_k8s:discover(?OPTIONS),
+    {ok, ['ekka@192.168.10.10']} = ekka_cluster_k8s:discover([{app_name, "ekka"} | ?OPTIONS]),
+    %% below test relies on rebar3 ct is run with '--name ct@127.0.0.1'
+    {ok, ['ct@192.168.10.10']} = ekka_cluster_k8s:discover(?OPTIONS),
     ok = meck:unload(httpc).
 
 t_lock(_) ->