Merge pull request #13250 from thalesmg/ds-singleton-m-20240613

feat: enforce singleton discovery strategy when using DS `builtin_local` backend

apps/emqx/rebar.config

@@ -28,7 +28,7 @@
     {gproc, {git, "https://github.com/emqx/gproc", {tag, "0.9.0.1"}}},
     {cowboy, {git, "https://github.com/emqx/cowboy", {tag, "2.9.2"}}},
     {esockd, {git, "https://github.com/emqx/esockd", {tag, "5.11.2"}}},
-    {ekka, {git, "https://github.com/emqx/ekka", {tag, "0.19.3"}}},
+    {ekka, {git, "https://github.com/emqx/ekka", {tag, "0.19.4"}}},
     {gen_rpc, {git, "https://github.com/emqx/gen_rpc", {tag, "3.3.1"}}},
     {hocon, {git, "https://github.com/emqx/hocon.git", {tag, "0.42.2"}}},
     {emqx_http_lib, {git, "https://github.com/emqx/emqx_http_lib.git", {tag, "0.5.3"}}},

apps/emqx/src/emqx_schema.erl

@@ -1954,10 +1954,6 @@ zones_field_schema() ->
         }
     ).
 
-desc("persistent_session_store") ->
-    "Settings for message persistence.";
-desc("persistent_session_builtin") ->
-    "Settings for the built-in storage engine of persistent messages.";
 desc("persistent_table_mria_opts") ->
     "Tuning options for the mria table.";
 desc("stats") ->

apps/emqx_conf/src/emqx_conf_schema.erl

@@ -134,10 +134,27 @@ roots() ->
         lists:flatmap(fun roots/1, common_apps()).
 
 validations() ->
-    [{check_node_name_and_discovery_strategy, fun validate_cluster_strategy/1}] ++
+    [
+        {check_node_name_and_discovery_strategy, fun validate_cluster_strategy/1},
+        {validate_durable_sessions_strategy, fun validate_durable_sessions_strategy/1}
+    ] ++
         hocon_schema:validations(emqx_schema) ++
         lists:flatmap(fun hocon_schema:validations/1, common_apps()).
 
+validate_durable_sessions_strategy(Conf) ->
+    DSEnabled = hocon_maps:get("durable_sessions.enable", Conf),
+    DiscoveryStrategy = hocon_maps:get("cluster.discovery_strategy", Conf),
+    DSBackend = hocon_maps:get("durable_storage.messages.backend", Conf),
+    case {DSEnabled, DSBackend} of
+        {true, builtin_local} when DiscoveryStrategy =/= singleton ->
+            {error, <<
+                "cluster discovery strategy must be 'singleton' when"
+                " durable storage backend is 'builtin_local'"
+            >>};
+        _ ->
+            ok
+    end.
+
 common_apps() ->
     Edition = emqx_release:edition(),
     lists:filtermap(
@@ -166,7 +183,7 @@ fields("cluster") ->
             )},
         {"discovery_strategy",
             sc(
-                hoconsc:enum([manual, static, dns, etcd, k8s]),
+                hoconsc:enum([manual, static, singleton, dns, etcd, k8s]),
                 #{
                     default => manual,
                     desc => ?DESC(cluster_discovery_strategy),

changes/ce/feat-13250.en.md

@@ -0,0 +1 @@
+Added a new `cluster.discovery_strategy` value: `singleton`.  By choosing this option, there will be effectively no clustering, and the node will reject connection attempts to and from other nodes.

mix.exs

@@ -55,7 +55,7 @@ defmodule EMQXUmbrella.MixProject do
       {:cowboy, github: "emqx/cowboy", tag: "2.9.2", override: true},
       {:esockd, github: "emqx/esockd", tag: "5.11.2", override: true},
       {:rocksdb, github: "emqx/erlang-rocksdb", tag: "1.8.0-emqx-5", override: true},
-      {:ekka, github: "emqx/ekka", tag: "0.19.3", override: true},
+      {:ekka, github: "emqx/ekka", tag: "0.19.4", override: true},
       {:gen_rpc, github: "emqx/gen_rpc", tag: "3.3.1", override: true},
       {:grpc, github: "emqx/grpc-erl", tag: "0.6.12", override: true},
       {:minirest, github: "emqx/minirest", tag: "1.4.1", override: true},

rebar.config

@@ -83,7 +83,7 @@
     {cowboy, {git, "https://github.com/emqx/cowboy", {tag, "2.9.2"}}},
     {esockd, {git, "https://github.com/emqx/esockd", {tag, "5.11.2"}}},
     {rocksdb, {git, "https://github.com/emqx/erlang-rocksdb", {tag, "1.8.0-emqx-5"}}},
-    {ekka, {git, "https://github.com/emqx/ekka", {tag, "0.19.3"}}},
+    {ekka, {git, "https://github.com/emqx/ekka", {tag, "0.19.4"}}},
     {gen_rpc, {git, "https://github.com/emqx/gen_rpc", {tag, "3.3.1"}}},
     {grpc, {git, "https://github.com/emqx/grpc-erl", {tag, "0.6.12"}}},
     {minirest, {git, "https://github.com/emqx/minirest", {tag, "1.4.1"}}},