ci(rocksdb): conditionally load mnesia_rocksdb in release

Otherwise, it might not be included in the release, since it's no
longer declared as a dependency on the mria app.

mix.exs

@@ -170,35 +170,40 @@ defmodule EMQXUmbrella.MixProject do
       hocon: :load,
       emqx: :load,
       emqx_conf: :load,
-      emqx_machine: :permanent,
+      emqx_machine: :permanent
-      mria: :load,
-      mnesia: :load,
-      ekka: :load,
-      emqx_plugin_libs: :load,
-      esasl: :load,
-      observer_cli: :permanent,
-      system_monitor: :load,
-      emqx_http_lib: :permanent,
-      emqx_resource: :permanent,
-      emqx_connector: :permanent,
-      emqx_authn: :permanent,
-      emqx_authz: :permanent,
-      emqx_auto_subscribe: :permanent,
-      emqx_gateway: :permanent,
-      emqx_exhook: :permanent,
-      emqx_bridge: :permanent,
-      emqx_rule_engine: :permanent,
-      emqx_modules: :permanent,
-      emqx_management: :permanent,
-      emqx_dashboard: :permanent,
-      emqx_retainer: :permanent,
-      emqx_statsd: :permanent,
-      emqx_prometheus: :permanent,
-      emqx_psk: :permanent,
-      emqx_slow_subs: :permanent,
-      emqx_plugins: :permanent,
-      emqx_mix: :none
     ] ++
+      if(enable_rocksdb?(),
+        do: [mnesia_rocksdb: :load],
+        else: []
+      ) ++
+      [
+        mnesia: :load,
+        ekka: :load,
+        emqx_plugin_libs: :load,
+        esasl: :load,
+        observer_cli: :permanent,
+        system_monitor: :load,
+        emqx_http_lib: :permanent,
+        emqx_resource: :permanent,
+        emqx_connector: :permanent,
+        emqx_authn: :permanent,
+        emqx_authz: :permanent,
+        emqx_auto_subscribe: :permanent,
+        emqx_gateway: :permanent,
+        emqx_exhook: :permanent,
+        emqx_bridge: :permanent,
+        emqx_rule_engine: :permanent,
+        emqx_modules: :permanent,
+        emqx_management: :permanent,
+        emqx_dashboard: :permanent,
+        emqx_retainer: :permanent,
+        emqx_statsd: :permanent,
+        emqx_prometheus: :permanent,
+        emqx_psk: :permanent,
+        emqx_slow_subs: :permanent,
+        emqx_plugins: :permanent,
+        emqx_mix: :none
+      ] ++
       if(enable_quicer?(), do: [quicer: :permanent], else: []) ++
       if(enable_bcrypt?(), do: [bcrypt: :permanent], else: []) ++
       if(enable_jq?(), do: [jq: :permanent], else: []) ++
@@ -616,6 +621,11 @@ defmodule EMQXUmbrella.MixProject do
     ]) or "1" == System.get_env("BUILD_WITH_QUIC")
   end
 
+  defp enable_rocksdb?() do
+    not build_without_rocksdb?() or
+      "1" == System.get_env("BUILD_WITH_QUIC")
+  end
+
   defp pkg_vsn() do
     %{edition_type: edition_type} = check_profile!()
     basedir = Path.dirname(__ENV__.file)
@@ -657,6 +667,12 @@ defmodule EMQXUmbrella.MixProject do
     String.downcase(opt) != "false"
   end
 
+  defp build_without_rocksdb?() do
+    opt = System.get_env("BUILD_WITHOUT_ROCKSDB", "false")
+
+    String.downcase(opt) != "false"
+  end
+
   defp from_rebar_to_eex_template(str) do
     # we must not consider surrounding space in the template var name
     # because some help strings contain informative variables that

rebar.config.erl

@@ -88,6 +88,10 @@ is_quicer_supported() ->
         is_win32() orelse is_centos_6()) orelse
         "1" == os:getenv("BUILD_WITH_QUIC").
 
+is_rocksdb_supported() ->
+    not (false =/= os:getenv("BUILD_WITHOUT_ROCKSDB")) orelse
+        "1" == os:getenv("BUILD_WITH_ROCKSDB").
+
 is_macos() ->
     {unix, darwin} =:= os:type().
 
@@ -318,34 +322,37 @@ relx_apps(ReleaseType, Edition) ->
         % started by emqx_machine
         {emqx, load},
         {emqx_conf, load},
-        emqx_machine,
+        emqx_machine
-        {mnesia, load},
-        {ekka, load},
-        {emqx_plugin_libs, load},
-        {esasl, load},
-        observer_cli,
-        % started by emqx_machine
-        {system_monitor, load},
-        emqx_http_lib,
-        emqx_resource,
-        emqx_connector,
-        emqx_authn,
-        emqx_authz,
-        emqx_auto_subscribe,
-        emqx_gateway,
-        emqx_exhook,
-        emqx_bridge,
-        emqx_rule_engine,
-        emqx_modules,
-        emqx_management,
-        emqx_dashboard,
-        emqx_retainer,
-        emqx_statsd,
-        emqx_prometheus,
-        emqx_psk,
-        emqx_slow_subs,
-        emqx_plugins
     ] ++
+        [{mnesia_rocksdb, load} || is_rocksdb_supported()] ++
+        [
+            {mnesia, load},
+            {ekka, load},
+            {emqx_plugin_libs, load},
+            {esasl, load},
+            observer_cli,
+            % started by emqx_machine
+            {system_monitor, load},
+            emqx_http_lib,
+            emqx_resource,
+            emqx_connector,
+            emqx_authn,
+            emqx_authz,
+            emqx_auto_subscribe,
+            emqx_gateway,
+            emqx_exhook,
+            emqx_bridge,
+            emqx_rule_engine,
+            emqx_modules,
+            emqx_management,
+            emqx_dashboard,
+            emqx_retainer,
+            emqx_statsd,
+            emqx_prometheus,
+            emqx_psk,
+            emqx_slow_subs,
+            emqx_plugins
+        ] ++
         [quicer || is_quicer_supported()] ++
         [bcrypt || provide_bcrypt_release(ReleaseType)] ++
         [jq || is_jq_supported()] ++