Add CQ and QQ Observer CLI plugins from boot steps

Do not hard code them, also preserve user-provided plugins list
Type fix by @kura

(cherry picked from commit 2d02964)

# Conflicts:
#	deps/rabbit/src/rabbit_observer_cli.erl

Author: ikavgo

deps/rabbit/src/rabbit_observer_cli.erl

@@ -10,7 +10,23 @@
 -export([init/0]).
 
 init() ->
+<<<<<<< HEAD
     application:set_env(observer_cli, plugins, [
         rabbit_observer_cli_classic_queues:plugin_info(),
         rabbit_observer_cli_quorum_queues:plugin_info()
     ]).
+=======
+    %% prepare observer_cli.plugins for add_plugin/1
+    application:set_env(observer_cli, plugins, application:get_env(observer_cli, plugins, [])).
+
+%% must be executed after observer_cli boot_step
+add_plugin(PluginInfo) ->
+    case application:get_env(observer_cli, plugins, undefined) of
+        undefined -> %% shouldn't be there, die
+            exit({rabbit_observer_cli_step_not_there, "Can't add observer_cli plugin, required boot_step wasn't executed"});
+        Plugins when is_list(Plugins) ->
+            application:set_env(observer_cli, plugins, Plugins ++ [PluginInfo]);
+        _ ->
+            exit({rabbit_observer_cli_plugins_error, "Can't add observer_cli plugin, existing entry is not a list"})
+    end.
+>>>>>>> 2d029649a (Add CQ and QQ Observer CLI plugins from boot steps)

deps/rabbit/src/rabbit_observer_cli_classic_queues.erl

@@ -7,11 +7,20 @@
 
 -module(rabbit_observer_cli_classic_queues).
 
--export([plugin_info/0]).
+-export([add_plugin/0, plugin_info/0]).
 -export([attributes/1, sheet_header/0, sheet_body/1]).
 
 -include_lib("rabbit_common/include/rabbit.hrl").
 
+-rabbit_boot_step({?MODULE,
+                   [{description, "Classic queues observer_cli plugin"},
+                    {mfa,         {?MODULE, add_plugin, []}},
+                    {requires,    [rabbit_observer_cli]},
+                    {enables,     routing_ready}]}).
+
+add_plugin() ->
+    rabbit_observer_cli:add_plugin(plugin_info()).
+
 plugin_info() ->
     #{
         module => rabbit_observer_cli_classic_queues,

deps/rabbit/src/rabbit_observer_cli_quorum_queues.erl

@@ -7,11 +7,20 @@
 
 -module(rabbit_observer_cli_quorum_queues).
 
--export([plugin_info/0]).
+-export([add_plugin/0, plugin_info/0]).
 -export([attributes/1, sheet_header/0, sheet_body/1]).
 
 -include_lib("rabbit_common/include/rabbit.hrl").
 
+-rabbit_boot_step({?MODULE,
+                   [{description, "Quorum queues observer_cli plugin"},
+                    {mfa,         {?MODULE, add_plugin, []}},
+                    {requires,    [rabbit_observer_cli]},
+                    {enables,     routing_ready}]}).
+
+add_plugin() ->
+    rabbit_observer_cli:add_plugin(plugin_info()).
+
 plugin_info() ->
     #{
         module => rabbit_observer_cli_quorum_queues,