See #7777. Use vhost_max to stop vhost creation in rabbitmq

(cherry picked from commit 574ca55)

Author: SimonUnge

deps/rabbit/priv/schema/rabbit.schema

@@ -897,6 +897,19 @@ end}.
  end
 }.
 
+{mapping, "vhost_max", "rabbit.vhost_max",
+  [{datatype, [{atom, infinity}, integer]}]}.
+
+{translation, "rabbit.vhost_max",
+ fun(Conf) ->
+  case cuttlefish:conf_get("vhost_max", Conf, undefined) of
+      undefined -> cuttlefish:unset();
+      infinity  -> infinity;
+      Val when is_integer(Val) -> Val;
+      _         -> cuttlefish:invalid("should be a non-negative integer")
+  end
+ end
+}.
 
 {mapping, "max_message_size", "rabbit.max_message_size",
     [{datatype, integer}, {validators, ["max_message_size"]}]}.

deps/rabbit/src/rabbit_vhost.erl

@@ -161,6 +161,7 @@ add(Name, Metadata, ActingUser) ->
     end.
 
 do_add(Name, Metadata, ActingUser) ->
+    ok = is_over_vhost_limit(Name),
     Description = maps:get(description, Metadata, undefined),
     Tags = maps:get(tags, Metadata, []),
 
@@ -333,6 +334,23 @@ put_vhost(Name, Description, Tags0, DefaultQueueType, Trace, Username) ->
     end,
     Result.
 
+is_over_vhost_limit(Name) ->
+    Limit = rabbit_misc:get_env(rabbit, vhost_max, infinity),
+    is_over_vhost_limit(Name, Limit).
+
+is_over_vhost_limit(_Name, infinity) ->
+    ok;
+is_over_vhost_limit(Name, Limit) when is_integer(Limit) ->
+    case length(list_names()) >= Limit of
+        false ->
+            ok;
+        true ->
+            ErrorMsg = rabbit_misc:format("cannot create vhost '~ts': "
+                                          "vhost limit '~tp' is reached",
+                                          [Name, Limit]),
+            exit({vhost_precondition_failed, ErrorMsg})
+    end.
+
 %% when definitions are loaded on boot, Username here will be ?INTERNAL_USER,
 %% which does not actually exist
 maybe_grant_full_permissions(_Name, ?INTERNAL_USER) ->

deps/rabbit/test/per_node_limit_SUITE.erl

@@ -21,7 +21,8 @@ all() ->
 groups() ->
     [
      {parallel_tests, [parallel], [
-                                   node_connection_limit
+                                   node_connection_limit,
+                                   vhost_limit
                                   ]}
     ].
 
@@ -58,6 +59,9 @@ end_per_group(_Group, Config) ->
 init_per_testcase(Testcase, Config) ->
     rabbit_ct_helpers:testcase_started(Config, Testcase).
 
+end_per_testcase(vhost_limit = Testcase, Config) ->
+    [rabbit_ct_broker_helpers:delete_vhost(Config, integer_to_binary(I)) || I <- lists:seq(1,4)],
+    rabbit_ct_helpers:testcase_finished(Config, Testcase);
 end_per_testcase(Testcase, Config) ->
     rabbit_ct_helpers:testcase_finished(Config, Testcase).
 
@@ -78,7 +82,25 @@ node_connection_limit(Config) ->
 
     set_node_limit(Config, infinity),
     C = rabbit_ct_client_helpers:open_unmanaged_connection(Config, 0),
-    true = is_pid(C).
+    true = is_pid(C),
+    close_all_connections([C]),
+    ok.
+
+vhost_limit(Config) ->
+    set_vhost_limit(Config, 0),
+    {'EXIT',{vhost_precondition_failed, _}} = rabbit_ct_broker_helpers:add_vhost(Config, <<"foo">>),
+
+    set_vhost_limit(Config, 5),
+    [ok = rabbit_ct_broker_helpers:add_vhost(Config, integer_to_binary(I)) || I <- lists:seq(1,4)],
+    {'EXIT',{vhost_precondition_failed, _}} = rabbit_ct_broker_helpers:add_vhost(Config, <<"5">>),
+    [rabbit_ct_broker_helpers:delete_vhost(Config, integer_to_binary(I)) || I <- lists:seq(1,4)],
+
+    set_vhost_limit(Config, infinity),
+    [ok = rabbit_ct_broker_helpers:add_vhost(Config, integer_to_binary(I)) || I <- lists:seq(1,4)],
+    ok = rabbit_ct_broker_helpers:add_vhost(Config, <<"5">>),
+    [rabbit_ct_broker_helpers:delete_vhost(Config, integer_to_binary(I)) || I <- lists:seq(1,5)],
+    ok.
+
 
 %% -------------------------------------------------------------------
 %% Implementation
@@ -97,3 +119,8 @@ set_node_limit(Config, Limit) ->
     rabbit_ct_broker_helpers:rpc(Config, 0,
                                  application,
                                  set_env, [rabbit, connection_max, Limit]).
+
+set_vhost_limit(Config, Limit) ->
+    rabbit_ct_broker_helpers:rpc(Config, 0,
+                                 application,
+                                 set_env, [rabbit, vhost_max, Limit]).

deps/rabbitmq_cli/lib/rabbitmq/cli/ctl/commands/add_vhost_command.ex

@@ -72,6 +72,10 @@ defmodule RabbitMQ.CLI.Ctl.Commands.AddVhostCommand do
     {:error, ExitCodes.exit_usage(), "Unsupported default queue type"}
   end
 
+  def output({:badrpc, {:EXIT, {:vhost_precondition_failed, msg}}}, _opts) do
+    {:error, ExitCodes.exit_usage(), msg}
+  end
+
   use RabbitMQ.CLI.DefaultOutput
 
   def usage,

deps/rabbitmq_management/src/rabbit_mgmt_wm_vhost.erl

@@ -60,25 +60,28 @@ accept_content(ReqData0, Context = #context{user = #user{username = Username}})
     rabbit_mgmt_util:with_decode(
       [], ReqData0, Context,
       fun(_, BodyMap, ReqData) ->
-        Trace = rabbit_mgmt_util:parse_bool(maps:get(tracing, BodyMap, undefined)),
-        Description = maps:get(description, BodyMap, <<"">>),
-        Tags = maps:get(tags, BodyMap, <<"">>),
-        %% defaultqueuetype was an unfortunate name picked originally for 3.11.0,
-        %% so fall back to it. See rabbitmq/rabbitmq-server#7734.
-        FallbackQT = maps:get(defaultqueuetype, BodyMap, undefined),
-        DefaultQT = maps:get(default_queue_type, BodyMap, FallbackQT),
-        case put_vhost(Name, Description, Tags, DefaultQT, Trace, Username) of
-            ok ->
-                {true, ReqData, Context};
-            {error, timeout} = E ->
-                rabbit_mgmt_util:internal_server_error(
-                  "Timed out while waiting for the vhost to initialise", E,
-                  ReqData0, Context);
-            {error, E} ->
-                rabbit_mgmt_util:internal_server_error(
-                  "Error occured while adding vhost", E,
-                  ReqData0, Context)
-        end
+              Trace = rabbit_mgmt_util:parse_bool(maps:get(tracing, BodyMap, undefined)),
+              Description = maps:get(description, BodyMap, <<"">>),
+              Tags = maps:get(tags, BodyMap, <<"">>),
+              %% defaultqueuetype was an unfortunate name picked originally for 3.11.0,
+              %% so fall back to it. See rabbitmq/rabbitmq-server#7734.
+              FallbackQT = maps:get(defaultqueuetype, BodyMap, undefined),
+              DefaultQT = maps:get(default_queue_type, BodyMap, FallbackQT),
+              case put_vhost(Name, Description, Tags, DefaultQT, Trace, Username) of
+                  ok ->
+                      {true, ReqData, Context};
+                  {'EXIT', {vhost_precondition_failed,
+                            Explanation}} ->
+                      rabbit_mgmt_util:bad_request(list_to_binary(Explanation), ReqData, Context);
+                  {error, timeout} = E ->
+                      rabbit_mgmt_util:internal_server_error(
+                        "Timed out while waiting for the vhost to initialise", E,
+                        ReqData0, Context);
+                  {error, E} ->
+                      rabbit_mgmt_util:internal_server_error(
+                        "Error occured while adding vhost", E,
+                        ReqData0, Context)
+              end
       end).
 
 delete_resource(ReqData, Context = #context{user = #user{username = Username}}) ->