Add endpoints for memory: absolute and relative

src/rabbit_mgmt_dispatcher.erl

@@ -41,6 +41,8 @@ dispatcher() ->
      {["cluster-name"],                                            rabbit_mgmt_wm_cluster_name, []},
      {["nodes"],                                                   rabbit_mgmt_wm_nodes, []},
      {["nodes", node],                                             rabbit_mgmt_wm_node, []},
+     {["nodes", node, "memory"],                                   rabbit_mgmt_wm_node_memory, [absolute]},
+     {["nodes", node, "memory", "relative"],                       rabbit_mgmt_wm_node_memory, [relative]},
      {["extensions"],                                              rabbit_mgmt_wm_extensions, []},
      {["all-configuration"],                                       rabbit_mgmt_wm_definitions, []}, %% This was the old name, let's not break things gratuitously.
      {["definitions"],                                             rabbit_mgmt_wm_definitions, []},

src/rabbit_mgmt_wm_node_memory.erl

@@ -0,0 +1,92 @@
+%%   The contents of this file are subject to the Mozilla Public License
+%%   Version 1.1 (the "License"); you may not use this file except in
+%%   compliance with the License. You may obtain a copy of the License at
+%%   http://www.mozilla.org/MPL/
+%%
+%%   Software distributed under the License is distributed on an "AS IS"
+%%   basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
+%%   License for the specific language governing rights and limitations
+%%   under the License.
+%%
+%%   The Original Code is RabbitMQ Management Console.
+%%
+%%   The Initial Developer of the Original Code is GoPivotal, Inc.
+%%   Copyright (c) 2007-2016 Pivotal Software, Inc.  All rights reserved.
+%%
+
+-module(rabbit_mgmt_wm_node_memory).
+
+-export([init/1, to_json/2, content_types_provided/2, is_authorized/2]).
+-export([finish_request/2, allowed_methods/2]).
+-export([encodings_provided/2]).
+-export([resource_exists/2]).
+
+-include("rabbit_mgmt.hrl").
+-include_lib("webmachine/include/webmachine.hrl").
+-include_lib("rabbit_common/include/rabbit.hrl").
+
+%%--------------------------------------------------------------------
+
+init([Mode]) -> {ok, {Mode, #context{}}}.
+
+finish_request(ReqData, {Mode, Context}) ->
+    {ok, rabbit_mgmt_cors:set_headers(ReqData, Context), {Mode, Context}}.
+
+allowed_methods(ReqData, Context) ->
+    {['HEAD', 'GET', 'OPTIONS'], ReqData, Context}.
+
+content_types_provided(ReqData, Context) ->
+   {[{"application/json", to_json}], ReqData, Context}.
+
+encodings_provided(ReqData, Context) ->
+    {[{"identity", fun(X) -> X end},
+     {"gzip", fun(X) -> zlib:gzip(X) end}], ReqData, Context}.
+
+resource_exists(ReqData, Context) ->
+    {node_exists(ReqData, get_node(ReqData)), ReqData, Context}.
+
+to_json(ReqData, {Mode, Context}) ->
+    rabbit_mgmt_util:reply(augment(Mode, ReqData), ReqData, {Mode, Context}).
+
+is_authorized(ReqData, {Mode, Context}) ->
+    {Res, RD, C} = rabbit_mgmt_util:is_authorized_monitor(ReqData, Context),
+    {Res, RD, {Mode, C}}.
+
+%%--------------------------------------------------------------------
+get_node(ReqData) ->
+    list_to_atom(binary_to_list(rabbit_mgmt_util:id(node, ReqData))).
+
+node_exists(ReqData, Node) ->
+    case [N || N <- rabbit_mgmt_wm_nodes:all_nodes(ReqData),
+               proplists:get_value(name, N) == Node] of
+        [] -> false;
+        [_] -> true
+    end.
+
+augment(Mode, ReqData) ->
+    Node = get_node(ReqData),
+    case node_exists(ReqData, Node) of
+        false ->
+            not_found;
+        true ->
+            case rpc:call(Node, rabbit_vm, memory, [], infinity) of
+                {badrpc, _} -> [{memory, not_available}];
+                Result      -> [{memory, format(Mode, Result)}]
+            end
+    end.
+
+format(absolute, Result) ->
+    Result;
+format(relative, Result) ->
+    {[{total, Total}], Rest} = lists:splitwith(fun({Key, _}) ->
+                                                       Key == total
+                                               end, Result),
+    [{total, 100} | [{K, percentage(V, Total)} || {K, V} <- Rest]].
+
+percentage(Part, Total) ->
+    case round((Part/Total) * 100) of
+        0 when Part =/= 0 ->
+            1;
+        Int ->
+            Int
+    end.

test/src/rabbit_mgmt_test_http.erl

@@ -20,7 +20,8 @@
 
 -export([http_get/1, http_put/3, http_delete/2]).
 
--import(rabbit_mgmt_test_util, [assert_list/2, assert_item/2, test_item/2]).
+-import(rabbit_mgmt_test_util, [assert_list/2, assert_item/2, test_item/2,
+                                assert_keys/2]).
 -import(rabbit_misc, [pget/2]).
 
 cors_test() ->
@@ -104,6 +105,39 @@ nodes_test() ->
     http_delete("/users/monitor", ?NO_CONTENT),
     ok.
 
+memory_test() ->
+    [Node] = http_get("/nodes"),
+    Path = "/nodes/" ++ binary_to_list(pget(name, Node)) ++ "/memory",
+    Result = http_get(Path, ?OK),
+    assert_keys([memory], Result),
+    Keys = [total, connection_readers, connection_writers, connection_channels,
+            connection_other, queue_procs, queue_slave_procs, plugins,
+            other_proc, mnesia, mgmt_db, msg_index, other_ets, binary, code,
+            atom, other_system],
+    assert_keys(Keys, pget(memory, Result)),
+    http_get("/nodes/nonode/memory", ?NOT_FOUND),
+    %% Relative memory as a percentage of the total
+    Result1 = http_get(Path ++ "/relative", ?OK),
+    assert_keys([memory], Result1),
+    Breakdown = pget(memory, Result1),
+    assert_keys(Keys, Breakdown),
+    assert_item([{total, 100}], Breakdown),
+    assert_percentage(Breakdown),
+    http_get("/nodes/nonode/memory/relative", ?NOT_FOUND),
+    ok.
+
+assert_percentage(Breakdown) ->
+    Total = lists:sum([P || {K, P} <- Breakdown, K =/= total]),
+    Count = length(Breakdown) - 1,
+    %% Rounding up and down can lose some digits. Never more than the number
+    %% of items in the breakdown.
+    case ((Total =< 100 + Count) andalso (Total >= 100 - Count)) of
+        false ->
+            throw({bad_percentage, Total, Breakdown});
+        true ->
+            ok
+    end.
+
 auth_test() ->
     http_put("/users/user", [{password, <<"user">>},
                              {tags, <<"">>}], [?CREATED, ?NO_CONTENT]),

test/src/rabbit_mgmt_test_util.erl

@@ -16,7 +16,7 @@
 
 -module(rabbit_mgmt_test_util).
 
--export([assert_list/2, assert_item/2, test_item/2]).
+-export([assert_list/2, assert_item/2, test_item/2, assert_keys/2]).
 
 assert_list(Exp, Act) ->
     case length(Exp) == length(Act) of
@@ -43,3 +43,13 @@ test_item(Exp, Act) ->
 test_item0(Exp, Act) ->
     [{did_not_find, ExpI, in, Act} || ExpI <- Exp,
                                       not lists:member(ExpI, Act)].
+
+assert_keys(Exp, Act) ->
+    case test_key0(Exp, Act) of
+        [] -> ok;
+        Or -> throw(Or)
+    end.
+
+test_key0(Exp, Act) ->
+    [{did_not_find, ExpI, in, Act} || ExpI <- Exp,
+                                      not proplists:is_defined(ExpI, Act)].