If there's nothing in the querystring about a range, don't return any samples or averages or anything.

deps/rabbitmq_management/src/rabbit_mgmt_db.erl

@@ -775,6 +775,14 @@ pick_range(K, {RangeL, RangeM, RangeD}) ->
         {false, false, true} -> RangeD
     end.
 
+format_sample_details(no_range, #stats{diffs = Diffs, base = Base}, Interval) ->
+    Rate = case nth_largest(Diffs, 2) of
+               false    -> 0;
+               {_TS, S} -> S * 1000 / Interval
+           end,
+    Count = sum_entire_tree(gb_trees:iterator(Diffs), Base),
+    {[{rate, Rate}], Count};
+
 format_sample_details(Range, #stats{diffs = Diffs, base = Base}, Interval) ->
     RangePoint = Range#range.last - Interval,
     {Samples, Count} = extract_samples(
@@ -817,6 +825,12 @@ nth_largest(Tree, N) ->
                  end
     end.
 
+sum_entire_tree(Iter, Acc) ->
+    case gb_trees:next(Iter) of
+        none            -> Acc;
+        {_TS, S, Iter2} -> sum_entire_tree(Iter2, Acc + S)
+    end.
+
 %% What we want to do here is: given the #range{}, provide a set of
 %% samples such that we definitely provide a set of samples which
 %% covers the exact range requested, despite the fact that we might

deps/rabbitmq_management/src/rabbit_mgmt_util.erl

@@ -492,16 +492,27 @@ range(ReqData) -> {range("lengths",    ReqData),
                    range("data_rates", ReqData)}.
 
 range(Prefix, ReqData) ->
-    Age = int(wrq:get_qs_value(Prefix ++ "_age", ReqData), 5) * 1000,
-    Incr = int(wrq:get_qs_value(Prefix ++ "_incr", ReqData), 5) * 1000,
-    %% Take floor on queries so we make sure we only return samples
-    %% for which we've finished receiving events. Fixes the "drop at
-    %% the end" problem.
-    Last = (rabbit_mgmt_format:timestamp_ms(erlang:now()) div Incr) * Incr,
-    #range{first = Last - Age, last = Last, incr = Incr}.
-
-int(Str, Default) ->
-    case catch list_to_integer(Str) of
-        {'EXIT', _} -> Default;
-        Integer     -> Integer
+    Age = int(Prefix ++ "_age", ReqData),
+    Incr = int(Prefix ++ "_incr", ReqData),
+    if
+        is_integer(Age) andalso is_integer(Incr) ->
+            %% Take floor on queries so we make sure we only return samples
+            %% for which we've finished receiving events. Fixes the "drop at
+            %% the end" problem.
+            Now = rabbit_mgmt_format:timestamp_ms(erlang:now()),
+            Last = (Now div Incr) * Incr,
+            #range{first = (Last - Age) * 1000,
+                   last  = Last * 1000,
+                   incr  = Incr * 1000};
+        true ->
+            no_range
+    end.
+
+int(Name, ReqData) ->
+    case wrq:get_qs_value(Name, ReqData) of
+        undefined -> undefined;
+        Str       -> case catch list_to_integer(Str) of
+                         {'EXIT', _} -> undefined;
+                         Integer     -> Integer
+                     end
     end.

deps/rabbitmq_management/test/src/rabbit_mgmt_test_db_unit.erl

@@ -49,10 +49,10 @@ format_sample_details_test() ->
     T = fun ({First, Last, Incr}, Stats, Results) ->
                 ?assertEqual(format(Results),
                              rabbit_mgmt_db:format_sample_details(
-                                        #range{first = First * 1000,
-                                               last  = Last * 1000,
-                                               incr  = Incr * 1000},
-                                        stats(Stats),
+                               #range{first = First * 1000,
+                                      last  = Last * 1000,
+                                      incr  = Incr * 1000},
+                               stats(Stats),
                                Interval * 1000))
         end,
 
@@ -85,6 +85,20 @@ format_sample_details_test() ->
     %% TODO more?
     ok.
 
+format_sample_details_no_range_test() ->
+    Interval = 10,
+    T = fun (Stats, Results) ->
+                ?assertEqual(format(Results),
+                             rabbit_mgmt_db:format_sample_details(
+                               no_range, stats(Stats), Interval * 1000))
+        end,
+
+    %% Just three samples
+    T({[{10, 10}, {20, 20}, {30, 30}], 1},
+      {2.0, 61}),
+    ok.
+
+
 %%--------------------------------------------------------------------
 
 cutoff() ->
@@ -100,6 +114,10 @@ unstats(#stats{diffs = Diffs, base = Base}) ->
 secs_to_millis(L) -> [{TS * 1000, S} || {TS, S} <- L].
 millis_to_secs(L) -> [{TS div 1000, S} || {TS, S} <- L].
 
+format({Rate, Count}) ->
+    {[{rate,     Rate}],
+     Count};
+
 format({Samples, Rate, Count}) ->
     {[{rate,     Rate},
       {samples,  format_samples(Samples)}],