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% Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
%
% Unless required by applicable law or agreed to in writing, software
% distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
% WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
% License for the specific language governing permissions and limitations under
% the License.
-module(couch_stats_httpd).
-include_lib("couch/include/couch_db.hrl").
-export([handle_stats_req/1]).
%% exported for use by chttpd_misc
-export([transform_stats/1, nest/1, to_ejson/1, extract_path/2]).
handle_stats_req(#httpd{method='GET', path_parts=[_ | Path]}=Req) ->
flush(Req),
Stats0 = couch_stats:fetch(),
Stats = transform_stats(Stats0),
Nested = nest(Stats),
EJSON0 = to_ejson(Nested),
EJSON1 = extract_path(Path, EJSON0),
couch_httpd:send_json(Req, EJSON1).
transform_stats(Stats) ->
transform_stats(Stats, []).
transform_stats([], Acc) ->
Acc;
transform_stats([{Key, Props} | Rest], Acc) ->
{_, Type} = proplists:lookup(type, Props),
transform_stats(Rest, [{Key, transform_stat(Type, Props)} | Acc]).
transform_stat(counter, Props) ->
Props;
transform_stat(gauge, Props) ->
Props;
transform_stat(histogram, Props) ->
lists:map(fun
({value, Value}) ->
{value, lists:map(fun
({Key, List}) when Key == percentile; Key == histogram ->
{Key, [tuple_to_list(Item) || Item <- List]};
(Else) ->
Else
end, Value)};
(Else) ->
Else
end, Props).
nest(Proplist) ->
nest(Proplist, []).
nest([], Acc) ->
Acc;
nest([{[Key|Keys], Value}|Rest], Acc) ->
Acc1 = case proplists:lookup(Key, Acc) of
{Key, Old} ->
[{Key, nest([{Keys, Value}], Old)}|proplists:delete(Key, Acc)];
none ->
Term = lists:foldr(fun(K, A) -> [{K, A}] end, Value, Keys),
[{Key, Term}|Acc]
end,
nest(Rest, Acc1).
to_ejson([{_, _}|_]=Proplist) ->
EJSONProps = lists:map(
fun({Key, Value}) -> {maybe_format_key(Key), to_ejson(Value)} end,
Proplist
),
{EJSONProps};
to_ejson(NotAProplist) ->
NotAProplist.
extract_path([], EJSON) ->
EJSON;
extract_path([Key | Rest], {Props}) ->
case proplists:lookup(Key, Props) of
{Key, SubEJSON} ->
extract_path(Rest, SubEJSON);
none ->
null
end;
extract_path([_ | _], _NotAnObject) ->
null.
maybe_format_key(Key) when is_list(Key) ->
list_to_binary(Key);
maybe_format_key(Key) when is_atom(Key) ->
list_to_binary(atom_to_list(Key));
maybe_format_key(Key) when is_integer(Key) ->
list_to_binary(integer_to_list(Key));
maybe_format_key(Key) when is_binary(Key) ->
Key.
flush(Req) ->
case couch_util:get_value("flush", chttpd:qs(Req)) of
"true" ->
couch_stats_aggregator:flush();
_Else ->
ok
end.
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