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% Copyright 2010 Cloudant
%
% 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(fabric_util).
-export([submit_jobs/3, cleanup/1, recv/4, get_db/1, get_db/2, error_info/1,
update_counter/3, remove_ancestors/2, create_monitors/1, kv/2,
remove_down_workers/2]).
-include("fabric.hrl").
-include_lib("mem3/include/mem3.hrl").
-include_lib("couch/include/couch_db.hrl").
-include_lib("eunit/include/eunit.hrl").
remove_down_workers(Workers, BadNode) ->
Filter = fun(#shard{node = Node}, _) -> Node =/= BadNode end,
NewWorkers = fabric_dict:filter(Filter, Workers),
case fabric_view:is_progress_possible(NewWorkers) of
true ->
{ok, NewWorkers};
false ->
error
end.
submit_jobs(Shards, EndPoint, ExtraArgs) ->
lists:map(fun(#shard{node=Node, name=ShardName} = Shard) ->
Ref = rexi:cast(Node, {fabric_rpc, EndPoint, [ShardName | ExtraArgs]}),
Shard#shard{ref = Ref}
end, Shards).
cleanup(Workers) ->
[rexi:kill(Node, Ref) || #shard{node=Node, ref=Ref} <- Workers].
recv(Workers, Keypos, Fun, Acc0) ->
Timeout = case couch_config:get("fabric", "request_timeout", "60000") of
"infinity" -> infinity;
N -> list_to_integer(N)
end,
rexi_utils:recv(Workers, Keypos, Fun, Acc0, Timeout, infinity).
get_db(DbName) ->
get_db(DbName, []).
get_db(DbName, Options) ->
% prefer local shards
{Local, Remote} = lists:partition(fun(S) -> S#shard.node =:= node() end,
mem3:shards(DbName)),
% suppress shards from down nodes
Nodes = erlang:nodes(),
Live = [S || #shard{node = N} = S <- Remote, lists:member(N, Nodes)],
% sort the live remote shards so that we don't repeatedly try the same node
get_shard(Local ++ lists:keysort(#shard.name, Live), Options, 100).
get_shard([], _Opts, _Timeout) ->
erlang:error({internal_server_error, "No DB shards could be opened."});
get_shard([#shard{node = Node, name = Name} | Rest], Opts, Timeout) ->
case rpc:call(Node, couch_db, open, [Name, [{timeout, Timeout} | Opts]]) of
{ok, Db} ->
{ok, Db};
{unauthorized, _} = Error ->
throw(Error);
{badrpc, {'EXIT', {timeout, _}}} ->
get_shard(Rest, Opts, 2*Timeout);
_Else ->
get_shard(Rest, Opts, Timeout)
end.
error_info({{<<"reduce_overflow_error">>, _} = Error, _Stack}) ->
Error;
error_info({{timeout, _} = Error, _Stack}) ->
Error;
error_info({{Error, Reason}, Stack}) ->
{Error, Reason, Stack};
error_info({Error, Stack}) ->
{Error, nil, Stack}.
update_counter(Item, Incr, D) ->
UpdateFun = fun ({Old, Count}) -> {Old, Count + Incr} end,
orddict:update(make_key(Item), UpdateFun, {Item, Incr}, D).
make_key({ok, L}) when is_list(L) ->
make_key(L);
make_key([]) ->
[];
make_key([{ok, #doc{revs= {Pos,[RevId | _]}}} | Rest]) ->
[{ok, {Pos, RevId}} | make_key(Rest)];
make_key([{{not_found, missing}, Rev} | Rest]) ->
[{not_found, Rev} | make_key(Rest)];
make_key({ok, #doc{id=Id,revs=Revs}}) ->
{Id, Revs};
make_key(Else) ->
Else.
% this presumes the incoming list is sorted, i.e. shorter revlists come first
remove_ancestors([], Acc) ->
lists:reverse(Acc);
remove_ancestors([{_, {{not_found, _}, Count}} = Head | Tail], Acc) ->
% any document is a descendant
case lists:filter(fun({_,{{ok, #doc{}}, _}}) -> true; (_) -> false end, Tail) of
[{_,{{ok, #doc{}} = Descendant, _}} | _] ->
remove_ancestors(update_counter(Descendant, Count, Tail), Acc);
[] ->
remove_ancestors(Tail, [Head | Acc])
end;
remove_ancestors([{_,{{ok, #doc{revs = {Pos, Revs}}}, Count}} = Head | Tail], Acc) ->
Descendants = lists:dropwhile(fun
({_,{{ok, #doc{revs = {Pos2, Revs2}}}, _}}) ->
case lists:nthtail(erlang:min(Pos2 - Pos, length(Revs2)), Revs2) of
[] ->
% impossible to tell if Revs2 is a descendant - assume no
true;
History ->
% if Revs2 is a descendant, History is a prefix of Revs
not lists:prefix(History, Revs)
end
end, Tail),
case Descendants of [] ->
remove_ancestors(Tail, [Head | Acc]);
[{Descendant, _} | _] ->
remove_ancestors(update_counter(Descendant, Count, Tail), Acc)
end;
remove_ancestors([Error | Tail], Acc) ->
remove_ancestors(Tail, [Error | Acc]).
create_monitors(Shards) ->
MonRefs = lists:usort([{rexi_server, N} || #shard{node=N} <- Shards]),
rexi_monitor:start(MonRefs).
%% verify only id and rev are used in key.
update_counter_test() ->
Reply = {ok, #doc{id = <<"id">>, revs = <<"rev">>,
body = <<"body">>, atts = <<"atts">>}},
?assertEqual([{{<<"id">>,<<"rev">>}, {Reply, 1}}],
update_counter(Reply, 1, [])).
remove_ancestors_test() ->
Foo1 = {ok, #doc{revs = {1, [<<"foo">>]}}},
Foo2 = {ok, #doc{revs = {2, [<<"foo2">>, <<"foo">>]}}},
Bar1 = {ok, #doc{revs = {1, [<<"bar">>]}}},
Bar2 = {not_found, {1,<<"bar">>}},
?assertEqual(
[kv(Bar1,1), kv(Foo1,1)],
remove_ancestors([kv(Bar1,1), kv(Foo1,1)], [])
),
?assertEqual(
[kv(Bar1,1), kv(Foo2,2)],
remove_ancestors([kv(Bar1,1), kv(Foo1,1), kv(Foo2,1)], [])
),
?assertEqual(
[kv(Bar1,2)],
remove_ancestors([kv(Bar2,1), kv(Bar1,1)], [])
).
%% test function
kv(Item, Count) ->
{make_key(Item), {Item,Count}}.
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