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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_doc_open).
-export([go/3]).
-include("fabric.hrl").
-include_lib("mem3/include/mem3.hrl").
-include_lib("couch/include/couch_db.hrl").
go(DbName, Id, Options) ->
Workers = fabric_util:submit_jobs(mem3:shards(DbName,Id), open_doc,
[Id, [deleted|Options]]),
SuppressDeletedDoc = not lists:member(deleted, Options),
R = couch_util:get_value(r, Options, couch_config:get("cluster","r","2")),
RepairOpts = [{r, integer_to_list(mem3:n(DbName))} | Options],
Acc0 = {length(Workers), list_to_integer(R), []},
case fabric_util:recv(Workers, #shard.ref, fun handle_message/3, Acc0) of
{ok, Reply} ->
format_reply(Reply, SuppressDeletedDoc);
{error, needs_repair, Reply} ->
spawn(fabric, open_revs, [DbName, Id, all, RepairOpts]),
format_reply(Reply, SuppressDeletedDoc);
{error, needs_repair} ->
% we couldn't determine the correct reply, so we'll run a sync repair
{ok, Results} = fabric:open_revs(DbName, Id, all, RepairOpts),
case lists:partition(fun({ok, #doc{deleted=Del}}) -> Del end, Results) of
{[], []} ->
{not_found, missing};
{_DeletedDocs, []} when SuppressDeletedDoc ->
{not_found, deleted};
{DeletedDocs, []} ->
lists:last(lists:sort(DeletedDocs));
{_, LiveDocs} ->
lists:last(lists:sort(LiveDocs))
end;
Error ->
Error
end.
format_reply({ok, #doc{deleted=true}}, true) ->
{not_found, deleted};
format_reply(Else, _) ->
Else.
handle_message({rexi_DOWN, _, _, _}, _Worker, Acc0) ->
skip_message(Acc0);
handle_message({rexi_EXIT, _Reason}, _Worker, Acc0) ->
skip_message(Acc0);
handle_message(Reply, _Worker, {WaitingCount, R, Replies}) ->
NewReplies = orddict:update_counter(Reply, 1, Replies),
Reduced = fabric_util:remove_ancestors(NewReplies, []),
case lists:dropwhile(fun({_, Count}) -> Count < R end, Reduced) of
[{QuorumReply, _} | _] ->
if length(NewReplies) =:= 1 ->
{stop, QuorumReply};
true ->
% we had some disagreement amongst the workers, so repair is useful
{error, needs_repair, QuorumReply}
end;
[] ->
if WaitingCount =:= 1 ->
{error, needs_repair};
true ->
{ok, {WaitingCount-1, R, NewReplies}}
end
end.
skip_message({1, _R, _Replies}) ->
{error, needs_repair};
skip_message({WaitingCount, R, Replies}) ->
{ok, {WaitingCount-1, R, Replies}}.
open_doc_test() ->
Foo1 = {ok, #doc{revs = {1,[<<"foo">>]}}},
Foo2 = {ok, #doc{revs = {2,[<<"foo2">>,<<"foo">>]}}},
Bar1 = {ok, #doc{revs = {1,[<<"bar">>]}}},
Baz1 = {ok, #doc{revs = {1,[<<"baz">>]}}},
NF = {not_found, missing},
State0 = {3, 2, []},
State1 = {2, 2, [{Foo1,1}]},
State2 = {1, 2, [{Bar1,1}, {Foo1,1}]},
?assertEqual({ok, State1}, handle_message(Foo1, nil, State0)),
% normal case - quorum reached, no disagreement
?assertEqual({stop, Foo1}, handle_message(Foo1, nil, State1)),
% 2nd worker disagrees, voting continues
?assertEqual({ok, State2}, handle_message(Bar1, nil, State1)),
% 3rd worker resolves voting, but repair is needed
?assertEqual({error, needs_repair, Foo1}, handle_message(Foo1, nil, State2)),
% 2nd worker comes up with descendant of Foo1, voting resolved, run repair
?assertEqual({error, needs_repair, Foo2}, handle_message(Foo2, nil, State1)),
% not_found is considered to be an ancestor of everybody
?assertEqual({error, needs_repair, Foo1}, handle_message(NF, nil, State1)),
% 3 distinct edit branches result in quorum failure
?assertEqual({error, needs_repair}, handle_message(Baz1, nil, State2)),
% bad node concludes voting w/o success, run sync repair to get the result
?assertEqual(
{error, needs_repair},
handle_message({rexi_DOWN, 1, 2, 3}, nil, State2)
).
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