nickva commented on code in PR #4201: URL: https://github.com/apache/couchdb/pull/4201#discussion_r998889559
########## src/fabric/src/fabric_open_revs.erl: ########## @@ -0,0 +1,455 @@ +% 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_open_revs). + +-export([ + go/3 +]). + +-include_lib("mem3/include/mem3.hrl"). +-include_lib("couch/include/couch_db.hrl"). + +-record(req, { + idrevs, + wcnt = 0, + rcnt = 0, + responses = [] +}). + +-record(st, { + r, + args, + reqs, + workers +}). + +go(_DbName, [], _Options) -> + {ok, []}; +go(DbName, IdsRevsOpts, Options) -> + St = init_state(DbName, IdsRevsOpts, Options), + WShards = maps:keys(St#st.workers), + RexiMon = fabric_util:create_monitors(WShards), + try fabric_util:recv(WShards, #shard.ref, fun handle_message/3, St) of + {timeout, #st{workers = #{} = Workers1}} -> + stop_workers(Workers1), + fabric_util:log_timeout(maps:keys(Workers1), "open_revs"), + {error, timeout}; + Else -> + Else + after + rexi_monitor:stop(RexiMon) + end. + +handle_message([_ | _] = Resps, Worker, #st{} = St) -> + #st{workers = Workers, reqs = Reqs, r = R} = St, + {ArgsRefs, Workers1} = maps:take(Worker, Workers), + ArgsResps = lists:zip(ArgsRefs, Resps), + Reqs1 = lists:foldl(fun responses_fold/2, Reqs, ArgsResps), + case not r_met(Reqs1, R) andalso have_viable_workers(Workers1) of + true -> + {ok, St#st{workers = Workers1, reqs = Reqs1}}; + false -> + stop_workers(Workers1), + {stop, finalize(St#st.args, Reqs1)} + end; +handle_message({rexi_DOWN, _, {_, NodeRef}, _}, _Worker, #st{} = St) -> + #st{workers = Workers, reqs = Reqs} = St, + FilterFun = fun(#shard{node = N}) -> N =:= NodeRef end, + DeadKeys = lists:filter(FilterFun, maps:keys(Workers)), + Workers1 = maps:without(DeadKeys, Workers), + DeadWorkers = maps:with(DeadKeys, Workers), + FoldFun = fun(_, ArgRefs, Acc) -> update_wcnt(Acc, ArgRefs, -1) end, + Reqs1 = maps:fold(FoldFun, Reqs, DeadWorkers), + Error = {error, {nodedown, <<"progress not possible">>}}, + handle_error(Error, St#st{workers = Workers1, reqs = Reqs1}); +handle_message({rexi_EXIT, Reason}, Worker, #st{} = St) -> + handle_message(Reason, Worker, St); +handle_message({error, Reason}, Worker, #st{} = St) -> + handle_message(Reason, Worker, St); +handle_message(Reason, Worker, #st{} = St) -> + #st{workers = Workers, reqs = Reqs} = St, + {DeadArgRefs, Workers1} = maps:take(Worker, Workers), + Reqs1 = update_wcnt(Reqs, DeadArgRefs, -1), + handle_error(Reason, St#st{workers = Workers1, reqs = Reqs1}). + +init_state(DbName, IdsRevsOpts, Options) -> + DefaultR = integer_to_list(mem3:quorum(DbName)), + R = list_to_integer(couch_util:get_value(r, Options, DefaultR)), + {ArgRefs, Reqs0} = build_req_map(IdsRevsOpts), + ShardMap = build_worker_map(DbName, Reqs0), + {Workers, Reqs} = spawn_workers(Reqs0, ShardMap, Options), + #st{r = R, args = ArgRefs, reqs = Reqs, workers = Workers}. + +responses_fold({ArgRef, NewResp}, #{} = Reqs) -> Review Comment: In this case it would be a more general "folding over" the responses. That's the main iteration over all the requests and updating them with the new information returned. Inside we both dedupe and also do some accounting to update the response count and worker count. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
