From 8ea7e1aa67d2be6c22c93273a47923718a2d44d2 Mon Sep 17 00:00:00 2001 From: Adam Kocoloski Date: Thu, 16 Jul 2009 20:48:35 +0000 Subject: first cut at _changes feed consumer. not yet used by replication git-svn-id: https://svn.apache.org/repos/asf/couchdb/trunk@794848 13f79535-47bb-0310-9956-ffa450edef68 --- src/couchdb/Makefile.am | 2 + src/couchdb/couch_rep_changes_feed.erl | 174 +++++++++++++++++++++++++++++++++ 2 files changed, 176 insertions(+) create mode 100644 src/couchdb/couch_rep_changes_feed.erl (limited to 'src/couchdb') diff --git a/src/couchdb/Makefile.am b/src/couchdb/Makefile.am index 4b4f4ab2..80f4b541 100644 --- a/src/couchdb/Makefile.am +++ b/src/couchdb/Makefile.am @@ -72,6 +72,7 @@ source_files = \ couch_query_servers.erl \ couch_ref_counter.erl \ couch_rep.erl \ + couch_rep_changes_feed.erl \ couch_rep_sup.erl \ couch_server.erl \ couch_server_sup.erl \ @@ -116,6 +117,7 @@ compiled_files = \ couch_query_servers.beam \ couch_ref_counter.beam \ couch_rep.beam \ + couch_rep_changes_feed.beam \ couch_rep_sup.beam \ couch_server.beam \ couch_server_sup.beam \ diff --git a/src/couchdb/couch_rep_changes_feed.erl b/src/couchdb/couch_rep_changes_feed.erl new file mode 100644 index 00000000..bf69e100 --- /dev/null +++ b/src/couchdb/couch_rep_changes_feed.erl @@ -0,0 +1,174 @@ +% 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_rep_changes_feed). +-behaviour(gen_server). +-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, + code_change/3]). + +-export([start/2, start_link/2, next/1, stop/1]). + +-define(MIN_BUFFER_SIZE, 100). + +-include("couch_db.hrl"). +-include("../ibrowse/ibrowse.hrl"). + +-record (state, { + conn = nil, + reqid = nil, + count = 0, + reply_to = nil, + rows = queue:new(), + complete = false +}). + +start(Url, Options) -> + gen_server:start(?MODULE, [Url, Options], []). + +start_link(Url, Options) -> + gen_server:start_link(?MODULE, [Url, Options], []). + +next(Server) -> + ?LOG_DEBUG("~p at ~p received next_change call", [?MODULE, Server]), + gen_server:call(Server, next_change, infinity). + +stop(Server) -> + gen_server:call(Server, stop). + +init([{remote, Url}, Options]) -> + Since = proplists:get_value(since, Options, 0), + Continuous = proplists:get_value(continuous, Options, false), + {Pid, ReqId} = start_http_request(lists:concat([Url, "/_changes", + "?style=all_docs", "&since=", Since, "&continuous=", Continuous])), + {ok, #state{conn=Pid, reqid=ReqId}}; + +init([{local, DbName}, Options]) -> + init([{remote, "http://" ++ couch_config:get("httpd", "bind_address") ++ ":" + ++ couch_config:get("httpd", "port") ++ "/" ++ DbName}, Options]). + +handle_call(next_change, From, State) -> + #state{ + reqid = Id, + complete = Complete, + count = Count, + rows = Rows + } = State, + + ok = maybe_stream_next(Complete, Count, Id), + + case queue:out(Rows) of + {{value, Row}, NewRows} -> + {reply, Row, State#state{count=Count-1, rows=NewRows}}; + {empty, Rows} -> + if State#state.complete -> + {stop, normal, complete, State}; + % State#state.waiting_on_headers -> + % {noreply, State#state{reply_to=From}}; + true -> + {noreply, State#state{reply_to=From}} + end + end; + +handle_call(stop, _From, State) -> + catch ibrowse:stop_worker_process(State#state.conn), + {stop, normal, ok, State}. + +handle_cast(_Msg, State) -> + {noreply, State}. + +handle_info({ibrowse_async_headers, Id, "200", _}, #state{reqid=Id}=State) -> + #state{ + complete = Complete, + count = Count + } = State, + ?LOG_DEBUG("~p reqid ~p ibrowse_async_headers 200", [?MODULE, Id]), + ok = maybe_stream_next(Complete, Count, Id), + {noreply, State}; +handle_info({ibrowse_async_headers, Id, "301", Hdrs}, #state{reqid=Id}=State) -> + ?LOG_DEBUG("~p reqid ~p ibrowse_async_headers 301", [?MODULE, Id]), + catch ibrowse:stop_worker_process(State#state.conn), + Url = mochiweb_headers:get_value("Location", mochiweb_headers:make(Hdrs)), + {Pid, ReqId} = start_http_request(Url), + {noreply, State#state{conn=Pid, reqid=ReqId}}; +handle_info({ibrowse_async_headers, Id, Code, Hdrs}, #state{reqid=Id}=State) -> + ?LOG_ERROR("replicator changes feed failed with code ~s and Headers ~n~p", + [Code,Hdrs]), + {stop, {error, list_to_integer(Code)}, State}; + +handle_info({ibrowse_async_response, Id, Msg}, #state{reqid=Id} = State) -> + ?LOG_DEBUG("~p reqid ~p ibrowse_async_response ~p", [?MODULE, Id, Msg]), + #state{ + complete = Complete, + count = Count, + rows = Rows + } = State, + try + Row = decode_row(Msg), + case State of + #state{reply_to=nil} -> + {noreply, State#state{count=Count+1, rows = queue:in(Row, Rows)}}; + #state{count=0, reply_to=From}-> + gen_server:reply(From, Row), + {noreply, State#state{reply_to=nil}} + end + catch + throw:{invalid_json, Msg} -> + ?LOG_DEBUG("got invalid_json ~p", [Msg]), + ok = maybe_stream_next(Complete, Count, Id), + {noreply, State} + end; + +handle_info({ibrowse_async_response_end, Id}, #state{reqid=Id} = State) -> + ?LOG_DEBUG("got ibrowse_async_response_end ~p", [State#state.reply_to]), + case State of + #state{reply_to=nil} -> + {noreply, State#state{complete=true}}; + #state{count=0, reply_to=From}-> + gen_server:reply(From, complete), + {stop, normal, State} + end; + +handle_info(Msg, State) -> + ?LOG_INFO("unexpected message ~p", [Msg]), + {noreply, State}. + +terminate(_Reason, #state{conn=Pid}) when is_pid(Pid) -> + catch ibrowse:stop_worker_process(Pid), + ok; +terminate(_Reason, _State) -> + ok. + +code_change(_OldVsn, State, _Extra) -> + {ok, State}. + +decode_row([$,, $\n | Rest]) -> + decode_row(Rest); +decode_row(Row) -> + ?JSON_DECODE(Row). + +maybe_stream_next(false, Count, Id) when Count < ?MIN_BUFFER_SIZE -> + ?LOG_DEBUG("~p reqid ~p streaming next chunk", [?MODULE, Id]), + ibrowse:stream_next(Id); +maybe_stream_next(_Complete, _Count, Id) -> + ?LOG_DEBUG("~p reqid ~p not streaming", [?MODULE, Id]), + ok. + +start_http_request(RawUrl) -> + Url = ibrowse_lib:parse_url(RawUrl), + {ok, Pid} = ibrowse:spawn_link_worker_process(Url#url.host, Url#url.port), + Opts = [ + {stream_to, {self(), once}}, + {inactivity_timeout, 30000} + ], + {ibrowse_req_id, Id} = + ibrowse:send_req_direct(Pid, RawUrl, [], get, [], Opts, infinity), + {Pid, Id}. -- cgit v1.2.3