[GitHub] sagelywizard commented on a change in pull request #470: Scheduling Replicator

[gi...@git.apache.org]

sagelywizard commented on a change in pull request #470: Scheduling Replicator
URL: https://github.com/apache/couchdb/pull/470#discussion_r110499534
 
 

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 File path: src/couch_replicator/src/couch_replicator_connection.erl
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 @@ -0,0 +1,211 @@
+% 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_replicator_connection).
+
+-behavior(gen_server).
+-behavior(config_listener).
+
+-export([start_link/0]).
+-export([init/1, handle_call/3, handle_cast/2, handle_info/2]).
+-export([code_change/3, terminate/2]).
+
+-export([acquire/1, relinquish/1]).
+
+-export([handle_config_change/5, handle_config_terminate/3]).
+
+-define(DEFAULT_CLOSE_INTERVAL, 90000).
+-define(RELISTEN_DELAY, 5000).
+
+-record(state, {
+    close_interval,
+    timer
+}).
+
+-record(connection, {
+    worker,
+    host,
+    port,
+    mref
+}).
+
+-include_lib("ibrowse/include/ibrowse.hrl").
+
+
+start_link() ->
+    gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
+
+
+init([]) ->
+    process_flag(trap_exit, true),
+    ?MODULE = ets:new(?MODULE, [named_table, public, {keypos, #connection.worker}]),
+    ok = config:listen_for_changes(?MODULE, nil),
+    Interval = config:get_integer("replicator", "connection_close_interval", ?DEFAULT_CLOSE_INTERVAL),
+    {ok, Timer} = timer:send_after(Interval, close_idle_connections),
+    ibrowse:add_config([{inactivity_timeout, Interval}]),
+    {ok, #state{close_interval=Interval, timer=Timer}}.
+
+
+acquire(URL) when is_binary(URL) ->
+    acquire(binary_to_list(URL));
+
+acquire(URL) ->
+    case gen_server:call(?MODULE, {acquire, URL}) of
+        {ok, Worker} ->
+            link(Worker),
+            {ok, Worker};
+        {error, all_allocated} ->
+            {ok, Pid} = ibrowse:spawn_link_worker_process(URL),
+            ok = gen_server:call(?MODULE, {create, URL, Pid}),
+            {ok, Pid};
+        {error, Reason} ->
+            {error, Reason}
+    end.
+
+
+relinquish(Worker) ->
+    unlink(Worker),
+    gen_server:cast(?MODULE, {relinquish, Worker}).
+
+
+handle_call({acquire, URL}, From, State) ->
+    {Pid, _Ref} = From,
+    case ibrowse_lib:parse_url(URL) of
+        #url{host=Host, port=Port} ->
 
 Review comment:
   Yeah, I had the same concern too, but I did a dig through the ibrowse code and was satisfied that it didn't share credentials between requests. Just checked again and ibrowse doesn't even stick the auth in the initialization. It has to be passed in the request itself. Also, ibrowse keeps per-request state, which is where the auth is kept during the request. If the request completes successfully, that state is lost. If there's an error, the whole proc dies. If two clients make a request to the same worker (which shouldn't happen), the client pid is recorded alongside the request data, so the streams wouldn't get crossed.
 
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