diff options
Diffstat (limited to 'src/cowboy_listener.erl')
| -rw-r--r-- | src/cowboy_listener.erl | 55 |
1 files changed, 23 insertions, 32 deletions
diff --git a/src/cowboy_listener.erl b/src/cowboy_listener.erl index c19d079..8998e13 100644 --- a/src/cowboy_listener.erl +++ b/src/cowboy_listener.erl @@ -16,15 +16,16 @@ -module(cowboy_listener). -behaviour(gen_server). --export([start_link/0, stop/1, - add_connection/3, move_connection/3, remove_connection/2, wait/3]). %% API. +-export([start_link/1, stop/1, + add_connection/3, move_connection/3, remove_connection/2]). %% API. -export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]). %% gen_server. -record(state, { req_pools = [] :: [{atom(), non_neg_integer()}], reqs_table :: ets:tid(), - queue = [] :: [{pid(), reference()}] + queue = [] :: [{pid(), reference()}], + max_conns = undefined :: non_neg_integer() }). %% API. @@ -36,9 +37,10 @@ %% Setting the process priority to high ensures the connection-related code %% will always be executed when a connection needs it, allowing Cowboy to %% scale far beyond what it would with a normal priority. --spec start_link() -> {ok, pid()}. -start_link() -> - gen_server:start_link(?MODULE, [], [{spawn_opt, [{priority, high}]}]). +-spec start_link(non_neg_integer()) -> {ok, pid()}. +start_link(MaxConns) -> + gen_server:start_link(?MODULE, [MaxConns], + [{spawn_opt, [{priority, high}]}]). %% @private -spec stop(pid()) -> stopped. @@ -50,15 +52,16 @@ stop(ServerPid) -> %% Pools of connections are used to restrict the maximum number of connections %% depending on their type. By default, Cowboy add all connections to the %% pool <em>default</em>. It also checks for the maximum number of connections -%% in that pool before accepting again. +%% in that pool before accepting again. This function only returns when there +%% is free space in the pool. %% %% When a process managing a connection dies, the process is removed from the %% pool. If the socket has been sent to another process, it is up to the %% protocol code to inform the listener of the new <em>ConnPid</em> by removing %% the previous and adding the new one. --spec add_connection(pid(), atom(), pid()) -> {ok, non_neg_integer()}. +-spec add_connection(pid(), atom(), pid()) -> ok. add_connection(ServerPid, Pool, ConnPid) -> - gen_server:call(ServerPid, {add_connection, Pool, ConnPid}). + gen_server:call(ServerPid, {add_connection, Pool, ConnPid}, infinity). %% @doc Move a connection from one pool to another. -spec move_connection(pid(), atom(), pid()) -> ok. @@ -70,30 +73,22 @@ move_connection(ServerPid, DestPool, ConnPid) -> remove_connection(ServerPid, ConnPid) -> gen_server:cast(ServerPid, {remove_connection, ConnPid}). -%% @doc Wait until the number of connections in the given pool gets below -%% the given threshold. -%% -%% This function will not return until the number of connections in the pool -%% gets below <em>MaxConns</em>. It makes use of <em>gen_server:reply/2</em> -%% to make the process wait for a reply indefinitely. --spec wait(pid(), atom(), non_neg_integer()) -> ok. -wait(ServerPid, Pool, MaxConns) -> - gen_server:call(ServerPid, {wait, Pool, MaxConns}, infinity). - %% gen_server. %% @private --spec init([]) -> {ok, #state{}}. -init([]) -> +-spec init(list()) -> {ok, #state{}}. +init([MaxConns]) -> ReqsTablePid = ets:new(requests_table, [set, private]), - {ok, #state{reqs_table=ReqsTablePid}}. + {ok, #state{reqs_table=ReqsTablePid, max_conns=MaxConns}}. %% @private -spec handle_call(_, _, State) -> {reply, ignored, State} | {stop, normal, stopped, State}. -handle_call({add_connection, Pool, ConnPid}, _From, State=#state{ - req_pools=Pools, reqs_table=ReqsTable}) -> +handle_call({add_connection, Pool, ConnPid}, From, State=#state{ + req_pools=Pools, reqs_table=ReqsTable, + queue=Queue, max_conns=MaxConns}) -> MonitorRef = erlang:monitor(process, ConnPid), + ConnPid ! {shoot, self()}, {NbConnsRet, Pools2} = case lists:keyfind(Pool, 1, Pools) of false -> {1, [{Pool, 1}|Pools]}; @@ -102,14 +97,10 @@ handle_call({add_connection, Pool, ConnPid}, _From, State=#state{ {NbConns2, [{Pool, NbConns2}|lists:keydelete(Pool, 1, Pools)]} end, ets:insert(ReqsTable, {ConnPid, {MonitorRef, Pool}}), - {reply, {ok, NbConnsRet}, State#state{req_pools=Pools2}}; -handle_call({wait, Pool, MaxConns}, From, State=#state{ - req_pools=Pools, queue=Queue}) -> - case lists:keyfind(Pool, 1, Pools) of - {Pool, NbConns} when NbConns > MaxConns -> - {noreply, State#state{queue=[From|Queue]}}; - _Any -> - {reply, ok, State} + if NbConnsRet > MaxConns -> + {noreply, State#state{req_pools=Pools2, queue=[From|Queue]}}; + true -> + {reply, ok, State#state{req_pools=Pools2}} end; handle_call(stop, _From, State) -> {stop, normal, stopped, State}; |