diff options
Diffstat (limited to 'src/ranch_conns_sup.erl')
| -rw-r--r-- | src/ranch_conns_sup.erl | 172 |
1 files changed, 156 insertions, 16 deletions
diff --git a/src/ranch_conns_sup.erl b/src/ranch_conns_sup.erl index 3cc09be..eaa4d00 100644 --- a/src/ranch_conns_sup.erl +++ b/src/ranch_conns_sup.erl @@ -13,30 +13,170 @@ %% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. %% @private +%% +%% Make sure to never reload this module outside a release upgrade, +%% as calling l(ranch_conns_sup) twice will kill the process and all +%% the currently open connections. -module(ranch_conns_sup). --behaviour(supervisor). %% API. --export([start_link/1]). --export([start_protocol/5]). +-export([start_link/3]). +-export([start_protocol/2]). +-export([active_connections/1]). + +%% Supervisor internals. +-export([init/4]). +-export([system_continue/3]). +-export([system_terminate/4]). +-export([system_code_change/4]). -%% supervisor. --export([init/1]). +-record(state, { + parent = undefined :: pid(), + ref :: any(), + transport = undefined :: module(), + protocol = undefined :: module(), + opts :: any(), + max_conns = undefined :: non_neg_integer() | infinity +}). %% API. --spec start_link(any()) -> {ok, pid()}. -start_link(Ref) -> - supervisor:start_link(?MODULE, Ref). +-spec start_link(any(), module(), module()) -> {ok, pid()}. +start_link(Ref, Transport, Protocol) -> + proc_lib:start_link(?MODULE, init, [self(), Ref, Transport, Protocol]). + +%% We can safely assume we are on the same node as the supervisor. +%% +%% We can also safely avoid having a monitor and a timeout here +%% because only three things can happen: +%% * The supervisor died; rest_for_one strategy killed all acceptors +%% so this very calling process is going to di-- +%% * There's too many connections, the supervisor will resume the +%% acceptor only when we get below the limit again. +%% * The supervisor is overloaded, there's either too many acceptors +%% or the max_connections limit is too large. It's better if we +%% don't keep accepting connections because this leaves +%% more room for the situation to be resolved. +%% +%% We do not need the reply, we only need the ok from the supervisor +%% to continue. The supervisor sends its own pid when the acceptor can +%% continue. +-spec start_protocol(pid(), inet:socket()) -> ok. +start_protocol(SupPid, Socket) -> + SupPid ! {?MODULE, start_protocol, self(), Socket}, + receive SupPid -> ok end. --spec start_protocol(pid(), inet:socket(), module(), module(), any()) - -> {ok, pid()}. -start_protocol(ListenerPid, Socket, Transport, Protocol, Opts) -> - Protocol:start_link(ListenerPid, Socket, Transport, Opts). +%% We can't make the above assumptions here. This function might be +%% called from anywhere. +-spec active_connections(pid()) -> non_neg_integer(). +active_connections(SupPid) -> + Tag = erlang:monitor(process, SupPid), + erlang:send(SupPid, {?MODULE, active_connections, self(), Tag}, + [noconnect]), + receive + {Tag, Ret} -> + erlang:demonitor(Tag, [flush]), + Ret; + {'DOWN', Tag, _, _, noconnection} -> + exit({nodedown, node(SupPid)}); + {'DOWN', Tag, _, _, Reason} -> + exit(Reason) + after 5000 -> + erlang:demonitor(Tag, [flush]), + exit(timeout) + end. -%% supervisor. +%% Supervisor internals. -init(Ref) -> +-spec init(pid(), any(), module(), module()) -> no_return(). +init(Parent, Ref, Transport, Protocol) -> + process_flag(trap_exit, true), ok = ranch_server:set_connections_sup(Ref, self()), - {ok, {{simple_one_for_one, 0, 1}, [{?MODULE, {?MODULE, start_protocol, []}, - temporary, brutal_kill, worker, [?MODULE]}]}}. + MaxConns = ranch_server:get_max_connections(Ref), + Opts = ranch_server:get_protocol_options(Ref), + ok = proc_lib:init_ack(Parent, {ok, self()}), + loop(#state{parent=Parent, ref=Ref, transport=Transport, + protocol=Protocol, opts=Opts, max_conns=MaxConns}, 0, 0, []). + +loop(State=#state{parent=Parent, ref=Ref, + transport=Transport, protocol=Protocol, opts=Opts, + max_conns=MaxConns}, CurConns, NbChildren, Sleepers) -> + receive + {?MODULE, start_protocol, To, Socket} -> + case Protocol:start_link(Ref, Socket, Transport, Opts) of + {ok, Pid} -> + Transport:controlling_process(Socket, Pid), + Pid ! {shoot, Ref}, + put(Pid, true), + CurConns2 = CurConns + 1, + if CurConns2 < MaxConns -> + To ! self(), + loop(State, CurConns2, NbChildren + 1, + Sleepers); + true -> + loop(State, CurConns2, NbChildren + 1, + [To|Sleepers]) + end; + _ -> + To ! self(), + loop(State, CurConns, NbChildren, Sleepers) + end; + {?MODULE, active_connections, To, Tag} -> + To ! {Tag, CurConns}, + loop(State, CurConns, NbChildren, Sleepers); + %% Remove a connection from the count of connections. + {remove_connection, Ref} -> + loop(State, CurConns - 1, NbChildren, Sleepers); + %% Upgrade the max number of connections allowed concurrently. + %% We resume all sleeping acceptors if this number increases. + {set_max_conns, MaxConns2} when MaxConns2 > MaxConns -> + _ = [To ! self() || To <- Sleepers], + loop(State#state{max_conns=MaxConns2}, + CurConns, NbChildren, []); + {set_max_conns, MaxConns2} -> + loop(State#state{max_conns=MaxConns2}, + CurConns, NbChildren, Sleepers); + %% Upgrade the protocol options. + {set_opts, Opts2} -> + loop(State#state{opts=Opts2}, + CurConns, NbChildren, Sleepers); + {'EXIT', Parent, Reason} -> + exit(Reason); + {'EXIT', Pid, _} when Sleepers =:= [] -> + erase(Pid), + loop(State, CurConns - 1, NbChildren - 1, Sleepers); + %% Resume a sleeping acceptor if needed. + {'EXIT', Pid, _} -> + erase(Pid), + [To|Sleepers2] = Sleepers, + To ! self(), + loop(State, CurConns - 1, NbChildren - 1, Sleepers2); + {system, From, Request} -> + sys:handle_system_msg(Request, From, Parent, ?MODULE, [], + {State, CurConns, NbChildren, Sleepers}); + %% Calls from the supervisor module. + {'$gen_call', {To, Tag}, which_children} -> + Pids = get_keys(true), + Children = [{Protocol, Pid, worker, [Protocol]} + || Pid <- Pids], + To ! {Tag, Children}, + loop(State, CurConns, NbChildren, Sleepers); + {'$gen_call', {To, Tag}, count_children} -> + Counts = [{specs, 1}, {active, NbChildren}, + {supervisors, 0}, {workers, NbChildren}], + To ! {Tag, Counts}, + loop(State, CurConns, NbChildren, Sleepers); + {'$gen_call', {To, Tag}, _} -> + To ! {Tag, {error, ?MODULE}}, + loop(State, CurConns, NbChildren, Sleepers) + end. + +system_continue(_, _, {State, CurConns, NbChildren, Sleepers}) -> + loop(State, CurConns, NbChildren, Sleepers). + +-spec system_terminate(any(), _, _, _) -> no_return(). +system_terminate(Reason, _, _, _) -> + exit(Reason). + +system_code_change(Misc, _, _, _) -> + {ok, Misc}. |