From c0ec1ad4a932dfb9970909f20699bdc803692535 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Lo=C3=AFc=20Hoguin?= Date: Tue, 8 Aug 2017 21:39:23 +0200 Subject: Add missing cowboy_children module My bad! Still new at this. --- src/cowboy_children.erl | 160 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 160 insertions(+) create mode 100644 src/cowboy_children.erl diff --git a/src/cowboy_children.erl b/src/cowboy_children.erl new file mode 100644 index 0000000..28fcce4 --- /dev/null +++ b/src/cowboy_children.erl @@ -0,0 +1,160 @@ +%% Copyright (c) 2017, Loïc Hoguin +%% +%% Permission to use, copy, modify, and/or distribute this software for any +%% purpose with or without fee is hereby granted, provided that the above +%% copyright notice and this permission notice appear in all copies. +%% +%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES +%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF +%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR +%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN +%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF +%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + +-module(cowboy_children). + +-export([init/0]). +-export([up/4]). +-export([down/2]). +-export([shutdown/2]). +-export([shutdown_timeout/3]). +-export([terminate/1]). +-export([which_children/2]). +-export([count_children/1]). + +-record(child, { + pid :: pid(), + streamid :: cowboy_stream:streamid() | undefined, + shutdown :: timeout(), + timer = undefined :: undefined | reference() +}). + +-type children() :: [#child{}]. +-export_type([children/0]). + +-spec init() -> []. +init() -> + []. + +-spec up(Children, pid(), cowboy_stream:streamid(), timeout()) + -> Children when Children::children(). +up(Children, Pid, StreamID, Shutdown) -> + [#child{ + pid=Pid, + streamid=StreamID, + shutdown=Shutdown + }|Children]. + +-spec down(Children, pid()) + -> {ok, cowboy_stream:streamid() | undefined, Children} | error + when Children::children(). +down(Children0, Pid) -> + case lists:keytake(Pid, #child.pid, Children0) of + {value, #child{streamid=StreamID, timer=Ref}, Children} -> + _ = case Ref of + undefined -> ok; + _ -> erlang:cancel_timer(Ref, [{async, true}, {info, false}]) + end, + {ok, StreamID, Children}; + false -> + error + end. + +%% We ask the processes to shutdown first. This gives +%% a chance to processes that are trapping exits to +%% shut down gracefully. Others will exit immediately. +%% +%% @todo We currently fire one timer per process being +%% shut down. This is probably not the most efficient. +%% A more efficient solution could be to maintain a +%% single timer and decrease the shutdown time of all +%% processes when it fires. This is however much more +%% complex, and there aren't that many processes that +%% will need to be shutdown through this function, so +%% this is left for later. +-spec shutdown(Children, cowboy_stream:streamid()) + -> Children when Children::children(). +shutdown(Children0, StreamID) -> + [ + case Child of + #child{pid=Pid, streamid=StreamID, shutdown=Shutdown} -> + exit(Pid, shutdown), + Ref = erlang:start_timer(Shutdown, self(), {shutdown, Pid}), + Child#child{streamid=undefined, timer=Ref}; + _ -> + Child + end + || Child <- Children0]. + +-spec shutdown_timeout(children(), reference(), pid()) -> ok. +shutdown_timeout(Children, Ref, Pid) -> + case lists:keyfind(Pid, #child.pid, Children) of + #child{timer=Ref} -> + exit(Pid, kill), + ok; + _ -> + ok + end. + +-spec terminate(children()) -> ok. +terminate(Children) -> + %% Ask all children to shutdown first. + _ = [exit(Pid, shutdown) || #child{pid=Pid} <- Children], + %% Loop until that time or until all children are dead. + before_terminate_loop(Children). + +before_terminate_loop([]) -> + ok; +before_terminate_loop(Children) -> + %% Find the longest shutdown time. + Time = longest_shutdown_time(Children, 0), + %% We delay the creation of the timer if one of the + %% processes has an infinity shutdown value. + TRef = case Time of + infinity -> undefined; + _ -> erlang:start_timer(Time, self(), terminate) + end, + terminate_loop(Children, TRef). + +terminate_loop([], _) -> + ok; +terminate_loop(Children, TRef) -> + receive + {'EXIT', Pid, _} when TRef =:= undefined -> + {value, #child{shutdown=Shutdown}, Children1} + = lists:keytake(Pid, #child.pid, Children), + %% We delayed the creation of the timer. If a process with + %% infinity shutdown just ended, we might have to start that timer. + case Shutdown of + infinity -> before_terminate_loop(Children1); + _ -> terminate_loop(Children1, TRef) + end; + {'EXIT', Pid, _} -> + terminate_loop(lists:keydelete(Pid, #child.pid, Children), TRef); + {timeout, TRef, terminate} -> + %% Brutally kill any remaining children. + _ = [exit(Pid, kill) || #child{pid=Pid} <- Children], + ok + end. + +longest_shutdown_time([], Time) -> + Time; +longest_shutdown_time([#child{shutdown=ChildTime}|Tail], Time) when ChildTime > Time -> + longest_shutdown_time(Tail, ChildTime); +longest_shutdown_time([_|Tail], Time) -> + longest_shutdown_time(Tail, Time). + +-spec which_children(children(), module()) -> [{module(), pid(), worker, [module()]}]. +which_children(Children, Module) -> + [{Module, Pid, worker, [Module]} || #child{pid=Pid} <- Children]. + +-spec count_children(children()) -> [{atom(), non_neg_integer()}]. +count_children(Children) -> + Count = length(Children), + [ + {specs, 1}, + {active, Count}, + {supervisors, 0}, + {workers, Count} + ]. -- cgit v1.2.3