%-*-Mode:erlang;coding:utf-8;tab-width:4;c-basic-offset:4;indent-tabs-mode:()-*- % ex: set ft=erlang fenc=utf-8 sts=4 ts=4 sw=4 et nomod: %%% %%%------------------------------------------------------------------------ %%% @doc %%% ==Supervisor Pool== %%% Simple supervisor process pool with round-robin. %%% @end %%% %%% BSD LICENSE %%% %%% Copyright (c) 2011-2017, Michael Truog %%% All rights reserved. %%% %%% Redistribution and use in source and binary forms, with or without %%% modification, are permitted provided that the following conditions are met: %%% %%% * Redistributions of source code must retain the above copyright %%% notice, this list of conditions and the following disclaimer. %%% * Redistributions in binary form must reproduce the above copyright %%% notice, this list of conditions and the following disclaimer in %%% the documentation and/or other materials provided with the %%% distribution. %%% * All advertising materials mentioning features or use of this %%% software must display the following acknowledgment: %%% This product includes software developed by Michael Truog %%% * The name of the author may not be used to endorse or promote %%% products derived from this software without specific prior %%% written permission %%% %%% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND %%% CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, %%% INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES %%% OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE %%% DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR %%% CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, %%% SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, %%% BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR %%% SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS %%% INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, %%% WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING %%% NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE %%% OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH %%% DAMAGE. %%% %%% @author Michael Truog %%% @copyright 2011-2017 Michael Truog %%% @version 1.5.5 {@date} {@time} %%%------------------------------------------------------------------------ -module(supool). -author('mjtruog [at] gmail (dot) com'). -behaviour(gen_server). %% external interface -export([start_link/3, start_link/4, get/1]). %% internal interface -export([pool_worker_start_link/2]). %% gen_server callbacks -export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]). -include("supool_logging.hrl"). -record(state, { supervisor :: pid(), index = 1 :: pos_integer(), pool = undefined :: tuple() | undefined, count = undefined :: pos_integer() | undefined }). -type options() :: list({max_r, non_neg_integer()} | {max_t, pos_integer()}). -type child_spec() :: {Id :: any(), StartFunc :: {module(), atom(), list()}, Restart :: permanent | transient | temporary, Shutdown :: brutal_kill | pos_integer(), Type :: worker | supervisor, Modules :: [module()] | dynamic}. -export_type([options/0, child_spec/0]). %%%------------------------------------------------------------------------ %%% External interface functions %%%------------------------------------------------------------------------ %%------------------------------------------------------------------------- %% @doc %% ===Start the pool supervisor.=== %% @end %%------------------------------------------------------------------------- -spec start_link(Name :: atom(), Count :: pos_integer(), ChildSpec :: child_spec()) -> {ok, pid()} | {error, any()}. start_link(Name, Count, ChildSpec) -> supool_sup:start_link(Name, Count, ChildSpec, []). %%------------------------------------------------------------------------- %% @doc %% ===Start the pool supervisor with restart options.=== %% @end %%------------------------------------------------------------------------- -spec start_link(Name :: atom(), Count :: pos_integer(), ChildSpec :: child_spec(), Options :: options()) -> {ok, pid()} | {error, any()}. start_link(Name, Count, ChildSpec, Options) -> supool_sup:start_link(Name, Count, ChildSpec, Options). %%------------------------------------------------------------------------- %% @doc %% ===Get a pool process.=== %% @end %%------------------------------------------------------------------------- -spec get(Name :: atom()) -> pid() | undefined. get(Name) when is_atom(Name) -> try gen_server:call(Name, get, infinity) catch exit:{noproc, _} -> undefined end. %%%------------------------------------------------------------------------ %%% Internal interface functions %%%------------------------------------------------------------------------ -spec pool_worker_start_link(Name :: atom(), Supervisor :: pid()) -> {ok, pid()} | {error, any()}. pool_worker_start_link(Name, Supervisor) when is_atom(Name), is_pid(Supervisor) -> gen_server:start_link({local, Name}, ?MODULE, [Supervisor], []). %%%------------------------------------------------------------------------ %%% Callback functions from gen_server %%%------------------------------------------------------------------------ init([Supervisor]) -> self() ! restart, {ok, #state{supervisor = Supervisor}}. handle_call(get, _, #state{supervisor = Supervisor, index = I, pool = Pool, count = Count} = State) -> Pid = erlang:element(I, Pool), case erlang:is_process_alive(Pid) of true -> {reply, Pid, State#state{index = increment(I, Count)}}; false -> NewPids = supool_sup:which_children(Supervisor), case erlang:length(NewPids) of 0 -> {stop, {error, noproc}, undefined, State}; NewCount -> NewPool = erlang:list_to_tuple(NewPids), NewI = if I > NewCount -> 1; true -> I end, {reply, erlang:element(NewI, NewPool), State#state{index = increment(NewI, NewCount), pool = NewPool, count = NewCount}} end end; handle_call(Request, _, State) -> ?LOG_WARN("Unknown call \"~p\"", [Request]), {stop, lists:flatten(io_lib:format("Unknown call \"~p\"", [Request])), error, State}. handle_cast(Request, State) -> ?LOG_WARN("Unknown cast \"~p\"", [Request]), {noreply, State}. handle_info({start, ChildSpecs}, #state{supervisor = Supervisor} = State) -> case supool_sup:start_children(Supervisor, ChildSpecs) of {ok, []} -> {stop, {error, noproc}, State}; {ok, Pids} -> {noreply, State#state{pool = erlang:list_to_tuple(Pids), count = erlang:length(Pids)}}; {error, _} = Error -> {stop, Error, State} end; handle_info(restart, #state{supervisor = Supervisor} = State) -> Pids = supool_sup:which_children(Supervisor), case erlang:length(Pids) of 0 -> % pool worker started for the first time {noreply, State}; Count -> % pool worker restarted {noreply, State#state{pool = erlang:list_to_tuple(Pids), count = Count}} end; handle_info(Request, State) -> ?LOG_WARN("Unknown info \"~p\"", [Request]), {noreply, State}. terminate(_, _) -> ok. code_change(_, State, _) -> {ok, State}. %%%------------------------------------------------------------------------ %%% Private functions %%%------------------------------------------------------------------------ increment(Count, Count) -> 1; increment(I, _) -> I + 1.