Make listener supervisor failures less painful

Two general issues were addressed. The first one is the issue with
statically defined pids passed into childspecs. This issue prevents
regular supervisor' children restarts in the case of someone's
failure.

The second one is the not quite appropriate restart strategy.
Changed to rest_for_one which in pair with previous fixes assures
that live connections will not die in the case of partial failure.
Among possible failures are listening socket shutdown or frequent
accept errors.

5 files changed, 47 insertions, 30 deletions

diff --git a/src/ranch_acceptors_sup.erl b/src/ranch_acceptors_sup.erl
index 1d9503c..f1908a6 100644
--- a/src/ranch_acceptors_sup.erl
+++ b/src/ranch_acceptors_sup.erl
@@ -17,7 +17,7 @@
 -behaviour(supervisor).
 
 %% API.
--export([start_link/7]).
+-export([start_link/5]).
 
 %% supervisor.
 -export([init/1]).
@@ -25,16 +25,16 @@
 %% API.
 
 -spec start_link(any(), non_neg_integer(), module(), any(),
-	module(), pid(), pid()) -> {ok, pid()}.
-start_link(Ref, NbAcceptors, Transport, TransOpts,
-		Protocol, ListenerPid, ConnsPid) ->
+	module()) -> {ok, pid()}.
+start_link(Ref, NbAcceptors, Transport, TransOpts, Protocol) ->
 	supervisor:start_link(?MODULE, [Ref, NbAcceptors, Transport, TransOpts,
-		Protocol, ListenerPid, ConnsPid]).
+		Protocol]).
 
 %% supervisor.
 
-init([Ref, NbAcceptors, Transport, TransOpts,
-		Protocol, ListenerPid, ConnsPid]) ->
+init([Ref, NbAcceptors, Transport, TransOpts, Protocol]) ->
+	ListenerPid = ranch_server:lookup_listener(Ref),
+	ConnsPid = ranch_server:lookup_connections_sup(Ref),
 	LSocket = case proplists:get_value(socket, TransOpts) of
 		undefined ->
 			{ok, Socket} = Transport:listen(TransOpts),
diff --git a/src/ranch_conns_sup.erl b/src/ranch_conns_sup.erl
index 99853c5..3cc09be 100644
--- a/src/ranch_conns_sup.erl
+++ b/src/ranch_conns_sup.erl
@@ -17,7 +17,7 @@
 -behaviour(supervisor).
 
 %% API.
--export([start_link/0]).
+-export([start_link/1]).
 -export([start_protocol/5]).
 
 %% supervisor.
@@ -25,9 +25,9 @@
 
 %% API.
 
--spec start_link() -> {ok, pid()}.
-start_link() ->
-	supervisor:start_link(?MODULE, []).
+-spec start_link(any()) -> {ok, pid()}.
+start_link(Ref) ->
+	supervisor:start_link(?MODULE, Ref).
 
 -spec start_protocol(pid(), inet:socket(), module(), module(), any())
 	-> {ok, pid()}.
@@ -36,6 +36,7 @@ start_protocol(ListenerPid, Socket, Transport, Protocol, Opts) ->
 
 %% supervisor.
 
-init([]) ->
+init(Ref) ->
+	ok = ranch_server:set_connections_sup(Ref, self()),
 	{ok, {{simple_one_for_one, 0, 1}, [{?MODULE, {?MODULE, start_protocol, []},
 		temporary, brutal_kill, worker, [?MODULE]}]}}.
diff --git a/src/ranch_listener.erl b/src/ranch_listener.erl
index 83ee658..52e4c32 100644
--- a/src/ranch_listener.erl
+++ b/src/ranch_listener.erl
@@ -101,6 +101,7 @@ set_protocol_options(ServerPid, ProtoOpts) ->
 
 %% @private
 init([Ref, MaxConns, ProtoOpts]) ->
+	ok = ranch_server:insert_listener(Ref, self()),
 	{ok, #state{ref=Ref, max_conns=MaxConns, proto_opts=ProtoOpts}}.
 
 %% @private
diff --git a/src/ranch_listener_sup.erl b/src/ranch_listener_sup.erl
index c8ba12d..0147cf2 100644
--- a/src/ranch_listener_sup.erl
+++ b/src/ranch_listener_sup.erl
@@ -28,23 +28,25 @@
 	-> {ok, pid()}.
 start_link(Ref, NbAcceptors, Transport, TransOpts, Protocol, ProtoOpts) ->
 	MaxConns = proplists:get_value(max_connections, TransOpts, 1024),
-	{ok, SupPid} = supervisor:start_link(?MODULE, []),
-	{ok, ListenerPid} = supervisor:start_child(SupPid,
-		{ranch_listener, {ranch_listener, start_link,
-			[Ref, MaxConns, ProtoOpts]},
-		 permanent, 5000, worker, [ranch_listener]}),
-	ok = ranch_server:insert_listener(Ref, ListenerPid),
-	{ok, ConnsPid} = supervisor:start_child(SupPid,
-		{ranch_conns_sup, {ranch_conns_sup, start_link, []},
-		 permanent, 5000, supervisor, [ranch_conns_sup]}),
-	{ok, _PoolPid} = supervisor:start_child(SupPid,
-		{ranch_acceptors_sup, {ranch_acceptors_sup, start_link, [
-			Ref, NbAcceptors, Transport, TransOpts,
-			Protocol, ListenerPid, ConnsPid
-		]}, permanent, 5000, supervisor, [ranch_acceptors_sup]}),
-	{ok, SupPid}.
+	supervisor:start_link(?MODULE, {
+		Ref, NbAcceptors, MaxConns, Transport, TransOpts, Protocol, ProtoOpts
+		}).
 
 %% supervisor.
 
-init([]) ->
-	{ok, {{one_for_all, 10, 10}, []}}.
+init({Ref, NbAcceptors, MaxConns, Transport, TransOpts, Protocol, ProtoOpts}) ->
+	ChildSpecs = [
+		%% listener
+		{ranch_listener, {ranch_listener, start_link,
+			[Ref, MaxConns, ProtoOpts]},
+		 permanent, 5000, worker, [ranch_listener]},
+		%% conns_sup
+		{ranch_conns_sup, {ranch_conns_sup, start_link, [Ref]},
+		 permanent, infinity, supervisor, [ranch_conns_sup]},
+		%% acceptors_sup
+		{ranch_acceptors_sup, {ranch_acceptors_sup, start_link,
+			[Ref, NbAcceptors, Transport, TransOpts, Protocol]
+		 }, permanent, infinity, supervisor, [ranch_acceptors_sup]}
+	],
+	{ok, {{rest_for_one, 10, 10}, ChildSpecs}}.
+
diff --git a/src/ranch_server.erl b/src/ranch_server.erl
index b0ae612..078626f 100644
--- a/src/ranch_server.erl
+++ b/src/ranch_server.erl
@@ -20,6 +20,8 @@
 -export([start_link/0]).
 -export([insert_listener/2]).
 -export([lookup_listener/1]).
+-export([set_connections_sup/2]).
+-export([lookup_connections_sup/1]).
 -export([add_acceptor/2]).
 -export([send_to_acceptors/2]).
 -export([add_connection/1]).
@@ -52,7 +54,7 @@ start_link() ->
 %% @doc Insert a listener into the database.
 -spec insert_listener(any(), pid()) -> ok.
 insert_listener(Ref, Pid) ->
-	true = ets:insert_new(?TAB, {{listener, Ref}, Pid}),
+	true = ets:insert_new(?TAB, {{listener, Ref}, Pid, undefined}),
 	gen_server:cast(?MODULE, {insert_listener, Ref, Pid}).
 
 %% @doc Lookup a listener in the database.
@@ -60,6 +62,17 @@ insert_listener(Ref, Pid) ->
 lookup_listener(Ref) ->
 	ets:lookup_element(?TAB, {listener, Ref}, 2).
 
+%% @doc Set a connection supervisor associated with specific listener.
+-spec set_connections_sup(any(), pid()) -> ok.
+set_connections_sup(Ref, Pid) ->
+	true = ets:update_element(?TAB, {listener, Ref}, {3, Pid}),
+	ok.
+
+%% @doc Lookup a connection supervisor used by specific listener.
+-spec lookup_connections_sup(any()) -> pid() | undefined.
+lookup_connections_sup(Ref) ->
+	ets:lookup_element(?TAB, {listener, Ref}, 3).
+
 %% @doc Add an acceptor for the given listener.
 -spec add_acceptor(any(), pid()) -> ok.
 add_acceptor(Ref, Pid) ->