Synchronize the lazy setters in Server

They're all at risk of races on the first requests.

4 files changed, 31 insertions, 8 deletions

diff --git a/actioncable/lib/action_cable/subscription_adapter/async.rb b/actioncable/lib/action_cable/subscription_adapter/async.rb
index c88b03947a..cca6894289 100644
--- a/actioncable/lib/action_cable/subscription_adapter/async.rb
+++ b/actioncable/lib/action_cable/subscription_adapter/async.rb
@@ -4,8 +4,8 @@ module ActionCable
   module SubscriptionAdapter
     class Async < Inline # :nodoc:
       private
-        def subscriber_map
-          @subscriber_map ||= AsyncSubscriberMap.new
+        def new_subscriber_map
+          AsyncSubscriberMap.new
         end
 
         class AsyncSubscriberMap < SubscriberMap
diff --git a/actioncable/lib/action_cable/subscription_adapter/inline.rb b/actioncable/lib/action_cable/subscription_adapter/inline.rb
index 4a2a8d23a2..81357faead 100644
--- a/actioncable/lib/action_cable/subscription_adapter/inline.rb
+++ b/actioncable/lib/action_cable/subscription_adapter/inline.rb
@@ -1,6 +1,11 @@
 module ActionCable
   module SubscriptionAdapter
     class Inline < Base # :nodoc:
+      def initialize(*)
+        super
+        @subscriber_map = nil
+      end
+
       def broadcast(channel, payload)
         subscriber_map.broadcast(channel, payload)
       end
@@ -19,7 +24,11 @@ module ActionCable
 
       private
         def subscriber_map
-          @subscriber_map ||= SubscriberMap.new
+          @subscriber_map || @server.mutex.synchronize { @subscriber_map ||= new_subscriber_map }
+        end
+
+        def new_subscriber_map
+          SubscriberMap.new
         end
     end
   end
diff --git a/actioncable/lib/action_cable/subscription_adapter/postgresql.rb b/actioncable/lib/action_cable/subscription_adapter/postgresql.rb
index 3ce1bbed68..abaeb92e54 100644
--- a/actioncable/lib/action_cable/subscription_adapter/postgresql.rb
+++ b/actioncable/lib/action_cable/subscription_adapter/postgresql.rb
@@ -5,6 +5,11 @@ require 'thread'
 module ActionCable
   module SubscriptionAdapter
     class PostgreSQL < Base # :nodoc:
+      def initialize(*)
+        super
+        @listener = nil
+      end
+
       def broadcast(channel, payload)
         with_connection do |pg_conn|
           pg_conn.exec("NOTIFY #{pg_conn.escape_identifier(channel)}, '#{pg_conn.escape_string(payload)}'")
@@ -37,7 +42,7 @@ module ActionCable
 
       private
         def listener
-          @listener ||= Listener.new(self)
+          @listener || @server.mutex.synchronize { @listener ||= Listener.new(self) }
         end
 
         class Listener < SubscriberMap
diff --git a/actioncable/lib/action_cable/subscription_adapter/redis.rb b/actioncable/lib/action_cable/subscription_adapter/redis.rb
index a035e3988d..560b79df16 100644
--- a/actioncable/lib/action_cable/subscription_adapter/redis.rb
+++ b/actioncable/lib/action_cable/subscription_adapter/redis.rb
@@ -13,6 +13,11 @@ module ActionCable
     class Redis < Base # :nodoc:
       @@mutex = Mutex.new
 
+      def initialize(*)
+        super
+        @redis_connection_for_broadcasts = @redis_connection_for_subscriptions = nil
+      end
+
       def broadcast(channel, payload)
         redis_connection_for_broadcasts.publish(channel, payload)
       end
@@ -35,15 +40,19 @@ module ActionCable
       private
         def redis_connection_for_subscriptions
           ensure_reactor_running
-          @redis_connection_for_subscriptions ||= EM::Hiredis.connect(@server.config.cable[:url]).tap do |redis|
-            redis.on(:reconnect_failed) do
-              @logger.info "[ActionCable] Redis reconnect failed."
+          @redis_connection_for_subscriptions || @server.mutex.synchronize do
+            @redis_connection_for_subscriptions ||= EM::Hiredis.connect(@server.config.cable[:url]).tap do |redis|
+              redis.on(:reconnect_failed) do
+                @logger.info "[ActionCable] Redis reconnect failed."
+              end
             end
           end
         end
 
         def redis_connection_for_broadcasts
-          @redis_connection_for_broadcasts ||= ::Redis.new(@server.config.cable)
+          @redis_connection_for_broadcasts || @server.mutex.synchronize do
+            @redis_connection_for_broadcasts ||= ::Redis.new(@server.config.cable)
+          end
         end
 
         def ensure_reactor_running