diff options
Diffstat (limited to 'actioncable/lib/action_cable/subscription_adapter/redis.rb')
-rw-r--r-- | actioncable/lib/action_cable/subscription_adapter/redis.rb | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/actioncable/lib/action_cable/subscription_adapter/redis.rb b/actioncable/lib/action_cable/subscription_adapter/redis.rb new file mode 100644 index 0000000000..65434f7107 --- /dev/null +++ b/actioncable/lib/action_cable/subscription_adapter/redis.rb @@ -0,0 +1,172 @@ +require 'thread' + +gem 'redis', '~> 3.0' +require 'redis' + +module ActionCable + module SubscriptionAdapter + class Redis < Base # :nodoc: + # Overwrite this factory method for redis connections if you want to use a different Redis library than Redis. + # This is needed, for example, when using Makara proxies for distributed Redis. + cattr_accessor(:redis_connector) { ->(config) { ::Redis.new(url: config[:url]) } } + + def initialize(*) + super + @listener = nil + @redis_connection_for_broadcasts = nil + end + + def broadcast(channel, payload) + redis_connection_for_broadcasts.publish(channel, payload) + end + + def subscribe(channel, callback, success_callback = nil) + listener.add_subscriber(channel, callback, success_callback) + end + + def unsubscribe(channel, callback) + listener.remove_subscriber(channel, callback) + end + + def shutdown + @listener.shutdown if @listener + end + + def redis_connection_for_subscriptions + redis_connection + end + + private + def listener + @listener || @server.mutex.synchronize { @listener ||= Listener.new(self, @server.event_loop) } + end + + def redis_connection_for_broadcasts + @redis_connection_for_broadcasts || @server.mutex.synchronize do + @redis_connection_for_broadcasts ||= redis_connection + end + end + + def redis_connection + self.class.redis_connector.call(@server.config.cable) + end + + class Listener < SubscriberMap + def initialize(adapter, event_loop) + super() + + @adapter = adapter + @event_loop = event_loop + + @subscribe_callbacks = Hash.new { |h, k| h[k] = [] } + @subscription_lock = Mutex.new + + @raw_client = nil + + @when_connected = [] + + @thread = nil + end + + def listen(conn) + conn.without_reconnect do + original_client = conn.client + + conn.subscribe('_action_cable_internal') do |on| + on.subscribe do |chan, count| + @subscription_lock.synchronize do + if count == 1 + @raw_client = original_client + + until @when_connected.empty? + @when_connected.shift.call + end + end + + if callbacks = @subscribe_callbacks[chan] + next_callback = callbacks.shift + @event_loop.post(&next_callback) if next_callback + @subscribe_callbacks.delete(chan) if callbacks.empty? + end + end + end + + on.message do |chan, message| + broadcast(chan, message) + end + + on.unsubscribe do |chan, count| + if count == 0 + @subscription_lock.synchronize do + @raw_client = nil + end + end + end + end + end + end + + def shutdown + @subscription_lock.synchronize do + return if @thread.nil? + + when_connected do + send_command('unsubscribe') + @raw_client = nil + end + end + + Thread.pass while @thread.alive? + end + + def add_channel(channel, on_success) + @subscription_lock.synchronize do + ensure_listener_running + @subscribe_callbacks[channel] << on_success + when_connected { send_command('subscribe', channel) } + end + end + + def remove_channel(channel) + @subscription_lock.synchronize do + when_connected { send_command('unsubscribe', channel) } + end + end + + def invoke_callback(*) + @event_loop.post { super } + end + + private + def ensure_listener_running + @thread ||= Thread.new do + Thread.current.abort_on_exception = true + + conn = @adapter.redis_connection_for_subscriptions + listen conn + end + end + + def when_connected(&block) + if @raw_client + block.call + else + @when_connected << block + end + end + + def send_command(*command) + @raw_client.write(command) + + very_raw_connection = + @raw_client.connection.instance_variable_defined?(:@connection) && + @raw_client.connection.instance_variable_get(:@connection) + + if very_raw_connection && very_raw_connection.respond_to?(:flush) + very_raw_connection.flush + end + end + end + end + end +end |