Class: ActiveSupport::Notifications::Fanout

Inherits:
Object
  • Object
show all
Includes:
FanoutIteration
Defined in:
lib/active_support/notifications/fanout.rb

Overview

This is a default queue implementation that ships with Notifications. It just pushes events to all registered log subscribers.

This class is thread safe. All methods are reentrant.

Defined Under Namespace

Modules: NullHandle, Subscribers Classes: BaseGroup, BaseTimeGroup, EventObjectGroup, EventedGroup, Handle, MonotonicTimedGroup, TimedGroup

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Fanout

Returns a new instance of Fanout.



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# File 'lib/active_support/notifications/fanout.rb', line 56

def initialize
  @mutex = Mutex.new
  @string_subscribers = Concurrent::Map.new { |h, k| h.compute_if_absent(k) { [] } }
  @other_subscribers = []
  @all_listeners_for = Concurrent::Map.new
  @groups_for = Concurrent::Map.new
end

Instance Method Details

#all_listeners_for(name) ⇒ Object 



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# File 'lib/active_support/notifications/fanout.rb', line 319

def all_listeners_for(name)
  # this is correctly done double-checked locking (Concurrent::Map's lookups have volatile semantics)
  @all_listeners_for[name] || @mutex.synchronize do
    # use synchronisation when accessing @subscribers
    @all_listeners_for[name] ||=
      @string_subscribers[name] + @other_subscribers.select { |s| s.subscribed_to?(name) }
  end
end

#build_handle(name, id, payload) ⇒ Object 



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# File 'lib/active_support/notifications/fanout.rb', line 286

def build_handle(name, id, payload)
  groups = groups_for(name).map do |group_klass, grouped_listeners|
    group_klass.new(grouped_listeners, name, id, payload)
  end

  if groups.empty?
    NullHandle
  else
    Handle.new(self, name, id, groups, payload)
  end
end

#clear_cache(key = nil) ⇒ Object

:nodoc:



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# File 'lib/active_support/notifications/fanout.rb', line 106

def clear_cache(key = nil) # :nodoc:
  if key
    @all_listeners_for.delete(key)
    @groups_for.delete(key)
  else
    @all_listeners_for.clear
    @groups_for.clear
  end
end

#finish(name, id, payload, listeners = nil) ⇒ Object 



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# File 'lib/active_support/notifications/fanout.rb', line 305

def finish(name, id, payload, listeners = nil)
  handle_stack = IsolatedExecutionState[:_fanout_handle_stack]
  handle = handle_stack.pop
  handle.finish_with_values(name, id, payload)
end

#group_listeners(listeners) ⇒ Object

:nodoc:



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# File 'lib/active_support/notifications/fanout.rb', line 190

def group_listeners(listeners) # :nodoc:
  listeners.group_by(&:group_class).transform_values do |s|
    s.map(&:delegate).freeze
  end.freeze
end

#groups_for(name) ⇒ Object

:nodoc:



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# File 'lib/active_support/notifications/fanout.rb', line 196

def groups_for(name) # :nodoc:
  silenceable_groups, groups = @groups_for.compute_if_absent(name) do
    listeners = all_listeners_for(name)
    listeners.partition(&:silenceable).map { |l| group_listeners(l) }
  end

  unless silenceable_groups.empty?
    silenceable_groups.each do |group_class, subscriptions|
      active_subscriptions = subscriptions.reject { |s| s.silenced?(name) }
      unless active_subscriptions.empty?
        groups = groups.dup if groups.frozen?
        base_groups = groups[group_class]
        groups[group_class] = base_groups ? base_groups + active_subscriptions : active_subscriptions
      end
    end
  end

  groups
end

#inspect ⇒ Object

:nodoc:



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# File 'lib/active_support/notifications/fanout.rb', line 64

def inspect # :nodoc:
  total_patterns = @string_subscribers.size + @other_subscribers.size
  "#<#{self.class} (#{total_patterns} patterns)>"
end

#listeners_for(name) ⇒ Object 



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# File 'lib/active_support/notifications/fanout.rb', line 328

def listeners_for(name)
  all_listeners_for(name).reject { |s| s.silenced?(name) }
end

#listening?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_support/notifications/fanout.rb', line 332

def listening?(name)
  all_listeners_for(name).any? { |s| !s.silenced?(name) }
end

#publish(name) ⇒ Object 



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# File 'lib/active_support/notifications/fanout.rb', line 311

def publish(name, ...)
  iterate_guarding_exceptions(listeners_for(name)) { |s| s.publish(name, ...) }
end

#publish_event(event) ⇒ Object 



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# File 'lib/active_support/notifications/fanout.rb', line 315

def publish_event(event)
  iterate_guarding_exceptions(listeners_for(event.name)) { |s| s.publish_event(event) }
end

#start(name, id, payload) ⇒ Object 



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# File 'lib/active_support/notifications/fanout.rb', line 298

def start(name, id, payload)
  handle_stack = (IsolatedExecutionState[:_fanout_handle_stack] ||= [])
  handle = build_handle(name, id, payload)
  handle_stack << handle
  handle.start
end

#subscribe(pattern = nil, callable = nil, monotonic: false, &block) ⇒ Object 



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# File 'lib/active_support/notifications/fanout.rb', line 69

def subscribe(pattern = nil, callable = nil, monotonic: false, &block)
  subscriber = Subscribers.new(pattern, callable || block, monotonic)
  @mutex.synchronize do
    case pattern
    when String
      @string_subscribers[pattern] << subscriber
      clear_cache(pattern)
    when NilClass, Regexp
      @other_subscribers << subscriber
      clear_cache
    else
      raise ArgumentError,  "pattern must be specified as a String, Regexp or empty"
    end
  end
  subscriber
end

#unsubscribe(subscriber_or_name) ⇒ Object 



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# File 'lib/active_support/notifications/fanout.rb', line 86

def unsubscribe(subscriber_or_name)
  @mutex.synchronize do
    case subscriber_or_name
    when String
      @string_subscribers[subscriber_or_name].clear
      clear_cache(subscriber_or_name)
      @other_subscribers.each { |sub| sub.unsubscribe!(subscriber_or_name) }
    else
      pattern = subscriber_or_name.try(:pattern)
      if String === pattern
        @string_subscribers[pattern].delete(subscriber_or_name)
        clear_cache(pattern)
      else
        @other_subscribers.delete(subscriber_or_name)
        clear_cache
      end
    end
  end
end

#wait ⇒ Object

This is a sync queue, so there is no waiting.



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# File 'lib/active_support/notifications/fanout.rb', line 337

def wait
end