Class: Strongman::Batch

Inherits:
Object
  • Object
show all
Defined in:
lib/strongman.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(loader_block, name: nil, parent: nil, max_batch_size: Float::INFINITY) ⇒ Batch

Returns a new instance of Batch.



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# File 'lib/strongman.rb', line 17

def initialize(loader_block, name: nil, parent: nil, max_batch_size: Float::INFINITY)
  @name = name
  @queue = Concurrent::Array.new
  @promise = Concurrent::Promises.resolvable_future
  @loader_block = loader_block
  @lock = Concurrent::ReadWriteLock.new
  @parent = parent
  @children = Concurrent::Array.new
  @fulfilling = Concurrent::AtomicBoolean.new(false)
  @fulfilled = Concurrent::AtomicBoolean.new(false)
  @max_batch_size = max_batch_size

  @parent.children << self if @parent

  @root = nil
  @batch_chain = nil
end

Instance Attribute Details

#fulfilled ⇒ Object

Returns the value of attribute fulfilled.



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# File 'lib/strongman.rb', line 14

def fulfilled
  @fulfilled
end

#fulfilling ⇒ Object

Returns the value of attribute fulfilling.



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# File 'lib/strongman.rb', line 15

def fulfilling
  @fulfilling
end

#lock ⇒ Object

Returns the value of attribute lock.



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# File 'lib/strongman.rb', line 13

def lock
  @lock
end

#name ⇒ Object

Returns the value of attribute name.



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# File 'lib/strongman.rb', line 12

def name
  @name
end

#parent ⇒ Object

Returns the value of attribute parent.



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# File 'lib/strongman.rb', line 11

def parent
  @parent
end

Instance Method Details

#batch_chain ⇒ Object 



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# File 'lib/strongman.rb', line 123

def batch_chain
  if @batch_chain
    @batch_chain
  else
    @batch_chain = Concurrent::Array.new

    add_children = -> (batch) {
      @batch_chain << batch
      if batch.children.size > 0
        batch.children.flat_map(&add_children)
      end
    }
    add_children.(root)

    @batch_chain
  end
end

#children ⇒ Object 



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# File 'lib/strongman.rb', line 171

def children
  @children ||= Concurrent::Array.new
end

#fulfill! ⇒ Object 



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# File 'lib/strongman.rb', line 155

def fulfill!
  results = @loader_block.call(@queue)

  if results.is_a?(Concurrent::Promises::Future)
    # if the strongman loader block returns a promise (e.g. if the block uses another loader),
    # make sure to touch it to kick off any delayed effects before chaining
    results.touch.then do |inner_results|
      @promise.fulfill(normalize_results(inner_results))
    end.flat
  else
    @promise.fulfill(normalize_results(results))
  end

  self
end

#fulfill_hierarchy ⇒ Object

Raises:

  • (Error) 


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# File 'lib/strongman.rb', line 141

def fulfill_hierarchy
  raise Error.new("Only run #fulfill_hierarchy on root batches") if @parent

  with_lock do
    return if fulfilled?

    mark_fulfilling!
    batch_chain.reverse.each(&:fulfill!)
  ensure
    mark_fulfilled!
    mark_not_fulfilling!
  end
end

#fulfilled? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/strongman.rb', line 35

def fulfilled?
  root.fulfilled.true?
end

#fulfilling? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/strongman.rb', line 39

def fulfilling?
  root.fulfilling.true?
end

#mark_fulfilled! ⇒ Object 



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# File 'lib/strongman.rb', line 86

def mark_fulfilled!
  root.fulfilled.make_true
  self
end

#mark_fulfilling! ⇒ Object 



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# File 'lib/strongman.rb', line 91

def mark_fulfilling!
  root.fulfilling.make_true
  self
end

#mark_not_fulfilling! ⇒ Object 



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# File 'lib/strongman.rb', line 96

def mark_not_fulfilling!
  root.fulfilling.make_false
  self
end

#needs_fulfilling? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/strongman.rb', line 43

def needs_fulfilling?
  !fulfilled? && !fulfilling?
end

#queue(key) ⇒ Object 



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# File 'lib/strongman.rb', line 47

def queue(key)
  @queue << key

  future = @promise.then do |results|
    unless results.key?(key)
      raise StandardError, "Batch loader didn't resolve a key: #{key}. Resolved keys: #{results.keys}"
    end

    result = results[key]

    if result.is_a?(Concurrent::Promises::Future)
      result
    else
      Concurrent::Promises.resolvable_future.fulfill(result)
    end
  end.flat

  #
  # If our queue is full, fulfill immediately and return the bare future
  #
  if @queue.size >= @max_batch_size
    root.fulfill_hierarchy

    future
  else
    #
    # If the queue is not full, create a delayed future that fulfills when the value is requested and chains
    # to the inner future
    #
    Concurrent::Promises.delay do
      # with_lock do
      root.fulfill_hierarchy if root.needs_fulfilling?
      # end

      future
    end.flat
  end
end

#root ⇒ Object 



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# File 'lib/strongman.rb', line 107

def root
  if @root
    @root
  else
    find_top = -> (batch) {
      if batch.parent
        find_top.(batch.parent)
      else
        batch
      end
    }

    @root = find_top.(self)
  end
end

#with_lock ⇒ Object 



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# File 'lib/strongman.rb', line 101

def with_lock
  root.lock.with_write_lock do
    yield
  end
end