Class: Dataflow::Nodes::ComputeNode

Inherits:
Object
  • Object
show all
Includes:
EventMixin, Dataflow::Node, PropertiesMixin, SchemaMixin, Mongoid::Document
Defined in:
lib/dataflow/nodes/compute_node.rb

Overview

Represents a compution. May stores its output in a separate data node. It depends on other data nodes to compute its own data.

Constant Summary

Constants included from SchemaMixin

SchemaMixin::SAMPLE_DATA_OUTPUT, SchemaMixin::SEPARATOR

Class Method Summary collapse

Instance Method Summary collapse

Methods included from SchemaMixin

#infer_partial_schema, #infer_schema, #sample_data, #schema_inferrer

Methods included from Dataflow::Node

find, #validate!

Class Method Details

.data_node_opts ⇒ Object 



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# File 'lib/dataflow/nodes/compute_node.rb', line 30

def data_node_opts
  @data_node_opts || {}
end

.dependency_opts ⇒ Object 



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# File 'lib/dataflow/nodes/compute_node.rb', line 26

def dependency_opts
  @dependency_opts || {}
end

.ensure_data_node_exists ⇒ Object

DSL to ensure that a data node must be set before a computed node can be recomputed (as it will presumably use it to store data).



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# File 'lib/dataflow/nodes/compute_node.rb', line 52

def ensure_data_node_exists
  @data_node_opts = { ensure_exists: true }
end

.ensure_dependencies(opts) ⇒ Object

DSL to be used while making computeqd nodes. It supports enforcing validations by checking whether there is exactly, at_least (min) or at_most (max) a given number of dependencies. Usage: class MyComputeNode < ComputeNode

ensure_dependencies exactly: 1 # could be e.g.: min: 3, or max: 5

end

Raises:



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# File 'lib/dataflow/nodes/compute_node.rb', line 40

def ensure_dependencies(opts)
  raise Dataflow::Errors::InvalidConfigurationError, "ensure_dependencies must be given a hash. Received: #{opts.class}" unless opts.is_a?(Hash)
  valid_keys = i(exactly min max).freeze
  has_attributes = (valid_keys - opts.keys).count < valid_keys.count
  raise Dataflow::Errors::InvalidConfigurationError, "ensure_dependencies must have at least one of 'min', 'max' or 'exactly' attributes set. Given: #{opts.keys}" unless has_attributes

  add_property(:dependency_ids, opts)
  @dependency_opts = opts
end

Instance Method Details

#all_dependencies ⇒ Object

retrieve the whole dependency tree



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# File 'lib/dataflow/nodes/compute_node.rb', line 136

def all_dependencies
  (dependencies + dependencies.flat_map(&:all_dependencies)).uniq
end

#compute(depth: 0, force_compute: false, source: nil) ⇒ Object

Compute this node’s data if not already updated. Acquires a computing lock before computing. In the eventuality that the lock is already acquired, it awaits until it finishes or times out.

Parameters:

  • force_compute (Boolean) (defaults to: false) —

    if true, computes even if the node is already up to date.



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# File 'lib/dataflow/nodes/compute_node.rb', line 209

def compute(depth: 0, force_compute: false, source: nil)
  has_compute_lock = false
  validate!

  if updated? && !force_compute
    logger.log "#{'>' * (depth + 1)} #{name} is up-to-date."
    return
  end

  has_compute_lock = acquire_computing_lock!
  if has_compute_lock
    logger.log "#{'>' * (depth + 1)} #{name} started computing."
    on_computing_started
    start_time = Time.now

    if data_node.present? && clear_data_on_compute != data_node.use_double_buffering
      # make sure the data node has a compatible settings
      data_node.use_double_buffering = clear_data_on_compute
      data_node.save
    end
    
    pre_compute(force_compute: force_compute)

    # update this node's schema with the necessary fields
    data_node&.update_schema(required_schema)


    if clear_data_on_compute
      # Pre-compute, we recreate the table, the unique indexes
      data_node&.recreate_dataset(dataset_type: :write)
      data_node&.create_unique_indexes(dataset_type: :write)
    end

    send_heartbeat
    compute_impl

    if clear_data_on_compute
      # Post-compute, delay creating other indexes for insert speed
      data_node&.create_non_unique_indexes(dataset_type: :write)
      # swap read/write datasets
      data_node&.swap_read_write_datasets!
    end

    self.last_compute_starting_time = start_time
    duration = Time.now - start_time
    logger.log "#{'>' * (depth + 1)} #{name} took #{duration} seconds to compute."
    on_computing_finished(state: 'computed')
  else
    logger.log "#{'>' * (depth + 1)} [IS AWAITING] #{name}."
    await_computing!
    logger.log "#{'>' * (depth + 1)} [IS DONE AWAITING] #{name}."
  end

rescue StandardError => e
  on_computing_finished(state: 'error', error: e) if has_compute_lock
  logger.log "#{'>' * (depth + 1)} [ERROR] #{name} failed computing: #{e}"
  raise
ensure
  release_computing_lock! if has_compute_lock
  true
end

#data_node ⇒ Object

Fetch the data node if it is set



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# File 'lib/dataflow/nodes/compute_node.rb', line 123

def data_node
  @data_node ||= Dataflow::Nodes::DataNode.find(data_node_id) if data_node_id.present?
end

#dependencies(reload: false) ⇒ Object

Override the relation because self.dependencies is not ordered.



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# File 'lib/dataflow/nodes/compute_node.rb', line 128

def dependencies(reload: false)
  return @dependencies if @dependencies.present? && !reload
  @dependencies = dependency_ids.map do |x|
    Dataflow::Node.find(x)
  end
end

#force_computing_lock_release! ⇒ Object

Force the release of this node’s computing lock. Do not use unless there is a problem with the lock.



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# File 'lib/dataflow/nodes/compute_node.rb', line 299

def force_computing_lock_release!
  release_computing_lock!
end

#locked_for_computing? ⇒ Boolean

Check this node’s locking status.

Returns:

  • (Boolean) —

    Whtere this node is locked or not.



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# File 'lib/dataflow/nodes/compute_node.rb', line 293

def locked_for_computing?
  computing_state == 'computing'
end

#needs_automatic_recomputing? ⇒ Boolean

Checks whether an automatic recomputing is needed.

Returns:

  • (Boolean) 


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# File 'lib/dataflow/nodes/compute_node.rb', line 167

def needs_automatic_recomputing?
  interval = recompute_interval.to_i
  return false if interval <= 0
  return false if updated?
  return false if locked_for_computing?
  return true if updated_at.blank?

  updated_at + interval.seconds < Time.now
end

#recompute(depth: 0, force_recompute: false) ⇒ Object

Update the dependencies that need to be updated and then compute its own data.

Parameters:

  • force_recompute (Boolean) (defaults to: false) —

    if true, computes even if the node is already up to date.



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# File 'lib/dataflow/nodes/compute_node.rb', line 181

def recompute(depth: 0, force_recompute: false)
  logger.log "#{'>' * (depth + 1)} #{name} started recomputing..."
  start_time = Time.now

  parallel_each(dependencies) do |dependency|
    logger.log "#{'>' * (depth + 1)} #{name} checking deps: #{dependency.name}..."
    if !dependency.updated? || force_recompute
      dependency.recompute(depth: depth + 1, force_recompute: force_recompute)
    end
  end

  # Dependencies data may have changed in a child process.
  # Reload to make sure we have the latest metadata.
  logger.log "#{'>' * (depth + 1)} #{name} reloading dependencies..."
  dependencies(reload: true)

  compute(depth: depth, force_compute: force_recompute)
  logger.log "#{'>' * (depth + 1)} #{name} took #{Time.now - start_time} seconds to recompute."

  true
end

#set_defaults ⇒ Object

Sets the default parameters before creating the object.



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# File 'lib/dataflow/nodes/compute_node.rb', line 97

def set_defaults
  # support setting the fields with a Document rather
  # than an ObjectId. Handle the transformations here:
  if data_node_id.present?
    self.data_node_id = data_node_id._id unless data_node_id.is_a?(BSON::ObjectId)

    # the data node use_double_buffering setting
    # must match clear_data_on_compute:
    if data_node.use_double_buffering != clear_data_on_compute
      data_node.use_double_buffering = clear_data_on_compute
      data_node.save
    end
  end

  # Again support having an ObjectId or a document.
  self.dependency_ids = dependency_ids.map { |dep|
    next dep if dep.is_a? BSON::ObjectId
    dep._id
  }

  # Update the data node schema with the required schema
  # for this computed node.
  data_node&.update_schema(required_schema)
end

#updated? ⇒ Boolean

Returns false if any of our dependencies has been updated after our last update. We define a computed node’s last update as the time it started its last successful update (instead of the time it completed it, has dependencies may have changed in the mean time).

Returns:

  • (Boolean) 


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# File 'lib/dataflow/nodes/compute_node.rb', line 146

def updated?
  return false if updated_at.blank?

  dependencies.each do |dependency|
    return false unless dependency.updated?
    return false if dependency.updated_at > updated_at
  end
  true
end

#updated_at ⇒ Object

Keep a uniform interface with a DataNode.



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# File 'lib/dataflow/nodes/compute_node.rb', line 157

def updated_at
  last_compute_starting_time
end

#updated_at=(val) ⇒ Object 



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# File 'lib/dataflow/nodes/compute_node.rb', line 161

def updated_at=(val)
  self.last_compute_starting_time = val
end

#valid_for_computation? ⇒ Boolean

Check wethere this node can or not compute. Errors are added to the active model errors.

Returns:

  • (Boolean) —

    true has no errors and can be computed.



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# File 'lib/dataflow/nodes/compute_node.rb', line 274

def valid_for_computation?
  # Perform additional checks: also add errors to "self.errors"
  opts = self.class.dependency_opts
  if opts.key?(:exactly)
    ensure_exact_dependencies(count: opts[:exactly])
  elsif opts.key?(:max)
    ensure_at_most_dependencies(count: opts[:max])
  else # even if the min is not specified, we need at least 1 dependency
    ensure_at_least_dependencies(count: opts[:min] || 1)
  end
  ensure_no_cyclic_dependencies
  ensure_keys_are_set
  ensure_data_node_exists if self.class.data_node_opts[:ensure_exists]

  errors.count == 0
end