Class: AWS::Flow::Replayer::DecisionTaskProvider Abstract

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

Overview

This class is abstract.

Implement the ‘get_history_page` and `get_execution_info` methods to use it.

Used by AWS::Flow::Replayer to fetch a [DecisionTask][] which will be used by DecisionTaskHandler.

[DecisionTask]: docs.aws.amazon.com/AWSRubySDK/latest/AWS/SimpleWorkflow/DecisionTask.html

Direct Known Subclasses

ServiceDecisionTaskProvider

Instance Method Summary collapse

Instance Method Details

#get_decision_task(replay_upto = nil) ⇒ DecisionTask

Fetches the workflow history and wraps all the history events, workflow type and workflow execution inside a decision task for the decider to work on.



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# File 'lib/aws/replayer.rb', line 36

def get_decision_task(replay_upto = nil)

  # Get workflow execution info so that we can populate the workflowType
  # and execution fields of the [DecisionTask][].
  #
  # [DecisionTask]: http://docs.aws.amazon.com/AWSRubySDK/latest/AWS/SimpleWorkflow/DecisionTask.html
  #
  execution_info = get_execution_info
  events = get_history

  # Truncate history if replay_upto variable is set so that we only
  # replay the history till the specified event
  #
  events = truncate_history(events, replay_upto)
  return nil if events.nil?

  # Generate the hash to instantiate a [DecisionTask][]. We can set
  # *taskToken* and *nextPageToken* to nil since we don't need the
  # values in the replayer.
  #
  # [DecisionTask]: http://docs.aws.amazon.com/AWSRubySDK/latest/AWS/SimpleWorkflow/DecisionTask.html
  data = {
    'taskToken' => nil,
    'workflowExecution' => execution_info["execution"],
    'workflowType' => execution_info["workflowType"],
    'events' => events,
    'nextPageToken' => nil
  }
  AWS::SimpleWorkflow::DecisionTask.new(nil, nil, data)
end

#get_execution_info ⇒ Object

Fetches the workflow execution information used to fill in the

DecisionTask][

details. Implementing classes must override this

method.



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# File 'lib/aws/replayer.rb', line 113

def get_execution_info; end

#get_history(page_token = nil) ⇒ Object

Fetches the workflow history. Implementing classes must override this method.



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# File 'lib/aws/replayer.rb', line 103

def get_history(page_token = nil); end

#truncate_history(events, replay_upto = nil) ⇒ Object

Truncates workflow history to a specified event id.



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# File 'lib/aws/replayer.rb', line 78

def truncate_history(events, replay_upto = nil)
  return nil if events.nil? || events.empty?

  # Just return the original array of events if replay_upto is not set
  # or if the number of events is less than replay_upto
  return events if replay_upto.nil? || events.last['eventId'] <= replay_upto

  # Select the events whose eventId is lesser than replay_upto
  truncated = events.select { |event| event['eventId'] <= replay_upto }
  return nil if truncated.empty?
  truncated
end