Class: Trailblazer::Circuit

Inherits:
Object
  • Object
show all
Defined in:
lib/trailblazer/circuit.rb,
lib/trailblazer/circuit/task.rb,
lib/trailblazer/circuit/wrap.rb,
lib/trailblazer/circuit/trace.rb,
lib/trailblazer/circuit/present.rb,
lib/trailblazer/circuit/version.rb,
lib/trailblazer/circuit/activity.rb,
lib/trailblazer/circuit/testing.rb

Overview

Running a Circuit instance will run all tasks sequentially depending on the former’s result. Each task is called and retrieves the former task’s return values.

Note: Please use #Activity as a public circuit builder.

See Also:

Defined Under Namespace

Modules: Task, Trace, Wrap Classes: Activity, Direction, End, IllegalInputError, IllegalOutputSignalError, Left, Nested, Right, Start

Constant Summary collapse

Run = 
->(activity, direction, *args) { activity.(direction, *args) }
VERSION = 
"0.0.8"

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(map, stop_events, name) ⇒ Circuit

Returns a new instance of Circuit.



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# File 'lib/trailblazer/circuit.rb', line 18

def initialize(map, stop_events, name)
  @name        = name
  @map         = map
  @stop_events = stop_events
end

Class Method Details

.Activity(name = :default, events = {}, &block) ⇒ Object

Builder for an Activity with Circuit instance and events.



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# File 'lib/trailblazer/circuit/activity.rb', line 20

def self.Activity(name=:default, events={}, &block)
  # default events:
  start   = events[:start] || { default: Start.new(:default) }
  _end    = events[:end]   || { default: End.new(:default) }

  events = { start: start, end: _end }.merge(events)

  evts = Events(events)
  circuit = Circuit(name, evts, _end.values, &block)

  Activity.new(circuit, evts)
end

.ActivityInspect(activity, strip: ["AlterTest::"]) ⇒ Object 



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# File 'lib/trailblazer/circuit/testing.rb', line 20

def self.ActivityInspect(activity, strip: ["AlterTest::"])
  strip += ["Trailblazer::Circuit::"]
  stripped = ->(target) { strip_for(target, strip) }

  map, _ = activity.circuit.to_fields

  content = map.collect do |task, connections|
    bla =
    connections.collect do |direction, target|
      target_str = target.kind_of?(End) ? EndInspect(target) : stripped.(target)
      "#{stripped.(direction)}=>#{target_str}"
    end.join(", ")
    task_str = task.kind_of?(End) ? EndInspect(task) : stripped.(task)
    "#{task_str}=>{#{bla}}"
  end.join(", ")
  "{#{content}}"
end

.Circuit(name = :default, events, end_events) ⇒ Object 



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# File 'lib/trailblazer/circuit/activity.rb', line 33

def self.Circuit(name=:default, events, end_events)
  Circuit.new(yield(events), end_events, name)
end

.EndInspect(event) ⇒ Object 



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# File 'lib/trailblazer/circuit/testing.rb', line 16

def self.EndInspect(event)
  event.instance_eval { "#<#{self.class.to_s.split("::").last}: #{@name} #{@options}>" }
end

.Events(events) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



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# File 'lib/trailblazer/circuit/activity.rb', line 39

def self.Events(events)
  evts = Struct.new(*events.keys) do # [Start, End, Resume]
    def [](event, name=:default)
      cfg = super(event.downcase)
      cfg[name.to_sym] or raise "[Circuit] Event `#{event}.#{name} unknown."
      # DISCUSS: the event type's events should also be a Struct to avoid :symbol vs. string.
    end
  end

  evts.new(*events.values)
end

.strip_for(target, strings) ⇒ Object 



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# File 'lib/trailblazer/circuit/testing.rb', line 38

def self.strip_for(target, strings)
  strings.each { |stripped| target = target.to_s.gsub(stripped, "") }
  target
end

Instance Method Details

#call(activity, options, flow_options = {}, *args) ⇒ Object

Runs the circuit. Stops when hitting a End event or subclass thereof. This method throws exceptions when the return value of a task doesn’t match any wiring.

Parameters:

  • activity —

    A task from the circuit where to start

  • args —

    An array of options passed to the first task.



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# File 'lib/trailblazer/circuit.rb', line 32

def call(activity, options, flow_options={}, *args)
  direction = nil
  runner    = flow_options[:runner] || Run

  loop do
    direction, options, flow_options = runner.( activity, direction, options, flow_options, *args )

    # Stop execution of the circuit when we hit a stop event (< End). This could be an activity's End or Suspend.
    return [ direction, options, flow_options ] if @stop_events.include?(activity)

    activity = next_for(activity, direction) do |next_activity, in_map|
      activity_name = @name[activity] || activity # TODO: this must be implemented only once, somewhere.
      raise IllegalInputError.new("#{@name[:id]} #{activity_name}") unless in_map
      raise IllegalOutputSignalError.new("from #{@name[:id]}: `#{activity_name}`===>[ #{direction.inspect} ]") unless next_activity
    end
  end
end

#to_fields ⇒ Object

Returns the circuit’s components.



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# File 'lib/trailblazer/circuit.rb', line 51

def to_fields
  [ @map, @stop_events, @name]
end