Module: GoodData::Bam::Compiler

Defined in:
lib/compiler/compiler.rb,
lib/compiler/etl_visitor.rb

Defined Under Namespace

Classes: EtlVisitor

Class Method Summary collapse

Class Method Details

.change_metadata(state, metadata_change_description) ⇒ Object 



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

def self.change_metadata(state, metadata_change_description)
  metadata = state[metadata_change_description[:id]]

  # enrich meta with everything from descriptor. There might be additional stuff so we want this to be part of metadata
  enriched_meta = metadata.merge(metadata_change_description.reject {|k,v|  [:id, :steps, :type].include?(k)})

  metadata_change_description[:steps].reduce(Metadata.create(enriched_meta)) do |meta_accumulator, step|
    case step[:type]
    when :field_add
      Metadata.add_field(meta_accumulator, {:name => step[:name]})
    when :field_remove
      Metadata.remove_field(meta_accumulator, step[:name])
    end
  end
end

.check_metadata_existence(metadata_store, id, flow_description) ⇒ Object 



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# File 'lib/compiler/compiler.rb', line 29

def self.check_metadata_existence(metadata_store, id, flow_description)
  unless metadata_store.has_key?(id)
    fail "Metadata with id \"#{id}\" were not found. Check that you have them included in flow \"#{flow_description[:name]}\"."
  end
end

.compile_dsl(project) ⇒ Object 



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# File 'lib/compiler/compiler.rb', line 5

def self.compile_dsl(project)
  fail "There are no flow. Nothing to work on." if project[:flows_definitions].empty?
  compiled_flows = project[:flows_definitions].map do |flow_description|
    Compiler.compile_flow(project, flow_description)
  end
  Project.create(project.merge({:flows => compiled_flows}))
end

.compile_flow(project, flow_description) ⇒ Object 



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

def self.compile_flow(project, flow_description)
  flow = Flow.create({:name => flow_description[:name]})
  # metadata_state = {}
  out_port = nil

  # this nil magic is done so we have visibility to one step back and forward. Currently not used much but it is useful for detectin input to sink
  flow = [nil].concat(flow_description[:steps]).concat([nil]).each_cons(3).reduce(flow) do |flow_memo, steps|
    previous_step, current_step, next_step = steps
    id = current_step[:id] || current_step[:flow_id]

    case current_step[:type]
    when :dummy_tap
      Flow.add_step(flow_memo, Tap.create(current_step.merge(:source => :dummy, :id => :none)))
    when :tap
      tap = Project.find_tap_by_id(project, id)
      fail "Tap \"#{id}\" which was used in flow \"#{current_step[:flow_id]}\" is not defined" if tap.nil?
      Flow.add_step(flow_memo, Tap.create(tap.merge(current_step)))
    when :sink
      sink = Project.find_sink_by_id(project, id)
      fail "Sink \"#{id}\" not found" if sink.nil?
      out_step = Step.find_output_step(previous_step[:steps])
      Flow.add_step(flow_memo, Sink.create(sink.merge(current_step).merge({:in => out_step})))
    when :graph
      graph = Project.find_graph_by_path(project, current_step[:path])
      fail "Graph on the path \"#{current_step[:path]}\" could not be found. This was specified in step \"#{current_step}\"" if graph.nil?
      g = Graph.create(graph.merge(current_step))

      if !Step.has_output_step?(g[:steps]) && g[:steps].count > 1
        fail "You need to specify an output metadata."
      end

      Flow.add_step(flow_memo, Graph.create(g.merge({
        :input_ports => g[:steps],
        :output_port => Step.find_output_step(g[:steps])
      })))
    end
  end
end