Refactor workflow_image_generation and move to service class

app/models/experiment.rb

@@ -221,123 +221,8 @@ class Experiment < ApplicationRecord
     true
   end
 
-  # This method generate the workflow image and saves it as
-  # experiment attachment
   def generate_workflow_img
-    require 'graphviz'
+    WorkflowImageGenerator.execute(experiment_id: id)
-
-    graph = GraphViz.new(:G,
-                         type: :digraph,
-                         use: :neato)
-
-    graph[:size] = '4,4'
-    graph.node[color: Constants::COLOR_ALTO,
-               style: :filled,
-               fontcolor: Constants::COLOR_EMPEROR,
-               shape: 'circle',
-               fontname: 'Arial',
-               fontsize: '16.0']
-
-    graph.edge[color: Constants::COLOR_ALTO]
-
-    label = ''
-    subg = {}
-
-    # Draw orphan modules
-    my_modules.without_group.each do |my_module|
-      graph
-        .subgraph(rank: 'same')
-        .add_nodes("Orphan-#{my_module.id}",
-                   label: label,
-                   pos: "#{my_module.x / 10},-#{my_module.y / 10}!")
-    end
-
-    # Draw grouped modules
-    if my_module_groups.many?
-      my_module_groups.each_with_index do |group, gindex|
-        subgraph_name = "cluster-#{gindex}"
-        subg[subgraph_name] = graph.subgraph(rank: 'same')
-        group.ordered_modules.each_with_index do |my_module, index|
-          if my_module.outputs.any?
-            parent = subg[subgraph_name]
-                     .add_nodes("#{subgraph_name}-#{index}",
-                                label: label,
-                                pos: "#{my_module.x / 10},-#{my_module.y / 10}!")
-
-            my_module.outputs.each_with_index do |output, i|
-              child_mod = MyModule.find_by_id(output.input_id)
-              child_node = subg[subgraph_name]
-                           .add_nodes("#{subgraph_name}-O#{child_mod.id}-#{i}",
-                                      label: label,
-                                      pos: "#{child_mod.x / 10},-#{child_mod.y / 10}!")
-
-              subg[subgraph_name].add_edges(parent, child_node)
-            end
-          elsif my_module.inputs.any?
-            parent = subg[subgraph_name]
-                     .add_nodes("#{subgraph_name}-#{index}",
-                                label: label,
-                                pos: "#{my_module.x / 10},-#{my_module.y / 10}!")
-
-            my_module.inputs.each_with_index do |input, i|
-              child_mod = MyModule.find_by_id(input.output_id)
-              child_node = subg[subgraph_name]
-                           .add_nodes("#{subgraph_name}-I#{child_mod.id}-#{i}",
-                                      label: label,
-                                      pos: "#{child_mod.x / 10},-#{child_mod.y / 10}!")
-
-              subg[subgraph_name].add_edges(child_node, parent)
-            end
-          end
-        end
-      end
-    else
-      my_module_groups.each do |group|
-        group.ordered_modules.each_with_index do |my_module, index|
-          if my_module.outputs.any?
-            parent = graph.add_nodes("N-#{index}",
-                                     label: label,
-                                     pos: "#{my_module.x / 10},-#{ my_module.y / 10}!")
-
-            my_module.outputs.each_with_index do |output, i|
-              child_mod = MyModule.find_by_id(output.input_id)
-              child_node = graph
-                           .add_nodes("N-O#{child_mod.id}-#{i}",
-                                      label: label,
-                                      pos: "#{child_mod.x / 10},-#{child_mod.y / 10}!")
-              graph.add_edges(parent, child_node)
-            end
-          elsif my_module.inputs.any?
-            parent = graph.add_nodes("N-#{index}",
-                                     label: label,
-                                     pos: "#{my_module.x / 10},-#{my_module.y / 10}!")
-            my_module.inputs.each_with_index do |input, i|
-              child_mod = MyModule.find_by_id(input.output_id)
-              child_node = graph
-                           .add_nodes("N-I#{child_mod.id}-#{i}",
-                                      label: label,
-                                      pos: "#{child_mod.x / 10},-#{child_mod.y / 10}!")
-              graph.add_edges(child_node, parent)
-            end
-          end
-        end
-      end
-    end
-
-    file_location = Tempfile.open(['wimg', '.png'],
-                                  Rails.root.join('tmp'))
-
-    graph.output(png: file_location.path)
-
-    begin
-      file = File.open(file_location)
-      self.workflowimg = file
-      file.close
-      save
-      touch(:workflowimg_updated_at)
-    rescue => ex
-      logger.error ex.message
-    end
   end
 
   # Clone this experiment to given project

app/services/executable_service.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module ExecutableService
+  def execute(*args)
+    new(*args).execute
+  end
+end

app/services/workflow_image_generator.rb

@@ -0,0 +1,89 @@
+# frozen_string_literal: true
+
+class WorkflowImageGenerator
+  extend ExecutableService
+  require 'graphviz'
+
+  attr_reader :errors
+
+  def initialize(experiment_id:)
+    @exp = Experiment.find experiment_id
+    @graph = GraphViz.new(:G, type: :digraph, use: :neato)
+
+    @graph[:size] = '4,4'
+    @graph.node[color: Constants::COLOR_ALTO,
+                style: :filled,
+                fontcolor: Constants::COLOR_EMPEROR,
+                shape: 'circle',
+                fontname: 'Arial',
+                fontsize: '16.0']
+
+    @graph.edge[color: Constants::COLOR_ALTO]
+    @errors = []
+  end
+
+  def execute
+    draw_diagram
+    save_file
+    self
+  end
+
+  def succeed?
+    @errors.none?
+  end
+
+  private
+
+  def draw_diagram
+    # Draw orphan nodes
+    @exp.my_modules.without_group.each do |my_module|
+      @graph.subgraph(rank: 'same').add_nodes(
+        "Orphan-#{my_module.id}",
+        label: '',
+        pos: "#{my_module.x / 10},-#{my_module.y / 10}!"
+      )
+    end
+
+    # Draw grouped modules
+    subg = {}
+    @exp.my_module_groups.each_with_index do |group, gindex|
+      subgraph_id = "cluster-#{gindex}"
+      subg[subgraph_id] = @graph.subgraph(rank: 'same')
+      nodes = {}
+
+      group.my_modules.workflow_ordered.each_with_index do |my_module, index|
+        # draw nodes
+        node = subg[subgraph_id].add_nodes(
+          "#{subgraph_id}-#{index}",
+          label: '',
+          pos: "#{my_module.x / 10},-#{my_module.y / 10}!"
+        )
+        nodes[my_module.id] = node
+      end
+
+      # draw edges
+      group.my_modules.workflow_ordered.each do |m|
+        m.outputs.each do |output|
+          parent_node = nodes[m.id]
+          child_node = nodes[output.input_id]
+          subg[subgraph_id].add_edges(parent_node, child_node)
+        end
+      end
+    end
+  end
+
+  def save_file
+    t_file = Tempfile.open(%w(wimg .png), Rails.root.join('tmp'))
+    @graph.output(png: t_file.path)
+
+    begin
+      file = File.open(t_file)
+      @exp.workflowimg = file
+      file.close
+      @exp.save
+      @exp.touch(:workflowimg_updated_at)
+    rescue StandardError => ex
+      logger.error ex.message
+    end
+  end
+end

spec/services/workflow_image_generator_spec.rb

@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe WorkflowImageGenerator do
+end