Add an endpoint to get aggregate statistics for a workflow

This can be used to create the argo view https://argo.stanford.edu/report/workflow_grid
without having to look at Solr.

README.md

@@ -34,16 +34,28 @@ docker-compose run -e "RAILS_ENV=test" app rake spec
 ```
 
 ## Routes:
+`GET    /:repo/objects/:druid/lifecycle` - Returns the milestones in the lifecycle that have been completed
+
+
+`POST   /:repo/objects/:druid/versionClose` - Set all versioningWF steps to 'complete' and starts a new accessionWF unless `create-accession=false` is passed as a parameter.
+
+
+These methods deal with the workflow for a single object
 ```
-GET    /:repo/objects/:druid/lifecycle
-POST   /:repo/objects/:druid/versionClose
 PUT    /:repo/objects/:druid/workflows/:workflow
 PUT    /:repo/objects/:druid/workflows/:workflow/:process
 GET    /:repo/objects/:druid/workflows
 GET    /:repo/objects/:druid/workflows/:workflow
 DELETE /:repo/objects/:druid/workflows/:workflow
-GET    /workflow_archive
+```
+
+`GET    /workflow_archive` - Deprecated. Currently just returns a count of the number of items/versions for the workflow
+
+These processes are used by robot-master to discover which steps need to be performed.
+```
 GET    /workflow_queue/lane_ids
 GET    /workflow_queue/all_queued
 GET    /workflow_queue
 ```
+
+`GET    /workflow/:workflow` - Returns aggregate data of number of active processes in each workflow step

app/controllers/status_controller.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+##
+# API for handling requests about the state of all objects in a workflow
+class StatusController < ApplicationController
+  def show
+    workflow_name = params.require(:workflow)
+    @result = status_response(workflow_name)
+
+    render json: { steps: @result }
+  end
+
+  private
+
+  def status_response(workflow_name)
+    tree = steps_for_workflow(workflow_name)
+    xml = WorkflowTemplateService.template_for(workflow_name)
+    processes = WorkflowParser.new(xml).processes
+    step_names = processes.map(&:process)
+    step_names.map do |process_name|
+      { name: process_name, object_status: tree.fetch(process_name, {}) }
+    end
+  end
+
+  # Returns a hash of counts of objects in each step and status:
+  # @example
+  #  {"start-accession"=>{"completed"=>1}
+  def steps_for_workflow(workflow)
+    counts = WorkflowStep.active.where(workflow: workflow).group(:process, :status).count
+    {}.tap do |tree|
+      counts.each do |(step, status), val|
+        tree[step] ||= {}
+        tree[step][status] = val
+      end
+    end
+  end
+end

config/routes.rb

@@ -25,4 +25,6 @@
       get 'all_queued'
     end
   end
+
+  get '/workflow/:workflow', to: 'status#show', defaults: { format: :json }
 end

spec/requests/workflow_status_spec.rb

@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe 'Get the status for a workflow', type: :request do
+  include XmlFixtures
+
+  before do
+    allow(WorkflowTemplateService).to receive(:template_for).and_return(workflow_create)
+  end
+
+  context 'for all workflows' do
+    before do
+      FactoryBot.create(:workflow_step,
+                        status: 'completed',
+                        active_version: true)
+
+      FactoryBot.create(:workflow_step,
+                        status: 'completed',
+                        active_version: true)
+
+      FactoryBot.create(:workflow_step,
+                        status: 'waiting',
+                        active_version: true)
+
+      FactoryBot.create(:workflow_step,
+                        status: 'waiting',
+                        active_version: false)
+
+      FactoryBot.create(:workflow_step,
+                        status: 'error',
+                        process: 'descriptive-metadata',
+                        active_version: true)
+
+      FactoryBot.create(:workflow_step,
+                        status: 'error',
+                        process: 'descriptive-metadata',
+                        active_version: true)
+
+      FactoryBot.create(:workflow_step,
+                        status: 'waiting',
+                        process: 'descriptive-metadata',
+                        active_version: true)
+    end
+
+    it 'displays the counts' do
+      get '/workflow/accessionWF'
+      expect(response).to be_successful
+      expect(JSON.parse(response.body)).to eq(
+        'steps' => [
+          { 'name' => 'start-accession',
+            'object_status' => { 'completed' => 2, 'waiting' => 1 } },
+          { 'name' => 'descriptive-metadata',
+            'object_status' => { 'error' => 2, 'waiting' => 1 } },
+          { 'name' => 'rights-metadata', 'object_status' => {} },
+          { 'name' => 'content-metadata', 'object_status' => {} },
+          { 'name' => 'technical-metadata', 'object_status' => {} },
+          { 'name' => 'remediate-object', 'object_status' => {} },
+          { 'name' => 'shelve', 'object_status' => {} },
+          { 'name' => 'publish', 'object_status' => {} },
+          { 'name' => 'provenance-metadata', 'object_status' => {} },
+          { 'name' => 'sdr-ingest-transfer', 'object_status' => {} },
+          { 'name' => 'sdr-ingest-received', 'object_status' => {} },
+          { 'name' => 'reset-workspace', 'object_status' => {} },
+          { 'name' => 'end-accession', 'object_status' => {} }
+        ]
+      )
+    end
+  end
+end