Add profiler and version of seed_from_disk using it

  including specs

Gemfile

@@ -15,6 +15,7 @@ gem 'pg'
 # useful for debugging, even in prod
 gem 'pry-byebug' # Adds step-by-step debugging and stack navigation capabilities to pry using byebug
 gem 'pry-rails' # use pry as the rails console shell instead of IRB
+gem 'ruby-prof' # to profile methods
 # Use Puma as the app server
 gem 'puma', '~> 3.7'
 gem 'rails', '~> 5.1.3'
@@ -44,7 +45,6 @@ group :development do
   # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
   gem 'spring'
   gem 'spring-watcher-listen', '~> 2.0.0'
-  gem 'ruby-prof'
   gem 'hirb' # for db table display via rails console
 end
 

lib/audit/moab_to_catalog.rb

@@ -49,6 +49,12 @@ def seed_from_disk
     end
   end
 
+  def seed_from_disk_with_profiling
+    profiler = Profiler.new
+    profiler.prof { seed_from_disk }
+    profiler.print_results_flat('seed_from_disk')
+  end
+
   # Shameless green. Code duplication with seed_from_disk
   def check_existence_from_disk
     Settings.moab.storage_roots.each do |storage_root|

lib/profiler.rb

@@ -0,0 +1,23 @@
+# adapted from argo
+# takes a block of code, starts the profiler, runs the code, then
+# stops the profiler and returns the results of the profiling.
+# example usage:
+#  profiler = Profiler.new
+#  profiler.prof { MoabToCatalog.seed_catalog(storage_dir) }
+#  profiler.print_results_flat(out_file_id)
+class Profiler
+
+  attr_accessor :results
+
+  def prof
+    RubyProf.start
+    yield
+    @results = RubyProf.stop
+  end
+
+  def print_results_flat(out_file_id)
+    File.open "log/#{out_file_id}#{Time.current.localtime.strftime('%FT%T')}-flat.txt", 'w' do |file|
+      RubyProf::FlatPrinterWithLineNumbers.new(@results).print(file)
+    end
+  end
+end

spec/lib/audit/moab_to_catalog_spec.rb

@@ -41,6 +41,20 @@
     end
   end
 
+  describe "#seed_from_disk_with_profiling" do
+    let(:m2c) { described_class.new }
+
+    it "spins up a profiler, calling profiling and printing methods on it" do
+      mock_profiler = instance_double(Profiler)
+
+      expect(Profiler).to receive(:new).and_return(mock_profiler)
+      expect(mock_profiler).to receive(:prof)
+      expect(mock_profiler).to receive(:print_results_flat)
+
+      m2c.seed_from_disk_with_profiling
+    end
+  end
+
   describe ".check_existence" do
     let(:subject) { described_class.check_existence(storage_dir, true) }
 

spec/lib/profiler_spec.rb

@@ -0,0 +1,34 @@
+require_relative '../../lib/profiler.rb'
+require 'ruby-prof'
+
+RSpec.describe Profiler do
+  let(:profiler) { described_class.new }
+
+  describe '#prof' do
+    it 'starts, yields, stops, and returns results' do
+      rp_profile = instance_double(RubyProf::Profile)
+      expect(RubyProf).to receive(:start)
+      expect(RubyProf).to receive(:stop).and_return(rp_profile)
+      test_value = false
+      profiler.prof { test_value = true }
+      expect(test_value).to be true
+      expect(profiler.results).to eq rp_profile
+    end
+  end
+
+  describe '#print_results_flat' do
+    it 'returns the printer and prints to the path we pass in' do
+      printer = instance_double(RubyProf::FlatPrinterWithLineNumbers)
+      profiler.prof { 'we just want #prof to run' }
+      expected_filepath = "log/test#{Time.current.localtime.strftime('%FT%T')}-flat.txt"
+      expect(RubyProf::FlatPrinterWithLineNumbers).to receive(:new).with(profiler.results).and_return(printer)
+      expect(printer).to receive(:print) do |file|
+        # this expectation might need to relax
+        # if enough time lags between the timestamps
+        # in expected_filepath and the file name itself
+        expect(file.path).to eq expected_filepath
+      end
+      profiler.print_results_flat('test')
+    end
+  end
+end