Adds a report for version mismatches.

refs #5074

app/reports/preservation_versions.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+# Compare SDR versions against Preservation versions
+#  https://github.com/sul-dlss/dor-services-app/issues/5074
+# Invoke via:
+# bin/rails r -e production "PreservationVersions.report"
+class PreservationVersions
+  def self.report
+    new.report
+  end
+
+  def report
+    data = RepositoryObject.joins(:head_version).pluck(:external_identifier, :version)
+
+    progress_bar = tty_progress_bar(data.length)
+    progress_bar.start
+
+    results = Parallel.map(data.each_slice(10000),
+                           in_processes: 4,
+                           finish: ->(finish_data, _, _) { progress_bar.advance(finish_data.length) }) do |data_slice|
+      data_slice.map do |druid, version|
+        begin
+          preservation_version = Preservation::Client.objects.current_version(druid)
+        rescue Preservation::Client::NotFoundError
+          preservation_version = nil
+        end
+        preservation_version == version ? nil : [druid, version, preservation_version]
+      end
+    end.flatten(1).compact
+
+    CSV.open('preservation_versions_report.csv', 'w') do |csv|
+      csv << %w[druid version preservation_version]
+      results.each { |result| csv << result }
+    end
+  end
+
+  def tty_progress_bar(count)
+    TTY::ProgressBar.new(
+      '[:bar] (:percent (:current/:total), rate: :rate/s, mean rate: :mean_rate/s, :elapsed total, ETA: :eta_time)',
+      bar_format: :box,
+      advance: num_for_progress_advance(count),
+      total: count
+    )
+  end
+
+  def num_for_progress_advance(count)
+    return 1 if count < 100
+
+    count / 100
+  end
+end