Create batch jobs for preservation

Why these changes are being introduced:

We need a way to initiate SIP creation, bagging and streaming to
S3.

Relevant ticket(s):

https://mitlibraries.atlassian.net/browse/ETD-553

How this addresses that need:

This creates two jobs:
1. PreservationSubmissionJob attempts to send a single thesis to
preservation and modifies the preservation_status and preserved_at
fields accordingly.
2. PreservationSubmissionPrepJob loops through an array of theses
to preserve.

Side effects of this change:

* preservation_status is now an enum with three options: unpreserved
(the default), preserved, and error.
* Adds `preservation.rake` task to send a single thesis to
preservation via Rails CLI.
* The readme now indicates that the publishing workflow automatically
kicks off the preservation workflow. This is not yet accurate, but
will be once ETD-560 is implemented.

README.md

@@ -226,14 +226,35 @@ Example usage:
   heroku run rails dss:process_output_queue --app TARGET-HEROKU-APP
   ```
 
-## Publishing a single thesis
+### Publishing a single thesis
 
 You can publish a single thesis that is already in `Publication review` status by passing the `thesis_id` to a rake task like:
 
 ```shell
 heroku run rails dss:publish_thesis_by_id[THESIS_ID] --app TARGET-HEROKU-APP
 ```
 
+## Preservation workflow
+
+The publishing workflow will automatically trigger preservation for all of the published theses in the results queue.
+At this point a submission information package is generated for each thesis, then a bag is constructed, zipped, and
+streamed to an S3 bucket. (See the SubmissionInformationPackage and SubmissionInformationPackageZipper classes for more
+details on this part of the process.)
+
+Once the bags are in the S3 bucket, they are replicated to the Digital Preservation S3 bucket, where they can be
+ingested into Archivematica.
+
+A thesis can be sent to preservation more than once. In order to track provenance across multiple preservation events,
+we persist certain data about the SIP and audit the model using [paper_trail](https://github.com/paper-trail-gem/paper_trail).
+
+### Preserving a single thesis
+
+You can manually send a published thesis to preservation by passing the thesis ID to the following rake task:
+
+```shell
+heroku run rails preservation:preserve_thesis_by_id[THESIS_ID] --app TARGET-HEROKU-APP
+```
+
 ## Validation of thesis record
 
 Prior to theses being published to external systems (such as the repository, or

app/jobs/preservation_submission_job.rb

@@ -0,0 +1,19 @@
+class PreservationSubmissionJob < ActiveJob::Base
+  queue_as :default
+
+  def perform(thesis)
+    begin
+      Rails.logger.info("Thesis #{thesis.id} is now being prepared for preservation")
+      sip = thesis.submission_information_packages.create
+      SubmissionInformationPackageZipper.new(sip)
+      sip.preservation_status = 'preserved'
+      sip.preserved_at = DateTime.now
+      sip.save
+      Rails.logger.info("Thesis #{thesis.id} has been sent to preservation")
+    rescue StandardError, NoMethodError, Aws::Errors => e
+      Rails.logger.info ("Thesis #{thesis.id} could not be preserved: #{e}")
+      sip.preservation_status = 'error'
+      sip.save
+    end
+  end
+end

app/jobs/preservation_submission_prep_job.rb

@@ -0,0 +1,11 @@
+class PreservationSubmissionPrepJob < ActiveJob::Base
+  queue_as :default
+
+  def perform(theses)
+    Rails.logger.info("Preparing to send #{theses.count} theses to preservation")
+
+    theses.each do |thesis|
+      PreservationSubmissionJob.perform_later(thesis)
+    end
+  end
+end

app/models/submission_information_package.rb

@@ -29,6 +29,8 @@ class SubmissionInformationPackage < ApplicationRecord
 
   before_create :set_metadata, :set_bag_declaration, :set_manifest, :set_bag_name
 
+  enum preservation_status: [ :unpreserved, :preserved, :error ]
+
   def data
     file_locations = {}
     thesis.files.map { |f| file_locations["data/#{f.filename}"] = f.blob }

lib/tasks/preservation.rake

@@ -0,0 +1,19 @@
+namespace :preservation do
+  desc 'Sends a single thesis to preservation'
+  task :preserve_thesis_by_id, [:thesis_id] => :environment do |_t, args|
+    if args.thesis_id
+      Rails.logger.info("Attempting to send #{args.thesis_id} to preservation...")
+      thesis = Thesis.find(args.thesis_id)
+
+      # Only published theses may be sent to preservation. We already check for this in SubmissionInformationPackage
+      # validations, but double-checking here to save potential confusion.
+      if thesis.publication_status == 'Published'
+        PreservationSubmissionJob.perform_now(thesis)
+      else
+        Rails.logger.info("Thesis status of #{thesis.publication_status} cannot be preserved.")
+      end
+    else
+      Rails.logger.info('No thesis ID provided.')
+    end
+  end
+end

test/jobs/preservation_submission_job_prep_test.rb

@@ -0,0 +1,28 @@
+require 'test_helper'
+
+class PreservationSubmissionPrepJobTest < ActiveJob::TestCase
+
+  test 'queues 1 job for 1 thesis' do
+    theses = [theses(:one)].to_a
+
+    assert_enqueued_jobs 1 do
+      PreservationSubmissionPrepJob.perform_now(theses)
+    end
+  end
+
+  test 'queues 2 jobs for 2 theses' do
+    theses = [theses(:one), theses(:two)].to_a
+
+    assert_enqueued_jobs 2 do
+      PreservationSubmissionPrepJob.perform_now(theses)
+    end
+  end
+
+  test 'queues same number of theses it receives' do
+    theses = Thesis.in_review.to_a
+
+    assert_enqueued_jobs theses.count do
+      PreservationSubmissionPrepJob.perform_now(theses)
+    end
+  end
+end

test/jobs/preservation_submission_job_test.rb

@@ -0,0 +1,53 @@
+require 'test_helper'
+
+class PreservationSubmissionJobTest < ActiveJob::TestCase
+
+  # because we need to actually use the file it's easier to attach it in the test rather
+  # than use our fixtures as the fixtures oddly don't account for the file actually being
+  # where ActiveStorage expects them to be. We also need this to be a record that looks like
+  # a published record so we'll use the published fixture, remove the fixtured files, and attach
+  # one again.
+  def setup_thesis
+    thesis = theses(:published)
+    thesis.files = []
+    thesis.save
+    file = Rails.root.join('test', 'fixtures', 'files', 'registrar_data_small_sample.csv')
+    thesis.files.attach(io: File.open(file), filename: 'registrar_data_small_sample.csv')
+    thesis
+  end
+
+  test 'creates a SIP' do
+    thesis = setup_thesis
+    assert_equal 0, thesis.submission_information_packages.count
+
+    PreservationSubmissionJob.perform_now(thesis)
+    assert_equal 1, thesis.submission_information_packages.count
+  end
+
+  test 'updates preservation_status to "preserved" after successfully processing a thesis' do
+    thesis = setup_thesis
+    PreservationSubmissionJob.perform_now(thesis)
+    assert_equal 'preserved', thesis.submission_information_packages.last.preservation_status
+  end
+
+  test 'updates preserved_at to the current time after successfully processing a thesis' do
+    time = DateTime.now.getutc
+    Timecop.freeze(time) do
+      thesis = setup_thesis
+      PreservationSubmissionJob.perform_now(thesis)
+      assert_equal time, thesis.submission_information_packages.last.preserved_at
+    end
+  end
+
+  test 'rescues exceptions by updating preservation_status to "error"' do
+    thesis = theses(:one)
+    PreservationSubmissionJob.perform_now(thesis)
+    assert_equal 'error', thesis.submission_information_packages.last.preservation_status
+  end
+
+  test 'does not update preserved_at if the job enters an error state' do
+    thesis = theses(:one)
+    PreservationSubmissionJob.perform_now(thesis)
+    assert_nil thesis.submission_information_packages.last.preserved_at
+  end
+end

test/models/submission_information_package_test.rb

@@ -86,9 +86,9 @@ class SubmissionInformationPackageTest < ActiveSupport::TestCase
     assert_not_nil sip.metadata
   end
 
-  test 'preservation_status defaults to 0' do
+  test 'preservation_status defaults to unpreserved' do
     sip = theses(:published).submission_information_packages.create
-    assert_equal 0, sip.preservation_status
+    assert_equal 'unpreserved', sip.preservation_status
   end
 
   test 'data generates file location hash' do

test/models/submission_information_package_zipper_test.rb

@@ -2,7 +2,7 @@
 
 class SubmissionInformationPackageZipperTest < ActiveSupport::TestCase
 
-  # because we need to actually use the file it's easier to attache it in the test rather
+  # because we need to actually use the file it's easier to attach it in the test rather
   # than use our fixtures as the fixtures oddly don't account for the file actually being
   # where ActiveStorage expects them to be. We also need this to be a record that looks like
   # a published record so we'll use the published fixture, remove the fixtured files, and attach