Add Rake task and Resque job to delete old auto snapshots

app/jobs/pageflow/prune_auto_snapshots_job.rb

@@ -0,0 +1,9 @@
+module Pageflow
+  class PruneAutoSnapshotsJob
+    @queue = :prune
+
+    def self.perform(entry_id, options)
+      AutoSnapshotPruning.prune(Entry.find(entry_id), options.symbolize_keys)
+    end
+  end
+end

app/models/pageflow/auto_snapshot_pruning.rb

@@ -0,0 +1,26 @@
+module Pageflow
+  # @api private
+  module AutoSnapshotPruning
+    extend self
+
+    def dirty_entry_ids(options)
+      Revision
+        .auto_snapshots
+        .where('created_at < ?', options.fetch(:created_before))
+        .select('COUNT(*) as revisions_count, entry_id')
+        .group('entry_id')
+        .having('revisions_count > ?', options.fetch(:keep_count))
+        .map(&:entry_id)
+    end
+
+    def prune(entry, options)
+      entry
+        .revisions
+        .auto_snapshots
+        .where('created_at < ?', options[:created_before])
+        .order('created_at DESC')
+        .offset(options[:keep_count])
+        .each(&:destroy)
+    end
+  end
+end

app/models/pageflow/chapter.rb

@@ -3,7 +3,7 @@ class Chapter < ActiveRecord::Base
     include SerializedConfiguration
 
     belongs_to :storyline, touch: true
-    has_many :pages, -> { order('position ASC') }
+    has_many :pages, -> { order('position ASC') }, dependent: :destroy
 
     delegate :entry, to: :storyline
 

app/models/pageflow/revision.rb

@@ -13,11 +13,12 @@ class Revision < ActiveRecord::Base
     belongs_to :restored_from, :class_name => 'Pageflow::Revision'
 
     has_many :widgets, as: :subject, dependent: :destroy
-    has_many :storylines, -> { order('pageflow_storylines.position ASC') }
+
+    has_many :storylines, -> { order('pageflow_storylines.position ASC') }, dependent: :destroy
     has_many :chapters, -> { order('position ASC') }, through: :storylines
     has_many :pages, -> { reorder(PAGE_ORDER) }, through: :storylines
 
-    has_many :file_usages
+    has_many :file_usages, dependent: :destroy
 
     has_many :image_files, -> { extending WithFileUsageExtension },
     :through => :file_usages, :source => :file, :source_type => 'Pageflow::ImageFile'
@@ -39,6 +40,8 @@ class Revision < ActiveRecord::Base
 
     scope :publications, -> { where('published_at IS NOT NULL') }
     scope :publications_and_user_snapshots, -> { where('published_at IS NOT NULL OR snapshot_type = "user"') }
+    scope :user_snapshots, -> { where('snapshot_type = "user"') }
+    scope :auto_snapshots, -> { where('snapshot_type = "auto"') }
 
     validates :entry, :presence => true
     validates :creator, :presence => true, :if => :published?

app/models/pageflow/storyline.rb

@@ -5,7 +5,7 @@ class Storyline < ActiveRecord::Base
 
     belongs_to :revision, touch: true
 
-    has_many :chapters, -> { order('pageflow_chapters.position ASC') }
+    has_many :chapters, -> { order('pageflow_chapters.position ASC') }, dependent: :destroy
     has_many :pages, through: :chapters
 
     delegate :entry, to: :revision

lib/tasks/pageflow_tasks.rake

@@ -11,4 +11,18 @@ namespace :pageflow do
       system('bin/npm run build')
     end
   end
+
+  namespace :prune_auto_snapshots_jobs do
+    desc 'Enqueue jobs to destroy old auto snapshot revisions'
+    task :enqueue => :environment do
+      options = {
+        created_before: ENV['CREATED_BEFORE'] ? Time.parse(ENV['CREATED_BEFORE']) : 1.month.ago,
+        keep_count: ENV.fetch('KEEP_COUNT', 20)
+      }
+
+      Pageflow::AutoSnapshotPruning.dirty_entry_ids(options).each do |entry_id|
+        Resque.enqueue(Pageflow::PruneAutoSnapshotsJob, entry_id, options)
+      end
+    end
+  end
 end

spec/jobs/pageflow/prune_auto_snapshots_job_spec.rb

@@ -0,0 +1,18 @@
+require 'spec_helper'
+
+module Pageflow
+  describe PruneAutoSnapshotsJob do
+    it 'destroys old auto snapshots' do
+      user = create(:user)
+      entry = create(:entry)
+
+      Timecop.freeze(2.month.ago) do
+        3.times { entry.snapshot(creator: user) }
+      end
+
+      PruneAutoSnapshotsJob.perform(entry.id, keep_count: 2, created_before: 1.month.ago)
+
+      expect(entry.reload.revisions.auto_snapshots.count).to eq(2)
+    end
+  end
+end

spec/models/pageflow/auto_snapshot_pruning_spec.rb

@@ -0,0 +1,155 @@
+require 'spec_helper'
+
+module Pageflow
+  describe AutoSnapshotPruning do
+    describe '.dirty_entry_ids' do
+      it 'includes entries with more than keep_count auto snapshots created before given time' do
+        user = create(:user)
+        entry = create(:entry)
+
+        Timecop.freeze(2.month.ago) do
+          5.times { entry.snapshot(creator: user) }
+        end
+
+        result = AutoSnapshotPruning.dirty_entry_ids(keep_count: 4, created_before: 1.month.ago)
+
+        expect(result).to include(entry.id)
+      end
+
+      it 'does not includes entries with less than keep_count auto snapshots' do
+        user = create(:user)
+        entry = create(:entry)
+
+        Timecop.freeze(2.month.ago) do
+          2.times { entry.snapshot(creator: user) }
+        end
+
+        result = AutoSnapshotPruning.dirty_entry_ids(keep_count: 4, created_before: 1.month.ago)
+
+        expect(result).not_to include(entry.id)
+      end
+
+      it 'does not includes entries with auto snapshots created after given date' do
+        user = create(:user)
+        entry = create(:entry)
+
+        Timecop.freeze(1.day.ago) do
+          3.times { entry.snapshot(creator: user) }
+        end
+
+        result = AutoSnapshotPruning.dirty_entry_ids(keep_count: 2, created_before: 1.month.ago)
+
+        expect(result).not_to include(entry.id)
+      end
+
+      it 'does not includes entries with more than keep_count user snapshots' do
+        user = create(:user)
+        entry = create(:entry)
+
+        Timecop.freeze(2.month.ago) do
+          3.times { entry.snapshot(creator: user, type: 'user') }
+        end
+
+        result = AutoSnapshotPruning.dirty_entry_ids(keep_count: 2, created_before: 1.month.ago)
+
+        expect(result).not_to include(entry.id)
+      end
+
+      it 'does not includes entries with more than keep_count publications' do
+        user = create(:user)
+        entry = create(:entry)
+
+        Timecop.freeze(2.month.ago) do
+          3.times { entry.publish(creator: user) }
+        end
+
+        result = AutoSnapshotPruning.dirty_entry_ids(keep_count: 2, created_before: 1.month.ago)
+
+        expect(result).not_to include(entry.id)
+      end
+    end
+
+    describe '.prune' do
+      it 'destroy all but keep_count auto snapshots' do
+        user = create(:user)
+        entry = create(:entry)
+
+        Timecop.freeze(2.month.ago) do
+          3.times { entry.snapshot(creator: user) }
+        end
+
+        AutoSnapshotPruning.prune(entry, keep_count: 2, created_before: 1.month.ago)
+
+        expect(entry.revisions.auto_snapshots.count).to eq(2)
+      end
+
+      it 'triggers dependent destroys down to pages' do
+        user = create(:user)
+        entry = create(:entry)
+        chapter = create(:chapter, storyline: entry.draft.storylines.first)
+        create(:page, chapter: chapter)
+
+        Timecop.freeze(2.month.ago) do
+          3.times { entry.snapshot(creator: user) }
+        end
+
+        expect {
+          AutoSnapshotPruning.prune(entry, keep_count: 2, created_before: 1.month.ago)
+        }.to change { Pageflow::Page.count }
+      end
+
+      it 'destroys oldest auto snapshots first' do
+        user = create(:user)
+        entry = create(:entry)
+
+        Timecop.freeze(4.month.ago) { entry.snapshot(creator: user) }
+        Timecop.freeze(3.month.ago) { entry.snapshot(creator: user) }
+        Timecop.freeze(2.month.ago) { entry.snapshot(creator: user) }
+
+        AutoSnapshotPruning.prune(entry, keep_count: 2, created_before: 1.month.ago)
+        timestamps = entry.revisions.auto_snapshots.map(&:created_at)
+
+        expect(timestamps).to match_array([2.month.ago, 3.month.ago])
+      end
+
+      it 'ignores auto snapshots created after given data' do
+        user = create(:user)
+        entry = create(:entry)
+
+        Timecop.freeze(4.month.ago) { entry.snapshot(creator: user) }
+        Timecop.freeze(3.days.ago) { entry.snapshot(creator: user) }
+        Timecop.freeze(2.days.ago) { entry.snapshot(creator: user) }
+
+        AutoSnapshotPruning.prune(entry, keep_count: 2, created_before: 1.month.ago)
+
+        expect(entry.revisions.auto_snapshots.count).to eq(3)
+      end
+
+      it 'ignores user snapshots' do
+        user = create(:user)
+        entry = create(:entry)
+
+        Timecop.freeze(2.month.ago) do
+          3.times { entry.snapshot(creator: user, type: 'user') }
+        end
+
+        AutoSnapshotPruning.prune(entry, keep_count: 2, created_before: 1.month.ago)
+
+        expect(entry.revisions.user_snapshots.count).to eq(3)
+      end
+
+      it 'ignores publications' do
+        user = create(:user)
+        entry = create(:entry)
+
+        Timecop.freeze(2.month.ago) do
+          3.times { entry.publish(creator: user) }
+        end
+
+        AutoSnapshotPruning.prune(entry, keep_count: 2, created_before: 1.month.ago)
+
+        expect(entry.revisions.publications.count).to eq(3)
+      end
+    end
+  end
+end