Removing gaps caused by empty exports (#591)

app/services/exports/case_log_export_service.rb

@@ -21,6 +21,7 @@ module Exports
       export = build_export_run(start_time, full_update)
       daily_run = get_daily_run_number
       archive_datetimes = write_export_archive(export, case_logs)
+      export.empty_export = archive_datetimes.empty?
       write_master_manifest(daily_run, archive_datetimes)
       export.save!
     end
@@ -39,12 +40,14 @@ module Exports
     end
 
     def build_export_run(current_time, full_update)
-      if LogsExport.count.zero?
+      previous_exports_with_data = LogsExport.where(empty_export: false)
+
+      if previous_exports_with_data.empty?
         return LogsExport.new(started_at: current_time)
       end
 
-      base_number = LogsExport.maximum(:base_number)
-      increment_number = LogsExport.where(base_number:).maximum(:increment_number)
+      base_number = previous_exports_with_data.maximum(:base_number)
+      increment_number = previous_exports_with_data.where(base_number:).maximum(:increment_number)
 
       if full_update
         base_number += 1

db/migrate/20220519112604_add_empty_export_to_logs_exports.rb

@@ -0,0 +1,5 @@
+class AddEmptyExportToLogsExports < ActiveRecord::Migration[7.0]
+  def change
+    add_column :logs_exports, :empty_export, :boolean, default: false, null: false
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.0].define(version: 2022_05_18_115438) do
+ActiveRecord::Schema[7.0].define(version: 2022_05_19_112604) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
@@ -263,6 +263,7 @@ ActiveRecord::Schema[7.0].define(version: 2022_05_18_115438) do
     t.datetime "started_at", precision: nil, null: false
     t.integer "base_number", default: 1, null: false
     t.integer "increment_number", default: 1, null: false
+    t.boolean "empty_export", default: false, null: false
   end
 
   create_table "organisation_las", force: :cascade do |t|

spec/services/exports/case_log_export_service_spec.rb

@@ -166,7 +166,7 @@ RSpec.describe Exports::CaseLogExportService do
       end
     end
 
-    context "and a previous export has run the same day with logs" do
+    context "and a previous export has run the same day having case logs" do
       before do
         FactoryBot.create(:case_log, startdate: Time.zone.local(2022, 2, 1))
         export_service.export_case_logs
@@ -203,6 +203,16 @@ RSpec.describe Exports::CaseLogExportService do
       end
     end
 
+    context "and a previous export has run having no case logs" do
+      before { export_service.export_case_logs }
+
+      it "doesn't increment the manifest number by 1" do
+        export_service.export_case_logs
+
+        expect(LogsExport.last.increment_number).to eq(1)
+      end
+    end
+
     context "and the export has an error" do
       before { allow(storage_service).to receive(:write_file).and_raise(StandardError.new("This is an exception")) }