Process one installment at a time in background jobs

Instead of attempting to process multiple installments at a time, which
increases the chances something might go wrong, we are now only processing
one installment at a time.

This also improves the extension's performance, because the installments
can be processed in parallel.

2 files changed, 11 insertions, 24 deletions

diff --git a/app/jobs/solidus_subscriptions/process_installment_job.rb b/app/jobs/solidus_subscriptions/process_installment_job.rb
new file mode 100644
index 0000000..6beeec6
--- /dev/null
+++ b/app/jobs/solidus_subscriptions/process_installment_job.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module SolidusSubscriptions
+  class ProcessInstallmentJob < ApplicationJob
+    queue_as SolidusSubscriptions.configuration.processing_queue
+
+    def perform(installment)
+      Checkout.new([installment]).process
+    end
+  end
+end
diff --git a/app/jobs/solidus_subscriptions/process_installments_job.rb b/app/jobs/solidus_subscriptions/process_installments_job.rb
deleted file mode 100644
index e7e1f63..0000000
--- a/app/jobs/solidus_subscriptions/process_installments_job.rb
+++ /dev/null
@@ -1,24 +0,0 @@
-# frozen_string_literal: true
-
-# This job is responsible for creating a consolidated installment from a
-# list of installments and processing it.
-
-module SolidusSubscriptions
-  class ProcessInstallmentsJob < ApplicationJob
-    queue_as SolidusSubscriptions.configuration.processing_queue
-
-    # Process a collection of installments
-    #
-    # @param installment_ids [Array<Integer>] The ids of the
-    #   installments to be processed together and fulfilled by the same order
-    #
-    # @return [Spree::Order] The order which fulfills the list of installments
-    def perform(installment_ids)
-      return if installment_ids.empty?
-
-      installments = SolidusSubscriptions::Installment.where(id: installment_ids).
-                     includes(subscription: [:line_items, :user])
-      Checkout.new(installments).process
-    end
-  end
-end