Batch the item sync job

This commit takes advantage of the multi-asin item lookup requests and
performs the item sync job in batches of 10.

Author: leesharma

app/jobs/item_sync_job.rb

@@ -8,9 +8,12 @@
 # query the Amazon record associated with the ASIN and make any required local
 # updates.
 #
-# Bang methods (ex. `#amazon_item!`) perform an HTTP request.
+# Bang methods (ex. `#sync_batch!`) perform an HTTP request.
 #
 class ItemSyncJob < ApplicationJob
+  # Maximum number of ASINs in one request
+  BATCH_SIZE = AmazonProductAPI::ItemLookupEndpoint::ASIN_LIMIT
+
   queue_as :default
 
   def initialize
@@ -28,28 +31,52 @@ def perform(*_args)
 
   attr_reader :client
 
+  # Syncs all database items with their Amazon sources
   def sync_all!
-    # This is done in slices to avoid Amazon rate limits
-    Item.all.each_slice(3) do |items|
-      items.each { |item| sync! item }
+    # This is done in slices and batches to avoid Amazon rate limits
+    Item.all.each_slice(BATCH_SIZE * 3) do |batches|
+      batches.each_slice(BATCH_SIZE) { |batch| sync_batch! batch }
       sleep 2.seconds unless Rails.env.test?
     end
   end
 
-  def sync!(item)
-    Rails.logger.info green("Syncing item #{item.id}: #{item.name}")
-    update_hash = amazon_item!(item).update_hash
+  # Syncs one batch of items with Amazon (up to the batch size limit)
+  def sync_batch!(items)
+    count = items.count
+    validate_batch_size(count)
+
+    Rails.logger.info "Fetching #{count} items: #{items.map(&:asin).join(',')}"
+
+    items_updates = get_updates_for! items
+    items_updates.map { |item, updates| update_item(item, updates) }
+  end
+
+  # Returns pairs of items and their corresponding update hashes
+  def get_updates_for!(items)
+    query = client.item_lookup(*items.map(&:asin))
+    amazon_items = query.response
+    updates = amazon_items.map(&:update_hash)
+
+    items.zip(updates)
+  end
+
+  def validate_batch_size(count)
+    return unless count > BATCH_SIZE
+    raise ArgumentError,
+          "Batch size too large: #{count}/#{BATCH_SIZE}"
+  end
+
+  def update_item(item, update_hash)
+    Rails.logger.info green(
+      "Syncing item #{item.id}: (#{item.asin}) #{item.name.truncate(64)}"
+    )
     item.assign_attributes(update_hash)
     return unless item.changed?
 
     Rails.logger.info bold_green("Changed:\n") + item.changes.pretty_inspect
     item.save!
   end
 
-  def amazon_item!(item)
-    client.item_lookup(item.asin).response.first
-  end
-
   # Some styles for log text. This is so minor that it's not worth
   # bringing in a full library.
 

lib/amazon_product_api/endpoint.rb

@@ -38,7 +38,6 @@ def get(http: HTTParty)
     # Performs the search query and returns the processed response
     def response(http: HTTParty, logger: Rails.logger)
       response = parse_response get(http: http)
-      logger.debug response
       process_response(response)
     end