Save manifest load info when preloading them, too

This was a bit tricky! When I initially turned it on, running
`rails swf_assets:manifests:load` would trigger database errors of "oh
no we can't get a connection from the pool!", because too many records
were trying to concurrently save at once.

So now, we give ourselves the ability to say `save_changes: false`, and
then save them all in one batch after! That way, we're still saving by
default in the edge cases where we're downloading and saving a manifest
on the fly, but batching them in cases where we're likely to be dealing
with a lot of them!

app/models/swf_asset.rb

@@ -51,11 +51,16 @@ class SwfAsset < ApplicationRecord
   end
 
   def manifest
-    raise "manifest_url is blank" if manifest_url.blank?
     @manifest ||= load_manifest
   end
 
-  def load_manifest
+  def preload_manifest(save_changes: true)
+    load_manifest(return_content: false, save_changes:)
+  end
+
+  def load_manifest(return_content: true, save_changes: true)
+    raise "manifest_url is blank" if manifest_url.blank?
+
     # If we recently tried loading the manifest and got a 4xx HTTP status code
     # (e.g. a 404, there's a surprising amount of these!), don't try again. But
     # after enough time passes, if this is called again, we will!
@@ -74,22 +79,25 @@ class SwfAsset < ApplicationRecord
     end
 
     begin
-      NeopetsMediaArchive.load_file(manifest_url) => {content:, source:}
+      NeopetsMediaArchive.load_file(manifest_url, return_content:) =>
+        {content:, source:}
     rescue NeopetsMediaArchive::ResponseNotOK => error
       Rails.logger.warn "Failed to load manifest for asset #{id}: " +
         error.message
       self.manifest_loaded_at = Time.now
       self.manifest_status_code = error.status
-      save!
+      save! if save_changes
       return nil
     end
 
     if source == "network" || manifest_loaded_at.blank?
       self.manifest_loaded_at = Time.now
       self.manifest_status_code = 200
-      save!
+      save! if save_changes
     end
 
+    return nil unless return_content
+
     begin
       JSON.parse(content)
     rescue JSON::ParserError => error
@@ -99,11 +107,6 @@ class SwfAsset < ApplicationRecord
     end
   end
 
-  def preload_manifest
-    raise "manifest_url is blank" if manifest_url.blank?
-    NeopetsMediaArchive.preload_file(manifest_url)
-  end
-
   MANIFEST_BASE_URL = Addressable::URI.parse("https://images.neopets.com")
   def manifest_asset_urls
     return {} if manifest_url.nil?
@@ -306,7 +309,9 @@ class SwfAsset < ApplicationRecord
       swf_assets.map do |swf_asset|
         semaphore.async do
           begin
-            swf_asset.preload_manifest
+            # Don't save changes in this big async situation; we'll do it all
+            # in one batch after, to avoid too much database concurrency!
+            swf_asset.preload_manifest(save_changes: false)
           rescue StandardError => error
             Rails.logger.error "Could not preload manifest for asset " + 
               "#{swf_asset.id} (#{swf_asset.manifest_url}): #{error.message}"
@@ -319,6 +324,10 @@ class SwfAsset < ApplicationRecord
     ensure
       barrier.stop # If something goes wrong, clean up all tasks.
     end
+
+    SwfAsset.transaction do
+      swf_assets.each(&:save!)
+    end
   end
 
   before_save do

app/services/neopets_media_archive.rb

@@ -37,7 +37,7 @@ module NeopetsMediaArchive
       # we're not ready to use yet.)
       if File.exist?(local_path)
         debug "Source file is already loaded, skipping: #{local_path}"
-        return
+        return {content: nil, source: "filesystem"}
       end
     end
 

lib/tasks/swf_assets.rake

@@ -56,11 +56,7 @@ namespace :swf_assets do
 			Sync do
 				saved_count = 0
 				swf_assets.find_in_batches(batch_size: 1000) do |swf_assets|
-					# NOTE: Loading the manifests can both write to the filesystem *and*
-					# to the database, because we track timestamp and status in the db!
-					SwfAsset.transaction do
 					SwfAsset.preload_manifests(swf_assets)
-					end
 					saved_count += swf_assets.size
 					puts "Loaded #{saved_count} of #{total_count} manifests"
 				end