PERF: Improve cook_url performance for topic thumbnails (#11609)

- Only initialize the S3Helper when needed
- Skip initializing the S3Helper for S3Store#cdn_url
- Allow cook_url to be passed a `local` hint to skip unnecessary checks

lib/file_store/s3_store.rb

@@ -11,10 +11,12 @@ module FileStore
   class S3Store < BaseStore
     TOMBSTONE_PREFIX ||= "tombstone/"
 
-    attr_reader :s3_helper
-
     def initialize(s3_helper = nil)
-      @s3_helper = s3_helper || S3Helper.new(s3_bucket,
+      @s3_helper = s3_helper
+    end
+
+    def s3_helper
+      @s3_helper ||= S3Helper.new(s3_bucket,
         Rails.configuration.multisite ? multisite_tombstone_prefix : TOMBSTONE_PREFIX
       )
     end
@@ -68,7 +70,7 @@ module FileStore
       path.prepend(File.join(upload_path, "/")) if Rails.configuration.multisite
 
       # if this fails, it will throw an exception
-      path, etag = @s3_helper.upload(file, path, options)
+      path, etag = s3_helper.upload(file, path, options)
 
       # return the upload url and etag
       [File.join(absolute_base_url, path), etag]
@@ -77,12 +79,12 @@ module FileStore
     def remove_file(url, path)
       return unless has_been_uploaded?(url)
       # copy the removed file to tombstone
-      @s3_helper.remove(path, true)
+      s3_helper.remove(path, true)
     end
 
     def copy_file(url, source, destination)
       return unless has_been_uploaded?(url)
-      @s3_helper.copy(source, destination)
+      s3_helper.copy(source, destination)
     end
 
     def has_been_uploaded?(url)
@@ -119,11 +121,11 @@ module FileStore
     end
 
     def s3_bucket_folder_path
-      @s3_helper.s3_bucket_folder_path
+      S3Helper.get_bucket_and_folder_path(s3_bucket)[1]
     end
 
     def s3_bucket_name
-      @s3_helper.s3_bucket_name
+      S3Helper.get_bucket_and_folder_path(s3_bucket)[0]
     end
 
     def absolute_base_url
@@ -139,7 +141,7 @@ module FileStore
     end
 
     def purge_tombstone(grace_period)
-      @s3_helper.update_tombstone_lifecycle(grace_period)
+      s3_helper.update_tombstone_lifecycle(grace_period)
     end
 
     def multisite_tombstone_prefix
@@ -165,7 +167,7 @@ module FileStore
     def cdn_url(url)
       return url if SiteSetting.Upload.s3_cdn_url.blank?
       schema = url[/^(https?:)?\/\//, 1]
-      folder = @s3_helper.s3_bucket_folder_path.nil? ? "" : "#{@s3_helper.s3_bucket_folder_path}/"
+      folder = s3_bucket_folder_path.nil? ? "" : "#{s3_bucket_folder_path}/"
       url.sub(File.join("#{schema}#{absolute_base_url}", folder), File.join(SiteSetting.Upload.s3_cdn_url, "/"))
     end
 
@@ -177,7 +179,7 @@ module FileStore
     def cache_avatar(avatar, user_id)
       source = avatar.url.sub(absolute_base_url + "/", "")
       destination = avatar_template(avatar, user_id).sub(absolute_base_url + "/", "")
-      @s3_helper.copy(source, destination)
+      s3_helper.copy(source, destination)
     end
 
     def avatar_template(avatar, user_id)
@@ -213,7 +215,7 @@ module FileStore
     end
 
     def download_file(upload, destination_path)
-      @s3_helper.download_file(get_upload_key(upload), destination_path)
+      s3_helper.download_file(get_upload_key(upload), destination_path)
     end
 
     def copy_from(source_path)
@@ -258,7 +260,7 @@ module FileStore
         )
       end
 
-      obj = @s3_helper.object(url)
+      obj = s3_helper.object(url)
       obj.presigned_url(:get, opts)
     end
 
@@ -272,7 +274,7 @@ module FileStore
 
     def update_ACL(key, secure)
       begin
-        @s3_helper.object(key).acl.put(acl: secure ? "private" : "public-read")
+        s3_helper.object(key).acl.put(acl: secure ? "private" : "public-read")
       rescue Aws::S3::Errors::NoSuchKey
         Rails.logger.warn("Could not update ACL on upload with key: '#{key}'. Upload is missing.")
       end
@@ -282,7 +284,7 @@ module FileStore
       connection = ActiveRecord::Base.connection.raw_connection
       connection.exec('CREATE TEMP TABLE verified_ids(val integer PRIMARY KEY)')
       marker = nil
-      files = @s3_helper.list(prefix, marker)
+      files = s3_helper.list(prefix, marker)
 
       while files.count > 0 do
         verified_ids = []
@@ -295,7 +297,7 @@ module FileStore
 
         verified_id_clause = verified_ids.map { |id| "('#{PG::Connection.escape_string(id.to_s)}')" }.join(",")
         connection.exec("INSERT INTO verified_ids VALUES #{verified_id_clause}")
-        files = @s3_helper.list(prefix, marker)
+        files = s3_helper.list(prefix, marker)
       end
 
       missing_uploads = model.joins('LEFT JOIN verified_ids ON verified_ids.val = id').where("verified_ids.val IS NULL")