Error handling for attachment batch delete process (#28184)

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

app/lib/attachment_batch.rb

@@ -4,7 +4,8 @@ class AttachmentBatch
   # Maximum amount of objects you can delete in an S3 API call. It's
   # important to remember that this does not correspond to the number
   # of records in the batch, since records can have multiple attachments
-  LIMIT = 1_000
+  LIMIT = ENV.fetch('S3_BATCH_DELETE_LIMIT', 1000).to_i
+  MAX_RETRY = ENV.fetch('S3_BATCH_DELETE_RETRY', 3).to_i
 
   # Attributes generated and maintained by Paperclip (not all of them
   # are always used on every class, however)
@@ -95,6 +96,7 @@ class AttachmentBatch
     # objects can be processed at once, so we have to potentially
     # separate them into multiple calls.
 
+    retries = 0
     keys.each_slice(LIMIT) do |keys_slice|
       logger.debug { "Deleting #{keys_slice.size} objects" }
 
@@ -102,6 +104,17 @@ class AttachmentBatch
         objects: keys_slice.map { |key| { key: key } },
         quiet: true,
       })
+    rescue => e
+      retries += 1
+
+      if retries < MAX_RETRY
+        logger.debug "Retry #{retries}/#{MAX_RETRY} after #{e.message}"
+        sleep 2**retries
+        retry
+      else
+        logger.error "Batch deletion from S3 failed after #{e.message}"
+        raise e
+      end
     end
   end