作品投稿時のSlack複数チャンネル投稿を並列化

api/src/goduploader/graphql/type/mutation/upload_artwork.py

@@ -1,6 +1,7 @@
 import imghdr
 import logging
 import uuid
+from concurrent.futures import ThreadPoolExecutor
 from typing import List, Optional
 
 import graphene
@@ -118,17 +119,23 @@ def mutate_and_get_payload(cls, root, info, files: List[FileStorage], **input):
         session.commit()
 
         # 外部サービスへの共有時には Artwork.id に有効な値が設定されている必要があるのでcommit後に共有します
-        for ch_id in channel_ids:
+        # commit後にSQLAlchemyが全オブジェクトを期限切れにするため、スレッドプールに入る前に
+        # メインスレッドでリレーションを読み込んでおく（SQLiteのクロススレッドアクセス禁止対策）
+        _ = artwork.title
+        _ = artwork.account.name
+        _ = [t.name for t in artwork.tags]
+
+        image_path = top_illust.image_path("full")
+
+        def _post_to_channel(ch_id):
             try:
-                share_to_slack(
-                    artwork,
-                    top_illust.image_path("full"),
-                    share_option,
-                    ch_id,
-                )
+                share_to_slack(artwork, image_path, share_option, ch_id)
             except Exception as e:
                 logging.error(e)
 
+        with ThreadPoolExecutor() as executor:
+            executor.map(_post_to_channel, channel_ids)
+
         _share_to_twitter(input, current_user, artwork)
 
         return UploadArtwork(artwork=artwork)