transfer: Migrate from run_parallel to multiprocessing.

Signed-off-by: Anders Kaseorg <anders@zulipchat.com>

zerver/lib/transfer.py

@@ -1,4 +1,5 @@
 import logging
+import multiprocessing
 import os
 from mimetypes import guess_type
 
@@ -6,7 +7,6 @@ from django.conf import settings
 from django.db import connection
 
 from zerver.lib.avatar_hash import user_avatar_path
-from zerver.lib.parallel import run_parallel
 from zerver.lib.upload import S3UploadBackend, upload_image_to_s3
 from zerver.models import Attachment, RealmEmoji, UserProfile
 
@@ -18,73 +18,70 @@ def transfer_uploads_to_s3(processes: int) -> None:
     transfer_message_files_to_s3(processes)
     transfer_emoji_to_s3(processes)
 
-def transfer_avatars_to_s3(processes: int) -> None:
-    def _transfer_avatar_to_s3(user: UserProfile) -> int:
-        avatar_path = user_avatar_path(user)
-        file_path = os.path.join(settings.LOCAL_UPLOADS_DIR, "avatars", avatar_path) + ".original"
-        try:
-            with open(file_path, 'rb') as f:
-                s3backend.upload_avatar_image(f, user, user)
-                logging.info("Uploaded avatar for %s in realm %s", user.id, user.realm.name)
-        except FileNotFoundError:
-            pass
-        return 0
+def _transfer_avatar_to_s3(user: UserProfile) -> None:
+    avatar_path = user_avatar_path(user)
+    file_path = os.path.join(settings.LOCAL_UPLOADS_DIR, "avatars", avatar_path) + ".original"
+    try:
+        with open(file_path, 'rb') as f:
+            s3backend.upload_avatar_image(f, user, user)
+            logging.info("Uploaded avatar for %s in realm %s", user.id, user.realm.name)
+    except FileNotFoundError:
+        pass
 
+def transfer_avatars_to_s3(processes: int) -> None:
     users = list(UserProfile.objects.all())
     if processes == 1:
         for user in users:
             _transfer_avatar_to_s3(user)
     else:  # nocoverage
-        output = []
         connection.close()
-        for (status, job) in run_parallel(_transfer_avatar_to_s3, users, processes):
-            output.append(job)
+        with multiprocessing.Pool(processes) as p:
+            for out in p.imap_unordered(_transfer_avatar_to_s3, users):
+                pass
+
+def _transfer_message_files_to_s3(attachment: Attachment) -> None:
+    file_path = os.path.join(settings.LOCAL_UPLOADS_DIR, "files", attachment.path_id)
+    try:
+        with open(file_path, 'rb') as f:
+            guessed_type = guess_type(attachment.file_name)[0]
+            upload_image_to_s3(s3backend.uploads_bucket, attachment.path_id, guessed_type, attachment.owner, f.read())
+            logging.info("Uploaded message file in path %s", file_path)
+    except FileNotFoundError:  # nocoverage
+        pass
 
 def transfer_message_files_to_s3(processes: int) -> None:
-    def _transfer_message_files_to_s3(attachment: Attachment) -> int:
-        file_path = os.path.join(settings.LOCAL_UPLOADS_DIR, "files", attachment.path_id)
-        try:
-            with open(file_path, 'rb') as f:
-                guessed_type = guess_type(attachment.file_name)[0]
-                upload_image_to_s3(s3backend.uploads_bucket, attachment.path_id, guessed_type, attachment.owner, f.read())
-                logging.info("Uploaded message file in path %s", file_path)
-        except FileNotFoundError:  # nocoverage
-            pass
-        return 0
-
     attachments = list(Attachment.objects.all())
     if processes == 1:
         for attachment in attachments:
             _transfer_message_files_to_s3(attachment)
     else:  # nocoverage
-        output = []
         connection.close()
-        for status, job in run_parallel(_transfer_message_files_to_s3, attachments, processes):
-            output.append(job)
+        with multiprocessing.Pool(processes) as p:
+            for out in p.imap_unordered(_transfer_message_files_to_s3, attachments):
+                pass
+
+def _transfer_emoji_to_s3(realm_emoji: RealmEmoji) -> None:
+    if not realm_emoji.file_name or not realm_emoji.author:
+        return  # nocoverage
+    emoji_path = RealmEmoji.PATH_ID_TEMPLATE.format(
+        realm_id=realm_emoji.realm.id,
+        emoji_file_name=realm_emoji.file_name,
+    )
+    emoji_path = os.path.join(settings.LOCAL_UPLOADS_DIR, "avatars", emoji_path) + ".original"
+    try:
+        with open(emoji_path, 'rb') as f:
+            s3backend.upload_emoji_image(f, realm_emoji.file_name, realm_emoji.author)
+            logging.info("Uploaded emoji file in path %s", emoji_path)
+    except FileNotFoundError:  # nocoverage
+        pass
 
 def transfer_emoji_to_s3(processes: int) -> None:
-    def _transfer_emoji_to_s3(realm_emoji: RealmEmoji) -> int:
-        if not realm_emoji.file_name or not realm_emoji.author:
-            return 0  # nocoverage
-        emoji_path = RealmEmoji.PATH_ID_TEMPLATE.format(
-            realm_id=realm_emoji.realm.id,
-            emoji_file_name=realm_emoji.file_name,
-        )
-        emoji_path = os.path.join(settings.LOCAL_UPLOADS_DIR, "avatars", emoji_path) + ".original"
-        try:
-            with open(emoji_path, 'rb') as f:
-                s3backend.upload_emoji_image(f, realm_emoji.file_name, realm_emoji.author)
-                logging.info("Uploaded emoji file in path %s", emoji_path)
-        except FileNotFoundError:  # nocoverage
-            pass
-        return 0
-
     realm_emojis = list(RealmEmoji.objects.filter())
     if processes == 1:
         for realm_emoji in realm_emojis:
             _transfer_emoji_to_s3(realm_emoji)
     else:  # nocoverage
-        output = []
         connection.close()
-        for status, job in run_parallel(_transfer_emoji_to_s3, realm_emojis, processes):
-            output.append(job)
+        with multiprocessing.Pool(processes) as p:
+            for out in p.imap_unordered(_transfer_emoji_to_s3, realm_emojis):
+                pass