[4.x]: Remote temp upload directories recreated on every asset field render

[mattgrayisok]

What happened?

Description

Debugging some slow CP requests in a client project we found that whenever an Asset Field is rendered within a template, and the 'temp' directory for assets is set to a volume, Craft will try to recreate the directory structure for the temp path on every page load.

This was causing significant slowdowns for this particular project because the temp directory was set to a remote S3 FS and it had multiple path parts resulting in several sequential API calls to the remote storage to create directories, each taking a non negligible amount of time.

I profiled and tracked it down to this line:

cms/src/services/Assets.php

Line 799 in 264e1aa

$volume->getFs()->createDirectory($path);

Being called from:

cms/src/services/Assets.php

Line 922 in 264e1aa

return $this->ensureFolderByFullPathAndVolume($path, $tempVolume, false);

This is a particularly pronounced issue because most remote object storage platforms don't even need the directories to be created. Maybe it's worth allowing filesystems to define whether they need directories to be pre-created? Then object-key stores can opt out and save a load of API calls.

Steps to reproduce

1. Use a remote object storage volume
2. Set the temp upload path to use this volume
3. Add an asset field to a control panel page
4. Pages will now load slowly

Expected behavior

Humm, I guess it'd be nice if Craft didn't try to recreate the directories during field render, but instead during the actual upload which would use the temp directory. Alternatively allow remote filesystems to opt-out of directory pre-creation (maybe this is something flysystem should be doing?)

Craft CMS version

4.0.4

PHP version

8.0

Operating system and version

No response

Database type and version

No response

Image driver and version

No response

Installed plugins and versions

[mattgrayisok]

I should add that we fixed the issue for the time being by simply changing the temp upload directory to the local temp dir instead of the volume

[brandonkelly]

This should be resolved for the next Craft 3 and 4 releases. Thanks for reporting!

[brandonkelly]

Craft 3.7.45 and 4.0.5 are out now with this change.