enh(metadata): Introduce a memory limit for metadata generation

[solracsf]

Summary

Fix #42793

By introducing a (configurable) memory limit, one should not reach OOM on very big files that the server can't support.

TODO

• Once approved, document metadata_max_filesize param

Similar to:

server/config/config.sample.php

Lines 1241 to 1249 in 265e906

	/**
	* max memory for generating image previews with imagegd (default behavior)
	* Reads the image dimensions from the header and assumes 32 bits per pixel.
	* If creating the image would allocate more memory, preview generation will
	* be disabled and the default mimetype icon is shown. Set to -1 for no limit.
	*
	* Defaults to ``256`` megabytes
	*/
	'preview_max_memory' => 256,

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[joshtrichards]

Makes sense, but I'm not familiar enough with the metadata stuff to officially review (though code looks reasonable).

Suggestion: Add the new parameter to config.sample.php here too

[solracsf]

Suggestion: Add the new parameter to config.sample.php here too

It's the ToDo point on the PR summary 😉

[artonge]

Sorry for the delay, I forgot to submit the review

[kesselb]

Thank you, good idea 👍

I think the decision "can this file be processed" should live in the actual event listeners. But the event listeners I checked all read the file, and therefore it's a practical approach.

The naming is a bit misleading because it's not a memory limit but a file size limit.

[solracsf]

The naming is a bit misleading because it's not a memory limit but a file size limit.

If metadata_max_filesize fits best please let me know.

[kesselb]

The naming is a bit misleading because it's not a memory limit but a file size limit.

If metadata_max_filesize fits best please let me know.

That's good, thank you 👍

[kesselb]

Please don't forget to update the config.sample.php

I'm not sure how useful the debug log is, but without you have no idea why the metadata generation was skipped for a given file.

[st3iny]

/backport to stable29

[st3iny]

Amended to fix the commit message.

[kesselb]

Psalm is failing because the latest rebase brought in #46450 that changed IConfig to IAppConfig.