Distinguish between Error and Empty for GCS and S3 DataVaults

[frcroth]

URL of deployed dev instance (used for testing):

• https://___.webknossos.xyz

Steps to test:

• Should be done through tests ;)
• (check if GCS and S3 still work)

Issues:

• fixes Distinguish between error and Empty (404) for GCS and S3 DataVaults #7149

Since it is not user facing I guess no changelog.

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(Please delete unneeded items, merge only when none are left open)

• Needs datastore update after deployment

[fm3]

The implementation looks good to me :)

Props for writing tests 🎉

The test does not currently distinguish between Failure and Empty, though. Also, could you add a test case where a Failure is expected? (e.g. Forbidden?)

I think this is actually a user-facing change, I’d add something like this into the changelog

“Correctly use configured fill-value for missing chunks of remote datasets hosted on gcs or s3.” (since there is a distinction on Failure vs Empty in ChunkReader, which can now work here)

[frcroth]

For S3 I would need a public data set to actually validate that it works in the test. I haven't found anything by Amazon, so the tests could use some public dataset known to us or just test failure.

[fm3]

That’s fair then, I don’t have such a link ready either.

LGTM!

[frcroth]

@fm3 Tested it again before merging and a dataset with required credentials did not work because of "timeout waiting for connection pool". Turns out one has to close an s3object.