Allowed syntax for virtual refs

[jbms]

Do I understand correctly that there is basically no specific defined URL syntax for virtual refs --- and instead the URL prefix to virtual chunk store mapping must always be specified separately when opening an icechunk repository?

Currently in Neuroglancer there is no configuration mechanism for icechunk virtual refs and instead the URLs are just resolved according to the usual Neuroglancer URL syntax, and it would be somewhat awkward and inconvenient for users to have to specify a configuration.

I'm happy to change Neuroglancer's interpretation of virtual refs to match whatever is decided upon, but it would be very helpful to standardize on some specific URL syntax so that icechunk repositories can at least, in common cases, be used without configuration.

One specific thing I would recommend is to discourage the use of s3://bucket/path to ambiguously refer to either the official S3 endpoint bucket.s3.amazonaws.com or a separate S3-like endpoint. Instead, I would suggest using s3+https://hostname/path to indicate an S3-compatible server. Though, for purpose of virtual chunks it seems that just plain https://hostname/path would also be fine since you don't need to perform list operations.

[paraseba]

the URL prefix to virtual chunk store mapping must always be specified separately when opening an icechunk repository?

It can either be specified when opening the repo, or it can be stored as configuration together with the repo. In the later case, users don't need to pass it on open.