A near-term goal in early operations is to enable running an ObsTAP service exposing image metadata for image data in a regularly-updated Butler repository. This will enable using the Portal application to browse the images in the repository, and will enable other clients wanting Web-API-based image access to use the ObsTAP service.
The principal initial operational deployment of this capability is expected to be at the Summit.
salnikov has largely completed a body of work toward this goal, providing an optional adjunct capability to a Postgres-based Butler repository that maintains an ObsCore table with the required metadata, derived largely from the standard Butler registry tables, in synchrony with those tables.
Deploying this capability requires a) a configuration that provides specifics of the mapping from the registry to ObsCore and b) the installation of a suitable version of the pgsphere spherical-geometry extension in the Postgres service.
The remaining missing piece is to deploy a TAP service that exposes the resulting ObsCore table on the Butler-repository Postgres service as the ivoa.ObsCore table required to make this an "ObsTAP" service. (See Section 4 of the ObsCore 1.1 standard.)
ADQL geometry queries must be translated by the TAP service into Postgres SQL queries using pgsphere. Assuming the CADC TAP service code is used for this work, that translation should already be implemented, since this is the way CADC provides ObsTAP service.
The TAP service will then need to be configured with suitable TAP_SCHEMA data, and a suitably configured datalinker service providing access to the actual image data.
As usual, the access_url column in the ivoa.ObsCore service must be configured compatibly with the datalinker configuration, as the URLs returned are requried to be immediately usable with datalinker.
Initially no cutout/SODA service is required, but it is likely to be useful to deploy in the longer run.
Initially this TAP service is not required to provide any tables other than ivoa.ObsCore and the usual mandatory TAP_SCHEMA.* tables.