Relation between CS3 storage provider api and Reva's storage.FS interface

[michielbdejong]

The current CS3 storage provider api is not identical to the current Reva storage provider api. What is the (current/future) relation between the two?

[michielbdejong]

A (rough) comparison table:

method	reva	cs3
GetHome	Y	Y
CreateHome	Y	Y
Create[Dir Container]	Y	Y
Delete	Y	Y
Move	Y	Y
[GetMD Stat GetPath]	Y	Y
List[Folder Container ContainerStream]	Y	Y
Initiate[File]Upload	Y	Y
InitiateFileDownload		Y
Upload	Y
Download	Y
List[File]Revisions	Y	Y
DownloadRevision	Y
RestoreRevision	Y
ListRecycle	Y	Y
RestoreRecycleItem	Y	Y
PurgeRecycle[Item]	Y	Y
EmptyRecycle	Y
GetPathByID	Y
AddGrant	Y	Y
RemoveGrant	Y	Y
UpdateGrant	Y
ListGrants	Y
GetQuota	Y	Y
CreateReference	Y
Shutdown	Y
SetArbitraryMetadata	Y	Y
UnsetArbitraryMetadata	Y	Y
CreateStorageSpace		Y
ListStorageSpaces		Y
UpdateStorageSpace		Y
DeleteStorageSpace		Y

[michielbdejong]

Note that InitiateDownload does exist in reva, but only in https://github.com/cs3org/reva/blob/master/pkg/sdk/action/download.go#L90 and not in the storage FS interface.

[michielbdejong]

Ah, I think part of the answer is that the CS3 storage provider api describes the interface of the grpc storageprovider service, which in turn wraps around a storage.FS driver. For instance, the InitiateFileUpload method in https://github.com/cs3org/reva/blob/master/internal/grpc/services/storageprovider/storageprovider.go#L327 calls the underlying InitiateUpload but has some additional checks around it that the storage provider is expected to do, but that are not specific to the storage driver.