This moves the recursive BFS traversal of Directory closures from the
GRPCDirectoryServiceWrapper out into a a DirectoryTraverser struct
implementing Iterator.
It is then used from various implementors of DirectoryService in the
`get_recursive()` method.
This allows distinguishing between recursive requests and non-recursive
requests in the gRPC client trait implementation.
Change-Id: I50bfd4a0d9eb11832847329b78c587ec7c9dc7b1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8351
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI
This provides a GRPCDirectoryService struct implementing
DirectoryService, allowing a client to Directory objects from a (remote)
tvix-store.
Remote in this case is anything outside the current process, be it
another process, or an endpoint on the network.
To keep the sync interface in the `DirectoryService` trait, a handle to
some tokio runtime needs to be passed into the constructor, and the two
methods use `self.tokio_handle.spawn` to start an async function, and
`self.tokio_handle.block_on` to wait for its completion.
The client handle, called `grpc_client` itself is easy to clone, and
treats concurrent requests internally. This means, even though we keep
the `DirectoryService` trait sync, there's nothing preventing it from
being used concurrently, let's say from multiple threads.
There's still two limitations for now:
1) The trait doesn't make use of the `recursive` request, which
currently leads to a N+1 query problem. This can be fixed
by `GRPCDirectoryService` having a reference to another
`DirectoryService` acting as the local side.
I want to wait for general store composition code to pop up before
manually coding this here.
2) It's currently only possible to put() leaf directory nodes, as the
request normally requires uploading a whole closure. We might want
to add another batch function to upload a whole closure, and/or do
this batching in certain cases. This still needs some more thinking.
Change-Id: I7ffec791610b72c0960cf5307cefbb12ec946dc9
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8336
Tested-by: BuildkiteCI
Autosubmit: flokli <flokli@flokli.de>
Reviewed-by: tazjin <tazjin@tvl.su>
