use super::{naive_seeker::NaiveSeeker, BlobReader, BlobService, BlobWriter}; use crate::{proto, B3Digest}; use futures::sink::SinkExt; use futures::TryFutureExt; use std::{ collections::VecDeque, io::{self}, pin::pin, task::Poll, }; use tokio::io::AsyncWriteExt; use tokio::task::JoinHandle; use tokio_stream::{wrappers::ReceiverStream, StreamExt}; use tokio_util::{ io::{CopyToBytes, SinkWriter}, sync::{PollSendError, PollSender}, }; use tonic::{async_trait, transport::Channel, Code, Status}; use tracing::instrument; /// Connects to a (remote) tvix-store BlobService over gRPC. #[derive(Clone)] pub struct GRPCBlobService { /// The internal reference to a gRPC client. /// Cloning it is cheap, and it internally handles concurrent requests. grpc_client: proto::blob_service_client::BlobServiceClient, } impl GRPCBlobService { /// construct a [GRPCBlobService] from a [proto::blob_service_client::BlobServiceClient]. /// panics if called outside the context of a tokio runtime. pub fn from_client( grpc_client: proto::blob_service_client::BlobServiceClient, ) -> Self { Self { grpc_client } } } #[async_trait] impl BlobService for GRPCBlobService { #[instrument(skip(self, digest), fields(blob.digest=%digest))] async fn has(&self, digest: &B3Digest) -> Result { let mut grpc_client = self.grpc_client.clone(); let resp = grpc_client .stat(proto::StatBlobRequest { digest: digest.clone().into(), ..Default::default() }) .await; match resp { Ok(_blob_meta) => Ok(true), Err(e) if e.code() == Code::NotFound => Ok(false), Err(e) => Err(crate::Error::StorageError(e.to_string())), } } // On success, this returns a Ok(Some(io::Read)), which can be used to read // the contents of the Blob, identified by the digest. async fn open_read( &self, digest: &B3Digest, ) -> Result>, crate::Error> { // Get a stream of [proto::BlobChunk], or return an error if the blob // doesn't exist. let resp = self .grpc_client .clone() .read(proto::ReadBlobRequest { digest: digest.clone().into(), }) .await; // This runs the task to completion, which on success will return a stream. // On reading from it, we receive individual [proto::BlobChunk], so we // massage this to a stream of bytes, // then create an [AsyncRead], which we'll turn into a [io::Read], // that's returned from the function. match resp { Ok(stream) => { // map the stream of proto::BlobChunk to bytes. let data_stream = stream.into_inner().map(|x| { x.map(|x| VecDeque::from(x.data.to_vec())) .map_err(|e| std::io::Error::new(std::io::ErrorKind::InvalidInput, e)) }); // Use StreamReader::new to convert to an AsyncRead. let data_reader = tokio_util::io::StreamReader::new(data_stream); Ok(Some(Box::new(NaiveSeeker::new(data_reader)))) } Err(e) if e.code() == Code::NotFound => Ok(None), Err(e) => Err(crate::Error::StorageError(e.to_string())), } } /// Returns a BlobWriter, that'll internally wrap each write in a // [proto::BlobChunk], which is send to the gRPC server. async fn open_write(&self) -> Box { let mut grpc_client = self.grpc_client.clone(); // set up an mpsc channel passing around Bytes. let (tx, rx) = tokio::sync::mpsc::channel::(10); // bytes arriving on the RX side are wrapped inside a // [proto::BlobChunk], and a [ReceiverStream] is constructed. let blobchunk_stream = ReceiverStream::new(rx).map(|x| proto::BlobChunk { data: x }); // That receiver stream is used as a stream in the gRPC BlobService.put rpc call. let task: JoinHandle> = tokio::spawn(async move { Ok(grpc_client.put(blobchunk_stream).await?.into_inner()) }); // The tx part of the channel is converted to a sink of byte chunks. // We need to make this a function pointer, not a closure. fn convert_error(_: PollSendError) -> io::Error { io::Error::from(io::ErrorKind::BrokenPipe) } let sink = PollSender::new(tx) .sink_map_err(convert_error as fn(PollSendError) -> io::Error); // We need to explicitly cast here, otherwise rustc does error with "expected fn pointer, found fn item" // … which is turned into an [tokio::io::AsyncWrite]. let writer = SinkWriter::new(CopyToBytes::new(sink)); Box::new(GRPCBlobWriter { task_and_writer: Some((task, writer)), digest: None, }) } } pub struct GRPCBlobWriter { /// The task containing the put request, and the inner writer, if we're still writing. task_and_writer: Option<(JoinHandle>, W)>, /// The digest that has been returned, if we successfully closed. digest: Option, } #[async_trait] impl BlobWriter for GRPCBlobWriter { async fn close(&mut self) -> Result { if self.task_and_writer.is_none() { // if we're already closed, return the b3 digest, which must exist. // If it doesn't, we already closed and failed once, and didn't handle the error. match &self.digest { Some(digest) => Ok(digest.clone()), None => Err(crate::Error::StorageError( "previously closed with error".to_string(), )), } } else { let (task, mut writer) = self.task_and_writer.take().unwrap(); // invoke shutdown, so the inner writer closes its internal tx side of // the channel. writer .shutdown() .map_err(|e| crate::Error::StorageError(e.to_string())) .await?; // block on the RPC call to return. // This ensures all chunks are sent out, and have been received by the // backend. match task.await? { Ok(resp) => { // return the digest from the response, and store it in self.digest for subsequent closes. let digest: B3Digest = resp.digest.try_into().map_err(|_| { crate::Error::StorageError( "invalid root digest length in response".to_string(), ) })?; self.digest = Some(digest.clone()); Ok(digest) } Err(e) => Err(crate::Error::StorageError(e.to_string())), } } } } impl tokio::io::AsyncWrite for GRPCBlobWriter { fn poll_write( mut self: std::pin::Pin<&mut Self>, cx: &mut std::task::Context<'_>, buf: &[u8], ) -> std::task::Poll> { match &mut self.task_and_writer { None => Poll::Ready(Err(io::Error::new( io::ErrorKind::NotConnected, "already closed", ))), Some((_, ref mut writer)) => { let pinned_writer = pin!(writer); pinned_writer.poll_write(cx, buf) } } } fn poll_flush( mut self: std::pin::Pin<&mut Self>, cx: &mut std::task::Context<'_>, ) -> std::task::Poll> { match &mut self.task_and_writer { None => Poll::Ready(Err(io::Error::new( io::ErrorKind::NotConnected, "already closed", ))), Some((_, ref mut writer)) => { let pinned_writer = pin!(writer); pinned_writer.poll_flush(cx) } } } fn poll_shutdown( self: std::pin::Pin<&mut Self>, _cx: &mut std::task::Context<'_>, ) -> std::task::Poll> { // TODO(raitobezarius): this might not be a graceful shutdown of the // channel inside the gRPC connection. Poll::Ready(Ok(())) } } #[cfg(test)] mod tests { use std::sync::Arc; use std::time::Duration; use tempfile::TempDir; use tokio::net::UnixListener; use tokio_retry::strategy::ExponentialBackoff; use tokio_retry::Retry; use tokio_stream::wrappers::UnixListenerStream; use crate::blobservice::MemoryBlobService; use crate::fixtures; use crate::proto::blob_service_client::BlobServiceClient; use crate::proto::GRPCBlobServiceWrapper; use super::BlobService; use super::GRPCBlobService; /// This ensures connecting via gRPC works as expected. #[tokio::test] async fn test_valid_unix_path_ping_pong() { let tmpdir = TempDir::new().unwrap(); let socket_path = tmpdir.path().join("daemon"); let path_clone = socket_path.clone(); // Spin up a server tokio::spawn(async { let uds = UnixListener::bind(path_clone).unwrap(); let uds_stream = UnixListenerStream::new(uds); // spin up a new server let mut server = tonic::transport::Server::builder(); let router = server.add_service(crate::proto::blob_service_server::BlobServiceServer::new( GRPCBlobServiceWrapper::from( Arc::new(MemoryBlobService::default()) as Arc ), )); router.serve_with_incoming(uds_stream).await }); // wait for the socket to be created Retry::spawn( ExponentialBackoff::from_millis(20).max_delay(Duration::from_secs(10)), || async { if socket_path.exists() { Ok(()) } else { Err(()) } }, ) .await .expect("failed to wait for socket"); // prepare a client let grpc_client = { let url = url::Url::parse(&format!( "grpc+unix://{}?wait-connect=1", socket_path.display() )) .expect("must parse"); let client = BlobServiceClient::new( crate::tonic::channel_from_url(&url) .await .expect("must succeed"), ); GRPCBlobService::from_client(client) }; let has = grpc_client .has(&fixtures::BLOB_A_DIGEST) .await .expect("must not be err"); assert!(!has); } }