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<Channel>,
}
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<Channel>,
) -> 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<bool, crate::Error> {
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<Option<Box<dyn BlobReader>>, 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<dyn BlobWriter> {
let mut grpc_client = self.grpc_client.clone();
// set up an mpsc channel passing around Bytes.
let (tx, rx) = tokio::sync::mpsc::channel::<bytes::Bytes>(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<Result<_, Status>> =
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<bytes::Bytes>) -> io::Error {
io::Error::from(io::ErrorKind::BrokenPipe)
}
let sink = PollSender::new(tx)
.sink_map_err(convert_error as fn(PollSendError<bytes::Bytes>) -> 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<W: tokio::io::AsyncWrite> {
/// The task containing the put request, and the inner writer, if we're still writing.
task_and_writer: Option<(JoinHandle<Result<proto::PutBlobResponse, Status>>, W)>,
/// The digest that has been returned, if we successfully closed.
digest: Option<B3Digest>,
}
#[async_trait]
impl<W: tokio::io::AsyncWrite + Send + Sync + Unpin + 'static> BlobWriter for GRPCBlobWriter<W> {
async fn close(&mut self) -> Result<B3Digest, crate::Error> {
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<W: tokio::io::AsyncWrite + Unpin> tokio::io::AsyncWrite for GRPCBlobWriter<W> {
fn poll_write(
mut self: std::pin::Pin<&mut Self>,
cx: &mut std::task::Context<'_>,
buf: &[u8],
) -> std::task::Poll<Result<usize, io::Error>> {
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<Result<(), io::Error>> {
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<Result<(), io::Error>> {
// 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<dyn BlobService>
),
));
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);
}
}
