use std::collections::HashSet; use super::{DirectoryPutter, DirectoryService}; use crate::proto::{self, get_directory_request::ByWhat}; use crate::{B3Digest, Error}; use async_stream::try_stream; use futures::stream::BoxStream; use tokio::spawn; use tokio::sync::mpsc::UnboundedSender; use tokio::task::JoinHandle; use tokio_stream::wrappers::UnboundedReceiverStream; use tonic::async_trait; use tonic::Code; use tonic::{transport::Channel, Status}; use tracing::{instrument, warn}; /// Connects to a (remote) tvix-store DirectoryService over gRPC. #[derive(Clone)] pub struct GRPCDirectoryService { /// The internal reference to a gRPC client. /// Cloning it is cheap, and it internally handles concurrent requests. grpc_client: proto::directory_service_client::DirectoryServiceClient, } impl GRPCDirectoryService { /// construct a [GRPCDirectoryService] from a [proto::directory_service_client::DirectoryServiceClient]. /// panics if called outside the context of a tokio runtime. pub fn from_client( grpc_client: proto::directory_service_client::DirectoryServiceClient, ) -> Self { Self { grpc_client } } } #[async_trait] impl DirectoryService for GRPCDirectoryService { async fn get( &self, digest: &B3Digest, ) -> Result, crate::Error> { // Get a new handle to the gRPC client, and copy the digest. let mut grpc_client = self.grpc_client.clone(); let digest_cpy = digest.clone(); let message = async move { let mut s = grpc_client .get(proto::GetDirectoryRequest { recursive: false, by_what: Some(ByWhat::Digest(digest_cpy.into())), }) .await? .into_inner(); // Retrieve the first message only, then close the stream (we set recursive to false) s.message().await }; let digest = digest.clone(); match message.await { Ok(Some(directory)) => { // Validate the retrieved Directory indeed has the // digest we expect it to have, to detect corruptions. let actual_digest = directory.digest(); if actual_digest != digest { Err(crate::Error::StorageError(format!( "requested directory with digest {}, but got {}", digest, actual_digest ))) } else if let Err(e) = directory.validate() { // Validate the Directory itself is valid. warn!("directory failed validation: {}", e.to_string()); Err(crate::Error::StorageError(format!( "directory {} failed validation: {}", digest, e, ))) } else { Ok(Some(directory)) } } Ok(None) => Ok(None), Err(e) if e.code() == Code::NotFound => Ok(None), Err(e) => Err(crate::Error::StorageError(e.to_string())), } } async fn put(&self, directory: crate::proto::Directory) -> Result { let resp = self .grpc_client .clone() .put(tokio_stream::once(directory)) .await; match resp { Ok(put_directory_resp) => Ok(put_directory_resp .into_inner() .root_digest .try_into() .map_err(|_| { Error::StorageError("invalid root digest length in response".to_string()) })?), Err(e) => Err(crate::Error::StorageError(e.to_string())), } } #[instrument(skip_all, fields(directory.digest = %root_directory_digest))] fn get_recursive( &self, root_directory_digest: &B3Digest, ) -> BoxStream> { let mut grpc_client = self.grpc_client.clone(); let root_directory_digest = root_directory_digest.clone(); let stream = try_stream! { let mut stream = grpc_client .get(proto::GetDirectoryRequest { recursive: true, by_what: Some(ByWhat::Digest(root_directory_digest.clone().into())), }) .await .map_err(|e| crate::Error::StorageError(e.to_string()))? .into_inner(); // The Directory digests we received so far let mut received_directory_digests: HashSet = HashSet::new(); // The Directory digests we're still expecting to get sent. let mut expected_directory_digests: HashSet = HashSet::from([root_directory_digest]); loop { match stream.message().await { Ok(Some(directory)) => { // validate the directory itself. if let Err(e) = directory.validate() { Err(crate::Error::StorageError(format!( "directory {} failed validation: {}", directory.digest(), e, )))?; } // validate we actually expected that directory, and move it from expected to received. let directory_digest = directory.digest(); let was_expected = expected_directory_digests.remove(&directory_digest); if !was_expected { // FUTUREWORK: dumb clients might send the same stuff twice. // as a fallback, we might want to tolerate receiving // it if it's in received_directory_digests (as that // means it once was in expected_directory_digests) Err(crate::Error::StorageError(format!( "received unexpected directory {}", directory_digest )))?; } received_directory_digests.insert(directory_digest); // register all children in expected_directory_digests. for child_directory in &directory.directories { // We ran validate() above, so we know these digests must be correct. let child_directory_digest = child_directory.digest.clone().try_into().unwrap(); expected_directory_digests .insert(child_directory_digest); } yield directory; }, Ok(None) => { // If we were still expecting something, that's an error. if !expected_directory_digests.is_empty() { Err(crate::Error::StorageError(format!( "still expected {} directories, but got premature end of stream", expected_directory_digests.len(), )))? } else { return } }, Err(e) => { Err(crate::Error::StorageError(e.to_string()))?; }, } } }; Box::pin(stream) } #[instrument(skip_all)] fn put_multiple_start(&self) -> Box<(dyn DirectoryPutter + 'static)> where Self: Clone, { let mut grpc_client = self.grpc_client.clone(); let (tx, rx) = tokio::sync::mpsc::unbounded_channel(); let task: JoinHandle> = spawn(async move { let s = grpc_client .put(UnboundedReceiverStream::new(rx)) .await? .into_inner(); Ok(s) }); Box::new(GRPCPutter { rq: Some((task, tx)), }) } } /// Allows uploading multiple Directory messages in the same gRPC stream. pub struct GRPCPutter { /// Data about the current request - a handle to the task, and the tx part /// of the channel. /// The tx part of the pipe is used to send [proto::Directory] to the ongoing request. /// The task will yield a [proto::PutDirectoryResponse] once the stream is closed. #[allow(clippy::type_complexity)] // lol rq: Option<( JoinHandle>, UnboundedSender, )>, } impl GRPCPutter { // allows checking if the tx part of the channel is closed. // only used in the test case. #[cfg(test)] fn is_closed(&self) -> bool { match self.rq { None => true, Some((_, ref directory_sender)) => directory_sender.is_closed(), } } } #[async_trait] impl DirectoryPutter for GRPCPutter { async fn put(&mut self, directory: proto::Directory) -> Result<(), crate::Error> { match self.rq { // If we're not already closed, send the directory to directory_sender. Some((_, ref directory_sender)) => { if directory_sender.send(directory).is_err() { // If the channel has been prematurely closed, invoke close (so we can peek at the error code) // That error code is much more helpful, because it // contains the error message from the server. self.close().await?; } Ok(()) } // If self.close() was already called, we can't put again. None => Err(Error::StorageError( "DirectoryPutter already closed".to_string(), )), } } /// Closes the stream for sending, and returns the value async fn close(&mut self) -> Result { // get self.rq, and replace it with None. // This ensures we can only close it once. match std::mem::take(&mut self.rq) { None => Err(Error::StorageError("already closed".to_string())), Some((task, directory_sender)) => { // close directory_sender, so blocking on task will finish. drop(directory_sender); let root_digest = task .await? .map_err(|e| Error::StorageError(e.to_string()))? .root_digest; root_digest.try_into().map_err(|_| { Error::StorageError("invalid root digest length in response".to_string()) }) } } } } #[cfg(test)] mod tests { use core::time; use futures::StreamExt; use std::{any::Any, time::Duration}; use tempfile::TempDir; use tokio::net::UnixListener; use tokio_retry::{strategy::ExponentialBackoff, Retry}; use tokio_stream::wrappers::UnixListenerStream; use crate::{ directoryservice::{ grpc::GRPCPutter, DirectoryPutter, DirectoryService, GRPCDirectoryService, MemoryDirectoryService, }, fixtures::{self, DIRECTORY_A, DIRECTORY_B}, proto::{directory_service_client::DirectoryServiceClient, GRPCDirectoryServiceWrapper}, utils::gen_directorysvc_grpc_client, }; #[tokio::test] async fn test() { // create the GrpcDirectoryService let directory_service = super::GRPCDirectoryService::from_client(gen_directorysvc_grpc_client().await); // try to get DIRECTORY_A should return Ok(None) assert_eq!( None, directory_service .get(&DIRECTORY_A.digest()) .await .expect("must not fail") ); // Now upload it assert_eq!( DIRECTORY_A.digest(), directory_service .put(DIRECTORY_A.clone()) .await .expect("must succeed") ); // And retrieve it, compare for equality. assert_eq!( DIRECTORY_A.clone(), directory_service .get(&DIRECTORY_A.digest()) .await .expect("must succeed") .expect("must be some") ); // Putting DIRECTORY_B alone should fail, because it refers to DIRECTORY_A. directory_service .put(DIRECTORY_B.clone()) .await .expect_err("must fail"); // Putting DIRECTORY_B in a put_multiple will succeed, but the close // will always fail. { let mut handle = directory_service.put_multiple_start(); handle.put(DIRECTORY_B.clone()).await.expect("must succeed"); handle.close().await.expect_err("must fail"); } // Uploading A and then B should succeed, and closing should return the digest of B. let mut handle = directory_service.put_multiple_start(); handle.put(DIRECTORY_A.clone()).await.expect("must succeed"); handle.put(DIRECTORY_B.clone()).await.expect("must succeed"); let digest = handle.close().await.expect("must succeed"); assert_eq!(DIRECTORY_B.digest(), digest); // Now try to retrieve the closure of DIRECTORY_B, which should return B and then A. let mut directories_it = directory_service.get_recursive(&DIRECTORY_B.digest()); assert_eq!( DIRECTORY_B.clone(), directories_it .next() .await .expect("must be some") .expect("must succeed") ); assert_eq!( DIRECTORY_A.clone(), directories_it .next() .await .expect("must be some") .expect("must succeed") ); // Uploading B and then A should fail, because B refers to A, which // hasn't been uploaded yet. // However, the client can burst, so we might not have received the // error back from the server. { let mut handle = directory_service.put_multiple_start(); // sending out B will always be fine handle.put(DIRECTORY_B.clone()).await.expect("must succeed"); // whether we will be able to put A as well depends on whether we // already received the error about B. if handle.put(DIRECTORY_A.clone()).await.is_ok() { // If we didn't, and this was Ok(_), … // a subsequent close MUST fail (because it waits for the // server) handle.close().await.expect_err("must fail"); } } // Now we do the same test as before, send B, then A, but wait // a long long time so we already received the error from the server // (causing the internal stream to be closed). // Uploading anything else subsequently should then fail. { let mut handle = directory_service.put_multiple_start(); handle.put(DIRECTORY_B.clone()).await.expect("must succeed"); // get a GRPCPutter, so we can peek at [is_closed]. let handle_any = &mut handle as &mut dyn Any; // `unchecked_downcast_mut` is unstable for now, // https://github.com/rust-lang/rust/issues/90850 // We do the same thing here. // The reason for why we cannot use the checked downcast lies // in the fact that: // - GRPCPutter has type ID A // - Box has type ID B // - "Box" (invalid type) has type ID C // B seems different from C in this context. // We cannot unpack and perform upcast coercion of the traits as it's an unstable // feature. // We cannot add `as_any` in `DirectoryPutter` as that would defeat the whole purpose // of not making leak `is_closed` in the original trait. let handle = unsafe { &mut *(handle_any as *mut dyn Any as *mut Box) }; let mut is_closed = false; for _try in 1..1000 { if handle.is_closed() { is_closed = true; break; } tokio::time::sleep(time::Duration::from_millis(10)).await; } assert!( is_closed, "expected channel to eventually close, but never happened" ); handle .put(DIRECTORY_A.clone()) .await .expect_err("must fail"); } } /// 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::directory_service_server::DirectoryServiceServer::new( GRPCDirectoryServiceWrapper::new( Box::::default() as Box ), ), ); 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 = DirectoryServiceClient::new( crate::tonic::channel_from_url(&url) .await .expect("must succeed"), ); GRPCDirectoryService::from_client(client) }; assert!(grpc_client .get(&fixtures::DIRECTORY_A.digest()) .await .expect("must not fail") .is_none()) } }