use std::collections::HashSet;
use super::{DirectoryPutter, DirectoryService};
use crate::proto::{self, get_directory_request::ByWhat};
use crate::{B3Digest, Error};
use tokio::net::UnixStream;
use tokio::sync::mpsc::UnboundedSender;
use tokio_stream::wrappers::UnboundedReceiverStream;
use tonic::{transport::Channel, Status};
use tonic::{Code, Streaming};
use tracing::{instrument, warn};
/// Connects to a (remote) tvix-store DirectoryService over gRPC.
#[derive(Clone)]
pub struct GRPCDirectoryService {
/// A handle into the active tokio runtime. Necessary to spawn tasks.
tokio_handle: tokio::runtime::Handle,
/// The internal reference to a gRPC client.
/// Cloning it is cheap, and it internally handles concurrent requests.
grpc_client: proto::directory_service_client::DirectoryServiceClient<Channel>,
}
impl GRPCDirectoryService {
/// construct a [GRPCDirectoryService] from a [proto::directory_service_client::DirectoryServiceClient<Channel>].
/// panics if called outside the context of a tokio runtime.
pub fn from_client(
grpc_client: proto::directory_service_client::DirectoryServiceClient<Channel>,
) -> Self {
Self {
tokio_handle: tokio::runtime::Handle::current(),
grpc_client,
}
}
}
impl DirectoryService for GRPCDirectoryService {
/// Constructs a [GRPCDirectoryService] from the passed [url::Url]:
/// - scheme has to match `grpc+*://`.
/// That's normally grpc+unix for unix sockets, and grpc+http(s) for the HTTP counterparts.
/// - In the case of unix sockets, there must be a path, but may not be a host.
/// - In the case of non-unix sockets, there must be a host, but no path.
fn from_url(url: &url::Url) -> Result<Self, crate::Error> {
// Start checking for the scheme to start with grpc+.
match url.scheme().strip_prefix("grpc+") {
None => Err(crate::Error::StorageError("invalid scheme".to_string())),
Some(rest) => {
if rest == "unix" {
if url.host_str().is_some() {
return Err(crate::Error::StorageError(
"host may not be set".to_string(),
));
}
let path = url.path().to_string();
let channel = tonic::transport::Endpoint::try_from("http://[::]:50051") // doesn't matter
.unwrap()
.connect_with_connector_lazy(tower::service_fn(
move |_: tonic::transport::Uri| UnixStream::connect(path.clone()),
));
let grpc_client =
proto::directory_service_client::DirectoryServiceClient::new(channel);
Ok(Self::from_client(grpc_client))
} else {
// ensure path is empty, not supported with gRPC.
if !url.path().is_empty() {
return Err(crate::Error::StorageError(
"path may not be set".to_string(),
));
}
// clone the uri, and drop the grpc+ from the scheme.
// Recreate a new uri with the `grpc+` prefix dropped from the scheme.
// We can't use `url.set_scheme(rest)`, as it disallows
// setting something http(s) that previously wasn't.
let url = {
let url_str = url.to_string();
let s_stripped = url_str.strip_prefix("grpc+").unwrap();
url::Url::parse(s_stripped).unwrap()
};
let channel = tonic::transport::Endpoint::try_from(url.to_string())
.unwrap()
.connect_lazy();
let grpc_client =
proto::directory_service_client::DirectoryServiceClient::new(channel);
Ok(Self::from_client(grpc_client))
}
}
}
}
fn get(&self, digest: &B3Digest) -> Result<Option<crate::proto::Directory>, crate::Error> {
// Get a new handle to the gRPC client, and copy the digest.
let mut grpc_client = self.grpc_client.clone();
let digest_as_vec = digest.to_vec();
let task = self.tokio_handle.spawn(async move {
let mut s = grpc_client
.get(proto::GetDirectoryRequest {
recursive: false,
by_what: Some(ByWhat::Digest(digest_as_vec)),
})
.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 self.tokio_handle.block_on(task)? {
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())),
}
}
fn put(&self, directory: crate::proto::Directory) -> Result<B3Digest, crate::Error> {
let mut grpc_client = self.grpc_client.clone();
let task = self
.tokio_handle
.spawn(async move { grpc_client.put(tokio_stream::iter(vec![directory])).await });
match self.tokio_handle.block_on(task)? {
Ok(put_directory_resp) => Ok(B3Digest::from_vec(
put_directory_resp.into_inner().root_digest,
)
.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,
) -> Box<dyn Iterator<Item = Result<proto::Directory, Error>> + Send> {
let mut grpc_client = self.grpc_client.clone();
let root_directory_digest_as_vec = root_directory_digest.to_vec();
let task: tokio::task::JoinHandle<Result<Streaming<proto::Directory>, Status>> =
self.tokio_handle.spawn(async move {
let s = grpc_client
.get(proto::GetDirectoryRequest {
recursive: true,
by_what: Some(ByWhat::Digest(root_directory_digest_as_vec)),
})
.await?
.into_inner();
Ok(s)
});
let stream = self.tokio_handle.block_on(task).unwrap().unwrap();
Box::new(StreamIterator::new(
self.tokio_handle.clone(),
root_directory_digest.clone(),
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: tokio::task::JoinHandle<Result<proto::PutDirectoryResponse, Status>> =
self.tokio_handle.spawn(async move {
let s = grpc_client
.put(UnboundedReceiverStream::new(rx))
.await?
.into_inner();
Ok(s)
});
Box::new(GRPCPutter::new(self.tokio_handle.clone(), tx, task))
}
}
pub struct StreamIterator {
/// A handle into the active tokio runtime. Necessary to run futures to completion.
tokio_handle: tokio::runtime::Handle,
// A stream of [proto::Directory]
stream: Streaming<proto::Directory>,
// The Directory digests we received so far
received_directory_digests: HashSet<B3Digest>,
// The Directory digests we're still expecting to get sent.
expected_directory_digests: HashSet<B3Digest>,
}
impl StreamIterator {
pub fn new(
tokio_handle: tokio::runtime::Handle,
root_digest: B3Digest,
stream: Streaming<proto::Directory>,
) -> Self {
Self {
tokio_handle,
stream,
received_directory_digests: HashSet::new(),
expected_directory_digests: HashSet::from([root_digest]),
}
}
}
impl Iterator for StreamIterator {
type Item = Result<proto::Directory, crate::Error>;
fn next(&mut self) -> Option<Self::Item> {
match self.tokio_handle.block_on(self.stream.message()) {
Ok(ok) => match ok {
Some(directory) => {
// validate the directory itself.
if let Err(e) = directory.validate() {
return Some(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 = self.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)
return Some(Err(crate::Error::StorageError(format!(
"received unexpected directory {}",
directory_digest
))));
}
self.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 =
B3Digest::from_vec(child_directory.digest.clone()).unwrap();
self.expected_directory_digests
.insert(child_directory_digest);
}
Some(Ok(directory))
}
None => {
// If we were still expecting something, that's an error.
if !self.expected_directory_digests.is_empty() {
Some(Err(crate::Error::StorageError(format!(
"still expected {} directories, but got premature end of stream",
self.expected_directory_digests.len(),
))))
} else {
None
}
}
},
Err(e) => Some(Err(crate::Error::StorageError(e.to_string()))),
}
}
}
/// Allows uploading multiple Directory messages in the same gRPC stream.
pub struct GRPCPutter {
/// A handle into the active tokio runtime. Necessary to spawn tasks.
tokio_handle: tokio::runtime::Handle,
/// 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<(
tokio::task::JoinHandle<Result<proto::PutDirectoryResponse, Status>>,
UnboundedSender<proto::Directory>,
)>,
}
impl GRPCPutter {
pub fn new(
tokio_handle: tokio::runtime::Handle,
directory_sender: UnboundedSender<proto::Directory>,
task: tokio::task::JoinHandle<Result<proto::PutDirectoryResponse, Status>>,
) -> Self {
Self {
tokio_handle,
rq: Some((task, directory_sender)),
}
}
}
impl DirectoryPutter for GRPCPutter {
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()?;
}
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
fn close(&mut self) -> Result<B3Digest, crate::Error> {
// 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 = self
.tokio_handle
.block_on(task)?
.map_err(|e| Error::StorageError(e.to_string()))?
.root_digest;
B3Digest::from_vec(root_digest).map_err(|_| {
Error::StorageError("invalid root digest length in response".to_string())
})
}
}
}
// allows checking if the tx part of the channel is closed.
fn is_closed(&self) -> bool {
match self.rq {
None => true,
Some((_, ref directory_sender)) => directory_sender.is_closed(),
}
}
}
#[cfg(test)]
mod tests {
use core::time;
use std::thread;
use tempfile::TempDir;
use tokio::net::{UnixListener, UnixStream};
use tokio_stream::wrappers::UnixListenerStream;
use tonic::transport::{Endpoint, Server, Uri};
use crate::{
directoryservice::DirectoryService,
proto,
proto::{directory_service_server::DirectoryServiceServer, GRPCDirectoryServiceWrapper},
tests::{
fixtures::{DIRECTORY_A, DIRECTORY_B},
utils::gen_directory_service,
},
};
#[test]
fn test() -> anyhow::Result<()> {
let tmpdir = TempDir::new().unwrap();
let socket_path = tmpdir.path().join("socket");
// Spin up a server, in a thread far away, which spawns its own tokio runtime,
// and blocks on the task.
let socket_path_clone = socket_path.clone();
thread::spawn(move || {
// Create the runtime
let rt = tokio::runtime::Runtime::new().unwrap();
// Get a handle from this runtime
let handle = rt.handle();
let task = handle.spawn(async {
let uds = UnixListener::bind(socket_path_clone).unwrap();
let uds_stream = UnixListenerStream::new(uds);
// spin up a new DirectoryService
let mut server = Server::builder();
let router = server.add_service(DirectoryServiceServer::new(
GRPCDirectoryServiceWrapper::from(gen_directory_service()),
));
router.serve_with_incoming(uds_stream).await
});
handle.block_on(task)
});
// set up the local client runtime. This is similar to what the [tokio:test] macro desugars to.
let tester_runtime = tokio::runtime::Builder::new_current_thread()
.enable_all()
.build()
.unwrap();
// wait for the socket to be created
{
let mut socket_created = false;
for _try in 1..20 {
if socket_path.exists() {
socket_created = true;
break;
}
std::thread::sleep(time::Duration::from_millis(20))
}
assert!(
socket_created,
"expected socket path to eventually get created, but never happened"
);
}
let task = tester_runtime.spawn_blocking(move || {
// Create a channel, connecting to the uds at socket_path.
// The URI is unused.
let channel = Endpoint::try_from("http://[::]:50051")
.unwrap()
.connect_with_connector_lazy(tower::service_fn(move |_: Uri| {
UnixStream::connect(socket_path.clone())
}));
let grpc_client = proto::directory_service_client::DirectoryServiceClient::new(channel);
// create the GrpcDirectoryService, using the tester_runtime.
let directory_service = super::GRPCDirectoryService::from_client(grpc_client);
// try to get DIRECTORY_A should return Ok(None)
assert_eq!(
None,
directory_service
.get(&DIRECTORY_A.digest())
.expect("must not fail")
);
// Now upload it
assert_eq!(
DIRECTORY_A.digest(),
directory_service
.put(DIRECTORY_A.clone())
.expect("must succeed")
);
// And retrieve it, compare for equality.
assert_eq!(
DIRECTORY_A.clone(),
directory_service
.get(&DIRECTORY_A.digest())
.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())
.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()).expect("must succeed");
handle.close().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()).expect("must succeed");
handle.put(DIRECTORY_B.clone()).expect("must succeed");
let digest = handle.close().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()
.expect("must be some")
.expect("must succeed")
);
assert_eq!(
DIRECTORY_A.clone(),
directories_it
.next()
.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()).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()).is_ok() {
// If we didn't, and this was Ok(_), …
// a subsequent close MUST fail (because it waits for the
// server)
handle.close().expect_err("must fail");
}
}
// Now we do the same test as before, send B, then A, but wait
// sufficiently enough for the server to have s
// to close us the stream,
// and then assert that uploading anything else via the handle will fail.
{
let mut handle = directory_service.put_multiple_start();
handle.put(DIRECTORY_B.clone()).expect("must succeed");
let mut is_closed = false;
for _try in 1..1000 {
if handle.is_closed() {
is_closed = true;
break;
}
std::thread::sleep(time::Duration::from_millis(10))
}
assert!(
is_closed,
"expected channel to eventually close, but never happened"
);
handle.put(DIRECTORY_A.clone()).expect_err("must fail");
}
});
tester_runtime.block_on(task)?;
Ok(())
}
}
