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|
use crate::utils::AsyncIoBridge;
use super::{NarCalculationService, RenderError};
use count_write::CountWrite;
use nix_compat::nar::writer::r#async as nar_writer;
use sha2::{Digest, Sha256};
use tokio::io::{self, AsyncWrite, BufReader};
use tonic::async_trait;
use tracing::instrument;
use tvix_castore::{blobservice::BlobService, directoryservice::DirectoryService, Node};
pub struct SimpleRenderer<BS, DS> {
blob_service: BS,
directory_service: DS,
}
impl<BS, DS> SimpleRenderer<BS, DS> {
pub fn new(blob_service: BS, directory_service: DS) -> Self {
Self {
blob_service,
directory_service,
}
}
}
#[async_trait]
impl<BS, DS> NarCalculationService for SimpleRenderer<BS, DS>
where
BS: BlobService + Clone,
DS: DirectoryService + Clone,
{
async fn calculate_nar(
&self,
root_node: &Node,
) -> Result<(u64, [u8; 32]), tvix_castore::Error> {
calculate_size_and_sha256(
root_node,
self.blob_service.clone(),
self.directory_service.clone(),
)
.await
.map_err(|e| tvix_castore::Error::StorageError(format!("failed rendering nar: {}", e)))
}
}
/// Invoke [write_nar], and return the size and sha256 digest of the produced
/// NAR output.
#[instrument(skip_all)]
pub async fn calculate_size_and_sha256<BS, DS>(
root_node: &Node,
blob_service: BS,
directory_service: DS,
) -> Result<(u64, [u8; 32]), RenderError>
where
BS: BlobService + Send,
DS: DirectoryService + Send,
{
let mut h = Sha256::new();
let mut cw = CountWrite::from(&mut h);
write_nar(
// The hasher doesn't speak async. It doesn't
// actually do any I/O, so it's fine to wrap.
AsyncIoBridge(&mut cw),
root_node,
blob_service,
directory_service,
)
.await?;
Ok((cw.count(), h.finalize().into()))
}
/// Accepts a [Node] pointing to the root of a (store) path,
/// and uses the passed blob_service and directory_service to perform the
/// necessary lookups as it traverses the structure.
/// The contents in NAR serialization are writen to the passed [AsyncWrite].
pub async fn write_nar<W, BS, DS>(
mut w: W,
root_node: &Node,
blob_service: BS,
directory_service: DS,
) -> Result<(), RenderError>
where
W: AsyncWrite + Unpin + Send,
BS: BlobService + Send,
DS: DirectoryService + Send,
{
// Initialize NAR writer
let nar_root_node = nar_writer::open(&mut w)
.await
.map_err(RenderError::NARWriterError)?;
walk_node(
nar_root_node,
root_node,
b"",
blob_service,
directory_service,
)
.await?;
Ok(())
}
/// Process an intermediate node in the structure.
/// This consumes the node.
async fn walk_node<BS, DS>(
nar_node: nar_writer::Node<'_, '_>,
castore_node: &Node,
name: &[u8],
blob_service: BS,
directory_service: DS,
) -> Result<(BS, DS), RenderError>
where
BS: BlobService + Send,
DS: DirectoryService + Send,
{
match castore_node {
Node::Symlink { target, .. } => {
nar_node
.symlink(target.as_ref())
.await
.map_err(RenderError::NARWriterError)?;
}
Node::File {
digest,
size,
executable,
} => {
let mut blob_reader = match blob_service
.open_read(digest)
.await
.map_err(RenderError::StoreError)?
{
Some(blob_reader) => Ok(BufReader::new(blob_reader)),
None => Err(RenderError::NARWriterError(io::Error::new(
io::ErrorKind::NotFound,
format!("blob with digest {} not found", &digest),
))),
}?;
nar_node
.file(*executable, *size, &mut blob_reader)
.await
.map_err(RenderError::NARWriterError)?;
}
Node::Directory { digest, .. } => {
// look it up with the directory service
match directory_service
.get(digest)
.await
.map_err(|e| RenderError::StoreError(e.into()))?
{
// if it's None, that's an error!
None => Err(RenderError::DirectoryNotFound(
digest.clone(),
bytes::Bytes::copy_from_slice(name),
))?,
Some(directory) => {
// start a directory node
let mut nar_node_directory = nar_node
.directory()
.await
.map_err(RenderError::NARWriterError)?;
// We put blob_service, directory_service back here whenever we come up from
// the recursion.
let mut blob_service = blob_service;
let mut directory_service = directory_service;
// for each node in the directory, create a new entry with its name,
// and then recurse on that entry.
for (name, node) in directory.nodes() {
let child_node = nar_node_directory
.entry(name.as_ref())
.await
.map_err(RenderError::NARWriterError)?;
(blob_service, directory_service) = Box::pin(walk_node(
child_node,
node,
name.as_ref(),
blob_service,
directory_service,
))
.await?;
}
// close the directory
nar_node_directory
.close()
.await
.map_err(RenderError::NARWriterError)?;
return Ok((blob_service, directory_service));
}
}
}
}
Ok((blob_service, directory_service))
}
|
