Merge pull request 'some refactoring on data read/write path' (#729) from refactor-block into main

Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/garage/pulls/729

6 files changed, 130 insertions, 148 deletions

diff --git a/src/api/s3/get.rs b/src/api/s3/get.rs
index 53f0a345..efb8d4ab 100644
--- a/src/api/s3/get.rs
+++ b/src/api/s3/get.rs
@@ -13,7 +13,7 @@ use http::header::{
 use hyper::{body::Body, Request, Response, StatusCode};
 use tokio::sync::mpsc;
 
-use garage_block::manager::BlockStream;
+use garage_net::stream::ByteStream;
 use garage_rpc::rpc_helper::OrderTag;
 use garage_table::EmptyKey;
 use garage_util::data::*;
@@ -286,7 +286,7 @@ pub async fn handle_get(
 			Ok(resp_builder.body(bytes_body(bytes.to_vec().into()))?)
 		}
 		ObjectVersionData::FirstBlock(_, first_block_hash) => {
-			let (tx, rx) = mpsc::channel::<BlockStream>(2);
+			let (tx, rx) = mpsc::channel::<ByteStream>(2);
 
 			let order_stream = OrderTag::stream();
 			let first_block_hash = *first_block_hash;
@@ -494,7 +494,7 @@ fn body_from_blocks_range(
 	}
 
 	let order_stream = OrderTag::stream();
-	let (tx, rx) = mpsc::channel::<BlockStream>(2);
+	let (tx, rx) = mpsc::channel::<ByteStream>(2);
 
 	tokio::spawn(async move {
 		match async {
@@ -542,7 +542,7 @@ fn body_from_blocks_range(
 					})
 					.filter_map(futures::future::ready);
 
-				let block_stream: BlockStream = Box::pin(block_stream);
+				let block_stream: ByteStream = Box::pin(block_stream);
 				tx.send(Box::pin(block_stream))
 					.await
 					.ok_or_message("channel closed")?;
@@ -562,7 +562,7 @@ fn body_from_blocks_range(
 	response_body_from_block_stream(rx)
 }
 
-fn response_body_from_block_stream(rx: mpsc::Receiver<BlockStream>) -> ResBody {
+fn response_body_from_block_stream(rx: mpsc::Receiver<ByteStream>) -> ResBody {
 	let body_stream = tokio_stream::wrappers::ReceiverStream::new(rx)
 		.flatten()
 		.map(|x| {
@@ -572,7 +572,7 @@ fn response_body_from_block_stream(rx: mpsc::Receiver<BlockStream>) -> ResBody {
 	ResBody::new(http_body_util::StreamBody::new(body_stream))
 }
 
-fn error_stream_item<E: std::fmt::Display>(e: E) -> BlockStream {
+fn error_stream_item<E: std::fmt::Display>(e: E) -> ByteStream {
 	let err = std::io::Error::new(
 		std::io::ErrorKind::Other,
 		format!("Error while getting object data: {}", e),
diff --git a/src/block/block.rs b/src/block/block.rs
index 20f57aa5..504d11f8 100644
--- a/src/block/block.rs
+++ b/src/block/block.rs
@@ -2,107 +2,98 @@ use std::path::PathBuf;
 
 use bytes::Bytes;
 use serde::{Deserialize, Serialize};
-use zstd::stream::{decode_all as zstd_decode, Encoder};
+use zstd::stream::Encoder;
 
 use garage_util::data::*;
 use garage_util::error::*;
 
+use garage_net::stream::ByteStream;
+
 #[derive(Debug, Serialize, Deserialize, Copy, Clone)]
 pub enum DataBlockHeader {
 	Plain,
 	Compressed,
 }
 
-/// A possibly compressed block of data
-pub enum DataBlock {
-	/// Uncompressed data
-	Plain(Bytes),
-	/// Data compressed with zstd
-	Compressed(Bytes),
-}
-
 #[derive(Debug)]
-pub enum DataBlockPath {
-	/// Uncompressed data fail
-	Plain(PathBuf),
-	/// Compressed data fail
-	Compressed(PathBuf),
+pub struct DataBlockElem<T> {
+	header: DataBlockHeader,
+	elem: T,
 }
 
-impl DataBlock {
-	/// Query whether this block is compressed
+/// A possibly compressed block of data
+pub type DataBlock = DataBlockElem<Bytes>;
+
+/// A path to a possibly compressed block of data
+pub type DataBlockPath = DataBlockElem<PathBuf>;
+
+/// A stream of possibly compressed block data
+pub type DataBlockStream = DataBlockElem<ByteStream>;
+
+impl DataBlockHeader {
 	pub fn is_compressed(&self) -> bool {
-		matches!(self, DataBlock::Compressed(_))
+		matches!(self, DataBlockHeader::Compressed)
 	}
+}
 
-	/// Get the inner, possibly compressed buffer. You should probably use [`DataBlock::verify_get`]
-	/// instead
-	pub fn inner_buffer(&self) -> &[u8] {
-		use DataBlock::*;
-		let (Plain(ref res) | Compressed(ref res)) = self;
-		res
+impl<T> DataBlockElem<T> {
+	pub fn from_parts(header: DataBlockHeader, elem: T) -> Self {
+		Self { header, elem }
 	}
 
-	/// Get the buffer, possibly decompressing it, and verify it's integrity.
-	/// For Plain block, data is compared to hash, for Compressed block, zstd checksumming system
-	/// is used instead.
-	pub fn verify_get(self, hash: Hash) -> Result<Bytes, Error> {
-		match self {
-			DataBlock::Plain(data) => {
-				if blake2sum(&data) == hash {
-					Ok(data)
-				} else {
-					Err(Error::CorruptData(hash))
-				}
-			}
-			DataBlock::Compressed(data) => zstd_decode(&data[..])
-				.map_err(|_| Error::CorruptData(hash))
-				.map(Bytes::from),
+	pub fn plain(elem: T) -> Self {
+		Self {
+			header: DataBlockHeader::Plain,
+			elem,
+		}
+	}
+
+	pub fn compressed(elem: T) -> Self {
+		Self {
+			header: DataBlockHeader::Compressed,
+			elem,
 		}
 	}
 
-	/// Verify data integrity. Allocate less than [`DataBlock::verify_get`] and don't consume self, but
-	/// does not return the buffer content.
+	pub fn into_parts(self) -> (DataBlockHeader, T) {
+		(self.header, self.elem)
+	}
+
+	pub fn as_parts_ref(&self) -> (DataBlockHeader, &T) {
+		(self.header, &self.elem)
+	}
+}
+
+impl DataBlock {
+	/// Verify data integrity. Does not return the buffer content.
 	pub fn verify(&self, hash: Hash) -> Result<(), Error> {
-		match self {
-			DataBlock::Plain(data) => {
-				if blake2sum(data) == hash {
+		match self.header {
+			DataBlockHeader::Plain => {
+				if blake2sum(&self.elem) == hash {
 					Ok(())
 				} else {
 					Err(Error::CorruptData(hash))
 				}
 			}
-			DataBlock::Compressed(data) => zstd::stream::copy_decode(&data[..], std::io::sink())
-				.map_err(|_| Error::CorruptData(hash)),
+			DataBlockHeader::Compressed => {
+				zstd::stream::copy_decode(&self.elem[..], std::io::sink())
+					.map_err(|_| Error::CorruptData(hash))
+			}
 		}
 	}
 
 	pub async fn from_buffer(data: Bytes, level: Option<i32>) -> DataBlock {
 		tokio::task::spawn_blocking(move || {
 			if let Some(level) = level {
-				if let Ok(data) = zstd_encode(&data[..], level) {
-					return DataBlock::Compressed(data.into());
+				if let Ok(data_compressed) = zstd_encode(&data[..], level) {
+					return DataBlock::compressed(data_compressed.into());
 				}
 			}
-			DataBlock::Plain(data)
+			DataBlock::plain(data.into())
 		})
 		.await
 		.unwrap()
 	}
-
-	pub fn into_parts(self) -> (DataBlockHeader, Bytes) {
-		match self {
-			DataBlock::Plain(data) => (DataBlockHeader::Plain, data),
-			DataBlock::Compressed(data) => (DataBlockHeader::Compressed, data),
-		}
-	}
-
-	pub fn from_parts(h: DataBlockHeader, bytes: Bytes) -> Self {
-		match h {
-			DataBlockHeader::Plain => DataBlock::Plain(bytes),
-			DataBlockHeader::Compressed => DataBlock::Compressed(bytes),
-		}
-	}
 }
 
 fn zstd_encode<R: std::io::Read>(mut source: R, level: i32) -> std::io::Result<Vec<u8>> {
diff --git a/src/block/manager.rs b/src/block/manager.rs
index 848d9141..817866f6 100644
--- a/src/block/manager.rs
+++ b/src/block/manager.rs
@@ -1,5 +1,4 @@
 use std::path::PathBuf;
-use std::pin::Pin;
 use std::sync::Arc;
 use std::time::Duration;
 
@@ -9,8 +8,6 @@ use bytes::Bytes;
 use rand::prelude::*;
 use serde::{Deserialize, Serialize};
 
-use futures::Stream;
-use futures_util::stream::StreamExt;
 use tokio::fs;
 use tokio::io::{AsyncReadExt, AsyncWriteExt, BufReader};
 use tokio::sync::{mpsc, Mutex, MutexGuard};
@@ -20,7 +17,7 @@ use opentelemetry::{
 	Context,
 };
 
-use garage_net::stream::{stream_asyncread, ByteStream};
+use garage_net::stream::{read_stream_to_end, stream_asyncread, ByteStream};
 
 use garage_db as db;
 
@@ -53,9 +50,6 @@ pub const INLINE_THRESHOLD: usize = 3072;
 // to delete the block locally.
 pub(crate) const BLOCK_GC_DELAY: Duration = Duration::from_secs(600);
 
-pub type BlockStream =
-	Pin<Box<dyn Stream<Item = Result<Bytes, std::io::Error>> + Send + Sync + 'static>>;
-
 /// RPC messages used to share blocks of data between nodes
 #[derive(Debug, Serialize, Deserialize)]
 pub enum BlockRpc {
@@ -235,11 +229,9 @@ impl BlockManager {
 		&self,
 		hash: &Hash,
 		order_tag: Option<OrderTag>,
-	) -> Result<(DataBlockHeader, ByteStream), Error> {
-		self.rpc_get_raw_block_internal(hash, order_tag, |header, stream| async move {
-			Ok((header, stream))
-		})
-		.await
+	) -> Result<DataBlockStream, Error> {
+		self.rpc_get_raw_block_internal(hash, order_tag, |stream| async move { Ok(stream) })
+			.await
 	}
 
 	/// Ask nodes that might have a (possibly compressed) block for it
@@ -249,10 +241,12 @@ impl BlockManager {
 		hash: &Hash,
 		order_tag: Option<OrderTag>,
 	) -> Result<DataBlock, Error> {
-		self.rpc_get_raw_block_internal(hash, order_tag, |header, stream| async move {
+		self.rpc_get_raw_block_internal(hash, order_tag, |block_stream| async move {
+			let (header, stream) = block_stream.into_parts();
 			read_stream_to_end(stream)
 				.await
-				.map(|data| DataBlock::from_parts(header, data))
+				.err_context("error in block data stream")
+				.map(|data| DataBlock::from_parts(header, data.into_bytes()))
 		})
 		.await
 	}
@@ -264,7 +258,7 @@ impl BlockManager {
 		f: F,
 	) -> Result<T, Error>
 	where
-		F: Fn(DataBlockHeader, ByteStream) -> Fut,
+		F: Fn(DataBlockStream) -> Fut,
 		Fut: futures::Future<Output = Result<T, Error>>,
 	{
 		let who = self.replication.read_nodes(hash);
@@ -286,8 +280,8 @@ impl BlockManager {
 							continue;
 						}
 					};
-					let (header, stream) = match res.into_parts() {
-						(Ok(BlockRpc::PutBlock { hash: _, header }), Some(stream)) => (header, stream),
+					let block_stream = match res.into_parts() {
+						(Ok(BlockRpc::PutBlock { hash: _, header }), Some(stream)) => DataBlockStream::from_parts(header, stream),
 						(Ok(_), _) => {
 							debug!("Get block {:?}: node {:?} returned a malformed response", hash, node);
 							continue;
@@ -297,7 +291,7 @@ impl BlockManager {
 							continue;
 						}
 					};
-					match f(header, stream).await {
+					match f(block_stream).await {
 						Ok(ret) => return Ok(ret),
 						Err(e) => {
 							debug!("Get block {:?}: error reading stream from node {:?}: {}", hash, node, e);
@@ -321,14 +315,14 @@ impl BlockManager {
 
 	// ---- Public interface ----
 
-	/// Ask nodes that might have a block for it,
-	/// return it as a stream
+	/// Ask nodes that might have a block for it, return it as a stream
 	pub async fn rpc_get_block_streaming(
 		&self,
 		hash: &Hash,
 		order_tag: Option<OrderTag>,
-	) -> Result<BlockStream, Error> {
-		let (header, stream) = self.rpc_get_raw_block_streaming(hash, order_tag).await?;
+	) -> Result<ByteStream, Error> {
+		let block_stream = self.rpc_get_raw_block_streaming(hash, order_tag).await?;
+		let (header, stream) = block_stream.into_parts();
 		match header {
 			DataBlockHeader::Plain => Ok(stream),
 			DataBlockHeader::Compressed => {
@@ -341,15 +335,14 @@ impl BlockManager {
 		}
 	}
 
-	/// Ask nodes that might have a block for it
+	/// Ask nodes that might have a block for it, return it as one big Bytes
 	pub async fn rpc_get_block(
 		&self,
 		hash: &Hash,
 		order_tag: Option<OrderTag>,
 	) -> Result<Bytes, Error> {
-		self.rpc_get_raw_block(hash, order_tag)
-			.await?
-			.verify_get(*hash)
+		let stream = self.rpc_get_block_streaming(hash, order_tag).await?;
+		Ok(read_stream_to_end(stream).await?.into_bytes())
 	}
 
 	/// Send block to nodes that should have it
@@ -482,7 +475,7 @@ impl BlockManager {
 		stream: Option<ByteStream>,
 	) -> Result<(), Error> {
 		let stream = stream.ok_or_message("missing stream")?;
-		let bytes = read_stream_to_end(stream).await?;
+		let bytes = read_stream_to_end(stream).await?.into_bytes();
 		let data = DataBlock::from_parts(header, bytes);
 		self.write_block(&hash, &data).await
 	}
@@ -553,10 +546,7 @@ impl BlockManager {
 		hash: &Hash,
 		block_path: &DataBlockPath,
 	) -> Result<DataBlock, Error> {
-		let (path, compressed) = match block_path {
-			DataBlockPath::Plain(p) => (p, false),
-			DataBlockPath::Compressed(p) => (p, true),
-		};
+		let (header, path) = block_path.as_parts_ref();
 
 		let mut f = fs::File::open(&path).await?;
 		let mut data = vec![];
@@ -564,11 +554,7 @@ impl BlockManager {
 		self.metrics.bytes_read.add(data.len() as u64);
 		drop(f);
 
-		let data = if compressed {
-			DataBlock::Compressed(data.into())
-		} else {
-			DataBlock::Plain(data.into())
-		};
+		let data = DataBlock::from_parts(header, data.into());
 
 		if data.verify(*hash).is_err() {
 			self.metrics.corruption_counter.add(1);
@@ -621,20 +607,20 @@ impl BlockManager {
 				// first and then a compressed one (as compression may have been
 				// previously enabled).
 				if fs::metadata(&path).await.is_ok() {
-					return Some(DataBlockPath::Plain(path));
+					return Some(DataBlockPath::plain(path));
 				}
 				path.set_extension("zst");
 				if fs::metadata(&path).await.is_ok() {
-					return Some(DataBlockPath::Compressed(path));
+					return Some(DataBlockPath::compressed(path));
 				}
 			} else {
 				path.set_extension("zst");
 				if fs::metadata(&path).await.is_ok() {
-					return Some(DataBlockPath::Compressed(path));
+					return Some(DataBlockPath::compressed(path));
 				}
 				path.set_extension("");
 				if fs::metadata(&path).await.is_ok() {
-					return Some(DataBlockPath::Plain(path));
+					return Some(DataBlockPath::plain(path));
 				}
 			}
 		}
@@ -704,8 +690,8 @@ impl BlockManagerLocked {
 		mgr: &BlockManager,
 		existing_path: Option<DataBlockPath>,
 	) -> Result<(), Error> {
-		let compressed = data.is_compressed();
-		let data = data.inner_buffer();
+		let (header, data) = data.as_parts_ref();
+		let compressed = header.is_compressed();
 
 		let directory = mgr.data_layout.load().primary_block_dir(hash);
 
@@ -715,24 +701,25 @@ impl BlockManagerLocked {
 			tgt_path.set_extension("zst");
 		}
 
-		let to_delete = match (existing_path, compressed) {
+		let existing_info = existing_path.map(|x| x.into_parts());
+		let to_delete = match (existing_info, compressed) {
 			// If the block is stored in the wrong directory,
 			// write it again at the correct path and delete the old path
-			(Some(DataBlockPath::Plain(p)), false) if p != tgt_path => Some(p),
-			(Some(DataBlockPath::Compressed(p)), true) if p != tgt_path => Some(p),
+			(Some((DataBlockHeader::Plain, p)), false) if p != tgt_path => Some(p),
+			(Some((DataBlockHeader::Compressed, p)), true) if p != tgt_path => Some(p),
 
 			// If the block is already stored not compressed but we have a compressed
 			// copy, write the compressed copy and delete the uncompressed one
-			(Some(DataBlockPath::Plain(plain_path)), true) => Some(plain_path),
+			(Some((DataBlockHeader::Plain, plain_path)), true) => Some(plain_path),
 
 			// If the block is already stored compressed,
 			// keep the stored copy, we have nothing to do
-			(Some(DataBlockPath::Compressed(_)), _) => return Ok(()),
+			(Some((DataBlockHeader::Compressed, _)), _) => return Ok(()),
 
 			// If the block is already stored not compressed,
 			// and we don't have a compressed copy either,
 			// keep the stored copy, we have nothing to do
-			(Some(DataBlockPath::Plain(_)), false) => return Ok(()),
+			(Some((DataBlockHeader::Plain, _)), false) => return Ok(()),
 
 			// If the block isn't stored already, just store what is given to us
 			(None, _) => None,
@@ -784,18 +771,14 @@ impl BlockManagerLocked {
 	}
 
 	async fn move_block_to_corrupted(&self, block_path: &DataBlockPath) -> Result<(), Error> {
-		let (path, path2) = match block_path {
-			DataBlockPath::Plain(p) => {
-				let mut p2 = p.clone();
-				p2.set_extension("corrupted");
-				(p, p2)
-			}
-			DataBlockPath::Compressed(p) => {
-				let mut p2 = p.clone();
-				p2.set_extension("zst.corrupted");
-				(p, p2)
-			}
-		};
+		let (header, path) = block_path.as_parts_ref();
+
+		let mut path2 = path.clone();
+		if header.is_compressed() {
+			path2.set_extension("zst.corrupted");
+		} else {
+			path2.set_extension("corrupted");
+		}
 
 		fs::rename(path, path2).await?;
 		Ok(())
@@ -805,9 +788,7 @@ impl BlockManagerLocked {
 		let rc = mgr.rc.get_block_rc(hash)?;
 		if rc.is_deletable() {
 			while let Some(path) = mgr.find_block(hash).await {
-				let path = match path {
-					DataBlockPath::Plain(p) | DataBlockPath::Compressed(p) => p,
-				};
+				let (_header, path) = path.as_parts_ref();
 				fs::remove_file(path).await?;
 				mgr.metrics.delete_counter.add(1);
 			}
@@ -824,24 +805,10 @@ impl BlockManagerLocked {
 		let data = mgr.read_block_from(hash, &wrong_path).await?;
 		self.write_block_inner(hash, &data, mgr, Some(wrong_path))
 			.await?;
-		Ok(data.inner_buffer().len())
+		Ok(data.as_parts_ref().1.len())
 	}
 }
 
-async fn read_stream_to_end(mut stream: ByteStream) -> Result<Bytes, Error> {
-	let mut parts: Vec<Bytes> = vec![];
-	while let Some(part) = stream.next().await {
-		parts.push(part.ok_or_message("error in stream")?);
-	}
-
-	Ok(parts
-		.iter()
-		.map(|x| &x[..])
-		.collect::<Vec<_>>()
-		.concat()
-		.into())
-}
-
 struct DeleteOnDrop(Option<PathBuf>);
 
 impl DeleteOnDrop {
diff --git a/src/block/repair.rs b/src/block/repair.rs
index 77ee0d14..2c8acbc9 100644
--- a/src/block/repair.rs
+++ b/src/block/repair.rs
@@ -584,8 +584,8 @@ impl Worker for RebalanceWorker {
 			let prim_loc = self.manager.data_layout.load().primary_block_dir(&hash);
 			if path.ancestors().all(|x| x != prim_loc) {
 				let block_path = match path.extension() {
-					None => DataBlockPath::Plain(path.clone()),
-					Some(x) if x.to_str() == Some("zst") => DataBlockPath::Compressed(path.clone()),
+					None => DataBlockPath::plain(path.clone()),
+					Some(x) if x.to_str() == Some("zst") => DataBlockPath::compressed(path.clone()),
 					_ => {
 						warn!("not rebalancing file: {}", path.to_string_lossy());
 						return Ok(WorkerState::Busy);
diff --git a/src/net/bytes_buf.rs b/src/net/bytes_buf.rs
index 3929a860..1d928ffb 100644
--- a/src/net/bytes_buf.rs
+++ b/src/net/bytes_buf.rs
@@ -3,6 +3,8 @@ use std::collections::VecDeque;
 
 use bytes::BytesMut;
 
+use crate::stream::ByteStream;
+
 pub use bytes::Bytes;
 
 /// A circular buffer of bytes, internally represented as a list of Bytes
@@ -119,6 +121,17 @@ impl BytesBuf {
 	pub fn into_slices(self) -> VecDeque<Bytes> {
 		self.buf
 	}
+
+	/// Return the entire buffer concatenated into a single big Bytes
+	pub fn into_bytes(mut self) -> Bytes {
+		self.take_all()
+	}
+
+	/// Return the content as a stream of individual chunks
+	pub fn into_stream(self) -> ByteStream {
+		use futures::stream::StreamExt;
+		Box::pin(futures::stream::iter(self.buf).map(|x| Ok(x)))
+	}
 }
 
 impl Default for BytesBuf {
diff --git a/src/net/stream.rs b/src/net/stream.rs
index 88c3fed4..3ac6896d 100644
--- a/src/net/stream.rs
+++ b/src/net/stream.rs
@@ -200,3 +200,14 @@ pub fn asyncread_stream<R: AsyncRead + Send + Sync + 'static>(reader: R) -> Byte
 pub fn stream_asyncread(stream: ByteStream) -> impl AsyncRead + Send + Sync + 'static {
 	tokio_util::io::StreamReader::new(stream)
 }
+
+/// Reads all of the content of a `ByteStream` into a BytesBuf
+/// that contains everything
+pub async fn read_stream_to_end(mut stream: ByteStream) -> Result<BytesBuf, std::io::Error> {
+	let mut buf = BytesBuf::new();
+	while let Some(part) = stream.next().await {
+		buf.extend(part?);
+	}
+
+	Ok(buf)
+}