Merge branch 'xline-kv:master' into refactor-config

crates/curp/src/server/storage/wal/mod.rs

@@ -6,5 +6,8 @@ mod codec;
 /// WAL errors
 mod error;
 
+/// File pipeline
+mod pipeline;
+
 /// File utils
 mod util;

crates/curp/src/server/storage/wal/pipeline.rs

@@ -0,0 +1,186 @@
+use std::{
+    io,
+    path::{Path, PathBuf},
+    sync::{
+        atomic::{AtomicBool, Ordering},
+        Arc,
+    },
+    task::Poll,
+};
+
+use clippy_utilities::OverflowArithmetic;
+use event_listener::Event;
+use flume::r#async::RecvStream;
+use futures::{FutureExt, StreamExt};
+use thiserror::Error;
+use tokio::task::JoinHandle;
+use tokio_stream::Stream;
+use tracing::error;
+
+use super::util::LockedFile;
+
+/// The temp file extension
+const TEMP_FILE_EXT: &str = ".tmp";
+
+/// The file pipeline, used for pipelining the creation of temp file
+pub(super) struct FilePipeline {
+    /// The directory where the temp files are created
+    dir: PathBuf,
+    /// The size of the temp file
+    file_size: u64,
+    /// The file receive stream
+    file_stream: RecvStream<'static, LockedFile>,
+    /// Stopped flag
+    stopped: Arc<AtomicBool>,
+}
+
+impl FilePipeline {
+    /// Creates a new `FilePipeline`
+    pub(super) fn new(dir: PathBuf, file_size: u64) -> io::Result<Self> {
+        Self::clean_up(&dir)?;
+
+        let (file_tx, file_rx) = flume::bounded(1);
+        let dir_c = dir.clone();
+        let stopped = Arc::new(AtomicBool::new(false));
+        let stopped_c = Arc::clone(&stopped);
+
+        #[cfg(not(madsim))]
+        let _ignore = std::thread::spawn(move || {
+            let mut file_count = 0;
+            loop {
+                match Self::alloc(&dir_c, file_size, &mut file_count) {
+                    Ok(file) => {
+                        if file_tx.send(file).is_err() {
+                            // The receiver is already dropped, stop this task
+                            break;
+                        }
+                        if stopped_c.load(Ordering::Relaxed) {
+                            if let Err(e) = Self::clean_up(&dir_c) {
+                                error!("failed to clean up pipeline temp files: {e}");
+                            }
+                            break;
+                        }
+                    }
+                    Err(e) => {
+                        error!("failed to allocate file: {e}");
+                        break;
+                    }
+                }
+            }
+        });
+
+        #[cfg(madsim)]
+        let _ignore = tokio::spawn(async move {
+            let mut file_count = 0;
+            loop {
+                match Self::alloc(&dir_c, file_size, &mut file_count) {
+                    Ok(file) => {
+                        if file_tx.send_async(file).await.is_err() {
+                            // The receiver is already dropped, stop this task
+                            break;
+                        }
+                        if stopped_c.load(Ordering::Relaxed) {
+                            if let Err(e) = Self::clean_up(&dir_c) {
+                                error!("failed to clean up pipeline temp files: {e}");
+                            }
+                            break;
+                        }
+                    }
+                    Err(e) => {
+                        error!("failed to allocate file: {e}");
+                        break;
+                    }
+                }
+            }
+        });
+
+        Ok(Self {
+            dir,
+            file_size,
+            file_stream: file_rx.into_stream(),
+            stopped,
+        })
+    }
+
+    /// Stops the pipeline
+    pub(super) fn stop(&mut self) {
+        self.stopped.store(true, Ordering::Relaxed);
+    }
+
+    /// Allocates a a new tempfile
+    fn alloc(dir: &PathBuf, file_size: u64, file_count: &mut usize) -> io::Result<LockedFile> {
+        let fpath = PathBuf::from(dir).join(format!("{file_count}{TEMP_FILE_EXT}"));
+        let mut file = LockedFile::open_rw(fpath)?;
+        file.preallocate(file_size)?;
+        *file_count = file_count.wrapping_add(1);
+        Ok(file)
+    }
+
+    /// Cleans up all unused tempfiles
+    fn clean_up(dir: &PathBuf) -> io::Result<()> {
+        for result in std::fs::read_dir(dir)? {
+            let file = result?;
+            if let Some(filename) = file.file_name().to_str() {
+                if filename.ends_with(TEMP_FILE_EXT) {
+                    std::fs::remove_file(file.path())?;
+                }
+            }
+        }
+        Ok(())
+    }
+}
+
+impl Drop for FilePipeline {
+    fn drop(&mut self) {
+        self.stop();
+    }
+}
+
+impl Stream for FilePipeline {
+    type Item = io::Result<LockedFile>;
+
+    fn poll_next(
+        mut self: std::pin::Pin<&mut Self>,
+        cx: &mut std::task::Context<'_>,
+    ) -> Poll<Option<Self::Item>> {
+        if self.stopped.load(Ordering::Relaxed) {
+            return Poll::Ready(None);
+        }
+
+        self.file_stream.poll_next_unpin(cx).map(|opt| opt.map(Ok))
+    }
+}
+
+impl std::fmt::Debug for FilePipeline {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("FilePipeline")
+            .field("dir", &self.dir)
+            .field("file_size", &self.file_size)
+            .finish()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::server::storage::wal::util::get_file_paths_with_ext;
+
+    use super::*;
+
+    #[tokio::test]
+    async fn file_pipeline_is_ok() {
+        let file_size = 1024;
+        let dir = tempfile::tempdir().unwrap();
+        let mut pipeline = FilePipeline::new(dir.as_ref().into(), file_size).unwrap();
+
+        let check_size = |mut file: LockedFile| {
+            let file = file.into_std();
+            assert_eq!(file.metadata().unwrap().len(), file_size,);
+        };
+        let file0 = pipeline.next().await.unwrap().unwrap();
+        check_size(file0);
+        let file1 = pipeline.next().await.unwrap().unwrap();
+        check_size(file1);
+        pipeline.stop();
+        assert!(pipeline.next().await.is_none());
+    }
+}