[pbs-devel] [PATCH v3 proxmox-backup 20/58] client: backup: split payload to dedicated stream

[Christian Ebner <c.ebner@proxmox.com>]

This patch is in preparation for being able to quickly lookup
metadata for previous snapshots, by splitting the upload of
a pxar archive into two dedicated streams, one for metadata,
being assigned a .mpxar.didx suffix and one for payload
data, being assigned a .ppxar.didx suffix.

The patch constructs all the required duplicate chunk stream,
backup writer and upload stream instances required for the
split archive uploads.

This not only makes it possible reuse the payload chunks for
further backup runs but keeps the metadata archive small,
with the outlook of even making the currently used catalog
obsolete.

Signed-off-by: Christian Ebner <c.ebner@proxmox.com>
---
changes since version 2:
- pass optional combined writer struct
- s/backup_stream_payload/backup_payload_stream/
- use new mpxar and ppxar file extensions

 pbs-client/src/pxar/create.rs                 | 20 ++++-
 pbs-client/src/pxar_backup_stream.rs          | 49 ++++++++---
 proxmox-backup-client/src/main.rs             | 81 +++++++++++++++++--
 .../src/proxmox_restore_daemon/api.rs         |  2 +-
 pxar-bin/src/main.rs                          |  2 +-
 tests/catar.rs                                |  2 +-
 6 files changed, 129 insertions(+), 27 deletions(-)

diff --git a/pbs-client/src/pxar/create.rs b/pbs-client/src/pxar/create.rs
index 82f05889b..2bb5a6253 100644
--- a/pbs-client/src/pxar/create.rs
+++ b/pbs-client/src/pxar/create.rs
@@ -137,12 +137,21 @@ type Encoder<'a, T> = pxar::encoder::aio::Encoder<'a, T>;
 
 pub struct PxarWriters<T> {
     writer: T,
+    payload_writer: Option<T>,
     catalog: Option<Arc<Mutex<dyn BackupCatalogWriter + Send>>>,
 }
 
 impl<T> PxarWriters<T> {
-    pub fn new(writer: T, catalog: Option<Arc<Mutex<dyn BackupCatalogWriter + Send>>>) -> Self {
-        Self { writer, catalog }
+    pub fn new(
+        writer: T,
+        payload_writer: Option<T>,
+        catalog: Option<Arc<Mutex<dyn BackupCatalogWriter + Send>>>,
+    ) -> Self {
+        Self {
+            writer,
+            payload_writer,
+            catalog,
+        }
     }
 }
 
@@ -180,7 +189,12 @@ where
         set.insert(stat.st_dev);
     }
 
-    let mut encoder = Encoder::new(&mut writers.writer, &metadata, None).await?;
+    let mut encoder = Encoder::new(
+        &mut writers.writer,
+        &metadata,
+        writers.payload_writer.as_mut(),
+    )
+    .await?;
 
     let mut patterns = options.patterns;
 
diff --git a/pbs-client/src/pxar_backup_stream.rs b/pbs-client/src/pxar_backup_stream.rs
index bfa108a8b..95145cb0d 100644
--- a/pbs-client/src/pxar_backup_stream.rs
+++ b/pbs-client/src/pxar_backup_stream.rs
@@ -42,23 +42,37 @@ impl PxarBackupStream {
         dir: Dir,
         catalog: Arc<Mutex<CatalogWriter<W>>>,
         options: crate::pxar::PxarCreateOptions,
-    ) -> Result<Self, Error> {
-        let (tx, rx) = std::sync::mpsc::sync_channel(10);
-
+        separate_payload_stream: bool,
+    ) -> Result<(Self, Option<Self>), Error> {
         let buffer_size = 256 * 1024;
 
-        let error = Arc::new(Mutex::new(None));
-        let error2 = Arc::clone(&error);
-        let handler = async move {
-            let writer = TokioWriterAdapter::new(std::io::BufWriter::with_capacity(
+        let (tx, rx) = std::sync::mpsc::sync_channel(10);
+        let writer = TokioWriterAdapter::new(std::io::BufWriter::with_capacity(
+            buffer_size,
+            StdChannelWriter::new(tx),
+        ));
+        let writer = pxar::encoder::sync::StandardWriter::new(writer);
+
+        let (payload_writer, payload_rx) = if separate_payload_stream {
+            let (tx, rx) = std::sync::mpsc::sync_channel(10);
+            let payload_writer = TokioWriterAdapter::new(std::io::BufWriter::with_capacity(
                 buffer_size,
                 StdChannelWriter::new(tx),
             ));
+            (
+                Some(pxar::encoder::sync::StandardWriter::new(payload_writer)),
+                Some(rx),
+            )
+        } else {
+            (None, None)
+        };
 
-            let writer = pxar::encoder::sync::StandardWriter::new(writer);
+        let error = Arc::new(Mutex::new(None));
+        let error2 = Arc::clone(&error);
+        let handler = async move {
             if let Err(err) = crate::pxar::create_archive(
                 dir,
-                PxarWriters::new(writer, Some(catalog)),
+                PxarWriters::new(writer, payload_writer, Some(catalog)),
                 crate::pxar::Flags::DEFAULT,
                 move |path| {
                     log::debug!("{:?}", path);
@@ -77,21 +91,30 @@ impl PxarBackupStream {
         let future = Abortable::new(handler, registration);
         tokio::spawn(future);
 
-        Ok(Self {
+        let backup_stream = Self {
+            rx: Some(rx),
+            handle: Some(handle.clone()),
+            error: Arc::clone(&error),
+        };
+
+        let backup_payload_stream = payload_rx.map(|rx| Self {
             rx: Some(rx),
             handle: Some(handle),
             error,
-        })
+        });
+
+        Ok((backup_stream, backup_payload_stream))
     }
 
     pub fn open<W: Write + Send + 'static>(
         dirname: &Path,
         catalog: Arc<Mutex<CatalogWriter<W>>>,
         options: crate::pxar::PxarCreateOptions,
-    ) -> Result<Self, Error> {
+        separate_payload_stream: bool,
+    ) -> Result<(Self, Option<Self>), Error> {
         let dir = nix::dir::Dir::open(dirname, OFlag::O_DIRECTORY, Mode::empty())?;
 
-        Self::new(dir, catalog, options)
+        Self::new(dir, catalog, options, separate_payload_stream)
     }
 }
 
diff --git a/proxmox-backup-client/src/main.rs b/proxmox-backup-client/src/main.rs
index 931c841c7..dc6fe0e8d 100644
--- a/proxmox-backup-client/src/main.rs
+++ b/proxmox-backup-client/src/main.rs
@@ -187,18 +187,24 @@ async fn backup_directory<P: AsRef<Path>>(
     client: &BackupWriter,
     dir_path: P,
     archive_name: &str,
+    payload_target: Option<&str>,
     chunk_size: Option<usize>,
     catalog: Arc<Mutex<CatalogWriter<TokioWriterAdapter<StdChannelWriter<Error>>>>>,
     pxar_create_options: pbs_client::pxar::PxarCreateOptions,
     upload_options: UploadOptions,
-) -> Result<BackupStats, Error> {
+) -> Result<(BackupStats, Option<BackupStats>), Error> {
     if upload_options.fixed_size.is_some() {
         bail!("cannot backup directory with fixed chunk size!");
     }
 
-    let pxar_stream = PxarBackupStream::open(dir_path.as_ref(), catalog, pxar_create_options)?;
-    let mut chunk_stream = ChunkStream::new(pxar_stream, chunk_size);
+    let (pxar_stream, payload_stream) = PxarBackupStream::open(
+        dir_path.as_ref(),
+        catalog,
+        pxar_create_options,
+        payload_target.is_some(),
+    )?;
 
+    let mut chunk_stream = ChunkStream::new(pxar_stream, chunk_size);
     let (tx, rx) = mpsc::channel(10); // allow to buffer 10 chunks
 
     let stream = ReceiverStream::new(rx).map_err(Error::from);
@@ -210,12 +216,43 @@ async fn backup_directory<P: AsRef<Path>>(
         }
     });
 
+    let stats = client.upload_stream(archive_name, stream, upload_options.clone());
 
-    let stats = client
-        .upload_stream(archive_name, stream, upload_options)
-        .await?;
+    if let Some(payload_stream) = payload_stream {
+        let payload_target = payload_target
+            .ok_or_else(|| format_err!("got payload stream, but no target archive name"))?;
 
-    Ok(stats)
+        let mut payload_chunk_stream = ChunkStream::new(
+            payload_stream,
+            chunk_size,
+        );
+        let (payload_tx, payload_rx) = mpsc::channel(10); // allow to buffer 10 chunks
+        let stream = ReceiverStream::new(payload_rx).map_err(Error::from);
+
+        // spawn payload chunker inside a separate task so that it can run parallel
+        tokio::spawn(async move {
+            while let Some(v) = payload_chunk_stream.next().await {
+                let _ = payload_tx.send(v).await;
+            }
+        });
+
+        let payload_stats = client.upload_stream(
+            &payload_target,
+            stream,
+            upload_options,
+        );
+
+        match futures::join!(stats, payload_stats) {
+            (Ok(stats), Ok(payload_stats)) => Ok((stats, Some(payload_stats))),
+            (Err(err), Ok(_)) => Err(format_err!("upload failed: {err}")),
+            (Ok(_), Err(err)) => Err(format_err!("upload failed: {err}")),
+            (Err(err), Err(payload_err)) => {
+                Err(format_err!("upload failed: {err} - {payload_err}"))
+            }
+        }
+    } else {
+        Ok((stats.await?, None))
+    }
 }
 
 async fn backup_image<P: AsRef<Path>>(
@@ -986,6 +1023,23 @@ async fn create_backup(
                 manifest.add_file(target, stats.size, stats.csum, crypto.mode)?;
             }
             (BackupSpecificationType::PXAR, false) => {
+                let metadata_mode = false; // Until enabled via param
+
+                let target_base = if let Some(base) = target_base.strip_suffix(".pxar") {
+                    base.to_string()
+                } else {
+                    bail!("unexpected suffix in target: {target_base}");
+                };
+
+                let (target, payload_target) = if metadata_mode {
+                    (
+                        format!("{target_base}.mpxar.{extension}"),
+                        Some(format!("{target_base}.ppxar.{extension}")),
+                    )
+                } else {
+                    (target, None)
+                };
+
                 // start catalog upload on first use
                 if catalog.is_none() {
                     let catalog_upload_res =
@@ -1016,16 +1070,27 @@ async fn create_backup(
                     ..UploadOptions::default()
                 };
 
-                let stats = backup_directory(
+                let (stats, payload_stats) = backup_directory(
                     &client,
                     &filename,
                     &target,
+                    payload_target.as_deref(),
                     chunk_size_opt,
                     catalog.clone(),
                     pxar_options,
                     upload_options,
                 )
                 .await?;
+
+                if let Some(payload_stats) = payload_stats {
+                    manifest.add_file(
+                        payload_target
+                            .ok_or_else(|| format_err!("missing payload target archive"))?,
+                        payload_stats.size,
+                        payload_stats.csum,
+                        crypto.mode,
+                    )?;
+                }
                 manifest.add_file(target, stats.size, stats.csum, crypto.mode)?;
                 catalog.lock().unwrap().end_directory()?;
             }
diff --git a/proxmox-restore-daemon/src/proxmox_restore_daemon/api.rs b/proxmox-restore-daemon/src/proxmox_restore_daemon/api.rs
index 4e63978b7..ea97976e6 100644
--- a/proxmox-restore-daemon/src/proxmox_restore_daemon/api.rs
+++ b/proxmox-restore-daemon/src/proxmox_restore_daemon/api.rs
@@ -360,7 +360,7 @@ fn extract(
                     let pxar_writer = TokioWriter::new(writer);
                     create_archive(
                         dir,
-                        PxarWriters::new(pxar_writer, None),
+                        PxarWriters::new(pxar_writer, None, None),
                         Flags::DEFAULT,
                         |_| Ok(()),
                         options,
diff --git a/pxar-bin/src/main.rs b/pxar-bin/src/main.rs
index 7083a4b82..6c13c3b17 100644
--- a/pxar-bin/src/main.rs
+++ b/pxar-bin/src/main.rs
@@ -377,7 +377,7 @@ async fn create_archive(
     let writer = pxar::encoder::sync::StandardWriter::new(writer);
     pbs_client::pxar::create_archive(
         dir,
-        PxarWriters::new(writer, None),
+        PxarWriters::new(writer, None, None),
         feature_flags,
         move |path| {
             log::debug!("{:?}", path);
diff --git a/tests/catar.rs b/tests/catar.rs
index f414da8c9..9e96a8610 100644
--- a/tests/catar.rs
+++ b/tests/catar.rs
@@ -35,7 +35,7 @@ fn run_test(dir_name: &str) -> Result<(), Error> {
     let rt = tokio::runtime::Runtime::new().unwrap();
     rt.block_on(create_archive(
         dir,
-        PxarWriters::new(writer, None),
+        PxarWriters::new(writer, None, None),
         Flags::DEFAULT,
         |_| Ok(()),
         options,
-- 
2.39.2