ocirender 0.2.1

Stream and merge OCI image layers into squashfs, tar, or directory output
Documentation 
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//! Tar file output sink for the OCI layer merge pipeline.
//!
//! Provides [`write_tar`] and [`write_tar_with_progress`], which write the
//! merged tar stream directly to a file. This is the simplest output sink:
//! unlike the squashfs sink there is no subprocess, and unlike the directory
//! sink there is no concurrent consumer — the merge engine writes directly to
//! the output file handle.

use anyhow::{Context, Result};
use std::{path::Path, sync::mpsc};

use crate::{PackerProgress, image::LayerBlob, overlay::merge_layers_into_streaming};

/// Stream the merged OCI layers into a plain tar file at `output`, emitting
/// progress events on `progress_tx` as each layer is processed.
///
/// On error the partially written output file is removed before returning, so
/// callers never observe a truncated tar.
pub fn write_tar_with_progress(
    receiver: mpsc::Receiver<Result<LayerBlob>>,
    total_layers: usize,
    output: &Path,
    progress_tx: Option<std::sync::mpsc::SyncSender<PackerProgress>>,
) -> Result<()> {
    let file = std::fs::File::create(output)
        .with_context(|| format!("creating tar output {}", output.display()))?;

    let result = merge_layers_into_streaming(receiver, total_layers, file, progress_tx.as_ref());

    if result.is_err() {
        let _ = std::fs::remove_file(output);
    }

    result
}

/// Stream the merged OCI layers into a plain tar file at `output`.
///
/// Convenience wrapper around [`write_tar_with_progress`] with no progress
/// channel. On error the partially written output file is removed before
/// returning.
pub fn write_tar(
    receiver: mpsc::Receiver<Result<LayerBlob>>,
    total_layers: usize,
    output: &Path,
) -> Result<()> {
    write_tar_with_progress(receiver, total_layers, output, None)
}