From 92b64f6b9a9a6c94e872932ff63bcbb7d0dbce12 Mon Sep 17 00:00:00 2001
From: Ben Boeckel <ben.boeckel@kitware.com>
Date: Tue, 7 Jul 2026 12:54:01 -0400
Subject: [PATCH] fix(save): match tart push format exactly for skopeo
 compatibility

Use the same OCI manifest format and custom Cirrus Labs layer media
types (config.v1, disk.v2, nvram.v1) that tart push produces. skopeo
copy --format oci already works with images pushed by tart push, so the
archive now matches that format exactly.
---
 Sources/tart/OCI/Manifest.swift           |  3 --
 Sources/tart/OCI/OCIArchiveWriter.swift   |  2 +-
 Sources/tart/VMDirectory+OCIArchive.swift | 51 ++++++++---------------
 3 files changed, 19 insertions(+), 37 deletions(-)

diff --git a/Sources/tart/OCI/Manifest.swift b/Sources/tart/OCI/Manifest.swift
index 77a6bdd..c466435 100644
--- a/Sources/tart/OCI/Manifest.swift
+++ b/Sources/tart/OCI/Manifest.swift
@@ -8,9 +8,6 @@ let ociConfigMediaType = "application/vnd.oci.image.config.v1+json"
 let dockerManifestMediaType = "application/vnd.docker.distribution.manifest.v2+json"
 let dockerConfigMediaType = "application/vnd.docker.container.image.v1+json"
 
-// Standard OCI layer media type
-let ociLayerMediaType = "application/vnd.oci.image.layer.v1.tar+gzip"
-
 // Layer media types
 let configMediaType = "application/vnd.cirruslabs.tart.config.v1"
 let diskV2MediaType = "application/vnd.cirruslabs.tart.disk.v2"
diff --git a/Sources/tart/OCI/OCIArchiveWriter.swift b/Sources/tart/OCI/OCIArchiveWriter.swift
index 49ab36a..6c814d4 100644
--- a/Sources/tart/OCI/OCIArchiveWriter.swift
+++ b/Sources/tart/OCI/OCIArchiveWriter.swift
@@ -1,7 +1,7 @@
 import Foundation
 
 class OCIArchiveWriter {
-  let tmpDir: URL
+  private let tmpDir: URL
   private let blobsDir: URL
   private let lock: FileLock
   private var manifestDigest: String?
diff --git a/Sources/tart/VMDirectory+OCIArchive.swift b/Sources/tart/VMDirectory+OCIArchive.swift
index 6d3c63a..c336989 100644
--- a/Sources/tart/VMDirectory+OCIArchive.swift
+++ b/Sources/tart/VMDirectory+OCIArchive.swift
@@ -4,40 +4,27 @@ extension VMDirectory {
   func saveToArchive(path: String, concurrency: UInt, labels: [String: String] = [:], tag: String? = nil) async throws {
     let archive = try OCIArchiveWriter()
 
-    let diskSize = try FileManager.default.attributesOfItem(atPath: diskURL.path)[.size] as! Int64
-
-    // Create a standard tar+gzip layer containing VM files
-    defaultLogger.appendNewLine("archiving disk... this will take a while...")
-    let progress = Progress(totalUnitCount: diskSize)
-    ProgressObserver(progress).log(defaultLogger)
-
-    let layerTarGz = archive.tmpDir.appendingPathComponent("layer.tar.gz")
-
-    let tarProcess = Process()
-    tarProcess.executableURL = URL(fileURLWithPath: "/usr/bin/tar")
-    tarProcess.arguments = ["-czf", layerTarGz.path, "-C", baseURL.path,
-                            "disk.img", "nvram.bin", "config.json"]
-
-    let tarPipe = Pipe()
-    tarProcess.standardError = tarPipe
-
-    try tarProcess.run()
-    tarProcess.waitUntilExit()
-
-    if tarProcess.terminationStatus != 0 {
-      let errorData = tarPipe.fileHandleForReading.readDataToEndOfFile()
-      throw RuntimeError.Generic(
-        "creating archive layer failed: \(String(data: errorData, encoding: .utf8) ?? "unknown error")"
-      )
-    }
-
-    let layerData = try Data(contentsOf: layerTarGz, options: .alwaysMapped)
-    let layerDigest = try await archive.pushBlob(fromData: layerData, chunkSizeMb: 0, digest: nil)
-    progress.completedUnitCount = diskSize
+    var layers = [OCIManifestLayer]()
 
     let config = try VMConfig(fromURL: configURL)
     var labels = labels
     labels[diskFormatLabel] = config.diskFormat.rawValue
+    let configJSON = try JSONEncoder().encode(config)
+    defaultLogger.appendNewLine("saving config...")
+    let configDigest = try await archive.pushBlob(fromData: configJSON, chunkSizeMb: 0, digest: nil)
+    layers.append(OCIManifestLayer(mediaType: configMediaType, size: configJSON.count, digest: configDigest))
+
+    let diskSize = try FileManager.default.attributesOfItem(atPath: diskURL.path)[.size] as! Int64
+    defaultLogger.appendNewLine("saving disk... this will take a while...")
+    let progress = Progress(totalUnitCount: diskSize)
+    ProgressObserver(progress).log(defaultLogger)
+
+    layers.append(contentsOf: try await DiskV2.push(diskURL: diskURL, registry: archive, chunkSizeMb: 0, concurrency: concurrency, progress: progress))
+
+    defaultLogger.appendNewLine("saving NVRAM...")
+    let nvram = try FileHandle(forReadingFrom: nvramURL).readToEnd()!
+    let nvramDigest = try await archive.pushBlob(fromData: nvram, chunkSizeMb: 0, digest: nil)
+    layers.append(OCIManifestLayer(mediaType: nvramMediaType, size: nvram.count, digest: nvramDigest))
 
     let ociConfigContainer = OCIConfig.ConfigContainer(Labels: labels)
     let ociConfigJSON = try OCIConfig(architecture: config.arch, os: config.os, config: ociConfigContainer).toJSON()
@@ -45,9 +32,7 @@ extension VMDirectory {
 
     let manifest = OCIManifest(
       config: OCIManifestConfig(size: ociConfigJSON.count, digest: ociConfigDigest),
-      layers: [
-        OCIManifestLayer(mediaType: ociLayerMediaType, size: layerData.count, digest: layerDigest)
-      ],
+      layers: layers,
       uncompressedDiskSize: UInt64(diskSize),
       uploadDate: Date()
     )