Posibility to add Labels when pushing OCI Image (#1052)

* Posibility to add Labels when pushing OCI Image

Example running:
tart push $image ${registry}/org/${image}-testing --labels com.org.revision=testing --labels com.org.repo.buildid=123456

* Fix Linting

Run swift package plugin --allow-writing-to-package-directory swiftformat --cache ignore

* Update Sources/tart/Commands/Push.swift

Co-authored-by: Nikolay Edigaryev <edigaryev@gmail.com>

* Update Sources/tart/Commands/Push.swift

Co-authored-by: Nikolay Edigaryev <edigaryev@gmail.com>

* Update Sources/tart/Commands/Push.swift

Co-authored-by: Nikolay Edigaryev <edigaryev@gmail.com>

* Update Sources/tart/OCI/Manifest.swift

Co-authored-by: Nikolay Edigaryev <edigaryev@gmail.com>

* Update Sources/tart/Commands/Push.swift

Co-authored-by: Nikolay Edigaryev <edigaryev@gmail.com>

* Update Sources/tart/Commands/Push.swift

* Do not use a variable to store parseLabels() results

* Trim spaces before splitting labels and support empty values

---------

Co-authored-by: Victor Serbu <victors@4psa.com>
Co-authored-by: Nikolay Edigaryev <edigaryev@gmail.com>
Co-authored-by: Fedor Korotkov <fedor.korotkov@gmail.com>

Sources/tart/Commands/Push.swift

@@ -26,6 +26,11 @@ struct Push: AsyncParsableCommand {
                              """))
   var chunkSize: Int = 0
 
+
+  @Option(name: [.customLong("label")], help: ArgumentHelp("additional metadata to attach to the OCI image configuration in key=value format",
+                                                           discussion: "Can be specified multiple times to attach multiple labels."))
+  var labels: [String] = []
+
   @Option(help: .hidden)
   var diskFormat: String = "v2"
 
@@ -81,7 +86,8 @@ struct Push: AsyncParsableCommand {
           references: references,
           chunkSizeMb: chunkSize,
           diskFormat: diskFormat,
-          concurrency: concurrency
+          concurrency: concurrency,
+          labels: parseLabels()
         )
         // Populate the local cache (if requested)
         if populateCache {
@@ -115,6 +121,28 @@ struct Push: AsyncParsableCommand {
     return RemoteName(host: registry.host!, namespace: registry.namespace,
                       reference: Reference(digest: digest))
   }
+
+  // Helper method to convert labels array to dictionary
+  func parseLabels() -> [String: String] {
+    var result = [String: String]()
+
+    for label in labels {
+      let parts = label.trimmingCharacters(in: .whitespaces).split(separator: "=", maxSplits: 1, omittingEmptySubsequences: false)
+
+      let key = parts.count > 0 ? String(parts[0]) : ""
+      let value = parts.count > 1 ? String(parts[1]) : ""
+
+      // It sometimes makes sense to provide an empty value,
+      // but not an empty key
+      if key.isEmpty {
+        continue
+      }
+
+      result[key] = value
+    }
+
+    return result
+  }  
 }
 
 extension Collection where Element == RemoteName {

Sources/tart/OCI/Manifest.swift

@@ -66,6 +66,11 @@ struct OCIManifest: Codable, Equatable {
 struct OCIConfig: Codable {
   var architecture: Architecture = .arm64
   var os: OS = .darwin
+  var config: ConfigContainer?
+
+  struct ConfigContainer: Codable {
+    var Labels: [String: String]?
+  }
 
   func toJSON() throws -> Data {
     try Config.jsonEncoder().encode(self)

Sources/tart/VMDirectory+OCI.swift

@@ -87,7 +87,7 @@ extension VMDirectory {
     try manifest.toJSON().write(to: manifestURL)
   }
 
-  func pushToRegistry(registry: Registry, references: [String], chunkSizeMb: Int, diskFormat: String, concurrency: UInt) async throws -> RemoteName {
+  func pushToRegistry(registry: Registry, references: [String], chunkSizeMb: Int, diskFormat: String, concurrency: UInt, labels: [String: String] = [:]) async throws -> RemoteName {
     var layers = Array<OCIManifestLayer>()
 
     // Read VM's config and push it as blob
@@ -121,7 +121,8 @@ extension VMDirectory {
     layers.append(OCIManifestLayer(mediaType: nvramMediaType, size: nvram.count, digest: nvramDigest))
 
     // Craft a stub OCI config for Docker Hub compatibility
-    let ociConfigJSON = try OCIConfig(architecture: config.arch, os: config.os).toJSON()
+    let ociConfigContainer = OCIConfig.ConfigContainer(Labels: labels)
+    let ociConfigJSON = try OCIConfig(architecture: config.arch, os: config.os, config: ociConfigContainer).toJSON()
     let ociConfigDigest = try await registry.pushBlob(fromData: ociConfigJSON, chunkSizeMb: chunkSizeMb)
     let manifest = OCIManifest(
       config: OCIManifestConfig(size: ociConfigJSON.count, digest: ociConfigDigest),