OCI: make sure annotations are sorted (#138)

Sources/tart/Config.swift

@@ -6,4 +6,16 @@ struct Config {
           .appendingPathComponent(".tart", isDirectory: true)
 
   public static let tartCacheDir: URL = tartHomeDir.appendingPathComponent("cache", isDirectory: true)
+
+  static func jsonEncoder() -> JSONEncoder {
+    let encoder = JSONEncoder()
+
+    encoder.outputFormatting = [.sortedKeys]
+
+    return encoder
+  }
+
+  static func jsonDecoder() -> JSONDecoder {
+    JSONDecoder()
+  }
 }

Sources/tart/OCI/Manifest.swift

@@ -24,8 +24,16 @@ struct OCIManifest: Codable, Equatable {
     }
   }
 
+  init(fromJSON: Data) throws {
+    self = try Config.jsonDecoder().decode(Self.self, from: fromJSON)
+  }
+
+  func toJSON() throws -> Data {
+    try Config.jsonEncoder().encode(self)
+  }
+
   func digest() throws -> String {
-    try Digest.hash(JSONEncoder().encode(self))
+    try Digest.hash(toJSON())
   }
 
   func uncompressedDiskSize() -> UInt64? {
@@ -37,6 +45,15 @@ struct OCIManifest: Codable, Equatable {
   }
 }
 
+struct OCIConfig: Codable {
+  var architecture: String = "arm64"
+  var os: String = "darwin"
+
+  func toJSON() throws -> Data {
+    try Config.jsonEncoder().encode(self)
+  }
+}
+
 struct OCIManifestConfig: Codable, Equatable {
   var mediaType: String = ociConfigMediaType
   var size: Int

Sources/tart/OCI/Registry.swift

@@ -34,7 +34,7 @@ struct TokenResponse: Decodable {
   var issuedAt: Date?
 
   static func parse(fromData: Data) throws -> Self {
-    let decoder = JSONDecoder()
+    let decoder = Config.jsonDecoder()
 
     decoder.keyDecodingStrategy = .convertFromSnakeCase
 
@@ -116,7 +116,7 @@ class Registry {
   }
 
   func pushManifest(reference: String, manifest: OCIManifest) async throws -> String {
-    let manifestJSON = try JSONEncoder().encode(manifest)
+    let manifestJSON = try manifest.toJSON()
 
     let response = try await endpointRequest(.PUT, "\(namespace)/manifests/\(reference)",
       headers: ["Content-Type": manifest.mediaType],
@@ -139,7 +139,7 @@ class Registry {
     }
 
     let manifestData = try await response.body.readResponse()
-    let manifest = try JSONDecoder().decode(OCIManifest.self, from: manifestData)
+    let manifest = try OCIManifest(fromJSON: manifestData)
 
     return (manifest, manifestData)
   }

Sources/tart/VMConfig.swift

@@ -59,12 +59,16 @@ struct VMConfig: Codable {
     memorySize = memorySizeMin
   }
 
-  init(fromData: Data) throws {
-    self = try JSONDecoder().decode(VMConfig.self, from: fromData)
+  init(fromJSON: Data) throws {
+    self = try Config.jsonDecoder().decode(Self.self, from: fromJSON)
   }
 
   init(fromURL: URL) throws {
-    self = try Self(fromData: try Data(contentsOf: fromURL))
+    self = try Self(fromJSON: try Data(contentsOf: fromURL))
+  }
+
+  func toJSON() throws -> Data {
+    try Config.jsonEncoder().encode(self)
   }
 
   func save(toURL: URL) throws {

Sources/tart/VMDirectory+OCI.swift

@@ -139,12 +139,7 @@ extension VMDirectory {
     layers.append(OCIManifestLayer(mediaType: Self.nvramMediaType, size: nvram.count, digest: nvramDigest))
 
     // Craft a stub OCI config for Docker Hub compatibility
-    struct OCIConfig: Codable {
-      var architecture: String = "arm64"
-      var os: String = "darwin"
-    }
-
-    let ociConfigJSON = try JSONEncoder().encode(OCIConfig())
+    let ociConfigJSON = try OCIConfig().toJSON()
     let ociConfigDigest = try await registry.pushBlob(fromData: ociConfigJSON)
     let manifest = OCIManifest(
             config: OCIManifestConfig(size: ociConfigJSON.count, digest: ociConfigDigest),

Tests/TartTests/RegistryTests.swift

@@ -62,11 +62,7 @@ final class RegistryTests: XCTestCase {
 
     func testPushPullManifest() async throws {
         // Craft a basic config
-        struct OCIConfig: Codable {
-            var architecture: String = "arm64"
-            var os: String = "darwin"
-        }
-        let configData = try JSONEncoder().encode(OCIConfig())
+        let configData = try OCIConfig().toJSON()
         let configDigest = try await registry.pushBlob(fromData: configData)
 
         // Craft a basic layer