extract image index creation from DockerCli into ImageIndexGenerator

Author: Surayya Huseyn Zada

src/Containers/Microsoft.NET.Build.Containers/ImageIndexGenerator.cs

@@ -2,9 +2,8 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Text.Json;
-using System.Text.Json.Nodes;
+using System.Text.Json.Serialization;
 using Microsoft.NET.Build.Containers.Resources;
-using Microsoft.NET.Build.Containers.Tasks;
 
 namespace Microsoft.NET.Build.Containers;
 
@@ -43,48 +42,85 @@ internal static (string, string) GenerateImageIndex(BuiltImage[] images)
 
         if (manifestMediaType == SchemaTypes.DockerManifestV2)
         {
-            return GenerateImageIndex(images, SchemaTypes.DockerManifestV2, SchemaTypes.DockerManifestListV2);
+            return (GenerateImageIndex(images, SchemaTypes.DockerManifestV2, SchemaTypes.DockerManifestListV2), SchemaTypes.DockerManifestListV2);
         }
         else if (manifestMediaType == SchemaTypes.OciManifestV1)
         {
-            return GenerateImageIndex(images, SchemaTypes.OciManifestV1, SchemaTypes.OciImageIndexV1);
+            return (GenerateImageIndex(images, SchemaTypes.OciManifestV1, SchemaTypes.OciImageIndexV1), SchemaTypes.OciImageIndexV1);
         }
         else
         {
             throw new NotSupportedException(string.Format(Strings.UnsupportedMediaType, manifestMediaType));
         }
     }
 
-    private static (string, string) GenerateImageIndex(BuiltImage[] images, string manifestMediaType, string imageIndexMediaType)
+    internal static string GenerateImageIndex(BuiltImage[] images, string manifestMediaType, string imageIndexMediaType)
     {
         // Here we are using ManifestListV2 struct, but we could use ImageIndexV1 struct as well.
         // We are filling the same fields, so we can use the same struct.
         var manifests = new PlatformSpecificManifest[images.Length];
+        
         for (int i = 0; i < images.Length; i++)
         {
-            var image = images[i];
-
-            var manifest = new PlatformSpecificManifest
+            manifests[i] = new PlatformSpecificManifest
             {
                 mediaType = manifestMediaType,
-                size = image.Manifest.Length,
-                digest = image.ManifestDigest,
+                size = images[i].Manifest.Length,
+                digest = images[i].ManifestDigest,
                 platform = new PlatformInformation
                 {
-                    architecture = image.Architecture!,
-                    os = image.OS!
+                    architecture = images[i].Architecture!,
+                    os = images[i].OS!
                 }
             };
-            manifests[i] = manifest;
         }
 
-        var manifestList = new ManifestListV2
+        var imageIndex = new ManifestListV2
         {
             schemaVersion = 2,
             mediaType = imageIndexMediaType,
             manifests = manifests
         };
 
-        return (JsonSerializer.SerializeToNode(manifestList)?.ToJsonString() ?? "", manifestList.mediaType);
+        var options = new JsonSerializerOptions
+        {
+            DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
+        };
+        
+        return JsonSerializer.SerializeToNode(imageIndex, options)?.ToJsonString() ?? "";
+    }
+
+    internal static string GenerateImageIndexWithAnnotations(string manifestMediaType, string manifestDigest, long manifestSize, string repository, string[] tags)
+    {
+        var manifests = new PlatformSpecificOciManifest[tags.Length];
+        for (int i = 0; i < tags.Length; i++)
+        {
+            var tag = tags[i];
+            manifests[i] = new PlatformSpecificOciManifest
+            {
+                mediaType = manifestMediaType,
+                size = manifestSize,
+                digest = manifestDigest,
+                annotations = new Dictionary<string, string> 
+                {
+                    { "io.containerd.image.name", $"{repository}:{tag}" },
+                    { "org.opencontainers.image.ref.name", tag } 
+                }
+            };
+        }
+
+        var index = new ImageIndexV1
+        {
+            schemaVersion = 2,
+            mediaType = SchemaTypes.OciImageIndexV1,
+            manifests = manifests
+        };
+
+        var options = new JsonSerializerOptions
+        {
+            DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
+        };
+
+        return JsonSerializer.SerializeToNode(index, options)?.ToJsonString() ?? "";
     }
 }

src/Containers/Microsoft.NET.Build.Containers/LocalDaemons/DockerCli.cs

@@ -7,7 +7,6 @@
 #endif
 using System.Text.Json;
 using System.Text.Json.Nodes;
-using System.Text.Json.Serialization;
 using Microsoft.DotNet.Cli.Utils;
 using Microsoft.Extensions.Logging;
 using Microsoft.NET.Build.Containers.Resources;
@@ -461,35 +460,14 @@ private static async Task WriteIndexJsonForOciImage(
     {
         cancellationToken.ThrowIfCancellationRequested();
 
-        var manifests = new PlatformSpecificOciManifest[destinationReference.Tags.Length];
-        for (int i = 0; i < destinationReference.Tags.Length; i++)
-        {
-            var tag = destinationReference.Tags[i];
-            manifests[i] = new PlatformSpecificOciManifest
-            {
-                mediaType = SchemaTypes.OciManifestV1,
-                size = image.Manifest.Length,
-                digest = image.ManifestDigest,
-                annotations = new Dictionary<string, string> 
-                {
-                    { "io.containerd.image.name", $"{destinationReference.Repository}:{tag}" },
-                    { "org.opencontainers.image.ref.name", tag } 
-                }
-            };
-        }
+        string indexJson = ImageIndexGenerator.GenerateImageIndexWithAnnotations(
+            SchemaTypes.OciManifestV1,
+            image.ManifestDigest,
+            image.Manifest.Length,
+            destinationReference.Repository,
+            destinationReference.Tags);
 
-        var index = new ImageIndexV1
-        {
-            schemaVersion = 2,
-            mediaType = SchemaTypes.OciImageIndexV1,
-            manifests = manifests
-        };
-
-        var options = new JsonSerializerOptions
-        {
-            DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
-        };
-        using (MemoryStream indexStream = new(Encoding.UTF8.GetBytes(JsonSerializer.SerializeToNode(index, options)!.ToJsonString())))
+        using (MemoryStream indexStream = new(Encoding.UTF8.GetBytes(indexJson)))
         {
             PaxTarEntry indexEntry = new(TarEntryType.RegularFile, "index.json")
             {
@@ -548,31 +526,9 @@ private static async Task WriteIndexJsonForMultiArchOciImage(
         // 1. create manifest list for the blobs
         cancellationToken.ThrowIfCancellationRequested();
 
-        var manifests = new PlatformSpecificOciManifest[images.Length];
-        for (int i = 0; i < images.Length; i++)
-        {
-            var manifest = new PlatformSpecificOciManifest
-            {
-                mediaType = SchemaTypes.OciManifestV1,
-                size = images[i].Manifest.Length,
-                digest = images[i].ManifestDigest,
-                platform = new PlatformInformation { architecture = images[i].Architecture!, os = images[i].OS! }
-            };
-            manifests[i] = manifest;
-        }
+        // For multi-arch we publish only oci-formatted image tarballs.
+        string manifestListJson = ImageIndexGenerator.GenerateImageIndex(images, SchemaTypes.OciManifestV1, SchemaTypes.OciImageIndexV1);
 
-        var manifestList = new ImageIndexV1
-        {
-            schemaVersion = 2,
-            mediaType = SchemaTypes.OciImageIndexV1,
-            manifests = manifests
-        };
-
-        var options = new JsonSerializerOptions
-        {
-            DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
-        };
-        var manifestListJson = JsonSerializer.SerializeToNode(manifestList, options)!.ToJsonString();
         var manifestListDigest = DigestUtils.GetDigest(manifestListJson);
         var manifestListSha = DigestUtils.GetShaFromDigest(manifestListDigest);
         var manifestListPath = $"{_blobsPath}/{manifestListSha}";
@@ -586,34 +542,17 @@ private static async Task WriteIndexJsonForMultiArchOciImage(
             await writer.WriteEntryAsync(indexEntry, cancellationToken).ConfigureAwait(false);
         }
 
-        // 2. create index json that points to manifest list in the blobs
+        // 2. create index.json that points to manifest list in the blobs
         cancellationToken.ThrowIfCancellationRequested();
 
-        var manifestsIndexJson = new PlatformSpecificOciManifest[destinationReference.Tags.Length];
-        for (int i = 0; i < destinationReference.Tags.Length; i++)
-        {
-            var tag = destinationReference.Tags[i];
-            manifestsIndexJson[i] = new PlatformSpecificOciManifest
-            {
-                mediaType = SchemaTypes.OciImageIndexV1,
-                size = manifestListJson.Length,
-                digest = manifestListDigest,
-                annotations = new Dictionary<string, string> 
-                {
-                    { "io.containerd.image.name", $"{destinationReference.Repository}:{tag}" },
-                    { "org.opencontainers.image.ref.name", tag } 
-                }
-            };
-        }
-
-        var index = new ImageIndexV1
-        {
-            schemaVersion = 2,
-            mediaType = SchemaTypes.OciImageIndexV1,
-            manifests = manifestsIndexJson
-        };
+        string indexJson = ImageIndexGenerator.GenerateImageIndexWithAnnotations(
+            SchemaTypes.OciImageIndexV1, 
+            manifestListDigest, 
+            manifestListJson.Length, 
+            destinationReference.Repository, 
+            destinationReference.Tags);
 
-        using (MemoryStream indexStream = new(Encoding.UTF8.GetBytes(JsonSerializer.SerializeToNode(index, options)!.ToJsonString())))
+        using (MemoryStream indexStream = new(Encoding.UTF8.GetBytes(indexJson)))
         {
             PaxTarEntry indexEntry = new(TarEntryType.RegularFile, "index.json")
             {

src/Tests/Microsoft.NET.Build.Containers.UnitTests/ImageIndexGeneratorTests.cs

@@ -96,7 +96,7 @@ public void GenerateDockerManifestList()
         ];
 
         var (imageIndex, mediaType) = ImageIndexGenerator.GenerateImageIndex(images);
-        Assert.Equal("{\"schemaVersion\":2,\"mediaType\":\"application/vnd.docker.distribution.manifest.list.v2\\u002Bjson\",\"manifests\":[{\"mediaType\":\"application/vnd.docker.distribution.manifest.v2\\u002Bjson\",\"size\":3,\"digest\":\"sha256:digest1\",\"platform\":{\"architecture\":\"arch1\",\"os\":\"os1\",\"variant\":null,\"features\":null,\"os.version\":null}},{\"mediaType\":\"application/vnd.docker.distribution.manifest.v2\\u002Bjson\",\"size\":3,\"digest\":\"sha256:digest2\",\"platform\":{\"architecture\":\"arch2\",\"os\":\"os2\",\"variant\":null,\"features\":null,\"os.version\":null}}]}", imageIndex);
+        Assert.Equal("{\"schemaVersion\":2,\"mediaType\":\"application/vnd.docker.distribution.manifest.list.v2\\u002Bjson\",\"manifests\":[{\"mediaType\":\"application/vnd.docker.distribution.manifest.v2\\u002Bjson\",\"size\":3,\"digest\":\"sha256:digest1\",\"platform\":{\"architecture\":\"arch1\",\"os\":\"os1\"}},{\"mediaType\":\"application/vnd.docker.distribution.manifest.v2\\u002Bjson\",\"size\":3,\"digest\":\"sha256:digest2\",\"platform\":{\"architecture\":\"arch2\",\"os\":\"os2\"}}]}", imageIndex);
         Assert.Equal(SchemaTypes.DockerManifestListV2, mediaType);
     }
 
@@ -130,7 +130,7 @@ public void GenerateOciImageIndex()
         ];
 
         var (imageIndex, mediaType) = ImageIndexGenerator.GenerateImageIndex(images);
-        Assert.Equal("{\"schemaVersion\":2,\"mediaType\":\"application/vnd.oci.image.index.v1\\u002Bjson\",\"manifests\":[{\"mediaType\":\"application/vnd.oci.image.manifest.v1\\u002Bjson\",\"size\":3,\"digest\":\"sha256:digest1\",\"platform\":{\"architecture\":\"arch1\",\"os\":\"os1\",\"variant\":null,\"features\":null,\"os.version\":null}},{\"mediaType\":\"application/vnd.oci.image.manifest.v1\\u002Bjson\",\"size\":3,\"digest\":\"sha256:digest2\",\"platform\":{\"architecture\":\"arch2\",\"os\":\"os2\",\"variant\":null,\"features\":null,\"os.version\":null}}]}", imageIndex);
+        Assert.Equal("{\"schemaVersion\":2,\"mediaType\":\"application/vnd.oci.image.index.v1\\u002Bjson\",\"manifests\":[{\"mediaType\":\"application/vnd.oci.image.manifest.v1\\u002Bjson\",\"size\":3,\"digest\":\"sha256:digest1\",\"platform\":{\"architecture\":\"arch1\",\"os\":\"os1\"}},{\"mediaType\":\"application/vnd.oci.image.manifest.v1\\u002Bjson\",\"size\":3,\"digest\":\"sha256:digest2\",\"platform\":{\"architecture\":\"arch2\",\"os\":\"os2\"}}]}", imageIndex);
         Assert.Equal(SchemaTypes.OciImageIndexV1, mediaType);
     }
 }