Display image size for multiarch container images (#23821)

Fixes #23771

Changes the display of different architectures for multiarch images to
show the image size:

![grafik](https://user-images.githubusercontent.com/1666336/228781477-cc76c4d1-4728-434f-8a27-fc008790d924.png)

models/migrations/migrations.go

@@ -477,6 +477,8 @@ var migrations = []Migration{
 	NewMigration("Add version column to action_runner table", v1_20.AddVersionToActionRunner),
 	// v249 -> v250
 	NewMigration("Improve Action table indices v3", v1_20.ImproveActionTableIndices),
+	// v250 -> v251
+	NewMigration("Change Container Metadata", v1_20.ChangeContainerMetadataMultiArch),
 }
 
 // GetCurrentDBVersion returns the current db version

models/migrations/v1_20/v250.go

@@ -0,0 +1,135 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package v1_20 //nolint
+
+import (
+	"strings"
+
+	"code.gitea.io/gitea/modules/json"
+
+	"xorm.io/xorm"
+)
+
+func ChangeContainerMetadataMultiArch(x *xorm.Engine) error {
+	sess := x.NewSession()
+	defer sess.Close()
+
+	if err := sess.Begin(); err != nil {
+		return err
+	}
+
+	type PackageVersion struct {
+		ID           int64  `xorm:"pk"`
+		MetadataJSON string `xorm:"metadata_json"`
+	}
+
+	type PackageBlob struct{}
+
+	// Get all relevant packages (manifest list images have a container.manifest.reference property)
+
+	var pvs []*PackageVersion
+	err := sess.
+		Table("package_version").
+		Select("id, metadata_json").
+		Where("id IN (SELECT DISTINCT ref_id FROM package_property WHERE ref_type = 0 AND name = 'container.manifest.reference')").
+		Find(&pvs)
+	if err != nil {
+		return err
+	}
+
+	type MetadataOld struct {
+		Type             string            `json:"type"`
+		IsTagged         bool              `json:"is_tagged"`
+		Platform         string            `json:"platform,omitempty"`
+		Description      string            `json:"description,omitempty"`
+		Authors          []string          `json:"authors,omitempty"`
+		Licenses         string            `json:"license,omitempty"`
+		ProjectURL       string            `json:"project_url,omitempty"`
+		RepositoryURL    string            `json:"repository_url,omitempty"`
+		DocumentationURL string            `json:"documentation_url,omitempty"`
+		Labels           map[string]string `json:"labels,omitempty"`
+		ImageLayers      []string          `json:"layer_creation,omitempty"`
+		MultiArch        map[string]string `json:"multiarch,omitempty"`
+	}
+
+	type Manifest struct {
+		Platform string `json:"platform"`
+		Digest   string `json:"digest"`
+		Size     int64  `json:"size"`
+	}
+
+	type MetadataNew struct {
+		Type             string            `json:"type"`
+		IsTagged         bool              `json:"is_tagged"`
+		Platform         string            `json:"platform,omitempty"`
+		Description      string            `json:"description,omitempty"`
+		Authors          []string          `json:"authors,omitempty"`
+		Licenses         string            `json:"license,omitempty"`
+		ProjectURL       string            `json:"project_url,omitempty"`
+		RepositoryURL    string            `json:"repository_url,omitempty"`
+		DocumentationURL string            `json:"documentation_url,omitempty"`
+		Labels           map[string]string `json:"labels,omitempty"`
+		ImageLayers      []string          `json:"layer_creation,omitempty"`
+		Manifests        []*Manifest       `json:"manifests,omitempty"`
+	}
+
+	for _, pv := range pvs {
+		var old *MetadataOld
+		if err := json.Unmarshal([]byte(pv.MetadataJSON), &old); err != nil {
+			return err
+		}
+
+		// Calculate the size of every contained manifest
+
+		manifests := make([]*Manifest, 0, len(old.MultiArch))
+		for platform, digest := range old.MultiArch {
+			size, err := sess.
+				Table("package_blob").
+				Join("INNER", "package_file", "package_blob.id = package_file.blob_id").
+				Join("INNER", "package_version pv", "pv.id = package_file.version_id").
+				Join("INNER", "package_version pv2", "pv2.package_id = pv.package_id").
+				Where("pv.lower_version = ? AND pv2.id = ?", strings.ToLower(digest), pv.ID).
+				SumInt(new(PackageBlob), "size")
+			if err != nil {
+				return err
+			}
+
+			manifests = append(manifests, &Manifest{
+				Platform: platform,
+				Digest:   digest,
+				Size:     size,
+			})
+		}
+
+		// Convert to new metadata format
+
+		new := &MetadataNew{
+			Type:             old.Type,
+			IsTagged:         old.IsTagged,
+			Platform:         old.Platform,
+			Description:      old.Description,
+			Authors:          old.Authors,
+			Licenses:         old.Licenses,
+			ProjectURL:       old.ProjectURL,
+			RepositoryURL:    old.RepositoryURL,
+			DocumentationURL: old.DocumentationURL,
+			Labels:           old.Labels,
+			ImageLayers:      old.ImageLayers,
+			Manifests:        manifests,
+		}
+
+		metadataJSON, err := json.Marshal(new)
+		if err != nil {
+			return err
+		}
+
+		pv.MetadataJSON = string(metadataJSON)
+
+		if _, err := sess.ID(pv.ID).Update(pv); err != nil {
+			return err
+		}
+	}
+
+	return sess.Commit()
+}