Create config struct to take user input

Signed-off-by: Tony Fang <nhfang@amazon.com>

plugins/transfer/plugin.go

@@ -17,9 +17,14 @@
 package transfer
 
 import (
+	"fmt"
+
+	"github.com/containerd/containerd"
 	"github.com/containerd/containerd/leases"
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/pkg/transfer/local"
+	"github.com/containerd/containerd/pkg/unpack"
+	"github.com/containerd/containerd/platforms"
 	"github.com/containerd/containerd/plugin"
 
 	// Load packages with type registrations
@@ -36,9 +41,9 @@ func init() {
 			plugin.LeasePlugin,
 			plugin.MetadataPlugin,
 		},
-		Config: local.DefaultConfig(),
+		Config: defaultConfig(),
 		InitFn: func(ic *plugin.InitContext) (interface{}, error) {
-			config := ic.Config.(*local.TransferConfig)
+			config := ic.Config.(*transferConfig)
 			m, err := ic.Get(plugin.MetadataPlugin)
 			if err != nil {
 				return nil, err
@@ -49,7 +54,57 @@ func init() {
 				return nil, err
 			}
 
-			return local.NewTransferService(l.(leases.Manager), ms.ContentStore(), metadata.NewImageStore(ms), config), nil
+			// Set configuration based on default or user input
+			var lc local.TransferConfig
+			lc.MaxConcurrentDownloads = config.maxConcurrentDownloads
+			lc.MaxConcurrentUploadedLayers = config.maxConcurrentUploadedLayers
+			for _, uc := range config.unpackConfiguration {
+				p, err := platforms.Parse(uc.platform)
+				if err != nil {
+					return nil, fmt.Errorf("%s: platform configuration %v invalid", plugin.TransferPlugin, uc.platform)
+				}
+
+				up := unpack.Platform{
+					Platform:       platforms.OnlyStrict(p),
+					SnapshotterKey: uc.snapshotter,
+				}
+				lc.UnpackPlatforms = append(lc.UnpackPlatforms, up)
+			}
+			lc.RegistryConfigPath = config.registryConfigPath
+
+			return local.NewTransferService(l.(leases.Manager), ms.ContentStore(), metadata.NewImageStore(ms), &lc), nil
 		},
 	})
 }
+
+type transferConfig struct {
+	// maxConcurrentDownloads is the max concurrent content downloads for pull.
+	maxConcurrentDownloads int `toml:"max_concurrent_downloads"`
+
+	// maxConcurrentUploadedLayers is the max concurrent uploads for push
+	maxConcurrentUploadedLayers int `toml:"max_concurrent_uploaded_layers"`
+
+	// unpackConfiguration is used to read config from toml
+	unpackConfiguration []unpackConfiguration `toml:"unpack_config"`
+
+	// registryConfigPath is a path to the root directory containing registry-specific configurations
+	registryConfigPath string `toml:"config_path"`
+}
+
+type unpackConfiguration struct {
+	platform    string
+	snapshotter string
+}
+
+func defaultConfig() *transferConfig {
+	return &transferConfig{
+		maxConcurrentDownloads:      3,
+		maxConcurrentUploadedLayers: 3,
+		unpackConfiguration: []unpackConfiguration{
+			{
+				platform:    platforms.Format(platforms.DefaultSpec()),
+				snapshotter: containerd.DefaultSnapshotter,
+			},
+		},
+	}
+}