Transfer: Registry: Enable plain HTTP

Currenlty transfer service doesn't handle plain HTTP connection.
This commit fixes this issue by propagating
`(core/remotes/docker/config).HostOptions.DefaultScheme` from client to the
transfer service.
This commit also fixes ctr to use this feature for "--plain-http" flag.

Signed-off-by: Kohei Tokunaga <[email protected]>

Author: ktock

api/next.pb.txt

@@ -7468,6 +7468,13 @@ file {
       type: TYPE_STRING
       json_name: "hostDir"
     }
+    field {
+      name: "default_scheme"
+      number: 4
+      label: LABEL_OPTIONAL
+      type: TYPE_STRING
+      json_name: "defaultScheme"
+    }
     nested_type {
       name: "HeadersEntry"
       field {

api/types/transfer/registry.pb.go

@@ -36,8 +36,9 @@ message RegistryResolver {
 	map<string, string> headers = 2;
 
 	string host_dir = 3;
+
+	string default_scheme = 4;
 	// Force skip verify
-	// Force HTTP
 	// CA callback? Client TLS callback?
 }
 

api/types/transfer/registry.proto

@@ -132,7 +132,11 @@ command. As part of this process, we do the following:
 				sopts = append(sopts, image.WithAllMetadata)
 			}
 
-			reg, err := registry.NewOCIRegistry(ctx, ref, registry.WithCredentials(ch), registry.WithHostDir(context.String("hosts-dir")))
+			opts := []registry.Opt{registry.WithCredentials(ch), registry.WithHostDir(context.String("hosts-dir"))}
+			if context.Bool("plain-http") {
+				opts = append(opts, registry.WithDefaultScheme("http"))
+			}
+			reg, err := registry.NewOCIRegistry(ctx, ref, opts...)
 			if err != nil {
 				return err
 			}

cmd/ctr/commands/images/pull.go

@@ -104,7 +104,11 @@ var pushCommand = &cli.Command{
 			if local == "" {
 				local = ref
 			}
-			reg, err := registry.NewOCIRegistry(ctx, ref, registry.WithCredentials(ch), registry.WithHostDir(context.String("hosts-dir")))
+			opts := []registry.Opt{registry.WithCredentials(ch), registry.WithHostDir(context.String("hosts-dir"))}
+			if context.Bool("plain-http") {
+				opts = append(opts, registry.WithDefaultScheme("http"))
+			}
+			reg, err := registry.NewOCIRegistry(ctx, ref, opts...)
 			if err != nil {
 				return err
 			}

cmd/ctr/commands/images/push.go

@@ -44,9 +44,10 @@ func init() {
 }
 
 type registryOpts struct {
-	headers http.Header
-	creds   CredentialHelper
-	hostDir string
+	headers       http.Header
+	creds         CredentialHelper
+	hostDir       string
+	defaultScheme string
 }
 
 // Opt sets registry-related configurations.
@@ -76,6 +77,14 @@ func WithHostDir(hostDir string) Opt {
 	}
 }
 
+// WithDefaultScheme specifies the default scheme for registry configuration
+func WithDefaultScheme(s string) Opt {
+	return func(o *registryOpts) error {
+		o.defaultScheme = s
+		return nil
+	}
+}
+
 // NewOCIRegistry initializes with hosts, authorizer callback, and headers
 func NewOCIRegistry(ctx context.Context, ref string, opts ...Opt) (*OCIRegistry, error) {
 	var ropts registryOpts
@@ -99,16 +108,20 @@ func NewOCIRegistry(ctx context.Context, ref string, opts ...Opt) (*OCIRegistry,
 			return c.Username, c.Secret, nil
 		}
 	}
+	if ropts.defaultScheme != "" {
+		hostOptions.DefaultScheme = ropts.defaultScheme
+	}
 	resolver := docker.NewResolver(docker.ResolverOptions{
 		Hosts:   config.ConfigureHosts(ctx, hostOptions),
 		Headers: ropts.headers,
 	})
 	return &OCIRegistry{
-		reference: ref,
-		headers:   ropts.headers,
-		creds:     ropts.creds,
-		resolver:  resolver,
-		hostDir:   ropts.hostDir,
+		reference:     ref,
+		headers:       ropts.headers,
+		creds:         ropts.creds,
+		resolver:      resolver,
+		hostDir:       ropts.hostDir,
+		defaultScheme: ropts.defaultScheme,
 	}, nil
 }
 
@@ -135,6 +148,8 @@ type OCIRegistry struct {
 
 	hostDir string
 
+	defaultScheme string
+
 	// This could be an interface which returns resolver?
 	// Resolver could also be a plug-able interface, to call out to a program to fetch?
 }
@@ -234,6 +249,7 @@ func (r *OCIRegistry) MarshalAny(ctx context.Context, sm streaming.StreamCreator
 		res.AuthStream = sid
 	}
 	res.HostDir = r.hostDir
+	res.DefaultScheme = r.defaultScheme
 	s := &transfertypes.OCIRegistry{
 		Reference: r.reference,
 		Resolver:  res,
@@ -253,6 +269,9 @@ func (r *OCIRegistry) UnmarshalAny(ctx context.Context, sm streaming.StreamGette
 		if s.Resolver.HostDir != "" {
 			hostOptions.HostDir = config.HostDirFromRoot(s.Resolver.HostDir)
 		}
+		if s.Resolver.DefaultScheme != "" {
+			hostOptions.DefaultScheme = s.Resolver.DefaultScheme
+		}
 		if sid := s.Resolver.AuthStream; sid != "" {
 			stream, err := sm.Get(ctx, sid)
 			if err != nil {