feat: configurable preference for relative access creation for uploader (#1412)

<!-- markdownlint-disable MD041 -->
#### What this PR does / why we need it

By default the OCI uploader used to handle the implicit OCI uploads for
OCI based OCM repositories
creates an absolute access method.

A new global attribute `preferrelativeaccess` (bool) can be used now to
switch this behavior
to prefer a relative access method.

With the new config object `local.oci.uploader.config.ocm.software` it
is possible to configure
host/port combinations for which the relative access should be
preferred. (For example `localhost`).

```
type: local.oci.uploader.config.ocm.software
preferRelativeAccess: true
repositories:
- localhost
- other:5000
```

#### Which issue(s) this PR fixes
Fixes #1410

---------

Signed-off-by: Gergely Brautigam <182850+Skarlso@users.noreply.github.com>
Co-authored-by: Jakob Möller <jakob.moeller@sap.com>
Co-authored-by: Gergely Brautigam <182850+Skarlso@users.noreply.github.com>

Author: 3 people

api/ocm/extensions/accessmethods/relativeociref/method.go

@@ -24,7 +24,7 @@ func init() {
 
 var _ accspeccpi.HintProvider = (*AccessSpec)(nil)
 
-// New creates a new localFilesystemBlob accessor.
+// New creates a new relativeOciReference accessor.
 func New(ref string) *AccessSpec {
 	return &AccessSpec{
 		ObjectVersionedType: runtime.NewVersionedObjectType(Type),
@@ -82,7 +82,15 @@ func (a *AccessSpec) GetOCIReference(cv accspeccpi.ComponentVersionAccess) (stri
 	defer m.Close()
 
 	if o, ok := accspeccpi.GetAccessMethodImplementation(m).(ociartifact.OCIArtifactReferenceProvider); ok {
-		return o.GetOCIReference(nil)
+		im, err := o.GetOCIReference(cv)
+		if err == nil {
+			spec := cv.Repository().GetSpecification().AsUniformSpec(cv.GetContext())
+			// not supported for fake repos
+			if spec.Host != "" {
+				im = spec.Host + "/" + im
+			}
+		}
+		return im, err
 	}
 	return "", nil
 }

api/ocm/extensions/attrs/preferrelativeattr/attr.go

@@ -0,0 +1,66 @@
+package preferrelativeattr
+
+import (
+	"fmt"
+
+	"ocm.software/ocm/api/datacontext"
+	"ocm.software/ocm/api/utils/runtime"
+)
+
+const (
+	ATTR_SHORT = "preferrelativeaccess"
+	ATTR_KEY   = "ocm.software/ocm/oci/" + ATTR_SHORT
+)
+
+func init() {
+	datacontext.RegisterAttributeType(ATTR_KEY, AttributeType{}, ATTR_SHORT)
+}
+
+type AttributeType struct{}
+
+func (a AttributeType) Name() string {
+	return ATTR_KEY
+}
+
+func (a AttributeType) Description() string {
+	return `
+*bool*
+If an artifact blob is uploaded to the technical repository
+used as OCM repository, the uploader should prefer to return
+a relative access method.
+`
+}
+
+func (a AttributeType) Encode(v interface{}, marshaller runtime.Marshaler) ([]byte, error) {
+	if _, ok := v.(bool); !ok {
+		return nil, fmt.Errorf("boolean required")
+	}
+	return marshaller.Marshal(v)
+}
+
+func (a AttributeType) Decode(data []byte, unmarshaller runtime.Unmarshaler) (interface{}, error) {
+	var value bool
+	err := unmarshaller.Unmarshal(data, &value)
+	return value, err
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+func Get(ctx datacontext.Context) bool {
+	a := ctx.GetAttributes().GetAttribute(ATTR_KEY)
+	if a == nil {
+		return false
+	}
+	return a.(bool)
+}
+
+func Set(ctx datacontext.Context, flag bool) error {
+	return ctx.GetAttributes().SetAttribute(ATTR_KEY, flag)
+}
+
+func ApplyTo(ctx datacontext.Context, flag *bool) bool {
+	if a := ctx.GetAttributes().GetAttribute(ATTR_KEY); a != nil {
+		*flag = a.(bool)
+	}
+	return *flag
+}

api/ocm/extensions/attrs/preferrelativeattr/attr_test.go

@@ -0,0 +1,41 @@
+package preferrelativeattr_test
+
+import (
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+
+	"ocm.software/ocm/api/config"
+	"ocm.software/ocm/api/credentials"
+	"ocm.software/ocm/api/datacontext"
+	"ocm.software/ocm/api/oci"
+	"ocm.software/ocm/api/ocm"
+	me "ocm.software/ocm/api/ocm/extensions/attrs/keepblobattr"
+	"ocm.software/ocm/api/utils/runtime"
+)
+
+var _ = Describe("attribute", func() {
+	var ctx ocm.Context
+	var cfgctx config.Context
+
+	BeforeEach(func() {
+		cfgctx = config.WithSharedAttributes(datacontext.New(nil)).New()
+		credctx := credentials.WithConfigs(cfgctx).New()
+		ocictx := oci.WithCredentials(credctx).New()
+		ctx = ocm.WithOCIRepositories(ocictx).New()
+	})
+	It("local setting", func() {
+		Expect(me.Get(ctx)).To(BeFalse())
+		Expect(me.Set(ctx, true)).To(Succeed())
+		Expect(me.Get(ctx)).To(BeTrue())
+	})
+
+	It("global setting", func() {
+		Expect(me.Get(cfgctx)).To(BeFalse())
+		Expect(me.Set(ctx, true)).To(Succeed())
+		Expect(me.Get(ctx)).To(BeTrue())
+	})
+
+	It("parses string", func() {
+		Expect(me.AttributeType{}.Decode([]byte("true"), runtime.DefaultJSONEncoding)).To(BeTrue())
+	})
+})

api/ocm/extensions/attrs/preferrelativeattr/suite_test.go

@@ -0,0 +1,13 @@
+package preferrelativeattr_test
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+func TestConfig(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "OCM Prefer Relative Access Attribute")
+}

api/ocm/extensions/blobhandler/handlers/oci/ocirepo/blobhandler.go

@@ -11,6 +11,7 @@ import (
 	"github.com/mandelsoft/goutils/sliceutils"
 	"github.com/opencontainers/go-digest"
 
+	cfgcpi "ocm.software/ocm/api/config/cpi"
 	"ocm.software/ocm/api/oci"
 	"ocm.software/ocm/api/oci/artdesc"
 	"ocm.software/ocm/api/oci/extensions/repositories/artifactset"
@@ -23,10 +24,13 @@ import (
 	"ocm.software/ocm/api/ocm/extensions/accessmethods/localociblob"
 	"ocm.software/ocm/api/ocm/extensions/accessmethods/ociartifact"
 	"ocm.software/ocm/api/ocm/extensions/accessmethods/ociblob"
+	"ocm.software/ocm/api/ocm/extensions/accessmethods/relativeociref"
 	"ocm.software/ocm/api/ocm/extensions/attrs/compatattr"
 	"ocm.software/ocm/api/ocm/extensions/attrs/keepblobattr"
 	"ocm.software/ocm/api/ocm/extensions/attrs/mapocirepoattr"
+	"ocm.software/ocm/api/ocm/extensions/attrs/preferrelativeattr"
 	storagecontext "ocm.software/ocm/api/ocm/extensions/blobhandler/handlers/oci"
+	"ocm.software/ocm/api/ocm/extensions/blobhandler/handlers/oci/ocirepo/config"
 	"ocm.software/ocm/api/utils/accessobj"
 	"ocm.software/ocm/api/utils/blobaccess/blobaccess"
 )
@@ -226,6 +230,15 @@ func (b *artifactHandler) StoreBlob(blob cpi.BlobAccess, artType, hint string, g
 
 	keep := keepblobattr.Get(ctx.GetContext())
 
+	opts := &config.UploadOptions{}
+	if err := cfgcpi.NewUpdater(ctx.GetContext().ConfigContext(), opts).Update(); err != nil {
+		return nil, err
+	}
+
+	// this attribute (only if set) overrides the enabling set in the
+	// config.
+	preferrelativeattr.ApplyTo(ctx.GetContext(), &opts.PreferRelativeAccess)
+
 	if m, ok := blob.(blobaccess.AnnotatedBlobAccess[accspeccpi.AccessMethodView]); ok {
 		// prepare for optimized point to point implementation
 		log.Debug("oci artifact handler with ocm access source",
@@ -340,6 +353,10 @@ func (b *artifactHandler) StoreBlob(blob cpi.BlobAccess, artType, hint string, g
 	if tag != "" {
 		tag = ":" + tag
 	}
+	if opts.PreferRelativeAccessFor(base) {
+		ref := namespace.GetNamespace() + tag + version
+		return relativeociref.New(ref), nil
+	}
 	ref := scheme + path.Join(base, namespace.GetNamespace()) + tag + version
 	return ociartifact.New(ref), nil
 }

api/ocm/extensions/blobhandler/handlers/oci/ocirepo/config/option.go

@@ -0,0 +1,49 @@
+package config
+
+import (
+	"net"
+)
+
+// UploadOptions is used to configure
+// the implicit OCI uploader for a local OCM repository.
+// It can be used to request the generation of relative
+// OCI access methods, generally or for dedicated targets.
+type UploadOptions struct {
+	// PreferRelativeAccess enables or disables the settings.
+	PreferRelativeAccess bool `json:"preferRelativeAccess,omitempty"`
+	// Repositories is list of repository specs, with or without port.
+	// If no filters are configured all repos are matched.
+	Repositories []string `json:"repositories,omitempty"`
+}
+
+// PreferRelativeAccessFor checks a repo spec for using
+// a relative access method instead of an absolute one.
+// It checks hostname and optionally a port name.
+// The most specific configuration wins.
+func (o *UploadOptions) PreferRelativeAccessFor(repo string) bool {
+	if len(o.Repositories) == 0 || !o.PreferRelativeAccess {
+		return o.PreferRelativeAccess
+	}
+
+	fallback := false
+
+	host, port, err := net.SplitHostPort(repo)
+	if err != nil {
+		host = repo
+	}
+	for _, r := range o.Repositories {
+		rhost, rport, err := net.SplitHostPort(r)
+		if err != nil {
+			rhost = r
+		}
+		if host == rhost {
+			if rport == "" {
+				fallback = true
+			}
+			if port == rport {
+				return true
+			}
+		}
+	}
+	return fallback
+}

api/ocm/extensions/blobhandler/handlers/oci/ocirepo/config/suite_test.go

@@ -0,0 +1,13 @@
+package config_test
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+func TestConfig(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "OCI Uploader forOCI OCM Repositories Test Suite")
+}

api/ocm/extensions/blobhandler/handlers/oci/ocirepo/config/type.go

@@ -0,0 +1,67 @@
+package config
+
+import (
+	"ocm.software/ocm/api/config"
+	cfgcpi "ocm.software/ocm/api/config/cpi"
+	"ocm.software/ocm/api/ocm/extensions/attrs/preferrelativeattr"
+	"ocm.software/ocm/api/utils/runtime"
+)
+
+const (
+	ConfigType   = "oci.uploader" + cfgcpi.OCM_CONFIG_TYPE_SUFFIX
+	ConfigTypeV1 = ConfigType + runtime.VersionSeparator + "v1"
+)
+
+func init() {
+	cfgcpi.RegisterConfigType(cfgcpi.NewConfigType[*Config](ConfigType, usage))
+	cfgcpi.RegisterConfigType(cfgcpi.NewConfigType[*Config](ConfigTypeV1))
+}
+
+// Config describes a memory based config interface.
+type Config struct {
+	runtime.ObjectVersionedType `json:",inline"`
+	UploadOptions
+}
+
+// New creates a new memory ConfigSpec.
+func New() *Config {
+	return &Config{
+		ObjectVersionedType: runtime.NewVersionedTypedObject(ConfigType),
+	}
+}
+
+func (a *Config) ApplyTo(ctx config.Context, target interface{}) error {
+	t, ok := target.(*UploadOptions)
+	if !ok {
+		return config.ErrNoContext(ConfigType)
+	}
+	t.Repositories = append(t.Repositories, a.Repositories...)
+	t.PreferRelativeAccess = a.PreferRelativeAccess
+	return nil
+}
+
+const usage = `
+WARNING: This is an experimental feature. Will be replaced with native local
+blob support in OCM in the future.
+
+The config type <code>` + ConfigType + `</code> can be used to set some
+configurations for the implicit OCI artifact upload for OCI based OCM repositories.
+
+<pre>
+    type: ` + ConfigType + `
+    preferRelativeAccess: true # use relative access methods for given target repositories.
+    repositories:
+	- localhost:5000
+</pre>
+
+If <code>preferRelativeAccess</code> is set to <code>true</code> the 
+OCI uploader for OCI based OCM repositories does not use the
+OCI repository to create absolute OCI access methods
+if the target repository is in the <code>repositories</code> list.
+Instead, a relative  <code>relativeOciReference</code> access method 
+is created.
+If this list is empty, all uploads are handled this way.
+
+If the global attribute <code>` + preferrelativeattr.ATTR_SHORT + `</code> 
+is configured, it overrides the <code>preferRelativeAccess</code> setting.
+`