Initial commit for OCI dist spec v1.1.0 agent support

Partially addresses kubeflow/community#682

Signed-off-by: Ramkumar Chinchani <rchincha@cisco.com>

Makefile

@@ -126,6 +126,9 @@ deploy-ci: manifests
 deploy-helm: manifests
 	helm install kserve-crd charts/kserve-crd/ --wait --timeout 180s
 	helm install kserve charts/kserve-resources/ --wait --timeout 180s
+	# deploy a OCI dist spec v1.1.0 registry
+	helm repo add project-zot http://zotregistry.dev/helm-charts
+	helm install --set service.port=5000 zot project-zot/zot
 
 undeploy:
 	kubectl delete -k config/default

pkg/agent/storage/oci.go

@@ -0,0 +1,27 @@
+/*
+Copyright 2021 The KServe Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package storage
+
+import "net/http"
+
+type OCIProvider struct {
+	Client *http.Client
+}
+
+func (p *OCIProvider) DownloadModel(modelDir string, modelName string, storageUri string) error {
+	return nil
+}

pkg/agent/storage/provider.go

@@ -29,9 +29,11 @@ const (
 	//File  Protocol = "file://"
 	HTTPS Protocol = "https://"
 	HTTP  Protocol = "http://"
+	// OCI dist spec v1.1.0
+	OCI Protocol = "oci://"
 )
 
-var SupportedProtocols = []Protocol{S3, GCS, HTTPS, HTTP}
+var SupportedProtocols = []Protocol{S3, GCS, HTTPS, HTTP, OCI}
 
 func GetAllProtocol() (protocols []string) {
 	for _, protocol := range SupportedProtocols {

pkg/utils/utils_test.go

@@ -520,6 +520,7 @@ func TestIsPrefixSupported(t *testing.T) {
 		"GCS://",
 		"HTTP://",
 		"HTTPS://",
+		"OCI://",
 	}
 	scenarios := map[string]struct {
 		input    string