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 +1,107 @@
+/*
+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 (
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"path/filepath"
+	"strings"
+)
+
+type OCIProvider struct {
+	Client *http.Client
+}
+
+func (m *OCIProvider) DownloadModel(modelDir string, modelName string, storageUri string) error {
+	log.Info("Download model ", "modelName", modelName, "storageUri", storageUri, "modelDir", modelDir)
+	uri, err := url.Parse(storageUri)
+	if err != nil {
+		return fmt.Errorf("unable to parse storage uri: %w", err)
+	}
+	OCIDownloader := &OCIDownloader{
+		StorageUri: storageUri,
+		ModelDir:   modelDir,
+		ModelName:  modelName,
+		Uri:        uri,
+	}
+	if err := OCIDownloader.Download(*m.Client); err != nil {
+		return err
+	}
+	return nil
+}
+
+type OCIDownloader struct {
+	StorageUri string
+	ModelDir   string
+	ModelName  string
+	Uri        *url.URL
+}
+
+func (h *OCIDownloader) Download(client http.Client) error {
+	// Create request
+	req, err := http.NewRequest("GET", h.StorageUri, nil)
+	if err != nil {
+		return err
+	}
+
+	// Query request
+	resp, err := client.Do(req)
+	if err != nil {
+		return fmt.Errorf("failed to make a request: %w", err)
+	}
+
+	defer func(Body io.ReadCloser) {
+		closeErr := Body.Close()
+		if closeErr != nil {
+			log.Error(closeErr, "failed to close body")
+		}
+	}(resp.Body)
+	if resp.StatusCode != 200 {
+		return fmt.Errorf("URI: %s returned a %d response code", h.StorageUri, resp.StatusCode)
+	}
+
+	// Write content into file(s)
+	contentType := resp.Header.Get("Content-type")
+	fileDirectory := filepath.Join(h.ModelDir, h.ModelName)
+
+	if strings.Contains(contentType, "application/zip") {
+		if err := extractZipFiles(resp.Body, fileDirectory); err != nil {
+			return err
+		}
+	} else if strings.Contains(contentType, "application/x-tar") || strings.Contains(contentType, "application/x-gtar") ||
+		strings.Contains(contentType, "application/x-gzip") || strings.Contains(contentType, "application/gzip") {
+		if err := extractTarFiles(resp.Body, fileDirectory); err != nil {
+			return err
+		}
+	} else {
+		paths := strings.Split(h.Uri.Path, "/")
+		fileName := paths[len(paths)-1]
+		fileFullName := filepath.Join(fileDirectory, fileName)
+		file, err := createNewFile(fileFullName)
+		if err != nil {
+			return err
+		}
+		if _, err = io.Copy(file, resp.Body); err != nil {
+			return fmt.Errorf("unable to copy file content: %w", err)
+		}
+	}
+
+	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/agent/storage/utils.go

@@ -173,6 +173,11 @@ func GetProvider(providers map[Protocol]Provider, protocol Protocol) (Provider,
 		providers[HTTP] = &HTTPSProvider{
 			Client: httpsClient,
 		}
+	case OCI:
+		httpsClient := &http.Client{}
+		providers[OCI] = &OCIProvider{
+			Client: httpsClient,
+		}
 	}
 
 	return providers[protocol], nil

pkg/utils/utils_test.go

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