feat: load model from oci image

vendor/oras.land/oras-go/v2/internal/registryutil/auth.go

@@ -0,0 +1,29 @@
+/*
+Copyright The ORAS 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 registryutil
+
+import (
+	"context"
+
+	"oras.land/oras-go/v2/registry"
+	"oras.land/oras-go/v2/registry/remote/auth"
+)
+
+// WithScopeHint adds a hinted scope to the context.
+func WithScopeHint(ctx context.Context, ref registry.Reference, actions ...string) context.Context {
+	scope := auth.ScopeRepository(ref.Repository, actions...)
+	return auth.AppendScopes(ctx, scope)
+}

vendor/oras.land/oras-go/v2/internal/registryutil/proxy.go

@@ -0,0 +1,102 @@
+/*
+Copyright The ORAS 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 registryutil
+
+import (
+	"context"
+	"io"
+	"sync"
+
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+	"oras.land/oras-go/v2/content"
+	"oras.land/oras-go/v2/internal/cas"
+	"oras.land/oras-go/v2/internal/ioutil"
+	"oras.land/oras-go/v2/registry"
+)
+
+// ReferenceStorage represents a CAS that supports registry.ReferenceFetcher.
+type ReferenceStorage interface {
+	content.ReadOnlyStorage
+	registry.ReferenceFetcher
+}
+
+// Proxy is a caching proxy dedicated for registry.ReferenceFetcher.
+// The first fetch call of a described content will read from the remote and
+// cache the fetched content.
+// The subsequent fetch call will read from the local cache.
+type Proxy struct {
+	registry.ReferenceFetcher
+	*cas.Proxy
+}
+
+// NewProxy creates a proxy for the `base` ReferenceStorage, using the `cache`
+// storage as the cache.
+func NewProxy(base ReferenceStorage, cache content.Storage) *Proxy {
+	return &Proxy{
+		ReferenceFetcher: base,
+		Proxy:            cas.NewProxy(base, cache),
+	}
+}
+
+// FetchReference fetches the content identified by the reference from the
+// remote and cache the fetched content.
+func (p *Proxy) FetchReference(ctx context.Context, reference string) (ocispec.Descriptor, io.ReadCloser, error) {
+	target, rc, err := p.ReferenceFetcher.FetchReference(ctx, reference)
+	if err != nil {
+		return ocispec.Descriptor{}, nil, err
+	}
+
+	// skip caching if the content already exists in cache
+	exists, err := p.Cache.Exists(ctx, target)
+	if err != nil {
+		return ocispec.Descriptor{}, nil, err
+	}
+	if exists {
+		return target, rc, nil
+	}
+
+	// cache content while reading
+	pr, pw := io.Pipe()
+	var wg sync.WaitGroup
+	wg.Add(1)
+	var pushErr error
+	go func() {
+		defer wg.Done()
+		pushErr = p.Cache.Push(ctx, target, pr)
+		if pushErr != nil {
+			pr.CloseWithError(pushErr)
+		}
+	}()
+	closer := ioutil.CloserFunc(func() error {
+		rcErr := rc.Close()
+		if err := pw.Close(); err != nil {
+			return err
+		}
+		wg.Wait()
+		if pushErr != nil {
+			return pushErr
+		}
+		return rcErr
+	})
+
+	return target, struct {
+		io.Reader
+		io.Closer
+	}{
+		Reader: io.TeeReader(rc, pw),
+		Closer: closer,
+	}, nil
+}