compose/internal/oci/resolver.go

/*
   Copyright 2023 Docker Compose CLI 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 oci

import (
	"context"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"slices"
	"strings"

	"github.com/containerd/containerd/v2/core/remotes"
	"github.com/containerd/containerd/v2/core/remotes/docker"
	"github.com/containerd/containerd/v2/pkg/labels"
	"github.com/containerd/errdefs"
	"github.com/distribution/reference"
	"github.com/moby/buildkit/util/contentutil"
	spec "github.com/opencontainers/image-spec/specs-go/v1"

	"github.com/docker/compose/v5/internal/registry"
)

// NewResolver sets up an OCI Resolver using credentials to provide registry
// credentials. When transport is non-nil it is used as the HTTP
// transport for both registry calls and the authorizer's token fetches
// (e.g. to route both through Docker Desktop's PAC-aware proxy); nil falls
// back to containerd's default transport.
func NewResolver(credentials registry.AuthProvider, transport http.RoundTripper, insecureRegistries ...string) remotes.Resolver {
	authOpts := []docker.AuthorizerOpt{
		docker.WithAuthCreds(func(host string) (string, string, error) {
			host = registry.GetAuthConfigKey(host)
			auth, err := credentials.GetAuthConfig(host)
			if err != nil {
				return "", "", err
			}
			if auth.IdentityToken != "" {
				return "", auth.IdentityToken, nil
			}
			return auth.Username, auth.Password, nil
		}),
	}
	if transport != nil {
		authOpts = append(authOpts, docker.WithAuthClient(&http.Client{Transport: transport}))
	}
	opts := []docker.RegistryOpt{
		docker.WithAuthorizer(docker.NewDockerAuthorizer(authOpts...)),
		docker.WithPlainHTTP(func(domain string) (bool, error) {
			// Should be used for testing **only**
			return slices.Contains(insecureRegistries, domain), nil
		}),
	}
	if transport != nil {
		opts = append(opts, docker.WithClient(&http.Client{Transport: transport}))
	}
	return docker.NewResolver(docker.ResolverOptions{
		Hosts: docker.ConfigureDefaultRegistries(opts...),
	})
}

// Get retrieves a Named OCI resource and returns OCI Descriptor and Manifest
func Get(ctx context.Context, resolver remotes.Resolver, ref reference.Named) (spec.Descriptor, []byte, error) {
	_, descriptor, err := resolver.Resolve(ctx, ref.String())
	if err != nil {
		return spec.Descriptor{}, nil, err
	}

	fetcher, err := resolver.Fetcher(ctx, ref.String())
	if err != nil {
		return spec.Descriptor{}, nil, err
	}
	fetch, err := fetcher.Fetch(ctx, descriptor)
	if err != nil {
		return spec.Descriptor{}, nil, err
	}
	content, err := io.ReadAll(fetch)
	if err != nil {
		return spec.Descriptor{}, nil, err
	}
	return descriptor, content, nil
}

// GetBlob retrieves the content of a blob descriptor (e.g. an artifact layer)
// from the repository ref belongs to. Unlike Get it doesn't Resolve the
// digest, as the registry manifests endpoint only serves actual manifests;
// blob content must be fetched directly from the blobs endpoint.
func GetBlob(ctx context.Context, resolver remotes.Resolver, ref reference.Named, descriptor spec.Descriptor) ([]byte, error) {
	fetcher, err := resolver.Fetcher(ctx, ref.String())
	if err != nil {
		return nil, fmt.Errorf("creating fetcher for %s: %w", ref, err)
	}
	fetch, err := fetcher.Fetch(ctx, descriptor)
	if err != nil {
		return nil, fmt.Errorf("fetching blob %s: %w", descriptor.Digest, err)
	}
	defer func() { _ = fetch.Close() }()
	// bound the read by the declared size so a rogue registry can't cause
	// unbounded allocation; the extra byte detects oversized responses.
	content, err := io.ReadAll(io.LimitReader(fetch, descriptor.Size+1))
	if err != nil {
		return nil, fmt.Errorf("reading blob %s: %w", descriptor.Digest, err)
	}
	if int64(len(content)) != descriptor.Size {
		return nil, fmt.Errorf("blob %s size mismatch: expected %d bytes, got %d", descriptor.Digest, descriptor.Size, len(content))
	}
	// GetBlob bypasses containerd's content store, so integrity must be
	// checked here before callers write the bytes to disk.
	if err := descriptor.Digest.Validate(); err != nil {
		return nil, fmt.Errorf("invalid digest %s: %w", descriptor.Digest, err)
	}
	if actual := descriptor.Digest.Algorithm().FromBytes(content); actual != descriptor.Digest {
		return nil, fmt.Errorf("blob digest mismatch: expected %s, got %s", descriptor.Digest, actual)
	}
	return content, nil
}

func Copy(ctx context.Context, resolver remotes.Resolver, image reference.Named, named reference.Named) (spec.Descriptor, error) {
	src, desc, err := resolver.Resolve(ctx, image.String())
	if err != nil {
		return spec.Descriptor{}, err
	}
	if desc.Annotations == nil {
		desc.Annotations = make(map[string]string)
	}
	// set LabelDistributionSource so push will actually use a registry mount
	refspec := reference.TrimNamed(image).String()
	u, err := url.Parse("dummy://" + refspec)
	if err != nil {
		return spec.Descriptor{}, err
	}
	source, repo := u.Hostname(), strings.TrimPrefix(u.Path, "/")
	desc.Annotations[labels.LabelDistributionSource+"."+source] = repo

	p, err := resolver.Pusher(ctx, named.Name())
	if err != nil {
		return spec.Descriptor{}, err
	}
	f, err := resolver.Fetcher(ctx, src)
	if err != nil {
		return spec.Descriptor{}, err
	}

	err = contentutil.CopyChain(ctx,
		contentutil.FromPusher(p),
		contentutil.FromFetcher(f), desc)
	return desc, err
}

func Push(ctx context.Context, resolver remotes.Resolver, ref reference.Named, descriptor spec.Descriptor) error {
	pusher, err := resolver.Pusher(ctx, ref.String())
	if err != nil {
		return err
	}
	ctx = remotes.WithMediaTypeKeyPrefix(ctx, ComposeYAMLMediaType, "artifact-")
	ctx = remotes.WithMediaTypeKeyPrefix(ctx, ComposeEnvFileMediaType, "artifact-")
	ctx = remotes.WithMediaTypeKeyPrefix(ctx, ComposeEmptyConfigMediaType, "config-")
	ctx = remotes.WithMediaTypeKeyPrefix(ctx, spec.MediaTypeEmptyJSON, "config-")

	push, err := pusher.Push(ctx, descriptor)
	if errdefs.IsAlreadyExists(err) {
		return nil
	}
	if err != nil {
		return err
	}

	_, err = push.Write(descriptor.Data)
	if err != nil {
		// Close the writer on error since Commit won't be called
		_ = push.Close()
		return err
	}
	// Commit will close the writer
	return push.Commit(ctx, int64(len(descriptor.Data)), descriptor.Digest)
}