oras

ExampleCopyArtifactManifestRemoteToLocal gives an example of copying an artifact manifest from a remote repository into memory.

src, err := remote.NewRepository(fmt.Sprintf("%s/source", remoteHost))
if err != nil {
	panic(err)
}
dst := memory.New()
ctx := context.Background()

exampleDigest := "sha256:70c29a81e235dda5c2cebb8ec06eafd3cca346cbd91f15ac74cefd98681c5b3d"
descriptor, err := src.Resolve(ctx, exampleDigest)
if err != nil {
	panic(err)
}
err = oras.CopyGraph(ctx, src, dst, descriptor, oras.DefaultCopyGraphOptions)
if err != nil {
	panic(err)
}

// verify that the artifact manifest described by the descriptor exists in dst
contentExists, err := dst.Exists(ctx, descriptor)
if err != nil {
	panic(err)
}
fmt.Println(contentExists)

Output:

true

ExampleExtendedCopyArtifactAndReferrersRemoteToLocal gives an example of copying an artifact along with its referrers from a remote repository into memory.

src, err := remote.NewRepository(fmt.Sprintf("%s/source", remoteHost))
if err != nil {
	panic(err)
}
dst := memory.New()
ctx := context.Background()

tagName := "latest"
// ExtendedCopy will copy the artifact tagged by "latest" along with all of its
// referrers from src to dst.
desc, err := oras.ExtendedCopy(ctx, src, tagName, dst, tagName, oras.DefaultExtendedCopyOptions)
if err != nil {
	panic(err)
}

fmt.Println(desc.Digest)

Output:

sha256:f396bc4d300934a39ca28ab0d5ac8a3573336d7d63c654d783a68cd1e2057662

ExamplePullFilesFromRemoteRepository gives an example of pulling files from a remote repository to the local file system.

package main

import (
	"context"
	"fmt"

	oras "oras.land/oras-go/v2"
	"oras.land/oras-go/v2/content/file"
	"oras.land/oras-go/v2/registry/remote"
	"oras.land/oras-go/v2/registry/remote/auth"
	"oras.land/oras-go/v2/registry/remote/retry"
)

func main() {
	// 0. Create a file store
	fs, err := file.New("/tmp/")
	if err != nil {
		panic(err)
	}
	defer fs.Close()

	// 1. Connect to a remote repository
	ctx := context.Background()
	reg := "myregistry.example.com"
	repo, err := remote.NewRepository(reg + "/myrepo")
	if err != nil {
		panic(err)
	}
	// Note: The below code can be omitted if authentication is not required
	repo.Client = &auth.Client{
		Client: retry.DefaultClient,
		Cache:  auth.NewCache(),
		Credential: auth.StaticCredential(reg, auth.Credential{
			Username: "username",
			Password: "password",
		}),
	}

	// 2. Copy from the remote repository to the file store
	tag := "latest"
	manifestDescriptor, err := oras.Copy(ctx, repo, tag, fs, tag, oras.DefaultCopyOptions)
	if err != nil {
		panic(err)
	}
	fmt.Println("manifest descriptor:", manifestDescriptor)
}

Output:

ExamplePullImageFromRemoteRepository gives an example of pulling an image from a remote repository to an OCI Image layout folder.

package main

import (
	"context"
	"fmt"

	oras "oras.land/oras-go/v2"
	"oras.land/oras-go/v2/content/oci"
	"oras.land/oras-go/v2/registry/remote"
	"oras.land/oras-go/v2/registry/remote/auth"
	"oras.land/oras-go/v2/registry/remote/retry"
)

func main() {
	// 0. Create an OCI layout store
	store, err := oci.New("/tmp/oci-layout-root")
	if err != nil {
		panic(err)
	}

	// 1. Connect to a remote repository
	ctx := context.Background()
	reg := "myregistry.example.com"
	repo, err := remote.NewRepository(reg + "/myrepo")
	if err != nil {
		panic(err)
	}
	// Note: The below code can be omitted if authentication is not required
	repo.Client = &auth.Client{
		Client: retry.DefaultClient,
		Cache:  auth.NewCache(),
		Credential: auth.StaticCredential(reg, auth.Credential{
			Username: "username",
			Password: "password",
		}),
	}

	// 2. Copy from the remote repository to the OCI layout store
	tag := "latest"
	manifestDescriptor, err := oras.Copy(ctx, repo, tag, store, tag, oras.DefaultCopyOptions)
	if err != nil {
		panic(err)
	}
	fmt.Println("manifest descriptor:", manifestDescriptor)
}

Output:

ExamplePullImageUsingDockerCredentials gives an example of pulling an image from a remote repository to an OCI Image layout folder using Docker credentials.

package main

import (
	"context"
	"fmt"

	oras "oras.land/oras-go/v2"
	"oras.land/oras-go/v2/content/oci"
	"oras.land/oras-go/v2/registry/remote"
	"oras.land/oras-go/v2/registry/remote/auth"
	"oras.land/oras-go/v2/registry/remote/credentials"
	"oras.land/oras-go/v2/registry/remote/retry"
)

func main() {
	// 0. Create an OCI layout store
	store, err := oci.New("/tmp/oci-layout-root")
	if err != nil {
		panic(err)
	}

	// 1. Connect to a remote repository
	ctx := context.Background()
	reg := "docker.io"
	repo, err := remote.NewRepository(reg + "/user/my-repo")
	if err != nil {
		panic(err)
	}

	// prepare authentication using Docker credentials
	storeOpts := credentials.StoreOptions{}
	credStore, err := credentials.NewStoreFromDocker(storeOpts)
	if err != nil {
		panic(err)
	}
	repo.Client = &auth.Client{
		Client:     retry.DefaultClient,
		Cache:      auth.NewCache(),
		Credential: credentials.Credential(credStore), // Use the credentials store
	}

	// 2. Copy from the remote repository to the OCI layout store
	tag := "latest"
	manifestDescriptor, err := oras.Copy(ctx, repo, tag, store, tag, oras.DefaultCopyOptions)
	if err != nil {
		panic(err)
	}

	fmt.Println("manifest pulled:", manifestDescriptor.Digest, manifestDescriptor.MediaType)
}

Output:

ExamplePushFilesToRemoteRepository gives an example of pushing local files to a remote repository.

package main

import (
	"context"
	"fmt"

	v1 "github.com/opencontainers/image-spec/specs-go/v1"
	oras "oras.land/oras-go/v2"
	"oras.land/oras-go/v2/content/file"
	"oras.land/oras-go/v2/registry/remote"
	"oras.land/oras-go/v2/registry/remote/auth"
	"oras.land/oras-go/v2/registry/remote/retry"
)

func main() {
	// 0. Create a file store
	fs, err := file.New("/tmp/")
	if err != nil {
		panic(err)
	}
	defer fs.Close()
	ctx := context.Background()

	// 1. Add files to the file store
	mediaType := "application/vnd.test.file"
	fileNames := []string{"/tmp/myfile"}
	fileDescriptors := make([]v1.Descriptor, 0, len(fileNames))
	for _, name := range fileNames {
		fileDescriptor, err := fs.Add(ctx, name, mediaType, "")
		if err != nil {
			panic(err)
		}
		fileDescriptors = append(fileDescriptors, fileDescriptor)
		fmt.Printf("file descriptor for %s: %v\n", name, fileDescriptor)
	}

	// 2. Pack the files and tag the packed manifest
	artifactType := "application/vnd.test.artifact"
	opts := oras.PackManifestOptions{
		Layers: fileDescriptors,
	}
	manifestDescriptor, err := oras.PackManifest(ctx, fs, oras.PackManifestVersion1_1, artifactType, opts)
	if err != nil {
		panic(err)
	}
	fmt.Println("manifest descriptor:", manifestDescriptor)

	tag := "latest"
	if err = fs.Tag(ctx, manifestDescriptor, tag); err != nil {
		panic(err)
	}

	// 3. Connect to a remote repository
	reg := "myregistry.example.com"
	repo, err := remote.NewRepository(reg + "/myrepo")
	if err != nil {
		panic(err)
	}
	// Note: The below code can be omitted if authentication is not required
	repo.Client = &auth.Client{
		Client: retry.DefaultClient,
		Cache:  auth.NewCache(),
		Credential: auth.StaticCredential(reg, auth.Credential{
			Username: "username",
			Password: "password",
		}),
	}

	// 4. Copy from the file store to the remote repository
	_, err = oras.Copy(ctx, fs, tag, repo, tag, oras.DefaultCopyOptions)
	if err != nil {
		panic(err)
	}
}

Output: