### Install oras-go v2 Package

Source: https://github.com/oras-project/oras-go/blob/main/docs/tutorial/quickstart.md

Installs the oras-go v2 package and its dependencies using `go get`.

```console
$ go get oras.land/oras-go/v2
go: added github.com/opencontainers/go-digest v1.0.0
go: added github.com/opencontainers/image-spec v1.1.0
go: added golang.org/x/sync v0.6.0
go: added oras.land/oras-go/v2 v2.5.0
```

--------------------------------

### Graph Functions Example

Source: https://github.com/oras-project/oras-go/blob/main/docs/Modeling-Artifacts.md

Shows the expected results of Successors(), Predecessors(), and Referrers() functions on graph nodes.

```text
  Successors(m0) == [b0, b1, b2]
Predecessors(m0) == [m2, i0]
   Referrers(m0) == [m2]

  Successors(m2) == [m0, b0, b5]
Predecessors(m2) == []
   Referrers(m2) == []

  Successors(b0) == []
Predecessors(b0) == [m0, m2]
   Referrers(b0) == []
```

--------------------------------

### GraphStorage Interface Predecessors Example

Source: https://github.com/oras-project/oras-go/blob/main/docs/Targets.md

Demonstrates the functionality of the Predecessors function for the GraphStorage interface on a sample graph.

```text
Predecessors(b0) == [m0]
Predecessors(m0) == []
```

--------------------------------

### Graph Concepts Example

Source: https://github.com/oras-project/oras-go/blob/main/docs/Modeling-Artifacts.md

Illustrates a complex DAG integrating artifacts, their referrers, and indexes.

```mermaid
graph TD;

I0["Index i0"]--manifests-->M0
I0--manifests-->M1

M2["Manifest m2"]--config-->Blob0["Blob b0"]
M2--layers-->Blob5["Blob b5"]
M2--subject-->M0

M1["Manifest m1"]--config-->Blob3["Blob b3"]
M1--layers-->Blob4["Blob b4"]

M0["Manifest m0"]--config-->Blob0["Blob b0"]
M0--layers-->Blob1["Blob b1"]
M0--layers-->Blob2["Blob b2"]
```

--------------------------------

### Storage Interface Fetch and Exists Example

Source: https://github.com/oras-project/oras-go/blob/main/docs/Targets.md

Illustrates the expected outcomes of Fetch and Exists operations on a Storage interface for a given graph.

```text
Fetch(m0) == content_m0

Exists(b0) == true
Exists(b3) == false
```

--------------------------------

### Push Manifest to Repository with Tag

Source: https://github.com/oras-project/oras-go/blob/main/docs/tutorial/quickstart.md

Packs a manifest with specified layers and artifact type, then pushes it to the repository with the tag "quickstart". Requires the `oras.land/oras-go/v2` package.

```go
// 4. Push a manifest to the repository with the tag "quickstart"
packOpts := oras.PackManifestOptions{
	Layers: []ocispec.Descriptor{layerDescriptor},
}
artifactType := "application/vnd.example+type"
desc, err := oras.PackManifest(ctx, repo, oras.PackManifestVersion1_1, artifactType, packOpts)
if err != nil {
	panic(err)
}
tag := "quickstart"
err = repo.Tag(ctx, desc, tag)
if err != nil {
	panic(err)
}
fmt.Println("Pushed and tagged manifest")
```

--------------------------------

### OCI Image Manifest Descriptor Example

Source: https://github.com/oras-project/oras-go/blob/main/docs/Targets.md

An example of a descriptor for an OCI Image Manifest, including mediaType, size, and digest.

```json
{
  "mediaType": "application/vnd.oci.image.manifest.v1+json",
  "size": 7682,
  "digest": "sha256:5b0bcabd1ed22e9fb1310cf6c2dec7cdef19f0ad69efa1f392e94a4333501270"
}
```

--------------------------------

### Manifest Content Example

Source: https://github.com/oras-project/oras-go/blob/main/docs/Targets.md

An example of a manifest content that references blobs for a file and a directory, including their media types, digests, sizes, and annotations. The manifest itself is stored in memory.

```json
{
  "schemaVersion": 2,
  "mediaType": "application/vnd.oci.image.manifest.v1+json",
  "artifactType": "application/vnd.example",
  "config": {
    "mediaType": "application/vnd.oci.empty.v1+json",
    "digest": "sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a",
    "size": 2,
    "data": "e30="
  },
  "layers": [
    {
      "mediaType": "application/vnd.custom",
      "digest": "sha256:5891b5b522d5df086d0ff0b110fbd9d21bb4fc7163af34d08286a2e846f6be03",
      "size": 6,
      "annotations": {
        "org.opencontainers.image.title": "hello.txt"
      }
    },
    {
      "mediaType": "application/vnd.custom.tar+gzip",
      "digest": "sha256:b14fa80f5afd3822dce52a711566586c8f89e5dc211e4b0d2819f219b102fe7a",
      "size": 164,
      "annotations": {
        "io.deis.oras.content.digest": "sha256:9d418a0549e5bc45d195aacec889d30e520b9f2bd9feab57d57de6d9cdd66172",
        "io.deis.oras.content.unpack": "true",
        "org.opencontainers.image.title": "mydir"
      }
    }
  ],
  "annotations": {
    "org.opencontainers.image.created": "2025-03-07T08:34:23Z"
  }
}
```

--------------------------------

### Target Interface Resolve Example

Source: https://github.com/oras-project/oras-go/blob/main/docs/Targets.md

Shows the results of the Resolve function for a Target interface, including cases where tags exist and do not exist.

```text
Resolve("foo") == m0
Resolve("bar") == m0
Resolve("hello") == nil
```

--------------------------------

### Import ORAS Go v2 Package

Source: https://github.com/oras-project/oras-go/blob/main/MIGRATION_GUIDE.md

Import the v2 package into your Go project after installation.

```go
import "oras.land/oras-go/v2"
```

--------------------------------

### Copy Function Example: m0

Source: https://github.com/oras-project/oras-go/blob/main/docs/Modeling-Artifacts.md

Demonstrates the Copy function replicating the graph rooted by node m0, including m0 and its successors.

```mermaid
graph TD;

M0["Manifest m0"]--config-->Blob0["Blob b0"]
M0--layers-->Blob1["Blob b1"]
M0--layers-->Blob2["Blob b2"]
```

--------------------------------

### File Addition Descriptor Example

Source: https://github.com/oras-project/oras-go/blob/main/docs/Targets.md

Illustrates the descriptor generated when a single file is added to the file store. Includes the media type, digest, size, and an annotation for the original file name.

```json
{
  "mediaType": "application/vnd.custom",
  "digest": "sha256:5891b5b522d5df086d0ff0b110fbd9d21bb4fc7163af34d08286a2e846f6be03",
  "size": 6,
  "annotations": {
    "org.opencontainers.image.title": "hello.txt"
  }
}
```

--------------------------------

### Copy Function Example: b0

Source: https://github.com/oras-project/oras-go/blob/main/docs/Modeling-Artifacts.md

Shows the Copy function replicating only node b0 when it has no successors.

```mermaid
graph TD;

Blob0["Blob b0"]
```

--------------------------------

### OCI Index Manifest Example

Source: https://github.com/oras-project/oras-go/blob/main/docs/Modeling-Artifacts.md

Shows an OCI Index manifest, which is used to group multiple manifests together. Each entry in the 'manifests' array points to a specific artifact manifest.

```json
{
  "schemaVersion": 2,
  "mediaType": "application/vnd.oci.image.index.v1+json",
  "manifests": [
    {
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "digest": "sha256:314c7f20dd44ee1cca06af399a67f7c463a9f586830d630802d9e365933da9fb",
      "size": 762
    },
    {
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "digest": "sha256:eba50b7b7dfdf6294a375a3376b2b74e3b926c75119f7da04b1c671c7de662c9",
      "size": 588
    }
  ]
}
```

--------------------------------

### Get ORAS Go v2 Package

Source: https://github.com/oras-project/oras-go/blob/main/MIGRATION_GUIDE.md

Use this command to fetch the v2 package of the ORAS Go library.

```sh
go get oras.land/oras-go/v2
```

--------------------------------

### Directory Addition Descriptor Example

Source: https://github.com/oras-project/oras-go/blob/main/docs/Targets.md

Shows the descriptor for a directory added to the file store, which is tar-archived and compressed. It includes annotations for the original directory name, the digest of the tar'ed content, and a flag indicating it needs unpacking.

```json
{
  "mediaType": "application/vnd.custom.tar+gzip",
  "digest": "sha256:b14fa80f5afd3822dce52a711566586c8f89e5dc211e4b0d2819f219b102fe7a",
  "size": 164,
  "annotations": {
    "io.deis.oras.content.digest": "sha256:9d418a0549e5bc45d195aacec889d30e520b9f2bd9feab57d57de6d9cdd66172",
    "io.deis.oras.content.unpack": "true",
    "org.opencontainers.image.title": "mydir"
  }
}
```

--------------------------------

### Parse Fetched Manifest and Get Layers

Source: https://github.com/oras-project/oras-go/blob/main/docs/tutorial/quickstart.md

Parses the fetched manifest content using `encoding/json` and retrieves layer content using `content.FetchAll`. Requires `encoding/json` and `oras.land/oras-go/v2/content` imports.

```go
// 6. Parse the fetched manifest content and get the layers
var manifest ocispec.Manifest
if err := json.Unmarshal(fetchedManifestContent, &manifest); err != nil {
	panic(err)
}
for _, layer := range manifest.Layers {
	layerContent, err := content.FetchAll(ctx, repo, layer)
	if err != nil {
		panic(err)
	}
	fmt.Println(string(layerContent))
}
```

--------------------------------

### Content Store Decision Tree

Source: https://github.com/oras-project/oras-go/blob/main/docs/Targets.md

A flowchart to guide users in selecting the most appropriate content store based on their requirements.

```mermaid
flowchart TD;

Q1{"Access remote repository?"}
Q1--Y-->Repository["Repository Store"]
Q1--N-->Q2{"Reading/writing arbitrary files?"}
Q2--Y-->File["File Store"]
Q2--N-->Q3{"Need persistent storage?"}
Q3--Y-->OCI["OCI Store"]
Q3--N-->Memory["Memory Store"]
```

--------------------------------

### Copy Function Example: m2

Source: https://github.com/oras-project/oras-go/blob/main/docs/Modeling-Artifacts.md

Illustrates the Copy function replicating the graph rooted at node m2, including m2, its successor b5, and the subgraph rooted at m0.

```mermaid
graph TD;

M2["Manifest m2"]--config-->Blob0
M2--layers-->Blob5["Blob b5"]
M2--subject-->M0

M0["Manifest m0"]--config-->Blob0["Blob b0"]
M0--layers-->Blob1["Blob b1"]
M0--layers-->Blob2["Blob b2"]
```

--------------------------------

### OCI Signature Manifest Example

Source: https://github.com/oras-project/oras-go/blob/main/docs/Modeling-Artifacts.md

Demonstrates the structure of a signature manifest, which references a signature blob and specifies a 'subject' field pointing to the target artifact manifest. This is used when signing artifacts with tools like 'notation'.

```json
{
  "schemaVersion": 2,
  "mediaType": "application/vnd.oci.image.manifest.v1+json",
  "config": {
    "mediaType": "application/cncf.notary.signature",
    "digest": "sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a",
    "size": 2
  },
  "layers": [
    {
      "mediaType": "application/jose+json",
      "digest": "sha256:37f88486592fd90ace303ee38f8d1ff698193e76c76d3c1fef8627a39e677696",
      "size": 2090
    }
  ],
  "subject": {
    "mediaType": "application/vnd.oci.image.manifest.v1+json",
    "digest": "sha256:314c7f20dd44ee1cca06af399a67f7c463a9f586830d630802d9e365933da9fb",
    "size": 762
  },
  "annotations": {
    "io.cncf.notary.x509chain.thumbprint#S256": "[\"a9c85558943f197f41fe7cf3caf691f7df8d0088be426a33d895560717893962\"]",
    "org.opencontainers.image.created": "2025-02-01T09:50:52Z"
  }
}
```

--------------------------------

### OCI Image Manifest Example

Source: https://github.com/oras-project/oras-go/blob/main/docs/Modeling-Artifacts.md

This JSON structure represents an OCI Image Manifest, detailing the artifact's configuration, layers, and annotations. It serves as the root of the artifact's DAG.

```json
{
  "schemaVersion": 2,
  "mediaType": "application/vnd.oci.image.manifest.v1+json",
  "artifactType": "application/vnd.example+type",
  "config": {
    "mediaType": "application/vnd.oci.empty.v1+json",
    "digest": "sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a",
    "size": 2,
    "data": "e30="
  },
  "layers": [
    {
      "mediaType": "application/vnd.custom.type",
      "digest": "sha256:b5bb9d8014a0f9b1d61e21e796d78dccdf1352f23cd32812f4850b878ae4944c",
      "size": 4,
      "annotations": {
        "org.opencontainers.image.title": "foo.txt"
      }
    },
    {
      "mediaType": "application/vnd.custom.type",
      "digest": "sha256:7d865e959b2466918c9863afca942d0fb89d7c9ac0c99bafc3749504ded97730",
      "size": 4,
      "annotations": {
        "org.opencontainers.image.title": "bar.txt"
      }
    }
  ],
  "annotations": {
    "org.opencontainers.image.created": "2025-01-23T10:57:27Z"
  }
}
```

--------------------------------

### Create Directory and Initialize Go Module

Source: https://github.com/oras-project/oras-go/blob/main/docs/tutorial/quickstart.md

Sets up a new directory for your project and initializes a Go module for dependency management.

```shell
mkdir oras-go-v2-quickstart
cd oras-go-v2-quickstart
```

```console
$ go mod init quickstart/oras-go-v2
go: creating new go.mod: quickstart/oras-go-v2
```

--------------------------------

### Connect to Remote Repository with Token Authentication

Source: https://github.com/oras-project/oras-go/blob/main/docs/tutorial/quickstart.md

Demonstrates connecting to a remote OCI repository using token authentication with username and password. The `retry.DefaultClient` is used for HTTP requests.

```go
package main

import (
	"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() {
	// 1. Connect to a remote repository with token authentication
	ref := "example.registry.com/myrepo"
	repo, err := remote.NewRepository(ref)
	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(),
		CredentialFunc: credentials.StaticCredentialFunc(repo.Reference.Registry, credentials.Credential{
			Username: "username",
			Password: "password",
		}),
	}
}
```

--------------------------------

### Connect to Remote Repository and List Tags

Source: https://github.com/oras-project/oras-go/blob/main/docs/tutorial/quickstart.md

Connects to a remote OCI registry using token authentication and lists all tags in a specified repository. Ensure the registry URL and credentials are correct. This code can be omitted if authentication is not required.

```go
package main

import (
	"context"
	"fmt"
	"os"

	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
	"oras.land/oras-go/v2"
	"oras.land/oras-go/v2/content"
	"oras.land/oras-go/v2/content/oci"
	"oras.land/oras-go/v2/registry"
	"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() {
	// 1. Connect to a remote repository with token authentication
	ref := "example.registry.com/myrepo"
	repo, err := remote.NewRepository(ref)
	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(),
		CredentialFunc: credentials.StaticCredentialFunc(repo.Reference.Registry, credentials.Credential{
			Username: "username",
			Password: "password",
		}),
	}

	// 2. Show the tags in the repository
	ctx := context.Background()
	err = repo.Tags(ctx, "", func(tags []string) error {
		for _, tag := range tags {
			fmt.Println(tag)
		}
			return nil
	})
	if err != nil {
		panic(err)
	}

	// 3. push a layer to the repository
	layer := []byte("example manifest layer")
	layerDescriptor, err := oras.PushBytes(ctx, repo, ocispec.MediaTypeImageLayer, layer)
	if err != nil {
		panic(err)
	}
	fmt.Println("Pushed manifest layer:", layerDescriptor.Digest)

	// 4. Push a manifest to the repository with the tag "quickstart"
	packOpts := oras.PackManifestOptions{
		Layers: []ocispec.Descriptor{layerDescriptor},
	}
	artifactType := "application/vnd.example+type"
	desc, err := oras.PackManifest(ctx, repo, oras.PackManifestVersion1_1, artifactType, packOpts)
	if err != nil {
		panic(err)
	}
	tag := "quickstart"
	err = repo.Tag(ctx, desc, tag)
	if err != nil {
		panic(err)
	}
	fmt.Println("Pushed and tagged manifest")

	// 5. Fetch the manifest from the repository by tag
	_, fetchedManifestContent, err := oras.FetchBytes(ctx, repo, tag, oras.DefaultFetchBytesOptions)
	if err != nil {
		panic(err)
	}
	fmt.Println(string(fetchedManifestContent))

	// 6. Parse the fetched manifest content and get the layers
	var manifest ocispec.Manifest
	if err := json.Unmarshal(fetchedManifestContent, &manifest); err != nil {
		panic(err)
	}
	for _, layer := range manifest.Layers {
		layerContent, err := content.FetchAll(ctx, repo, layer)
		if err != nil {
			panic(err)
		}
		fmt.Println(string(layerContent))
	}

	// 7. Copy the artifact to local OCI layout directory with a tag "quickstartOCI"
	ociDir, err := os.MkdirTemp(".", "oras_oci_example_*")
	if err != nil {
		panic(err)
	}
	ociTarget, err := oci.New(ociDir)
	if err != nil {
		panic(err)
	}
	_, err = oras.Copy(ctx, repo, tag, ociTarget, "quickstartOCI", oras.DefaultCopyOptions)
	if err != nil {
		panic(err)
	}
	fmt.Println("Copied the artifact")
}

```

--------------------------------

### List Repository Tags

Source: https://github.com/oras-project/oras-go/blob/main/docs/tutorial/quickstart.md

Uses the `Tags` method to list all tags in a remote repository. Ensure `context` and `fmt` are imported.

```go
// 2. Show the tags in the repository
ctx := context.Background()
err = repo.Tags(ctx, "", func(tags []string) error {
	for _, tag := range tags {
		fmt.Println(tag)
	}
	return nil
})
if err != nil {
	panic(err)
}
```

--------------------------------

### Run Go Program

Source: https://github.com/oras-project/oras-go/blob/main/docs/tutorial/quickstart.md

Executes the Go program using `go run .`.

```shell
go run .
```

--------------------------------

### Fetch Manifest from Repository by Tag

Source: https://github.com/oras-project/oras-go/blob/main/docs/tutorial/quickstart.md

Fetches the content of a manifest from the repository using its tag. Uses `oras.FetchBytes` and requires the `oras.land/oras-go/v2` package.

```go
// 5. Fetch the manifest from the repository by tag
_, fetchedManifestContent, err := oras.FetchBytes(ctx, repo, tag, oras.DefaultFetchBytesOptions)
if err != nil {
	panic(err)
}
fmt.Println(string(fetchedManifestContent))
```

--------------------------------

### OCI Store File System Layout

Source: https://github.com/oras-project/oras-go/blob/main/docs/Targets.md

Illustrates the directory structure for an artifact and its signature stored using the OCI store, adhering to the OCI Image Layout specification.

```bash
repo/
├── blobs
│   └── sha256
│       ├── 314c7f20dd44ee1cca06af399a67f7c463a9f586830d630802d9e365933da9fb
│       ├── 37f88486592fd90ace303ee38f8d1ff698193e76c76d3c1fef8627a39e677696
│       ├── 44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a
│       ├── 7d865e959b2466918c9863afca942d0fb89d7c9ac0c99bafc3749504ded97730
│       ├── b5bb9d8014a0f9b1d61e21e796d78dccdf1352f23cd32812f4850b878ae4944c
│       └── e5727bebbcbbd9996446c34622ca96af67a54219edd58d261112f1af06e2537c
├── index.json
├── ingest
└── oci-layout
```

--------------------------------

### Tidy Go Modules

Source: https://github.com/oras-project/oras-go/blob/main/MIGRATION_GUIDE.md

Run this command to update your Go module dependencies after adding the v2 package.

```sh
go mod tidy
```

--------------------------------

### Repository Store API Mappings

Source: https://github.com/oras-project/oras-go/blob/main/docs/Targets.md

Mappings of Repository Store functions to their corresponding OCI distribution-spec API endpoints for manifests and blobs.

```markdown
| Function Name  | API endpoint                                                                                                         |
| -------------- | -------------------------------------------------------------------------------------------------------------------- |
| `Fetch`        | GET `/v2/<name>/manifests/<reference>`                                                                               |
| `Exists`       | HEAD `/v2/<name>/manifests/<reference>`                                                                              |
| `Push`         | PUT `/v2/<name>/manifests/<reference>`                                                                               |
| `Resolve`      | HEAD `/v2/<name>/manifests/<reference>`                                                                              |
| `Tag`          | PUT `/v2/<name>/manifests/<reference>`                                                                               |
| `Predecessors` | GET `/v2/<name>/referrers/<digest>?artifactType=<artifactType>`<br>Fallback to `Referrers Tag Schema` if unavailable |

| Function Name | API endpoint                                                                                   |
| ------------- | ---------------------------------------------------------------------------------------------- |
| `Fetch`       | GET `/v2/<name>/blobs/<reference>`                                                             |
| `Exists`      | HEAD `/v2/<name>/blobs/<reference>`                                                            |
| `Push`        | POST `/v2/<name>/blobs/uploads/`<br>PUT `/v2/<name>/blobs/uploads/<reference>?digest=<digest>` |
| `Resolve`     | HEAD `/v2/<name>/blobs/<reference>`                                                            |
```

--------------------------------

### Push Manifest Layer

Source: https://github.com/oras-project/oras-go/blob/main/docs/tutorial/quickstart.md

Pushes a manifest layer to the remote repository using `oras.PushBytes`. Requires `ocispec` and `oras` packages to be imported.

```go
// 3. push a layer to the repository
layer := []byte("example manifest layer")
layerDescriptor, err := oras.PushBytes(ctx, repo, ocispec.MediaTypeImageLayer, layer)
if err != nil {
	panic(err)
}
fmt.Println("Pushed manifest layer:", layerDescriptor.Digest)
```

--------------------------------

### Copy Artifact to Local OCI Layout Directory

Source: https://github.com/oras-project/oras-go/blob/main/docs/tutorial/quickstart.md

Copies an artifact from the repository by its tag and saves it to a temporary local directory in OCI layout format using `oras.Copy`. Requires `os` and `oras.land/oras-go/v2/content/oci` imports.

```go
// 7. Copy the artifact to local OCI layout directory with a tag "quickstartOCI"
ociDir, err := os.MkdirTemp(".", "oras_oci_example_*")
if err != nil {
	panic(err)
}
ociTarget, err := oci.New(ociDir)
if err != nil {
	panic(err)
}
_, err = oras.Copy(ctx, repo, tag, ociTarget, "quickstartOCI", oras.DefaultCopyOptions)
if err != nil {
	panic(err)
}
fmt.Println("Copied the artifact")
```

--------------------------------

### Manifest Store Mappings

Source: https://github.com/oras-project/oras-go/blob/main/docs/Targets.md

Mappings between Manifest Store functions and their corresponding registry API endpoints.

```APIDOC
## Manifest Store Operations

### Fetch

- **Method**: GET
- **Endpoint**: `/v2/<name>/manifests/<reference>`

### Exists

- **Method**: HEAD
- **Endpoint**: `/v2/<name>/manifests/<reference>`

### Push

- **Method**: PUT
- **Endpoint**: `/v2/<name>/manifests/<reference>`

### Resolve

- **Method**: HEAD
- **Endpoint**: `/v2/<name>/manifests/<reference>`

### Tag

- **Method**: PUT
- **Endpoint**: `/v2/<name>/manifests/<reference>`

### Predecessors

- **Description**: Retrieves predecessors using the Referrers API or Fallback to Referrers Tag Schema.
- **Method**: GET
- **Endpoint**: `/v2/<name>/referrers/<digest>?artifactType=<artifactType>`
```

--------------------------------

### Blob Store Mappings

Source: https://github.com/oras-project/oras-go/blob/main/docs/Targets.md

Mappings between Blob Store functions and their corresponding registry API endpoints.

```APIDOC
## Blob Store Operations

### Fetch

- **Method**: GET
- **Endpoint**: `/v2/<name>/blobs/<reference>`

### Exists

- **Method**: HEAD
- **Endpoint**: `/v2/<name>/blobs/<reference>`

### Push

- **Description**: Initiates blob upload and completes it.
- **Method**: POST
- **Endpoint**: `/v2/<name>/blobs/uploads/`
- **Method**: PUT
- **Endpoint**: `/v2/<name>/blobs/uploads/<reference>?digest=<digest>`

### Resolve

- **Method**: HEAD
- **Endpoint**: `/v2/<name>/blobs/<reference>`
```

--------------------------------

### GraphStorage Interface

Source: https://github.com/oras-project/oras-go/blob/main/docs/Targets.md

The GraphStorage interface extends Storage by adding support for predecessor finding, enabling navigation within the graph structure.

```APIDOC
## GraphStorage Interface

### Description
Extends the Storage interface by adding support for predecessor finding.

### Functions
- `Fetch(descriptor)`: Retrieves the content identified by the descriptor from the CAS.
- `Exists(descriptor)`: Checks whether the described content is present in the CAS.
- `Push(descriptor, content)`: Adds content matching the expected descriptor to the CAS.
- `Predecessors(descriptor)`: Finds the nodes directly pointing to a given node in the graph.
```

--------------------------------

### Storage Interface

Source: https://github.com/oras-project/oras-go/blob/main/docs/Targets.md

The Storage interface represents a content-addressable storage (CAS) where content is accessed via descriptors. It provides functions to Fetch, check existence with Exists, and add content with Push.

```APIDOC
## Storage Interface

### Description
Represents a content-addressable storage (CAS) where content is accessed via descriptors.

### Functions
- `Fetch(descriptor)`: Retrieves the content identified by the descriptor from the CAS.
- `Exists(descriptor)`: Checks whether the described content is present in the CAS.
- `Push(descriptor, content)`: Adds content matching the expected descriptor to the CAS.
```

--------------------------------

### GraphTarget Interface

Source: https://github.com/oras-project/oras-go/blob/main/docs/Targets.md

The GraphTarget interface combines the capabilities of GraphStorage and Target, offering full graph traversal and tagging functionality.

```APIDOC
## GraphTarget Interface

### Description
Combines the capabilities of GraphStorage and Target.

### Functions
- `Fetch(descriptor)`: Retrieves the content identified by the descriptor from the CAS.
- `Exists(descriptor)`: Checks whether the described content is present in the CAS.
- `Push(descriptor, content)`: Adds content matching the expected descriptor to the CAS.
- `Resolve(tag)`: Resolves a tag string to a descriptor.
- `Tag(descriptor, tag)`: Associates a descriptor with a tag string.
- `Predecessors(descriptor)`: Finds the nodes directly pointing to a given node in the graph.
```

--------------------------------

### Target Interface

Source: https://github.com/oras-project/oras-go/blob/main/docs/Targets.md

The Target interface represents a CAS with tagging capability, allowing descriptors to be associated with human-readable tags.

```APIDOC
## Target Interface

### Description
Represents a CAS with tagging capability.

### Functions
- `Fetch(descriptor)`: Retrieves the content identified by the descriptor from the CAS.
- `Exists(descriptor)`: Checks whether the described content is present in the CAS.
- `Push(descriptor, content)`: Adds content matching the expected descriptor to the CAS.
- `Resolve(tag)`: Resolves a tag string to a descriptor.
- `Tag(descriptor, tag)`: Associates a descriptor with a tag string.
```

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