Merging artifacts Branch: Add discover comand

cmd/oras/discover.go

@@ -0,0 +1,209 @@
+/*
+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 main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"os"
+	"strings"
+
+	"oras.land/oras-go/v2/registry/remote"
+	"oras.land/oras/cmd/oras/internal/option"
+
+	"github.com/need-being/go-tree"
+	digest "github.com/opencontainers/go-digest"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+	artifactspec "github.com/oras-project/artifacts-spec/specs-go/v1"
+	"github.com/spf13/cobra"
+)
+
+type discoverOptions struct {
+	option.Common
+	option.Remote
+
+	targetRef    string
+	artifactType string
+	outputType   string
+}
+
+func discoverCmd() *cobra.Command {
+	var opts discoverOptions
+	cmd := &cobra.Command{
+		Use:   "discover [options] <name:tag|name@digest>",
+		Short: "[Preview] Discover referrers of a manifest in the remote registry",
+		Long: `[Preview] Discover referrers of a manifest in the remote registry
+
+** This command is in preview and under development. **
+
+Example - Discover direct referrers of manifest 'hello:latest' in registry 'localhost:5000':
+  oras discover localhost:5000/hello
+
+Example - Discover all the referrers of manifest 'hello:latest' in registry 'localhost:5000' in a tree view:
+  oras discover localhost:5000/hello -o tree
+
+Example - Discover referrers with type 'test-artifact' of manifest 'hello:latest' in registry 'localhost:5000':
+  oras discover --artifact test-artifact localhost:5000/hello
+`,
+		Args: cobra.ExactArgs(1),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			opts.targetRef = args[0]
+			return runDiscover(opts)
+		},
+	}
+
+	cmd.Flags().StringVarP(&opts.artifactType, "artifact-type", "", "", "artifact type")
+	cmd.Flags().StringVarP(&opts.outputType, "output", "o", "table", "format in which to display referrers (table, json, or tree). tree format will also show indirect referrers")
+	option.ApplyFlags(&opts, cmd.Flags())
+	return cmd
+}
+
+func runDiscover(opts discoverOptions) error {
+	ctx, _ := opts.SetLoggerLevel()
+	repo, err := opts.NewRepository(opts.targetRef, opts.Common)
+	if err != nil {
+		return err
+	}
+
+	// discover artifacts
+	ref := repo.Reference.ReferenceOrDefault()
+	if ref != repo.Reference.Reference {
+		fmt.Println("Using default tag:", ref)
+		repo.Reference.Reference = ref
+	}
+	desc, err := repo.Resolve(ctx, ref)
+	if err != nil {
+		return err
+	}
+
+	if opts.outputType == "tree" {
+		root := tree.New(repo.Reference.String())
+		err = fetchAllReferrers(ctx, repo, desc, opts.artifactType, root)
+		if err != nil {
+			return err
+		}
+		return tree.Print(root)
+	}
+
+	refs, err := fetchReferrers(ctx, repo, desc, opts.artifactType)
+	if err != nil {
+		return err
+	}
+	if opts.outputType == "json" {
+		return printDiscoveredReferrersJSON(desc, refs)
+	}
+
+	fmt.Println("Discovered", len(refs), "artifacts referencing", repo.Reference)
+	fmt.Println("Digest:", desc.Digest)
+	if len(refs) > 0 {
+		fmt.Println()
+		printDiscoveredReferrersTable(refs, opts.Verbose)
+	}
+	return nil
+}
+
+func fetchReferrers(ctx context.Context, repo *remote.Repository, desc ocispec.Descriptor, artifactType string) ([]artifactspec.Descriptor, error) {
+	var results []artifactspec.Descriptor
+	err := repo.Referrers(ctx, desc, artifactType, func(referrers []artifactspec.Descriptor) error {
+		results = append(results, referrers...)
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	return results, nil
+}
+
+func fetchAllReferrers(ctx context.Context, repo *remote.Repository, desc ocispec.Descriptor, artifactType string, node *tree.Node) error {
+	results, err := fetchReferrers(ctx, repo, desc, artifactType)
+	if err != nil {
+		return err
+	}
+
+	for _, r := range results {
+		// Find all indirect referrers
+		referrerNode := node.AddPath(r.ArtifactType, r.Digest)
+		err := fetchAllReferrers(
+			ctx, repo,
+			ocispec.Descriptor{
+				Digest:    r.Digest,
+				Size:      r.Size,
+				MediaType: r.MediaType,
+			},
+			artifactType, referrerNode)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func printDiscoveredReferrersTable(refs []artifactspec.Descriptor, verbose bool) {
+	typeNameTitle := "Artifact Type"
+	typeNameLength := len(typeNameTitle)
+	for _, ref := range refs {
+		if length := len(ref.ArtifactType); length > typeNameLength {
+			typeNameLength = length
+		}
+	}
+
+	print := func(key string, value interface{}) {
+		fmt.Println(key, strings.Repeat(" ", typeNameLength-len(key)+1), value)
+	}
+
+	print(typeNameTitle, "Digest")
+	for _, ref := range refs {
+		print(ref.ArtifactType, ref.Digest)
+		if verbose {
+			printJSON(ref)
+		}
+	}
+}
+
+// printDiscoveredReferrersJSON prints referrer list in JSON equivalent to the
+// API result: https://github.com/oras-project/artifacts-spec/blob/v1.0.0-rc.1/manifest-referrers-api.md#artifact-referrers-api-results
+func printDiscoveredReferrersJSON(desc ocispec.Descriptor, refs []artifactspec.Descriptor) error {
+	type referrerDesc struct {
+		Digest    digest.Digest `json:"digest"`
+		MediaType string        `json:"mediaType"`
+		Artifact  string        `json:"artifactType"`
+		Size      int64         `json:"size"`
+	}
+	output := struct {
+		Referrers []referrerDesc `json:"referrers"`
+	}{
+		Referrers: make([]referrerDesc, len(refs)),
+	}
+
+	for i, ref := range refs {
+		output.Referrers[i] = referrerDesc{
+			Digest:    ref.Digest,
+			Artifact:  ref.ArtifactType,
+			Size:      ref.Size,
+			MediaType: ref.MediaType,
+		}
+	}
+
+	return printJSON(output)
+}
+
+func printJSON(object interface{}) error {
+	encoder := json.NewEncoder(os.Stdout)
+	encoder.SetEscapeHTML(false)
+	encoder.SetIndent("", "  ")
+	return encoder.Encode(object)
+}

cmd/oras/main.go

@@ -11,7 +11,7 @@ func main() {
 		Use:          "oras [command]",
 		SilenceUsage: true,
 	}
-	cmd.AddCommand(pullCmd(), pushCmd(), loginCmd(), logoutCmd(), versionCmd())
+	cmd.AddCommand(pullCmd(), pushCmd(), loginCmd(), logoutCmd(), versionCmd(), discoverCmd())
 	if err := cmd.Execute(); err != nil {
 		os.Exit(1)
 	}

go.mod

@@ -5,20 +5,21 @@ go 1.18
 require (
 	github.com/docker/cli v20.10.17+incompatible
 	github.com/moby/term v0.0.0-20210619224110-3f7ff695adc6
+	github.com/need-being/go-tree v0.1.0
 	github.com/opencontainers/go-digest v1.0.0
 	github.com/opencontainers/image-spec v1.0.3-0.20211202183452-c5a74bcca799
+	github.com/oras-project/artifacts-spec v1.0.0-rc.1
 	github.com/sirupsen/logrus v1.8.1
 	github.com/spf13/cobra v1.5.0
 	github.com/spf13/pflag v1.0.5
-	oras.land/oras-go/v2 v2.0.0-alpha
+	oras.land/oras-go/v2 v2.0.0-20220629060154-3f83f0c01a01
 )
 
 require (
 	github.com/Azure/go-ansiterm v0.0.0-20210617225240-d185dfc1b5a1 // indirect
 	github.com/docker/docker v20.10.17+incompatible // indirect
 	github.com/docker/docker-credential-helpers v0.6.4 // indirect
 	github.com/inconshreveable/mousetrap v1.0.0 // indirect
-	github.com/oras-project/artifacts-spec v1.0.0-draft.1.1 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c // indirect
 	golang.org/x/sys v0.0.0-20210616094352-59db8d763f22 // indirect

go.sum

@@ -20,12 +20,14 @@ github.com/inconshreveable/mousetrap v1.0.0 h1:Z8tu5sraLXCXIcARxBp/8cbvlwVa7Z1NH
 github.com/inconshreveable/mousetrap v1.0.0/go.mod h1:PxqpIevigyE2G7u3NXJIT2ANytuPF1OarO4DADm73n8=
 github.com/moby/term v0.0.0-20210619224110-3f7ff695adc6 h1:dcztxKSvZ4Id8iPpHERQBbIJfabdt4wUm5qy3wOL2Zc=
 github.com/moby/term v0.0.0-20210619224110-3f7ff695adc6/go.mod h1:E2VnQOmVuvZB6UYnnDB0qG5Nq/1tD9acaOpo6xmt0Kw=
+github.com/need-being/go-tree v0.1.0 h1:blQrtD006cFm97UDeMUfixwPc9o06A6c+uLaUskdNNw=
+github.com/need-being/go-tree v0.1.0/go.mod h1:UOHUchuOm+lxM+EtvQ9h/IO88hK/ke7FHai4oGhhEoI=
 github.com/opencontainers/go-digest v1.0.0 h1:apOUWs51W5PlhuyGyz9FCeeBIOUDA/6nW8Oi/yOhh5U=
 github.com/opencontainers/go-digest v1.0.0/go.mod h1:0JzlMkj0TRzQZfJkVvzbP0HBR3IKzErnv2BNG4W4MAM=
 github.com/opencontainers/image-spec v1.0.3-0.20211202183452-c5a74bcca799 h1:rc3tiVYb5z54aKaDfakKn0dDjIyPpTtszkjuMzyt7ec=
 github.com/opencontainers/image-spec v1.0.3-0.20211202183452-c5a74bcca799/go.mod h1:BtxoFyWECRxE4U/7sNtV5W15zMzWCbyJoFRP3s7yZA0=
-github.com/oras-project/artifacts-spec v1.0.0-draft.1.1 h1:2YMUDyDH0glYA4gNG/zEg9HNVzgGX8kr/NBLR9AQkLQ=
-github.com/oras-project/artifacts-spec v1.0.0-draft.1.1/go.mod h1:Xch2aLzSwtkhbFFN6LUzTfLtukYvMMdXJ4oZ8O7BOdc=
+github.com/oras-project/artifacts-spec v1.0.0-rc.1 h1:bCHf9mPbrgiNwQFyVzBX79BYZVAl0OUrmvICZOCOwts=
+github.com/oras-project/artifacts-spec v1.0.0-rc.1/go.mod h1:Xch2aLzSwtkhbFFN6LUzTfLtukYvMMdXJ4oZ8O7BOdc=
 github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
@@ -62,5 +64,5 @@ gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gotest.tools/v3 v3.0.2 h1:kG1BFyqVHuQoVQiR1bWGnfz/fmHvvuiSPIV7rvl360E=
 gotest.tools/v3 v3.0.2/go.mod h1:3SzNCllyD9/Y+b5r9JIKQ474KzkZyqLqEfYqMsX94Bk=
-oras.land/oras-go/v2 v2.0.0-alpha h1:Uwso3p1KMTmm7YheWBkGNjf8xqXZ2AYxMfxu1DoQiH0=
-oras.land/oras-go/v2 v2.0.0-alpha/go.mod h1:0IQiLwHUJuMs0+QYGavaeQWw5FD4ABD/RP5YamXT/sc=
+oras.land/oras-go/v2 v2.0.0-20220629060154-3f83f0c01a01 h1:jUTJqQr+wPBDESDdRuv9Vm4xRztjhJgzYrdvRtt9HVQ=
+oras.land/oras-go/v2 v2.0.0-20220629060154-3f83f0c01a01/go.mod h1:0IQiLwHUJuMs0+QYGavaeQWw5FD4ABD/RP5YamXT/sc=