Add list artifacts command

Signed-off-by: Stefan Prodan <stefan.prodan@gmail.com>

cmd/flux/list_artifact.go

@@ -0,0 +1,68 @@
+/*
+Copyright 2022 The Flux 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"
+	"fmt"
+	"github.com/fluxcd/flux2/internal/oci"
+	"github.com/fluxcd/flux2/pkg/printers"
+	"github.com/spf13/cobra"
+)
+
+var listArtifactsCmd = &cobra.Command{
+	Use:   "artifacts",
+	Short: "list artifacts",
+	Long: `The list command fetches the tags and their metadata from a remote OCI repository.
+The list command uses the credentials from '~/.docker/config.json'.`,
+	Example: `# list the artifacts stored in an OCI repository
+flux list artifact ghcr.io/org/manifests/app
+`,
+	RunE: listArtifactsCmdRun,
+}
+
+func init() {
+	listCmd.AddCommand(listArtifactsCmd)
+}
+
+func listArtifactsCmdRun(cmd *cobra.Command, args []string) error {
+	if len(args) < 1 {
+		return fmt.Errorf("artifact repository is required")
+	}
+	url := args[0]
+
+	ctx, cancel := context.WithTimeout(context.Background(), rootArgs.timeout)
+	defer cancel()
+
+	metas, err := oci.List(ctx, url)
+	if err != nil {
+		return err
+	}
+
+	var rows [][]string
+	for _, meta := range metas {
+		rows = append(rows, []string{meta.URL, meta.Digest, meta.Source, meta.Revision})
+	}
+
+	err = printers.TablePrinter([]string{"artifact", "digest", "source", "revision"}).Print(cmd.OutOrStdout(), rows)
+	if err != nil {
+		return err
+	}
+
+	return nil
+
+}