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// Copyright 2018 Google LLC All Rights Reserved.
//
// 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 cmd
import (
"fmt"
"io"
"log"
"os"
"github.com/google/go-containerregistry/pkg/crane"
v1 "github.com/google/go-containerregistry/pkg/v1"
"github.com/google/go-containerregistry/pkg/v1/tarball"
"github.com/spf13/cobra"
)
// NewCmdExport creates a new cobra.Command for the export subcommand.
func NewCmdExport(options *[]crane.Option) *cobra.Command {
return &cobra.Command{
Use: "export IMAGE|- TARBALL|-",
Short: "Export filesystem of a container image as a tarball",
Example: ` # Write tarball to stdout
crane export ubuntu -
# Write tarball to file
crane export ubuntu ubuntu.tar
# Read image from stdin
crane export - ubuntu.tar`,
Args: cobra.RangeArgs(1, 2),
RunE: func(_ *cobra.Command, args []string) error {
src, dst := args[0], "-"
if len(args) > 1 {
dst = args[1]
}
f, err := openFile(dst)
if err != nil {
return fmt.Errorf("failed to open %s: %w", dst, err)
}
defer f.Close()
var img v1.Image
if src == "-" {
tmpfile, err := os.CreateTemp("", "crane")
if err != nil {
log.Fatal(err)
}
defer os.Remove(tmpfile.Name())
if _, err := io.Copy(tmpfile, os.Stdin); err != nil {
log.Fatal(err)
}
tmpfile.Close()
img, err = tarball.ImageFromPath(tmpfile.Name(), nil)
if err != nil {
return fmt.Errorf("reading tarball from stdin: %w", err)
}
} else {
img, err = crane.Pull(src, *options...)
if err != nil {
return fmt.Errorf("pulling %s: %w", src, err)
}
}
return crane.Export(img, f)
},
}
}
func openFile(s string) (*os.File, error) {
if s == "-" {
return os.Stdout, nil
}
return os.Create(s)
}
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