rclone/cmd/checksum/checksum.go

// Package checksum provides the checksum command.
package checksum

import (
	"context"
	"fmt"
	"strings"

	"github.com/rclone/rclone/cmd"
	"github.com/rclone/rclone/cmd/check" // for common flags
	"github.com/rclone/rclone/fs/config/flags"
	"github.com/rclone/rclone/fs/hash"
	"github.com/rclone/rclone/fs/operations"
	"github.com/spf13/cobra"
)

var download = false

func init() {
	cmd.Root.AddCommand(commandDefinition)
	cmdFlags := commandDefinition.Flags()
	flags.BoolVarP(cmdFlags, &download, "download", "", download, "Check by hashing the contents", "")
	check.AddFlags(cmdFlags)
}

var commandDefinition = &cobra.Command{
	Use:   "checksum <hash> sumfile dst:path",
	Short: `Checks the files in the destination against a SUM file.`,
	Long: strings.ReplaceAll(`Checks that hashsums of destination files match the SUM file.
It compares hashes (MD5, SHA1, etc) and logs a report of files which
don't match.  It doesn't alter the file system.

The sumfile is treated as the source and the dst:path is treated as
the destination for the purposes of the output.

If you supply the |--download| flag, it will download the data from the remote
and calculate the content hash on the fly.  This can be useful for remotes
that don't support hashes or if you really want to check all the data.

Note that hash values in the SUM file are treated as case insensitive.
`, "|", "`") + check.FlagsHelp,
	Annotations: map[string]string{
		"versionIntroduced": "v1.56",
		"groups":            "Filter,Listing",
	},
	RunE: func(command *cobra.Command, args []string) error {
		cmd.CheckArgs(3, 3, command, args)
		var hashType hash.Type
		if err := hashType.Set(args[0]); err != nil {
			fmt.Println(hash.HelpString(0))
			return err
		}
		fsum, sumFile, fsrc := cmd.NewFsSrcFileDst(args[1:])

		cmd.Run(false, true, command, func() error {
			opt, close, err := check.GetCheckOpt(nil, fsrc)
			if err != nil {
				return err
			}
			defer close()

			return operations.CheckSum(context.Background(), fsrc, fsum, sumFile, hashType, opt, download)
		})
		return nil
	},
}