key: move add, list, remove, passwd to sub-commands

docs: improve the sub-command docs

changelog: add the unreleased changelog for the key command updates

key: update integration tests

cmd/restic/cmd_key_add.go

@@ -0,0 +1,128 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/restic/restic/internal/errors"
+	"github.com/restic/restic/internal/repository"
+	"github.com/spf13/cobra"
+)
+
+var cmdKeyAdd = &cobra.Command{
+	Use:   "add",
+	Short: "Add a new key (password) to the repository; returns the new key ID",
+	Long: `
+The "add" sub-command creates a new key and validates the key. Returns the new key ID.
+
+EXIT STATUS
+===========
+
+Exit status is 0 if the command is successful, and non-zero if there was any error.
+	`,
+	DisableAutoGenTag: true,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		return runKeyAdd(cmd.Context(), globalOptions, keyAddOpts, args)
+	},
+}
+
+type KeyAddOptions struct {
+	NewPasswordFile string
+	Username        string
+	Hostname        string
+}
+
+var keyAddOpts KeyAddOptions
+
+func init() {
+	cmdKey.AddCommand(cmdKeyAdd)
+
+	flags := cmdKeyAdd.Flags()
+	flags.StringVarP(&keyAddOpts.NewPasswordFile, "new-password-file", "", "", "`file` from which to read the new password")
+	flags.StringVarP(&keyAddOpts.Username, "user", "", "", "the username for new key")
+	flags.StringVarP(&keyAddOpts.Hostname, "host", "", "", "the hostname for new key")
+}
+
+func runKeyAdd(ctx context.Context, gopts GlobalOptions, opts KeyAddOptions, args []string) error {
+	if len(args) > 0 {
+		return fmt.Errorf("the key add command expects no arguments, only options - please see `restic help key add` for usage and flags")
+	}
+
+	repo, err := OpenRepository(ctx, gopts)
+	if err != nil {
+		return err
+	}
+
+	lock, ctx, err := lockRepo(ctx, repo, gopts.RetryLock, gopts.JSON)
+	defer unlockRepo(lock)
+	if err != nil {
+		return err
+	}
+
+	return addKey(ctx, repo, gopts, opts)
+}
+
+func addKey(ctx context.Context, repo *repository.Repository, gopts GlobalOptions, opts KeyAddOptions) error {
+	pw, err := getNewPassword(gopts, opts.NewPasswordFile)
+	if err != nil {
+		return err
+	}
+
+	id, err := repository.AddKey(ctx, repo, pw, opts.Username, opts.Hostname, repo.Key())
+	if err != nil {
+		return errors.Fatalf("creating new key failed: %v\n", err)
+	}
+
+	err = switchToNewKeyAndRemoveIfBroken(ctx, repo, id, pw)
+	if err != nil {
+		return err
+	}
+
+	Verbosef("saved new key with ID %s\n", id.ID())
+
+	return nil
+}
+
+// testKeyNewPassword is used to set a new password during integration testing.
+var testKeyNewPassword string
+
+func getNewPassword(gopts GlobalOptions, newPasswordFile string) (string, error) {
+	if testKeyNewPassword != "" {
+		return testKeyNewPassword, nil
+	}
+
+	if newPasswordFile != "" {
+		return loadPasswordFromFile(newPasswordFile)
+	}
+
+	// Since we already have an open repository, temporary remove the password
+	// to prompt the user for the passwd.
+	newopts := gopts
+	newopts.password = ""
+
+	return ReadPasswordTwice(newopts,
+		"enter new password: ",
+		"enter password again: ")
+}
+
+func loadPasswordFromFile(pwdFile string) (string, error) {
+	s, err := os.ReadFile(pwdFile)
+	if os.IsNotExist(err) {
+		return "", errors.Fatalf("%s does not exist", pwdFile)
+	}
+	return strings.TrimSpace(string(s)), errors.Wrap(err, "Readfile")
+}
+
+func switchToNewKeyAndRemoveIfBroken(ctx context.Context, repo *repository.Repository, key *repository.Key, pw string) error {
+	// Verify new key to make sure it really works. A broken key can render the
+	// whole repository inaccessible
+	err := repo.SearchKey(ctx, pw, 0, key.ID().String())
+	if err != nil {
+		// the key is invalid, try to remove it
+		_ = repository.RemoveKey(ctx, repo, key.ID())
+		return errors.Fatalf("failed to access repository with new key: %v", err)
+	}
+	return nil
+}