Revise swarm init/update flags, add unlocking capability

- Neither swarm init or swarm update should take an unlock key
- Add an autolock flag to turn on autolock
- Make the necessary docker api changes
- Add SwarmGetUnlockKey API call and use it when turning on autolock
- Add swarm unlock-key subcommand

Signed-off-by: Aaron Lehmann <aaron.lehmann@docker.com>

command/swarm/cmd.go

@@ -22,6 +22,7 @@ func NewSwarmCommand(dockerCli *command.DockerCli) *cobra.Command {
 		newInitCommand(dockerCli),
 		newJoinCommand(dockerCli),
 		newJoinTokenCommand(dockerCli),
+		newUnlockKeyCommand(dockerCli),
 		newUpdateCommand(dockerCli),
 		newLeaveCommand(dockerCli),
 		newUnlockCommand(dockerCli),

command/swarm/init.go

@@ -1,20 +1,15 @@
 package swarm
 
 import (
-	"bufio"
-	"crypto/rand"
-	"errors"
 	"fmt"
-	"io"
-	"math/big"
 	"strings"
 
-	"golang.org/x/crypto/ssh/terminal"
 	"golang.org/x/net/context"
 
 	"github.com/docker/docker/api/types/swarm"
 	"github.com/docker/docker/cli"
 	"github.com/docker/docker/cli/command"
+	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 )
@@ -25,7 +20,6 @@ type initOptions struct {
 	// Not a NodeAddrOption because it has no default port.
 	advertiseAddr   string
 	forceNewCluster bool
-	lockKey         bool
 }
 
 func newInitCommand(dockerCli *command.DockerCli) *cobra.Command {
@@ -45,7 +39,6 @@ func newInitCommand(dockerCli *command.DockerCli) *cobra.Command {
 	flags := cmd.Flags()
 	flags.Var(&opts.listenAddr, flagListenAddr, "Listen address (format: <ip|interface>[:port])")
 	flags.StringVar(&opts.advertiseAddr, flagAdvertiseAddr, "", "Advertised address (format: <ip|interface>[:port])")
-	flags.BoolVar(&opts.lockKey, flagLockKey, false, "Encrypt swarm with optionally provided key from stdin")
 	flags.BoolVar(&opts.forceNewCluster, "force-new-cluster", false, "Force create a new cluster from current state")
 	addSwarmFlags(flags, &opts.swarmOptions)
 	return cmd
@@ -55,31 +48,12 @@ func runInit(dockerCli *command.DockerCli, flags *pflag.FlagSet, opts initOption
 	client := dockerCli.Client()
 	ctx := context.Background()
 
-	var lockKey string
-	if opts.lockKey {
-		var err error
-		lockKey, err = readKey(dockerCli.In(), "Please enter key for encrypting swarm(leave empty to generate): ")
-		if err != nil {
-			return err
-		}
-		if len(lockKey) == 0 {
-			randBytes := make([]byte, 16)
-			if _, err := rand.Read(randBytes[:]); err != nil {
-				panic(fmt.Errorf("failed to general random lock key: %v", err))
-			}
-
-			var n big.Int
-			n.SetBytes(randBytes[:])
-			lockKey = n.Text(36)
-		}
-	}
-
 	req := swarm.InitRequest{
 		ListenAddr:       opts.listenAddr.String(),
 		AdvertiseAddr:    opts.advertiseAddr,
 		ForceNewCluster:  opts.forceNewCluster,
 		Spec:             opts.swarmOptions.ToSpec(flags),
-		LockKey:         lockKey,
+		AutoLockManagers: opts.swarmOptions.autolock,
 	}
 
 	nodeID, err := client.SwarmInit(ctx, req)
@@ -92,29 +66,19 @@ func runInit(dockerCli *command.DockerCli, flags *pflag.FlagSet, opts initOption
 
 	fmt.Fprintf(dockerCli.Out(), "Swarm initialized: current node (%s) is now a manager.\n\n", nodeID)
 
-	if len(lockKey) > 0 {
-		fmt.Fprintf(dockerCli.Out(), "Swarm is encrypted. When a node is restarted it needs to be unlocked by running command:\n\n    echo '%s' | docker swarm unlock\n\n", lockKey)
-	}
-
 	if err := printJoinCommand(ctx, dockerCli, nodeID, true, false); err != nil {
 		return err
 	}
 
 	fmt.Fprint(dockerCli.Out(), "To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.\n\n")
-	return nil
+
+	if req.AutoLockManagers {
+		unlockKeyResp, err := client.SwarmGetUnlockKey(ctx)
+		if err != nil {
+			return errors.Wrap(err, "could not fetch unlock key")
+		}
+		printUnlockCommand(ctx, dockerCli, unlockKeyResp.UnlockKey)
 	}
 
-func readKey(in *command.InStream, prompt string) (string, error) {
-	if in.IsTerminal() {
-		fmt.Print(prompt)
-		dt, err := terminal.ReadPassword(int(in.FD()))
-		fmt.Println()
-		return string(dt), err
-	} else {
-		key, err := bufio.NewReader(in).ReadString('\n')
-		if err == io.EOF {
-			err = nil
-		}
-		return strings.TrimSpace(key), err
-	}
+	return nil
 }

command/swarm/opts.go

@@ -27,6 +27,7 @@ const (
 	flagMaxSnapshots        = "max-snapshots"
 	flagSnapshotInterval    = "snapshot-interval"
 	flagLockKey             = "lock-key"
+	flagAutolock            = "autolock"
 )
 
 type swarmOptions struct {
@@ -36,6 +37,7 @@ type swarmOptions struct {
 	externalCA          ExternalCAOption
 	maxSnapshots        uint64
 	snapshotInterval    uint64
+	autolock            bool
 }
 
 // NodeAddrOption is a pflag.Value for listening addresses
@@ -174,6 +176,7 @@ func addSwarmFlags(flags *pflag.FlagSet, opts *swarmOptions) {
 	flags.Var(&opts.externalCA, flagExternalCA, "Specifications of one or more certificate signing endpoints")
 	flags.Uint64Var(&opts.maxSnapshots, flagMaxSnapshots, 0, "Number of additional Raft snapshots to retain")
 	flags.Uint64Var(&opts.snapshotInterval, flagSnapshotInterval, 10000, "Number of log entries between Raft snapshots")
+	flags.BoolVar(&opts.autolock, flagAutolock, false, "Enable or disable manager autolocking (requiring an unlock key to start a stopped manager)")
 }
 
 func (opts *swarmOptions) mergeSwarmSpec(spec *swarm.Spec, flags *pflag.FlagSet) {
@@ -195,6 +198,9 @@ func (opts *swarmOptions) mergeSwarmSpec(spec *swarm.Spec, flags *pflag.FlagSet)
 	if flags.Changed(flagSnapshotInterval) {
 		spec.Raft.SnapshotInterval = opts.snapshotInterval
 	}
+	if flags.Changed(flagAutolock) {
+		spec.EncryptionConfig.AutoLockManagers = opts.autolock
+	}
 }
 
 func (opts *swarmOptions) ToSpec(flags *pflag.FlagSet) swarm.Spec {

command/swarm/unlock.go

@@ -1,9 +1,14 @@
 package swarm
 
 import (
+	"bufio"
 	"context"
+	"fmt"
+	"io"
+	"strings"
 
 	"github.com/spf13/cobra"
+	"golang.org/x/crypto/ssh/terminal"
 
 	"github.com/docker/docker/api/types/swarm"
 	"github.com/docker/docker/cli"
@@ -24,7 +29,7 @@ func newUnlockCommand(dockerCli *command.DockerCli) *cobra.Command {
 				return err
 			}
 			req := swarm.UnlockRequest{
-				LockKey: string(key),
+				UnlockKey: key,
 			}
 
 			return client.SwarmUnlock(ctx, req)
@@ -33,3 +38,17 @@ func newUnlockCommand(dockerCli *command.DockerCli) *cobra.Command {
 
 	return cmd
 }
+
+func readKey(in *command.InStream, prompt string) (string, error) {
+	if in.IsTerminal() {
+		fmt.Print(prompt)
+		dt, err := terminal.ReadPassword(int(in.FD()))
+		fmt.Println()
+		return string(dt), err
+	}
+	key, err := bufio.NewReader(in).ReadString('\n')
+	if err == io.EOF {
+		err = nil
+	}
+	return strings.TrimSpace(key), err
+}

command/swarm/unlock_key.go

@@ -0,0 +1,57 @@
+package swarm
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+
+	"github.com/docker/docker/cli"
+	"github.com/docker/docker/cli/command"
+	"github.com/pkg/errors"
+	"golang.org/x/net/context"
+)
+
+func newUnlockKeyCommand(dockerCli *command.DockerCli) *cobra.Command {
+	var rotate, quiet bool
+
+	cmd := &cobra.Command{
+		Use:   "unlock-key [OPTIONS]",
+		Short: "Manage the unlock key",
+		Args:  cli.NoArgs,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			client := dockerCli.Client()
+			ctx := context.Background()
+
+			if rotate {
+				// FIXME(aaronl)
+			}
+
+			unlockKeyResp, err := client.SwarmGetUnlockKey(ctx)
+			if err != nil {
+				return errors.Wrap(err, "could not fetch unlock key")
+			}
+
+			if quiet {
+				fmt.Fprintln(dockerCli.Out(), unlockKeyResp.UnlockKey)
+			} else {
+				printUnlockCommand(ctx, dockerCli, unlockKeyResp.UnlockKey)
+			}
+			return nil
+		},
+	}
+
+	flags := cmd.Flags()
+	flags.BoolVar(&rotate, flagRotate, false, "Rotate unlock key")
+	flags.BoolVarP(&quiet, flagQuiet, "q", false, "Only display token")
+
+	return cmd
+}
+
+func printUnlockCommand(ctx context.Context, dockerCli *command.DockerCli, unlockKey string) {
+	if len(unlockKey) == 0 {
+		return
+	}
+
+	fmt.Fprintf(dockerCli.Out(), "To unlock a swarm manager after it restarts, run the `docker swarm unlock`\ncommand and provide the following key:\n\n    %s\n\nPlease remember to store this key in a password manager, since without it you\nwill not be able to restart the manager.\n", unlockKey)
+	return
+}

command/swarm/update.go

@@ -8,6 +8,7 @@ import (
 	"github.com/docker/docker/api/types/swarm"
 	"github.com/docker/docker/cli"
 	"github.com/docker/docker/cli/command"
+	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 )
@@ -39,8 +40,12 @@ func runUpdate(dockerCli *command.DockerCli, flags *pflag.FlagSet, opts swarmOpt
 		return err
 	}
 
+	prevAutoLock := swarm.Spec.EncryptionConfig.AutoLockManagers
+
 	opts.mergeSwarmSpec(&swarm.Spec, flags)
 
+	curAutoLock := swarm.Spec.EncryptionConfig.AutoLockManagers
+
 	err = client.SwarmUpdate(ctx, swarm.Version, swarm.Spec, updateFlags)
 	if err != nil {
 		return err
@@ -48,5 +53,13 @@ func runUpdate(dockerCli *command.DockerCli, flags *pflag.FlagSet, opts swarmOpt
 
 	fmt.Fprintln(dockerCli.Out(), "Swarm updated.")
 
+	if curAutoLock && !prevAutoLock {
+		unlockKeyResp, err := client.SwarmGetUnlockKey(ctx)
+		if err != nil {
+			return errors.Wrap(err, "could not fetch unlock key")
+		}
+		printUnlockCommand(ctx, dockerCli, unlockKeyResp.UnlockKey)
+	}
+
 	return nil
 }