[Elastic Agent] Improve version, restart, enroll CLI commands (#20359)

* Add improve version CLI cmd.

* Add new restart cmd. Perform restart at end of enroll.

* Fix yaml annotations on version struct.

* Fix control.Address on Windows.

* Fix control.Address on Windows.

* Fix windows dialer.

* Fix control.Address on Windows.

* Add to CHANGELOG.

* Review cleanups.

* Fix go vet.

* Update talking to communicating.

x-pack/elastic-agent/CHANGELOG.asciidoc

@@ -99,3 +99,6 @@
 - Add --staging option to enroll command {pull}20026[20026]
 - Add `event.dataset` to all events {pull}20076[20076]
 - Prepare packaging for endpoint and asc files {pull}20186[20186]
+- Improved version CLI {pull}20359[20359]
+- Enroll CLI now restarts running daemon {pull}20359[20359]
+- Add restart CLI cmd {pull}20359[20359]

x-pack/elastic-agent/control.proto

@@ -104,7 +104,7 @@ message StatusResponse {
   repeated ApplicationStatus applications = 3;
 }
 
-service ElasticAgent {
+service ElasticAgentControl {
   // Fetches the currently running version of the Elastic Agent.
   rpc Version(Empty) returns (VersionResponse);
 

x-pack/elastic-agent/pkg/agent/application/reexec/manager.go

@@ -5,16 +5,9 @@
 package reexec
 
 import (
-	"sync"
-
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/core/logger"
 )
 
-var (
-	execSingleton     ExecManager
-	execSingletonOnce sync.Once
-)
-
 // ExecManager is the interface that the global reexec manager implements.
 type ExecManager interface {
 	// ReExec asynchronously re-executes command in the same PID and memory address
@@ -30,14 +23,6 @@ type ExecManager interface {
 	ShutdownComplete()
 }
 
-// Manager returns the global reexec manager.
-func Manager(log *logger.Logger, exec string) ExecManager {
-	execSingletonOnce.Do(func() {
-		execSingleton = newManager(log, exec)
-	})
-	return execSingleton
-}
-
 type manager struct {
 	logger   *logger.Logger
 	exec     string
@@ -46,7 +31,8 @@ type manager struct {
 	complete chan bool
 }
 
-func newManager(log *logger.Logger, exec string) *manager {
+// NewManager returns the reexec manager.
+func NewManager(log *logger.Logger, exec string) ExecManager {
 	return &manager{
 		logger:   log,
 		exec:     exec,

x-pack/elastic-agent/pkg/agent/cmd/enroll.go

@@ -5,11 +5,14 @@
 package cmd
 
 import (
+	"context"
 	"fmt"
 	"math/rand"
 	"os"
 	"time"
 
+	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/control/client"
+
 	"github.com/spf13/cobra"
 
 	"github.com/elastic/beats/v7/libbeat/common/backoff"
@@ -45,6 +48,7 @@ func newEnrollCommandWithArgs(flags *globalFlags, _ []string, streams *cli.IOStr
 	cmd.Flags().BoolP("force", "f", false, "Force overwrite the current and do not prompt for confirmation")
 	cmd.Flags().BoolP("insecure", "i", false, "Allow insecure connection to Kibana")
 	cmd.Flags().StringP("staging", "", "", "Configures agent to download artifacts from a staging build")
+	cmd.Flags().Bool("no-restart", false, "Skip restarting the currently running daemon")
 
 	return cmd
 }
@@ -144,7 +148,25 @@ func enroll(streams *cli.IOStreams, cmd *cobra.Command, flags *globalFlags, args
 		return errors.New(err, "fail to enroll")
 	}
 
-	fmt.Fprintln(streams.Out, "Successfully enrolled the Agent.")
+	fmt.Fprintln(streams.Out, "Successfully enrolled the Elastic Agent.")
+
+	// skip restarting
+	noRestart, _ := cmd.Flags().GetBool("no-restart")
+	if noRestart {
+		return nil
+	}
+
+	daemon := client.New()
+	err = daemon.Connect(context.Background())
+	if err == nil {
+		defer daemon.Disconnect()
+		err = daemon.Restart(context.Background())
+		if err == nil {
+			fmt.Fprintln(streams.Out, "Successfully triggered restart on running Elastic Agent.")
+			return nil
+		}
+	}
+	fmt.Fprintln(streams.Out, "Elastic Agent might not be running; unable to trigger restart")
 	return nil
 }
 

x-pack/elastic-agent/pkg/agent/cmd/run.go

@@ -19,6 +19,7 @@ import (
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/application/paths"
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/application/reexec"
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/configuration"
+	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/control/server"
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/errors"
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/cli"
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/config"
@@ -80,7 +81,14 @@ func run(flags *globalFlags, streams *cli.IOStreams) error {
 		return err
 	}
 	rexLogger := logger.Named("reexec")
-	rex := reexec.Manager(rexLogger, execPath)
+	rex := reexec.NewManager(rexLogger, execPath)
+
+	// start the control listener
+	control := server.New(logger.Named("control"), rex)
+	if err := control.Start(); err != nil {
+		return err
+	}
+	defer control.Stop()
 
 	app, err := application.New(logger, pathConfigFile)
 	if err != nil {

x-pack/elastic-agent/pkg/agent/control/addr_windows.go

@@ -15,8 +15,8 @@ import (
 
 // Address returns the address to connect to Elastic Agent daemon.
 func Address() string {
-	data = paths.Data()
+	data := paths.Data()
 	// entire string cannot be longer than 256 characters, this forces the
 	// length to always be 87 characters (but unique per data path)
-	return fmt.Sprintf(`\\.\pipe\elastic-agent-%s`, sha256.Sum256(data))
+	return fmt.Sprintf(`\\.\pipe\elastic-agent-%x`, sha256.Sum256([]byte(data)))
 }

x-pack/elastic-agent/pkg/agent/control/client/client.go

@@ -8,11 +8,11 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+
 	"sync"
 	"time"
 
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/control"
-
 	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/control/proto"
 )
 
@@ -62,10 +62,10 @@ type AgentStatus struct {
 
 // Client communicates to Elastic Agent through the control protocol.
 type Client interface {
-	// Start starts the client.
-	Start(ctx context.Context) error
-	// Stop stops the client.
-	Stop()
+	// Connect connects to the running Elastic Agent.
+	Connect(ctx context.Context) error
+	// Disconnect disconnects from the running Elastic Agent.
+	Disconnect()
 	// Version returns the current version of the running agent.
 	Version(ctx context.Context) (Version, error)
 	// Status returns the current status of the running agent.
@@ -81,7 +81,7 @@ type client struct {
 	ctx     context.Context
 	cancel  context.CancelFunc
 	wg      sync.WaitGroup
-	client  proto.ElasticAgentClient
+	client  proto.ElasticAgentControlClient
 	cfgLock sync.RWMutex
 	obsLock sync.RWMutex
 }
@@ -91,19 +91,19 @@ func New() Client {
 	return &client{}
 }
 
-// Start starts the connection to Elastic Agent.
-func (c *client) Start(ctx context.Context) error {
+// Connect connects to the running Elastic Agent.
+func (c *client) Connect(ctx context.Context) error {
 	c.ctx, c.cancel = context.WithCancel(ctx)
 	conn, err := dialContext(ctx)
 	if err != nil {
 		return err
 	}
-	c.client = proto.NewElasticAgentClient(conn)
+	c.client = proto.NewElasticAgentControlClient(conn)
 	return nil
 }
 
-// Stop stops the connection to Elastic Agent.
-func (c *client) Stop() {
+// Disconnect disconnects from the running Elastic Agent.
+func (c *client) Disconnect() {
 	if c.cancel != nil {
 		c.cancel()
 		c.wg.Wait()

x-pack/elastic-agent/pkg/agent/control/client/dial_windows.go

@@ -22,5 +22,5 @@ func dialContext(ctx context.Context) (*grpc.ClientConn, error) {
 }
 
 func dialer(ctx context.Context, addr string) (net.Conn, error) {
-	return npipe.DialContext(arr)(ctx, "", "")
+	return npipe.DialContext(addr)(ctx, "", "")
 }

x-pack/elastic-agent/pkg/agent/control/control_test.go

@@ -20,15 +20,15 @@ import (
 )
 
 func TestServerClient_Version(t *testing.T) {
-	srv := server.New(newErrorLogger(t))
+	srv := server.New(newErrorLogger(t), nil)
 	err := srv.Start()
 	require.NoError(t, err)
 	defer srv.Stop()
 
 	c := client.New()
-	err = c.Start(context.Background())
+	err = c.Connect(context.Background())
 	require.NoError(t, err)
-	defer c.Stop()
+	defer c.Disconnect()
 
 	ver, err := c.Version(context.Background())
 	require.NoError(t, err)