internal driver plugin system

Signed-off-by: Ansuman Sahoo <anshumansahoo500@gmail.com>

Author: unsuman

cmd/limactl/main_darwin.go

@@ -0,0 +1,9 @@
+//go:build !external_vz
+
+// SPDX-FileCopyrightText: Copyright The Lima Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package main
+
+// Import vz driver to register it in the registry on darwin.
+import _ "github.com/lima-vm/lima/pkg/driver/vz"

cmd/limactl/main_qemu.go

@@ -0,0 +1,9 @@
+//go:build !external_qemu
+
+// SPDX-FileCopyrightText: Copyright The Lima Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package main
+
+// Import qemu driver to register it in the registry on all platforms.
+import _ "github.com/lima-vm/lima/pkg/driver/qemu"

cmd/limactl/main_windows.go

@@ -0,0 +1,9 @@
+//go:build !external_wsl2
+
+// SPDX-FileCopyrightText: Copyright The Lima Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package main
+
+// Import wsl2 driver to register it in the registry on windows.
+import _ "github.com/lima-vm/lima/pkg/driver/wsl2"

pkg/driver/driver.go

@@ -6,10 +6,12 @@ package driver
 import (
 	"context"
 	"net"
+
+	"github.com/lima-vm/lima/pkg/store"
 )
 
-// Driver interface is used by hostagent for managing vm.
-type Driver interface {
+// Lifecycle defines basic lifecycle operations.
+type Lifecycle interface {
 	// Validate returns error if the current driver isn't support for given config
 	Validate() error
 
@@ -29,43 +31,66 @@ type Driver interface {
 	// The second argument may contain error occurred while starting driver
 	Start(_ context.Context) (chan error, error)
 
-	// CanRunGUI returns bool to indicate if the hostagent need to run GUI synchronously
-	CanRunGUI() bool
-
-	// RunGUI is for starting GUI synchronously by hostagent. This method should be wait and return only after vm terminates
-	// It returns error if there are any failures
-	RunGUI() error
-
 	// Stop will terminate the running vm instance.
 	// It returns error if there are any errors during Stop
 	Stop(_ context.Context) error
+}
 
-	// Register will add an instance to a registry.
-	// It returns error if there are any errors during Register
-	Register(_ context.Context) error
+// GUI defines GUI-related operations.
+type GUI interface {
+	// RunGUI is for starting GUI synchronously by hostagent. This method should be wait and return only after vm terminates
+	// It returns error if there are any failures
+	RunGUI() error
 
-	// Unregister will perform any cleanup related to the vm instance.
-	// It returns error if there are any errors during Unregister
-	Unregister(_ context.Context) error
+	ChangeDisplayPassword(ctx context.Context, password string) error
+	DisplayConnection(ctx context.Context) (string, error)
+}
 
-	ChangeDisplayPassword(_ context.Context, password string) error
+// SnapshotManager defines operations for managing snapshots.
+type SnapshotManager interface {
+	CreateSnapshot(ctx context.Context, tag string) error
+	ApplySnapshot(ctx context.Context, tag string) error
+	DeleteSnapshot(ctx context.Context, tag string) error
+	ListSnapshots(ctx context.Context) (string, error)
+}
 
-	GetDisplayConnection(_ context.Context) (string, error)
+// Registration defines operations for registering and unregistering the driver instance.
+type Registration interface {
+	Register(ctx context.Context) error
+	Unregister(ctx context.Context) error
+}
 
-	CreateSnapshot(_ context.Context, tag string) error
+// GuestAgent defines operations for the guest agent.
+type GuestAgent interface {
+	// ForwardGuestAgent returns if the guest agent sock needs forwarding by host agent.
+	ForwardGuestAgent() bool
 
-	ApplySnapshot(_ context.Context, tag string) error
+	// GuestAgentConn returns the guest agent connection, or nil (if forwarded by ssh).
+	GuestAgentConn(_ context.Context) (net.Conn, string, error)
+}
 
-	DeleteSnapshot(_ context.Context, tag string) error
+// Driver interface is used by hostagent for managing vm.
+type Driver interface {
+	Lifecycle
+	GUI
+	SnapshotManager
+	Registration
+	GuestAgent
 
-	ListSnapshots(_ context.Context) (string, error)
+	Info() Info
 
-	// ForwardGuestAgent returns if the guest agent sock needs forwarding by host agent.
-	ForwardGuestAgent() bool
+	// SetConfig sets the configuration for the instance.
+	Configure(inst *store.Instance, sshLocalPort int) *ConfiguredDriver
+}
 
-	// GuestAgentConn returns the guest agent connection, or nil (if forwarded by ssh).
-	GuestAgentConn(_ context.Context) (net.Conn, error)
+type ConfiguredDriver struct {
+	Driver
+}
 
-	VSockPort() int
-	VirtioPort() string
+type Info struct {
+	DriverName  string `json:"driverName"`
+	CanRunGUI   bool   `json:"canRunGui,omitempty"`
+	VsockPort   int    `json:"vsockPort"`
+	VirtioPort  string `json:"virtioPort"`
+	InstanceDir string `json:"instanceDir,omitempty"`
 }

pkg/driver/qemu/qemu_driver.go

@@ -50,7 +50,7 @@ type LimaQemuDriver struct {
 
 var _ driver.Driver = (*LimaQemuDriver)(nil)
 
-func New(inst *store.Instance, sshLocalPort int) *LimaQemuDriver {
+func New() *LimaQemuDriver {
 	// virtserialport doesn't seem to work reliably: https://github.com/lima-vm/lima/issues/2064
 	// but on Windows default Unix socket forwarding is not available
 	var virtioPort string
@@ -59,10 +59,17 @@ func New(inst *store.Instance, sshLocalPort int) *LimaQemuDriver {
 		virtioPort = ""
 	}
 	return &LimaQemuDriver{
-		Instance:     inst,
-		vSockPort:    0,
-		virtioPort:   virtioPort,
-		SSHLocalPort: sshLocalPort,
+		vSockPort:  0,
+		virtioPort: virtioPort,
+	}
+}
+
+func (l *LimaQemuDriver) Configure(inst *store.Instance, sshLocalPort int) *driver.ConfiguredDriver {
+	l.Instance = inst
+	l.SSHLocalPort = sshLocalPort
+
+	return &driver.ConfiguredDriver{
+		Driver: l,
 	}
 }
 
@@ -238,7 +245,7 @@ func (l *LimaQemuDriver) ChangeDisplayPassword(_ context.Context, password strin
 	return l.changeVNCPassword(password)
 }
 
-func (l *LimaQemuDriver) GetDisplayConnection(_ context.Context) (string, error) {
+func (l *LimaQemuDriver) DisplayConnection(_ context.Context) (string, error) {
 	return l.getVNCDisplayPort()
 }
 
@@ -450,10 +457,10 @@ func (l *LimaQemuDriver) ListSnapshots(_ context.Context) (string, error) {
 	return List(qCfg, l.Instance.Status == store.StatusRunning)
 }
 
-func (l *LimaQemuDriver) GuestAgentConn(ctx context.Context) (net.Conn, error) {
+func (l *LimaQemuDriver) GuestAgentConn(ctx context.Context) (net.Conn, string, error) {
 	var d net.Dialer
 	dialContext, err := d.DialContext(ctx, "unix", filepath.Join(l.Instance.Dir, filenames.GuestAgentSock))
-	return dialContext, err
+	return dialContext, "unix", err
 }
 
 type qArgTemplateApplier struct {
@@ -508,12 +515,20 @@ func (a *qArgTemplateApplier) applyTemplate(qArg string) (string, error) {
 	return b.String(), nil
 }
 
-func (l *LimaQemuDriver) Initialize(_ context.Context) error {
-	return nil
+func (l *LimaQemuDriver) Info() driver.Info {
+	var info driver.Info
+	if l.Instance != nil && l.Instance.Dir != "" {
+		info.InstanceDir = l.Instance.Dir
+	}
+	info.DriverName = "qemu"
+	info.CanRunGUI = false
+	info.VirtioPort = l.virtioPort
+	info.VsockPort = l.vSockPort
+	return info
 }
 
-func (l *LimaQemuDriver) CanRunGUI() bool {
-	return false
+func (l *LimaQemuDriver) Initialize(_ context.Context) error {
+	return nil
 }
 
 func (l *LimaQemuDriver) RunGUI() error {
@@ -532,11 +547,3 @@ func (l *LimaQemuDriver) ForwardGuestAgent() bool {
 	// if driver is not providing, use host agent
 	return l.vSockPort == 0 && l.virtioPort == ""
 }
-
-func (l *LimaQemuDriver) VSockPort() int {
-	return l.vSockPort
-}
-
-func (l *LimaQemuDriver) VirtioPort() string {
-	return l.virtioPort
-}

pkg/driver/qemu/register.go

@@ -0,0 +1,12 @@
+//go:build !external_qemu
+
+// SPDX-FileCopyrightText: Copyright The Lima Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package qemu
+
+import "github.com/lima-vm/lima/pkg/registry"
+
+func init() {
+	registry.Register(New())
+}

pkg/driver/vz/errors_darwin.go

@@ -8,4 +8,7 @@ package vz
 import "errors"
 
 //nolint:revive,staticcheck // false positives with proper nouns
-var errRosettaUnsupported = errors.New("Rosetta is unsupported on non-ARM64 hosts")
+var (
+	errRosettaUnsupported = errors.New("Rosetta is unsupported on non-ARM64 hosts")
+	errUnimplemented      = errors.New("unimplemented")
+)

pkg/driver/vz/register.go

@@ -0,0 +1,12 @@
+//go:build darwin && !external_vz
+
+// SPDX-FileCopyrightText: Copyright The Lima Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package vz
+
+import "github.com/lima-vm/lima/pkg/registry"
+
+func init() {
+	registry.Register(New())
+}

pkg/driver/vz/vz_driver_darwin.go

@@ -80,12 +80,19 @@ type LimaVzDriver struct {
 
 var _ driver.Driver = (*LimaVzDriver)(nil)
 
-func New(inst *store.Instance, sshLocalPort int) *LimaVzDriver {
+func New() *LimaVzDriver {
 	return &LimaVzDriver{
-		Instance:     inst,
-		vSockPort:    2222,
-		virtioPort:   "",
-		SSHLocalPort: sshLocalPort,
+		vSockPort:  2222,
+		virtioPort: "",
+	}
+}
+
+func (l *LimaVzDriver) Configure(inst *store.Instance, sshLocalPort int) *driver.ConfiguredDriver {
+	l.Instance = inst
+	l.SSHLocalPort = sshLocalPort
+
+	return &driver.ConfiguredDriver{
+		Driver: l,
 	}
 }
 
@@ -197,7 +204,7 @@ func (l *LimaVzDriver) Start(ctx context.Context) (chan error, error) {
 	return errCh, nil
 }
 
-func (l *LimaVzDriver) CanRunGUI() bool {
+func (l *LimaVzDriver) canRunGUI() bool {
 	switch *l.Instance.Config.Video.Display {
 	case "vz", "default":
 		return true
@@ -207,7 +214,7 @@ func (l *LimaVzDriver) CanRunGUI() bool {
 }
 
 func (l *LimaVzDriver) RunGUI() error {
-	if l.CanRunGUI() {
+	if l.canRunGUI() {
 		return l.machine.StartGraphicApplication(1920, 1200)
 	}
 	return fmt.Errorf("RunGUI is not supported for the given driver '%s' and display '%s'", "vz", *l.Instance.Config.Video.Display)
@@ -243,14 +250,28 @@ func (l *LimaVzDriver) Stop(_ context.Context) error {
 	return errors.New("vz: CanRequestStop is not supported")
 }
 
-func (l *LimaVzDriver) GuestAgentConn(_ context.Context) (net.Conn, error) {
+func (l *LimaVzDriver) GuestAgentConn(_ context.Context) (net.Conn, string, error) {
 	for _, socket := range l.machine.SocketDevices() {
 		connect, err := socket.Connect(uint32(l.vSockPort))
-		if err == nil && connect.SourcePort() != 0 {
-			return connect, nil
-		}
+		return connect, "vsock", err
 	}
-	return nil, errors.New("unable to connect to guest agent via vsock port 2222")
+
+	return nil, "", errors.New("unable to connect to guest agent via vsock port 2222")
+}
+
+func (l *LimaVzDriver) Info() driver.Info {
+	var info driver.Info
+	if l.Instance != nil {
+		info.CanRunGUI = l.canRunGUI()
+	}
+
+	info.DriverName = "vz"
+	info.VsockPort = l.vSockPort
+	info.VirtioPort = l.virtioPort
+	if l.Instance != nil {
+		info.InstanceDir = l.Instance.Dir
+	}
+	return info
 }
 
 func (l *LimaVzDriver) Register(_ context.Context) error {
@@ -265,35 +286,27 @@ func (l *LimaVzDriver) ChangeDisplayPassword(_ context.Context, _ string) error
 	return nil
 }
 
-func (l *LimaVzDriver) GetDisplayConnection(_ context.Context) (string, error) {
+func (l *LimaVzDriver) DisplayConnection(_ context.Context) (string, error) {
 	return "", nil
 }
 
 func (l *LimaVzDriver) CreateSnapshot(_ context.Context, _ string) error {
-	return errors.New("unimplemented")
+	return errUnimplemented
 }
 
 func (l *LimaVzDriver) ApplySnapshot(_ context.Context, _ string) error {
-	return errors.New("unimplemented")
+	return errUnimplemented
 }
 
 func (l *LimaVzDriver) DeleteSnapshot(_ context.Context, _ string) error {
-	return errors.New("unimplemented")
+	return errUnimplemented
 }
 
 func (l *LimaVzDriver) ListSnapshots(_ context.Context) (string, error) {
-	return "", errors.New("unimplemented")
+	return "", errUnimplemented
 }
 
 func (l *LimaVzDriver) ForwardGuestAgent() bool {
 	// If driver is not providing, use host agent
 	return l.vSockPort == 0 && l.virtioPort == ""
 }
-
-func (l *LimaVzDriver) VSockPort() int {
-	return l.vSockPort
-}
-
-func (l *LimaVzDriver) VirtioPort() string {
-	return l.virtioPort
-}