Manager Interface

This is part of a long series of changes. It expands on the sentiment of
the Command interface, but with the goal of handing everything as a
method of the Manager interface.

Why? So its easier to test and change the functionality of the package.
Currently its nearly impossible for a consumer of the package to test,
as everything is operated using functions, and methods on structs such
as Machine. The Manager interface will contain every API call.

The code is currently 100% compatible with existing version, and simply
builds on the existing code. For convenience, Run() function is exposed,
which can be used to run any command using the default manager, while
the APIs are being migrated.

Once the full migration completes, the previous functions will be
deprecated and later removed. This most likely will mean v2 of the
library, but it is fair distance away.

cmd/vbhostd/vbhostd.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"log"
@@ -38,9 +39,11 @@ func main() {
 		logger.Print(msg + "\n")
 	}
 
+	manager := virtualbox.NewManager()
+
 	var vms []string
 	if *vm == "all" {
-		machines, err := virtualbox.ListMachines()
+		machines, err := manager.ListMachines(context.Background())
 		if err != nil {
 			panic(err)
 		}

gen.go

@@ -0,0 +1,3 @@
+package virtualbox
+
+//go:generate mockgen -package=virtualbox -source=vbcmd.go -destination=mockvbcmd_test.go

machine.go

@@ -260,7 +260,7 @@ func (m *Machine) Start() error {
 		args = []string{"startvm", m.Name, "--type", "headless"}
 	}
 
-	_, msg, err := Run(context.Background(), args...)
+	_, msg, err := vboxManageRun(context.Background(), args...)
 	if err != nil {
 		return errors.New(msg)
 	}
@@ -406,44 +406,44 @@ func CreateMachine(name, basefolder string) (*Machine, error) {
 	return m, nil
 }
 
-// Modify changes the settings of the machine.
-func (m *Machine) Modify() error {
-	args := []string{"modifyvm", m.Name,
-		"--firmware", m.Firmware,
+// UpdateMachine updates the machine details based on the struct fields.
+func (m *Manager) UpdateMachine(ctx context.Context, vm *Machine) error {
+	args := []string{"modifyvm", vm.Name,
+		"--firmware", vm.Firmware,
 		"--bioslogofadein", "off",
 		"--bioslogofadeout", "off",
 		"--bioslogodisplaytime", "0",
 		"--biosbootmenu", "disabled",
 
-		"--ostype", m.OSType,
-		"--cpus", fmt.Sprintf("%d", m.CPUs),
-		"--memory", fmt.Sprintf("%d", m.Memory),
-		"--vram", fmt.Sprintf("%d", m.VRAM),
-
-		"--acpi", m.Flag.Get(ACPI),
-		"--ioapic", m.Flag.Get(IOAPIC),
-		"--rtcuseutc", m.Flag.Get(RTCUSEUTC),
-		"--cpuhotplug", m.Flag.Get(CPUHOTPLUG),
-		"--pae", m.Flag.Get(PAE),
-		"--longmode", m.Flag.Get(LONGMODE),
-		"--hpet", m.Flag.Get(HPET),
-		"--hwvirtex", m.Flag.Get(HWVIRTEX),
-		"--triplefaultreset", m.Flag.Get(TRIPLEFAULTRESET),
-		"--nestedpaging", m.Flag.Get(NESTEDPAGING),
-		"--largepages", m.Flag.Get(LARGEPAGES),
-		"--vtxvpid", m.Flag.Get(VTXVPID),
-		"--vtxux", m.Flag.Get(VTXUX),
-		"--accelerate3d", m.Flag.Get(ACCELERATE3D),
-	}
-
-	for i, dev := range m.BootOrder {
+		"--ostype", vm.OSType,
+		"--cpus", fmt.Sprintf("%d", vm.CPUs),
+		"--memory", fmt.Sprintf("%d", vm.Memory),
+		"--vram", fmt.Sprintf("%d", vm.VRAM),
+
+		"--acpi", vm.Flag.Get(ACPI),
+		"--ioapic", vm.Flag.Get(IOAPIC),
+		"--rtcuseutc", vm.Flag.Get(RTCUSEUTC),
+		"--cpuhotplug", vm.Flag.Get(CPUHOTPLUG),
+		"--pae", vm.Flag.Get(PAE),
+		"--longmode", vm.Flag.Get(LONGMODE),
+		"--hpet", vm.Flag.Get(HPET),
+		"--hwvirtex", vm.Flag.Get(HWVIRTEX),
+		"--triplefaultreset", vm.Flag.Get(TRIPLEFAULTRESET),
+		"--nestedpaging", vm.Flag.Get(NESTEDPAGING),
+		"--largepages", vm.Flag.Get(LARGEPAGES),
+		"--vtxvpid", vm.Flag.Get(VTXVPID),
+		"--vtxux", vm.Flag.Get(VTXUX),
+		"--accelerate3d", vm.Flag.Get(ACCELERATE3D),
+	}
+
+	for i, dev := range vm.BootOrder {
 		if i > 3 {
 			break // Only four slots `--boot{1,2,3,4}`. Ignore the rest.
 		}
 		args = append(args, fmt.Sprintf("--boot%d", i+1), dev)
 	}
 
-	for i, nic := range m.NICs {
+	for i, nic := range vm.NICs {
 		n := i + 1
 		args = append(args,
 			fmt.Sprintf("--nic%d", n), string(nic.Network),
@@ -456,10 +456,14 @@ func (m *Machine) Modify() error {
 		}
 	}
 
-	if err := Manage().run(args...); err != nil {
+	if _, _, err := m.run(ctx, args...); err != nil {
 		return err
 	}
-	return m.Refresh()
+	return vm.Refresh()
+}
+
+func (m *Machine) Modify() error {
+	return defaultManager.UpdateMachine(context.Background(), m)
 }
 
 // AddNATPF adds a NAT port forarding rule to the n-th NIC with the given name.
@@ -513,22 +517,27 @@ func (m *Machine) DelStorageCtl(name string) error {
 
 // AttachStorage attaches a storage medium to the named storage controller.
 func (m *Machine) AttachStorage(ctlName string, medium StorageMedium) error {
-	return Manage().run("storageattach", m.Name, "--storagectl", ctlName,
+	_, _, err := defaultManager.run(context.Background(),
+		"storageattach", m.Name, "--storagectl", ctlName,
 		"--port", fmt.Sprintf("%d", medium.Port),
 		"--device", fmt.Sprintf("%d", medium.Device),
 		"--type", string(medium.DriveType),
 		"--medium", medium.Medium,
 	)
+	return err
 }
 
 // SetExtraData attaches custom string to the VM.
 func (m *Machine) SetExtraData(key, val string) error {
-	return Manage().run("setextradata", m.Name, key, val)
+	_, _, err := defaultManager.run(context.Background(),
+		"setextradata", m.Name, key, val)
+	return err
 }
 
 // GetExtraData retrieves custom string from the VM.
 func (m *Machine) GetExtraData(key string) (*string, error) {
-	value, err := Manage().runOut("getextradata", m.Name, key)
+	value, _, err := defaultManager.run(context.Background(),
+		"getextradata", m.Name, key)
 	if err != nil {
 		return nil, err
 	}
@@ -544,13 +553,19 @@ func (m *Machine) GetExtraData(key string) (*string, error) {
 
 // DeleteExtraData removes custom string from the VM.
 func (m *Machine) DeleteExtraData(key string) error {
-	return Manage().run("setextradata", m.Name, key)
+	_, _, err := defaultManager.run(context.Background(),
+		"setextradata", m.Name, key)
+	return err
 }
 
 // CloneMachine clones the given machine name into a new one.
 func CloneMachine(baseImageName string, newImageName string, register bool) error {
 	if register {
-		return Manage().run("clonevm", baseImageName, "--name", newImageName, "--register")
+		_, _, err := defaultManager.run(context.Background(),
+			"clonevm", baseImageName, "--name", newImageName, "--register")
+		return err
 	}
-	return Manage().run("clonevm", baseImageName, "--name", newImageName)
+	_, _, err := defaultManager.run(context.Background(),
+		"clonevm", baseImageName, "--name", newImageName)
+	return err
 }

mock/gen.go

@@ -0,0 +1,3 @@
+package mock
+
+//go:generate mockgen -package=mock -source=../interface.go -destination=interface_mock.go