Add cleanup feature as part of command set

The 'cleanup' methods should ignore as many errors as possible when
doing their job, to cope with both the nominal case, and cases where
some of the checks are disabled/skipped. Which would mean we don't need to
check the config options, as the 'cleanup' method will be appropriate
in both cases.

As of now, cleanup command for linux is partial since we are not sure
if virt installed packages as part of setup command or by the user.
Also user added himself as part of libvirt group or it happened by
setup command.

cmd/crc/cmd/cleanup.go

@@ -0,0 +1,27 @@
+package cmd
+
+import (
+	"fmt"
+
+	"github.com/code-ready/crc/pkg/crc/output"
+	"github.com/code-ready/crc/pkg/crc/preflight"
+	"github.com/spf13/cobra"
+)
+
+func init() {
+	rootCmd.AddCommand(cleanupCmd)
+}
+
+var cleanupCmd = &cobra.Command{
+	Use:   "cleanup",
+	Short: fmt.Sprintf("Undo config changes"),
+	Long:  "Undo all the configuration changes done by 'crc setup' command",
+	Run: func(cmd *cobra.Command, args []string) {
+		runCleanup(args)
+	},
+}
+
+func runCleanup(arguments []string) {
+	preflight.CleanUpHost()
+	output.Outln("Cleanup finished")
+}

pkg/crc/preflight/preflight.go

@@ -19,18 +19,22 @@ const (
 	// Indicates a PreflightCheck should only be run as part of "crc start"
 	StartOnly
 	NoFix
+	CleanUpOnly
 )
 
 type PreflightCheckFunc func() error
 type PreflightFixFunc func() error
+type PreflightCleanUpFunc func() error
 
 type PreflightCheck struct {
-	configKeySuffix  string
-	checkDescription string
-	check            PreflightCheckFunc
-	fixDescription   string
-	fix              PreflightFixFunc
-	flags            PreflightCheckFlags
+	configKeySuffix    string
+	checkDescription   string
+	check              PreflightCheckFunc
+	fixDescription     string
+	fix                PreflightFixFunc
+	flags              PreflightCheckFlags
+	cleanupDescription string
+	cleanup            PreflightCleanUpFunc
 }
 
 func (check *PreflightCheck) getSkipConfigName() string {
@@ -92,9 +96,19 @@ func (check *PreflightCheck) doFix() error {
 	return check.fix()
 }
 
+func (check *PreflightCheck) doCleanUp() error {
+	if check.cleanupDescription == "" {
+		panic(fmt.Sprintf("Should not happen, empty description for cleanup '%s'", check.configKeySuffix))
+	}
+
+	logging.Infof("%s", check.cleanupDescription)
+
+	return check.cleanup()
+}
+
 func doPreflightChecks(checks []PreflightCheck) {
 	for _, check := range checks {
-		if check.flags&SetupOnly == SetupOnly {
+		if check.flags&SetupOnly == SetupOnly || check.flags&CleanUpOnly == CleanUpOnly {
 			continue
 		}
 		err := check.doCheck()
@@ -110,7 +124,7 @@ func doPreflightChecks(checks []PreflightCheck) {
 
 func doFixPreflightChecks(checks []PreflightCheck) {
 	for _, check := range checks {
-		if check.flags&StartOnly == StartOnly {
+		if check.flags&StartOnly == StartOnly || check.flags&CleanUpOnly == CleanUpOnly {
 			continue
 		}
 		err := check.doCheck()
@@ -128,6 +142,20 @@ func doFixPreflightChecks(checks []PreflightCheck) {
 	}
 }
 
+func doCleanUpPreflightChecks(checks []PreflightCheck) {
+	// Do the cleanup in reverse order to avoid any dependency during cleanup
+	for i := len(checks) - 1; i >= 0; i-- {
+		check := checks[i]
+		if check.cleanup == nil {
+			continue
+		}
+		err := check.doCleanUp()
+		if err != nil {
+			logging.Fatal(err.Error())
+		}
+	}
+}
+
 func doRegisterSettings(checks []PreflightCheck) {
 	for _, check := range checks {
 		if check.configKeySuffix != "" {

pkg/crc/preflight/preflight_checks_linux.go

@@ -362,6 +362,56 @@ func fixLibvirtCrcNetworkAvailable() error {
 	return nil
 }
 
+func removeLibvirtCrcNetwork() error {
+	logging.Debug("Removing libvirt 'crc' network")
+	_, _, err := crcos.RunWithDefaultLocale("virsh", "--connect", "qemu:///system", "net-info", libvirt.DefaultNetwork)
+	if err != nil {
+		// Ignore if no crc network exists for libvirt
+		// User may have manually deleted the `crc` network from libvirt
+		return nil
+	}
+	_, stderr, err := crcos.RunWithDefaultLocale("virsh", "--connect", "qemu:///system", "net-destroy", libvirt.DefaultNetwork)
+	if err != nil {
+		logging.Debugf("%v : %s", err, stderr)
+		return fmt.Errorf("Failed to destroy libvirt 'crc' network")
+	}
+
+	_, stderr, err = crcos.RunWithDefaultLocale("virsh", "--connect", "qemu:///system", "net-undefine", libvirt.DefaultNetwork)
+	if err != nil {
+		logging.Debugf("%v : %s", err, stderr)
+		return fmt.Errorf("Failed to undefine libvirt 'crc' network")
+	}
+	logging.Debug("libvirt 'crc' network removed")
+	return nil
+}
+
+func removeCrcVM() error {
+	logging.Debug("Removing 'crc' VM")
+	_, _, err := crcos.RunWithDefaultLocale("virsh", "--connect", "qemu:///system", "dominfo", constants.DefaultName)
+	if err != nil {
+		//  User may have run `crc delete` before `crc cleanup`
+		//  in that case there is no crc vm so return early.
+		return nil
+	}
+	_, stderr, err := crcos.RunWithDefaultLocale("virsh", "--connect", "qemu:///system", "destroy", constants.DefaultName)
+	if err != nil {
+		logging.Debugf("%v : %s", err, stderr)
+		return fmt.Errorf("Failed to destroy 'crc' VM")
+	}
+	_, stderr, err = crcos.RunWithDefaultLocale("virsh", "--connect", "qemu:///system", "undefine", constants.DefaultName)
+	if err != nil {
+		logging.Debugf("%v : %s", err, stderr)
+		return fmt.Errorf("Failed to undefine 'crc' VM")
+	}
+	if err := os.RemoveAll(constants.MachineInstanceDir); err != nil {
+		logging.Debugf("Error removing %s dir: %v", constants.MachineInstanceDir, err)
+		return fmt.Errorf("Error removing %s dir", constants.MachineInstanceDir)
+	}
+	logging.Debug("'crc' VM is removed")
+
+	return nil
+}
+
 func trimSpacesFromXML(str string) string {
 	strs := strings.Split(str, "\n")
 	var builder strings.Builder
@@ -472,6 +522,32 @@ func fixCrcDnsmasqConfigFile() error {
 	return nil
 }
 
+func removeCrcDnsmasqConfigFile() error {
+	if err := checkNetworkManagerInstalled(); err != nil {
+		// When NetworkManager is not installed, this file won't exist
+		return nil
+	}
+	// Delete the `crcDnsmasqConfigPath` file if exists,
+	// ignore all the os PathError except `IsNotExist` one.
+	if _, err := os.Stat(crcDnsmasqConfigPath); !os.IsNotExist(err) {
+		logging.Debug("Removing dnsmasq configuration")
+		err := crcos.RemoveFileAsRoot(
+			fmt.Sprintf("removing dnsmasq configuration in %s", crcDnsmasqConfigPath),
+			crcDnsmasqConfigPath,
+		)
+		if err != nil {
+			return fmt.Errorf("Failed to remove dnsmasq config file: %s: %v", crcDnsmasqConfigPath, err)
+		}
+
+		logging.Debug("Reloading NetworkManager")
+		sd := systemd.NewHostSystemdCommander()
+		if _, err := sd.Reload("NetworkManager"); err != nil {
+			return fmt.Errorf("Failed to restart NetworkManager: %v", err)
+		}
+	}
+	return nil
+}
+
 func checkCrcNetworkManagerConfig() error {
 	logging.Debug("Checking NetworkManager configuration")
 	c := []byte(crcNetworkManagerConfig)
@@ -511,6 +587,30 @@ func fixCrcNetworkManagerConfig() error {
 	return nil
 }
 
+func removeCrcNetworkManagerConfig() error {
+	if err := checkNetworkManagerInstalled(); err != nil {
+		// When NetworkManager is not installed, this file won't exist
+		return nil
+	}
+	if _, err := os.Stat(crcNetworkManagerConfigPath); !os.IsNotExist(err) {
+		logging.Debug("Removing NetworkManager configuration")
+		err := crcos.RemoveFileAsRoot(
+			fmt.Sprintf("Removing NetworkManager config in %s", crcNetworkManagerConfigPath),
+			crcNetworkManagerConfigPath,
+		)
+		if err != nil {
+			return fmt.Errorf("Failed to remove NetworkManager config file: %s: %v", crcNetworkManagerConfigPath, err)
+		}
+
+		logging.Debug("Reloading NetworkManager")
+		sd := systemd.NewHostSystemdCommander()
+		if _, err := sd.Reload("NetworkManager"); err != nil {
+			return fmt.Errorf("Failed to restart NetworkManager: %v", err)
+		}
+	}
+	return nil
+}
+
 func checkNetworkManagerInstalled() error {
 	logging.Debug("Checking if 'nmcli' is available")
 	path, err := exec.LookPath("nmcli")

pkg/crc/preflight/preflight_darwin.go

@@ -2,6 +2,8 @@ package preflight
 
 import (
 	"fmt"
+
+	"github.com/code-ready/crc/pkg/crc/logging"
 )
 
 // SetupHost performs the prerequisite checks and setups the host to run the cluster
@@ -113,3 +115,8 @@ func SetupHost() {
 func RegisterSettings() {
 	doRegisterSettings(getPreflightChecks())
 }
+
+func CleanUpHost() {
+	logging.Warn("Cleanup is not supported for MacOS")
+	doCleanUpPreflightChecks(getPreflightChecks())
+}

pkg/crc/preflight/preflight_linux.go

@@ -65,11 +65,13 @@ var libvirtPreflightChecks = [...]PreflightCheck{
 		flags:            SetupOnly,
 	},
 	{
-		configKeySuffix:  "check-crc-network",
-		checkDescription: "Checking if libvirt 'crc' network is available",
-		check:            checkLibvirtCrcNetworkAvailable,
-		fixDescription:   "Setting up libvirt 'crc' network",
-		fix:              fixLibvirtCrcNetworkAvailable,
+		configKeySuffix:    "check-crc-network",
+		checkDescription:   "Checking if libvirt 'crc' network is available",
+		check:              checkLibvirtCrcNetworkAvailable,
+		fixDescription:     "Setting up libvirt 'crc' network",
+		fix:                fixLibvirtCrcNetworkAvailable,
+		cleanupDescription: "Removing 'crc' network from libvirt",
+		cleanup:            removeLibvirtCrcNetwork,
 	},
 	{
 		configKeySuffix:  "check-crc-network-active",
@@ -93,18 +95,27 @@ var libvirtPreflightChecks = [...]PreflightCheck{
 		fix:              fixNetworkManagerIsRunning,
 	},
 	{
-		configKeySuffix:  "check-network-manager-config",
-		checkDescription: "Checking if /etc/NetworkManager/conf.d/crc-nm-dnsmasq.conf exists",
-		check:            checkCrcNetworkManagerConfig,
-		fixDescription:   "Writing Network Manager config for crc",
-		fix:              fixCrcNetworkManagerConfig,
+		configKeySuffix:    "check-network-manager-config",
+		checkDescription:   "Checking if /etc/NetworkManager/conf.d/crc-nm-dnsmasq.conf exists",
+		check:              checkCrcNetworkManagerConfig,
+		fixDescription:     "Writing Network Manager config for crc",
+		fix:                fixCrcNetworkManagerConfig,
+		cleanupDescription: "Removing /etc/NetworkManager/conf.d/crc-nm-dnsmasq.conf file",
+		cleanup:            removeCrcNetworkManagerConfig,
 	},
 	{
-		configKeySuffix:  "check-crc-dnsmasq-file",
-		checkDescription: "Checking if /etc/NetworkManager/dnsmasq.d/crc.conf exists",
-		check:            checkCrcDnsmasqConfigFile,
-		fixDescription:   "Writing dnsmasq config for crc",
-		fix:              fixCrcDnsmasqConfigFile,
+		configKeySuffix:    "check-crc-dnsmasq-file",
+		checkDescription:   "Checking if /etc/NetworkManager/dnsmasq.d/crc.conf exists",
+		check:              checkCrcDnsmasqConfigFile,
+		fixDescription:     "Writing dnsmasq config for crc",
+		fix:                fixCrcDnsmasqConfigFile,
+		cleanupDescription: "Removing /etc/NetworkManager/dnsmasq.d/crc.conf file",
+		cleanup:            removeCrcDnsmasqConfigFile,
+	},
+	{
+		cleanupDescription: "Removing the crc VM if exists",
+		cleanup:            removeCrcVM,
+		flags:              CleanUpOnly,
 	},
 }
 
@@ -130,3 +141,7 @@ func SetupHost() {
 func RegisterSettings() {
 	doRegisterSettings(getPreflightChecks())
 }
+
+func CleanUpHost() {
+	doCleanUpPreflightChecks(getPreflightChecks())
+}

pkg/crc/preflight/preflight_windows.go

@@ -1,5 +1,7 @@
 package preflight
 
+import "github.com/code-ready/crc/pkg/crc/logging"
+
 var hypervPreflightChecks = [...]PreflightCheck{
 	{
 		configKeySuffix:  "check-administrator-user",
@@ -66,3 +68,8 @@ func SetupHost() {
 func RegisterSettings() {
 	doRegisterSettings(getPreflightChecks())
 }
+
+func CleanUpHost() {
+	logging.Warn("Cleanup is not supported for Windows")
+	doCleanUpPreflightChecks(getPreflightChecks())
+}

pkg/os/util_linux.go

@@ -20,3 +20,8 @@ func WriteToFileAsRoot(reason, content, filepath string) error {
 	}
 	return nil
 }
+
+func RemoveFileAsRoot(reason, filepath string) error {
+	_, _, err := RunWithPrivilege(reason, "rm", "-fr", filepath)
+	return err
+}