cli_tools/gce_windows_upgrade/upgrader/upgrader.go

//  Copyright 2020 Google Inc. All Rights Reserved.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.

package upgrader

import (
	"context"
	"fmt"
	"log"
	"os"

	daisy "github.com/GoogleCloudPlatform/compute-daisy"
	daisyCompute "github.com/GoogleCloudPlatform/compute-daisy/compute"
	"google.golang.org/api/option"

	"github.com/GoogleCloudPlatform/compute-image-tools/cli_tools/common/utils/compute"
	"github.com/GoogleCloudPlatform/compute-image-tools/cli_tools/common/utils/daisyutils"
	"github.com/GoogleCloudPlatform/compute-image-tools/cli_tools/common/utils/logging"
	"github.com/GoogleCloudPlatform/compute-image-tools/cli_tools/common/utils/path"
)

// Parameter key shared with external packages
const (
	ClientIDFlagKey = "client-id"
	DefaultTimeout  = "90m"
)

const (
	logPrefix = "[windows-upgrade]"

	metadataWindowsStartupScriptURL       = "windows-startup-script-url"
	metadataWindowsStartupScriptURLBackup = "windows-startup-script-url-backup"
)

type derivedVars struct {
	instanceProject string
	instanceZone    string
	instanceURI     string

	osDiskURI        string
	osDiskType       string
	osDiskDeviceName string
	osDiskAutoDelete bool

	instanceName           string
	machineImageBackupName string
	osDiskSnapshotName     string
	newOSDiskName          string
	installMediaDiskName   string

	originalWindowsStartupScriptURL *string
	executionID                     string
}

// InputParams contains input params for the upgrade.
type InputParams struct {
	ClientID               string
	ProjectPtr             *string
	Zone                   string
	Instance               string
	CreateMachineBackup    bool
	AutoRollback           bool
	SourceOS               string
	TargetOS               string
	Timeout                string
	UseStagingInstallMedia bool
	ScratchBucketGcsPath   string
	Oauth                  string
	Ce                     string
	GcsLogsDisabled        bool
	CloudLogsDisabled      bool
	StdoutLogsDisabled     bool
}

type upgrader struct {
	*InputParams
	*derivedVars

	ctx context.Context

	initFn                    func() error
	printIntroHelpTextFn      func() error
	validateAndDeriveParamsFn func() error
	prepareFn                 func() (daisyutils.DaisyWorker, error)
	upgradeFn                 func() (daisyutils.DaisyWorker, error)
	retryUpgradeFn            func() (daisyutils.DaisyWorker, error)
	rebootFn                  func() (daisyutils.DaisyWorker, error)
	cleanupFn                 func() (daisyutils.DaisyWorker, error)
	rollbackFn                func() (daisyutils.DaisyWorker, error)

	logger logging.Logger
}

// Run runs upgrader.
func Run(p *InputParams, logger logging.Logger) error {
	u := upgrader{
		InputParams: p,
		logger:      logger,
		derivedVars: &derivedVars{
			executionID: os.Getenv(daisyutils.BuildIDOSEnvVarName),
		},
	}
	if u.executionID == "" {
		u.executionID = path.RandString(5)
	}
	return u.run()
}

func (u *upgrader) run() error {
	if err := u.init(); err != nil {
		return err
	}
	if err := u.validateAndDeriveParams(); err != nil {
		return err
	}
	if err := u.printIntroHelpText(); err != nil {
		return err
	}
	_, err := u.runUpgradeWorkflow()
	return err
}

func (u *upgrader) init() error {
	if u.initFn != nil {
		return u.initFn()
	}

	log.SetPrefix(logPrefix + " ")

	var err error
	u.ctx = context.Background()
	computeClient, err = daisyCompute.NewClient(u.ctx, option.WithCredentialsFile(u.Oauth))
	mgce = &compute.MetadataGCE{}
	if err != nil {
		return daisy.Errf("Failed to create GCE client: %v", err)
	}
	return nil
}

func (u *upgrader) printIntroHelpText() error {
	if u.printIntroHelpTextFn != nil {
		return u.printIntroHelpTextFn()
	}

	guide, err := getIntroHelpText(u)
	if err != nil {
		return err
	}
	fmt.Print(guide, "\n\n")
	return nil
}

func (u *upgrader) runUpgradeWorkflow() (daisyutils.DaisyWorker, error) {
	var err error

	// If upgrade failed, run cleanup or rollback before exiting.
	defer func() {
		u.handleResult(err)
	}()

	// step 1: preparation - take snapshot, attach install media, backup/set startup script
	fmt.Print("\nPreparing for upgrade...\n\n")
	prepareWf, err := u.prepare()
	if err != nil {
		return prepareWf, err
	}

	// step 2: run upgrade.
	fmt.Print("\nRunning upgrade...\n\n")
	upgradeWf, err := u.upgrade()
	if err == nil {
		return upgradeWf, nil
	}

	// step 3: reboot if necessary.
	if !needReboot(err) {
		return upgradeWf, err
	}
	fmt.Print("\nRebooting...\n\n")
	rebootWf, err := u.reboot()
	if err != nil {
		return rebootWf, err
	}

	// step 4: retry upgrade.
	fmt.Print("\nRetrying upgrade...\n\n")
	retryUpgradeWf, err := u.retryUpgrade()
	return retryUpgradeWf, err
}

func (u *upgrader) handleResult(err error) {
	if err == nil {
		fmt.Printf("\nSuccessfully upgraded instance '%v' to '%v'.\n", u.instanceURI, u.TargetOS)
		fmt.Printf("\nPlease verify your application's functionality on the " +
			"instance, and if you run into any issues, please manually rollback following " +
			"the instructions in the guide." +
			"\nFull document: https://cloud.google.com/compute/docs/tutorials/performing-an-automated-in-place-upgrade-windows-server\n\n")
		if cleanupIntro, err := getCleanupIntroduction(u); err == nil {
			fmt.Printf(cleanupIntro)
		}
		return
	}

	isNewOSDiskAttached := isNewOSDiskAttached(u.instanceProject, u.instanceZone, u.instanceName, u.newOSDiskName)
	if u.AutoRollback {
		if isNewOSDiskAttached {
			fmt.Printf("\nUpgrade failed to finish. Rolling back to the "+
				"original state from the original boot disk '%v'...\n\n", u.osDiskURI)
			_, err := u.rollback()
			if err != nil {
				fmt.Printf("\nRollback failed. Error: %v\n"+
					"Please rollback the image manually following the instructions in the guide.\n\n", err)
			} else {
				fmt.Printf("\nCompleted rollback to the original boot disk. Please " +
					"verify the rollback. If the rollback does not function as expected, " +
					"consider restoring the instance from the machine image.\n\n")
			}
			return
		}
		fmt.Printf("\nNo boot disk attached during the failure. No need to rollback. "+
			"If the instance doesn't work as expected, please verify that the original "+
			"boot disk (%v) is attached and whether the instance has started. If necessary, "+
			"please manually rollback by using the instructions in the guide..\n\n", u.osDiskURI)
	}

	fmt.Printf("\nUpgrade failed. Please manually rollback following the " +
		"instructions in the guide.\n\n")

	fmt.Print("\nCleaning up temporary resources...\n\n")
	if _, err := u.cleanup(); err != nil {
		fmt.Printf("\nFailed to cleanup temporary resources: %v\n"+
			"Please cleanup the resources manually by following the instructions in the guide.\n\n", err)
	}
}