cache_images.go

/*
Copyright 2016 The Kubernetes Authors 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 machine

import (
	"fmt"
	"os"
	"path"
	"path/filepath"
	"strings"
	"sync"
	"time"

	"github.com/docker/docker/client"
	"github.com/docker/machine/libmachine/state"
	"github.com/pkg/errors"
	"golang.org/x/sync/errgroup"
	"k8s.io/klog/v2"
	"k8s.io/minikube/pkg/minikube/assets"
	"k8s.io/minikube/pkg/minikube/bootstrapper"
	"k8s.io/minikube/pkg/minikube/command"
	"k8s.io/minikube/pkg/minikube/config"
	"k8s.io/minikube/pkg/minikube/constants"
	"k8s.io/minikube/pkg/minikube/cruntime"
	"k8s.io/minikube/pkg/minikube/image"
	"k8s.io/minikube/pkg/minikube/localpath"
	"k8s.io/minikube/pkg/minikube/vmpath"
)

// loadRoot is where images should be loaded from within the guest VM
var loadRoot = path.Join(vmpath.GuestPersistentDir, "images")

// loadImageLock is used to serialize image loads to avoid overloading the guest VM
var loadImageLock sync.Mutex

// CacheImagesForBootstrapper will cache images for a bootstrapper
func CacheImagesForBootstrapper(imageRepository string, version string, clusterBootstrapper string) error {
	images, err := bootstrapper.GetCachedImageList(imageRepository, version, clusterBootstrapper)
	if err != nil {
		return errors.Wrap(err, "cached images list")
	}

	if err := image.SaveToDir(images, constants.ImageCacheDir); err != nil {
		return errors.Wrapf(err, "Caching images for %s", clusterBootstrapper)
	}

	return nil
}

// LoadCachedImages loads previously cached images into the container runtime
func LoadCachedImages(cc *config.ClusterConfig, runner command.Runner, images []string, cacheDir string) error {
	cr, err := cruntime.New(cruntime.Config{Type: cc.KubernetesConfig.ContainerRuntime, Runner: runner})
	if err != nil {
		return errors.Wrap(err, "runtime")
	}

	// Skip loading images if images already exist
	if cr.ImagesPreloaded(images) {
		klog.Infof("Images are preloaded, skipping loading")
		return nil
	}

	klog.Infof("LoadImages start: %s", images)
	start := time.Now()

	defer func() {
		klog.Infof("LoadImages completed in %s", time.Since(start))
	}()

	var g errgroup.Group

	var imgClient *client.Client
	if cr.Name() == "Docker" {
		imgClient, err = client.NewClientWithOpts(client.FromEnv) // image client
		if err != nil {
			klog.Infof("couldn't get a local image daemon which might be ok: %v", err)
		}
	}

	for _, image := range images {
		image := image
		g.Go(func() error {
			// Put a ten second limit on deciding if an image needs transfer
			// because it takes much less than that time to just transfer the image.
			// This is needed because if running in offline mode, we can spend minutes here
			// waiting for i/o timeout.
			err := timedNeedsTransfer(imgClient, image, cr, 10*time.Second)
			if err == nil {
				return nil
			}
			klog.Infof("%q needs transfer: %v", image, err)
			return transferAndLoadCachedImage(runner, cc.KubernetesConfig, image, cacheDir)
		})
	}
	if err := g.Wait(); err != nil {
		return errors.Wrap(err, "loading cached images")
	}
	klog.Infoln("Successfully loaded all cached images")
	return nil
}

func timedNeedsTransfer(imgClient *client.Client, imgName string, cr cruntime.Manager, t time.Duration) error {
	timeout := make(chan bool, 1)
	go func() {
		time.Sleep(t)
		timeout <- true
	}()

	transferFinished := make(chan bool, 1)
	var err error
	go func() {
		err = needsTransfer(imgClient, imgName, cr)
		transferFinished <- true
	}()

	select {
	case <-transferFinished:
		return err
	case <-timeout:
		return fmt.Errorf("needs transfer timed out in %f seconds", t.Seconds())
	}
}

// needsTransfer returns an error if an image needs to be retransfered
func needsTransfer(imgClient *client.Client, imgName string, cr cruntime.Manager) error {
	imgDgst := ""         // for instance sha256:7c92a2c6bbcb6b6beff92d0a940779769c2477b807c202954c537e2e0deb9bed
	if imgClient != nil { // if possible try to get img digest from Client lib which is 4s faster.
		imgDgst = image.DigestByDockerLib(imgClient, imgName)
		if imgDgst != "" {
			if !cr.ImageExists(imgName, imgDgst) {
				return fmt.Errorf("%q does not exist at hash %q in container runtime", imgName, imgDgst)
			}
			return nil
		}
	}
	// if not found with method above try go-container lib (which is 4s slower)
	imgDgst = image.DigestByGoLib(imgName)
	if imgDgst == "" {
		return fmt.Errorf("got empty img digest %q for %s", imgDgst, imgName)
	}
	if !cr.ImageExists(imgName, imgDgst) {
		return fmt.Errorf("%q does not exist at hash %q in container runtime", imgName, imgDgst)
	}
	return nil
}

// LoadLocalImages loads images into the container runtime
func LoadLocalImages(cc *config.ClusterConfig, runner command.Runner, images []string) error {
	var g errgroup.Group
	for _, image := range images {
		image := image
		g.Go(func() error {
			return transferAndLoadImage(runner, cc.KubernetesConfig, image)
		})
	}
	if err := g.Wait(); err != nil {
		return errors.Wrap(err, "loading images")
	}
	klog.Infoln("Successfully loaded all images")
	return nil
}

// CacheAndLoadImages caches and loads images to all profiles
func CacheAndLoadImages(images []string, profiles []*config.Profile) error {
	if len(images) == 0 {
		return nil
	}

	// This is the most important thing
	if err := image.SaveToDir(images, constants.ImageCacheDir); err != nil {
		return errors.Wrap(err, "save to dir")
	}

	return DoLoadImages(images, profiles, constants.ImageCacheDir)
}

// DoLoadImages loads images to all profiles
func DoLoadImages(images []string, profiles []*config.Profile, cacheDir string) error {
	api, err := NewAPIClient()
	if err != nil {
		return errors.Wrap(err, "api")
	}
	defer api.Close()

	succeeded := []string{}
	failed := []string{}

	for _, p := range profiles { // loading images to all running profiles
		pName := p.Name // capture the loop variable

		c, err := config.Load(pName)
		if err != nil {
			// Non-fatal because it may race with profile deletion
			klog.Errorf("Failed to load profile %q: %v", pName, err)
			failed = append(failed, pName)
			continue
		}

		for _, n := range c.Nodes {
			m := config.MachineName(*c, n)

			status, err := Status(api, m)
			if err != nil {
				klog.Warningf("error getting status for %s: %v", m, err)
				failed = append(failed, m)
				continue
			}

			if status == state.Running.String() { // the not running hosts will load on next start
				h, err := api.Load(m)
				if err != nil {
					klog.Warningf("Failed to load machine %q: %v", m, err)
					failed = append(failed, m)
					continue
				}
				cr, err := CommandRunner(h)
				if err != nil {
					return err
				}
				if cacheDir != "" {
					// loading image names, from cache
					err = LoadCachedImages(c, cr, images, cacheDir)
				} else {
					// loading image files
					err = LoadLocalImages(c, cr, images)
				}
				if err != nil {
					failed = append(failed, m)
					klog.Warningf("Failed to load cached images for profile %s. make sure the profile is running. %v", pName, err)
					continue
				}
				succeeded = append(succeeded, m)
			}
		}
	}

	klog.Infof("succeeded pushing to: %s", strings.Join(succeeded, " "))
	klog.Infof("failed pushing to: %s", strings.Join(failed, " "))
	// Live pushes are not considered a failure
	return nil
}

// transferAndLoadCachedImage transfers and loads a single image from the cache
func transferAndLoadCachedImage(cr command.Runner, k8s config.KubernetesConfig, imgName string, cacheDir string) error {
	src := filepath.Join(cacheDir, imgName)
	src = localpath.SanitizeCacheDir(src)
	return transferAndLoadImage(cr, k8s, src)
}

// transferAndLoadImage transfers and loads a single image
func transferAndLoadImage(cr command.Runner, k8s config.KubernetesConfig, src string) error {
	r, err := cruntime.New(cruntime.Config{Type: k8s.ContainerRuntime, Runner: cr})
	if err != nil {
		return errors.Wrap(err, "runtime")
	}
	klog.Infof("Loading image from: %s", src)
	filename := filepath.Base(src)
	if _, err := os.Stat(src); err != nil {
		return err
	}
	dst := path.Join(loadRoot, filename)
	f, err := assets.NewFileAsset(src, loadRoot, filename, "0644")
	if err != nil {
		return errors.Wrapf(err, "creating copyable file asset: %s", filename)
	}
	if err := cr.Copy(f); err != nil {
		return errors.Wrap(err, "transferring cached image")
	}

	loadImageLock.Lock()
	defer loadImageLock.Unlock()

	err = r.LoadImage(dst)
	if err != nil {
		return errors.Wrapf(err, "%s load %s", r.Name(), dst)
	}

	klog.Infof("Transferred and loaded %s from cache", src)
	return nil
}

// removeImages removes images from the container run time
func removeImages(cruntime cruntime.Manager, images []string) error {
	klog.Infof("RemovingImages start: %s", images)
	start := time.Now()

	defer func() {
		klog.Infof("RemovingImages completed in %s", time.Since(start))
	}()

	var g errgroup.Group

	for _, image := range images {
		image := image
		g.Go(func() error {
			return cruntime.RemoveImage(image)
		})
	}
	if err := g.Wait(); err != nil {
		return errors.Wrap(err, "error removing images")
	}
	klog.Infoln("Successfully removed images")
	return nil
}

func RemoveImages(images []string, profile *config.Profile) error {
	api, err := NewAPIClient()
	if err != nil {
		return errors.Wrap(err, "error creating api client")
	}
	defer api.Close()

	succeeded := []string{}
	failed := []string{}

	pName := profile.Name

	c, err := config.Load(pName)
	if err != nil {
		klog.Errorf("Failed to load profile %q: %v", pName, err)
		return errors.Wrapf(err, "error loading config for profile :%v", pName)
	}

	for _, n := range c.Nodes {
		m := config.MachineName(*c, n)

		status, err := Status(api, m)
		if err != nil {
			klog.Warningf("error getting status for %s: %v", m, err)
			continue
		}

		if status == state.Running.String() {
			h, err := api.Load(m)
			if err != nil {
				klog.Warningf("Failed to load machine %q: %v", m, err)
				continue
			}
			runner, err := CommandRunner(h)
			if err != nil {
				return err
			}
			cruntime, err := cruntime.New(cruntime.Config{Type: c.KubernetesConfig.ContainerRuntime, Runner: runner})
			if err != nil {
				return errors.Wrap(err, "error creating container runtime")
			}
			err = removeImages(cruntime, images)
			if err != nil {
				failed = append(failed, m)
				klog.Warningf("Failed to remove images for profile %s %v", pName, err.Error())
				continue
			}
			succeeded = append(succeeded, m)
		}
	}

	klog.Infof("succeeded removing from: %s", strings.Join(succeeded, " "))
	klog.Infof("failed removing from: %s", strings.Join(failed, " "))
	return nil
}