load_image.go

/*
Copyright 2019 The Kubernetes Authors.

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 nodetasks

import (
	"fmt"
	"os"
	"os/exec"
	"path"
	"path/filepath"
	"strings"

	"k8s.io/klog/v2"
	"k8s.io/kops/pkg/backoff"
	"k8s.io/kops/upup/pkg/fi"
	"k8s.io/kops/upup/pkg/fi/nodeup/local"
	"k8s.io/kops/upup/pkg/fi/utils"
	"k8s.io/kops/util/pkg/hashing"
)

// LoadImageTask is responsible for downloading a docker image
type LoadImageTask struct {
	Name    string
	Sources []string
	Hash    string
	Runtime string
}

var (
	_ fi.NodeupTask            = &LoadImageTask{}
	_ fi.NodeupHasDependencies = &LoadImageTask{}
)

func (t *LoadImageTask) GetDependencies(tasks map[string]fi.NodeupTask) []fi.NodeupTask {
	// LoadImageTask depends on the docker service to ensure we
	// sideload images after docker is completely updated and
	// configured.
	var deps []fi.NodeupTask
	for _, v := range tasks {
		if svc, ok := v.(*Service); ok && svc.Name == containerdService {
			deps = append(deps, v)
		}
		if svc, ok := v.(*Service); ok && svc.Name == dockerService {
			deps = append(deps, v)
		}
	}
	return deps
}

var _ fi.HasName = &LoadImageTask{}

func (t *LoadImageTask) GetName() *string {
	if t.Name == "" {
		return nil
	}
	return &t.Name
}

func (t *LoadImageTask) String() string {
	return fmt.Sprintf("LoadImageTask: %v", t.Sources)
}

func (e *LoadImageTask) Find(c *fi.NodeupContext) (*LoadImageTask, error) {
	klog.Warningf("LoadImageTask checking if image present not yet implemented")
	return nil, nil
}

func (e *LoadImageTask) Run(c *fi.NodeupContext) error {
	return fi.NodeupDefaultDeltaRunMethod(e, c)
}

func (_ *LoadImageTask) CheckChanges(a, e, changes *LoadImageTask) error {
	return nil
}

func (_ *LoadImageTask) RenderLocal(t *local.LocalTarget, a, e, changes *LoadImageTask) error {
	runtime := e.Runtime
	if runtime != "docker" && runtime != "containerd" {
		return fmt.Errorf("no runtime specified")
	}

	hash, err := hashing.FromString(e.Hash)
	if err != nil {
		return err
	}

	urls := e.Sources
	if len(urls) == 0 {
		return fmt.Errorf("no sources specified: %v", err)
	}

	// We assume the first url is the "main" url, and download to a local file based on that _name_, wherever we get it from
	primaryURL := urls[0]
	key := path.Base(primaryURL)
	localFile := filepath.Join(t.CacheDir, hash.String()+"_"+utils.SanitizeString(key))

	for _, url := range urls {
		_, err = fi.DownloadURL(url, localFile, hash)
		if err != nil {
			klog.Warningf("error downloading url %q: %v", url, err)
			continue
		} else {
			break
		}
	}
	if err != nil {
		// Hack to try to avoid failed downloads causing massive bandwidth bills
		backoff.DoGlobalBackoff(fmt.Errorf("failed to download image %s: %v", primaryURL, err))
		return err
	}

	// containerd can't import gzipped container images, if the image is gzipped extract it to tmp dir
	// TODO: Improve the naive gzip format detection by checking the content type bytes "\x1F\x8B\x08"
	var tarFile string
	if strings.HasSuffix(localFile, "gz") {
		tmpDir, err := os.MkdirTemp("", "loadimage")
		if err != nil {
			return fmt.Errorf("error creating temp dir: %v", err)
		}
		defer func() {
			if err := os.RemoveAll(tmpDir); err != nil {
				klog.Warningf("error deleting temp dir %q: %v", tmpDir, err)
			}
		}()
		tarFile = path.Join(tmpDir, utils.SanitizeString(primaryURL))
		err = utils.UngzipFile(localFile, tarFile)
		if err != nil {
			return fmt.Errorf("error ungzipping container image: %v", err)
		}
	} else {
		// Assume container image is tar file alerady
		tarFile = localFile
	}

	// Load the container image
	var args []string
	switch runtime {
	case "docker":
		args = []string{"docker", "load", "-i", tarFile}
	case "containerd":
		args = []string{"ctr", "--namespace", "k8s.io", "images", "import", tarFile}
	default:
		return fmt.Errorf("unknown container runtime: %s", runtime)
	}
	human := strings.Join(args, " ")

	klog.Infof("running command %s", human)
	cmd := exec.Command(args[0], args[1:]...)
	output, err := cmd.CombinedOutput()
	if err != nil {
		return fmt.Errorf("error loading docker image with '%s': %v: %s", human, err, string(output))
	}

	return nil
}