k3d/cli/image.go
2019-07-01 12:17:03 +02:00

130 lines
4.1 KiB
Go

package run
import (
"context"
"fmt"
"io"
"io/ioutil"
"log"
"os"
"strings"
"time"
"github.com/docker/docker/api/types"
"github.com/docker/docker/client"
)
const imageBasePathRemote = "/images/"
func importImage(clusterName string, images []string) error {
// get a docker client
ctx := context.Background()
docker, err := client.NewEnvClient()
if err != nil {
return fmt.Errorf("ERROR: couldn't create docker client\n%+v", err)
}
// get cluster directory to temporarily save the image tarball there
imageBasePathLocal, err := getClusterDir(clusterName)
imageBasePathLocal = imageBasePathLocal + "/images/"
if err != nil {
return fmt.Errorf("ERROR: couldn't get cluster directory for cluster [%s]\n%+v", clusterName, err)
}
//*** first, save the images using the local docker daemon
log.Printf("INFO: Saving images [%s] from local docker daemon...", images)
imageReader, err := docker.ImageSave(ctx, images)
if err != nil {
return fmt.Errorf("ERROR: failed to save images [%s] locally\n%+v", images, err)
}
// create tarball
imageTarName := "k3d-" + clusterName + "-images-" + time.Now().Format("20060102150405") + ".tar"
imageTar, err := os.Create(imageBasePathLocal + imageTarName)
if err != nil {
return err
}
defer imageTar.Close()
_, err = io.Copy(imageTar, imageReader)
if err != nil {
return fmt.Errorf("ERROR: couldn't save image [%s] to file [%s]\n%+v", images, imageTar.Name(), err)
}
// Get the container IDs for all containers in the cluster
clusters, err := getClusters(false, clusterName)
if err != nil {
return fmt.Errorf("ERROR: couldn't get cluster by name [%s]\n%+v", clusterName, err)
}
containerList := []types.Container{clusters[clusterName].server}
containerList = append(containerList, clusters[clusterName].workers...)
// *** second, import the images using ctr in the k3d nodes
// create exec configuration
cmd := []string{"ctr", "image", "import", imageBasePathRemote + imageTarName}
execConfig := types.ExecConfig{
AttachStderr: true,
AttachStdout: true,
Cmd: cmd,
Tty: true,
Detach: true,
}
execAttachConfig := types.ExecConfig{
Tty: true,
}
execStartConfig := types.ExecStartCheck{
Tty: true,
}
// import in each node separately
// TODO: create a shared image cache volume, so we don't need to import it separately
for _, container := range containerList {
containerName := container.Names[0][1:] // trimming the leading "/" from name
log.Printf("INFO: Importing image [%s] in container [%s]", images, containerName)
// create exec configuration
execResponse, err := docker.ContainerExecCreate(ctx, container.ID, execConfig)
if err != nil {
return fmt.Errorf("ERROR: Failed to create exec command for container [%s]\n%+v", containerName, err)
}
// attach to exec process in container
containerConnection, err := docker.ContainerExecAttach(ctx, execResponse.ID, execAttachConfig)
if err != nil {
return fmt.Errorf("ERROR: couldn't attach to container [%s]\n%+v", containerName, err)
}
defer containerConnection.Close()
// start exec
err = docker.ContainerExecStart(ctx, execResponse.ID, execStartConfig)
if err != nil {
return fmt.Errorf("ERROR: couldn't execute command in container [%s]\n%+v", containerName, err)
}
// get output from container
content, err := ioutil.ReadAll(containerConnection.Reader)
if err != nil {
return fmt.Errorf("ERROR: couldn't read output from container [%s]\n%+v", containerName, err)
}
// example output "unpacking image........ ...done"
if !strings.Contains(string(content), "done") {
return fmt.Errorf("ERROR: seems like something went wrong using `ctr image import` in container [%s]. Full output below:\n%s", containerName, string(content))
}
}
log.Printf("INFO: Successfully imported image [%s] in all nodes of cluster [%s]", images, clusterName)
log.Println("INFO: Cleaning up tarball...")
if err := os.Remove(imageBasePathLocal + imageTarName); err != nil {
return fmt.Errorf("ERROR: Couldn't remove tarball [%s]\n%+v", imageBasePathLocal+imageTarName, err)
}
log.Println("INFO: ...Done")
return nil
}