Refined engine implementations

Adapt the CLI to the host install model for 18.09.

Signed-off-by: Daniel Hiltgen <daniel.hiltgen@docker.com>
(cherry picked from commit 342afe44fb)
Signed-off-by: Daniel Hiltgen <daniel.hiltgen@docker.com>

internal/containerizedengine/update.go

@@ -2,13 +2,22 @@ package containerizedengine
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
+	"io/ioutil"
+	"path/filepath"
+	"strings"
 
 	"github.com/containerd/containerd"
+	"github.com/containerd/containerd/content"
 	"github.com/containerd/containerd/errdefs"
+	"github.com/containerd/containerd/images"
 	"github.com/containerd/containerd/namespaces"
 	clitypes "github.com/docker/cli/types"
+	"github.com/docker/distribution/reference"
 	"github.com/docker/docker/api/types"
+	ver "github.com/hashicorp/go-version"
+	"github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
 )
 
@@ -34,6 +43,20 @@ func (c *baseClient) DoUpdate(ctx context.Context, opts clitypes.EngineInitOptio
 		return fmt.Errorf("please pick the version you want to update to")
 	}
 
+	localMetadata, err := c.GetCurrentRuntimeMetadata(ctx, "")
+	if err == nil {
+		if opts.EngineImage == "" {
+			if strings.Contains(strings.ToLower(localMetadata.Platform), "enterprise") {
+				opts.EngineImage = "engine-enterprise"
+			} else {
+				opts.EngineImage = "engine-community"
+			}
+		}
+	}
+	if opts.EngineImage == "" {
+		return fmt.Errorf("please pick the engine image to update with (engine-community or engine-enterprise)")
+	}
+
 	imageName := fmt.Sprintf("%s/%s:%s", opts.RegistryPrefix, opts.EngineImage, opts.EngineVersion)
 
 	// Look for desired image
@@ -48,5 +71,137 @@ func (c *baseClient) DoUpdate(ctx context.Context, opts clitypes.EngineInitOptio
 			return errors.Wrapf(err, "unable to check for image %s", imageName)
 		}
 	}
-	return c.cclient.Install(ctx, image, containerd.WithInstallReplace, containerd.WithInstallPath("/usr"))
+
+	// Make sure we're safe to proceed
+	newMetadata, err := c.PreflightCheck(ctx, image)
+	if err != nil {
+		return err
+	}
+	// Grab current metadata for comparison purposes
+	if localMetadata != nil {
+		if localMetadata.Platform != newMetadata.Platform {
+			fmt.Fprintf(out, "\nNotice: you have switched to \"%s\".  Please refer to %s for update instructions.\n\n", newMetadata.Platform, c.GetReleaseNotesURL(imageName))
+		}
+	}
+
+	err = c.cclient.Install(ctx, image, containerd.WithInstallReplace, containerd.WithInstallPath("/usr"))
+	if err != nil {
+		return err
+	}
+
+	return c.WriteRuntimeMetadata(ctx, "", newMetadata)
+}
+
+var defaultDockerRoot = "/var/lib/docker"
+
+// GetCurrentRuntimeMetadata loads the current daemon runtime metadata information from the local host
+func (c *baseClient) GetCurrentRuntimeMetadata(_ context.Context, dockerRoot string) (*RuntimeMetadata, error) {
+	if dockerRoot == "" {
+		dockerRoot = defaultDockerRoot
+	}
+	filename := filepath.Join(dockerRoot, RuntimeMetadataName+".json")
+
+	data, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+	var res RuntimeMetadata
+	err = json.Unmarshal(data, &res)
+	if err != nil {
+		return nil, errors.Wrapf(err, "malformed runtime metadata file %s", filename)
+	}
+	return &res, nil
+}
+
+func (c *baseClient) WriteRuntimeMetadata(_ context.Context, dockerRoot string, metadata *RuntimeMetadata) error {
+	if dockerRoot == "" {
+		dockerRoot = defaultDockerRoot
+	}
+	filename := filepath.Join(dockerRoot, RuntimeMetadataName+".json")
+
+	data, err := json.Marshal(metadata)
+	if err != nil {
+		return err
+	}
+
+	return ioutil.WriteFile(filename, data, 0644)
+}
+
+// PreflightCheck verifies the specified image is compatible with the local system before proceeding to update/activate
+// If things look good, the RuntimeMetadata for the new image is returned and can be written out to the host
+func (c *baseClient) PreflightCheck(ctx context.Context, image containerd.Image) (*RuntimeMetadata, error) {
+	var metadata RuntimeMetadata
+	ic, err := image.Config(ctx)
+	if err != nil {
+		return nil, err
+	}
+	var (
+		ociimage v1.Image
+		config   v1.ImageConfig
+	)
+	switch ic.MediaType {
+	case v1.MediaTypeImageConfig, images.MediaTypeDockerSchema2Config:
+		p, err := content.ReadBlob(ctx, image.ContentStore(), ic)
+		if err != nil {
+			return nil, err
+		}
+
+		if err := json.Unmarshal(p, &ociimage); err != nil {
+			return nil, err
+		}
+		config = ociimage.Config
+	default:
+		return nil, fmt.Errorf("unknown image %s config media type %s", image.Name(), ic.MediaType)
+	}
+
+	metadataString, ok := config.Labels[RuntimeMetadataName]
+	if !ok {
+		return nil, fmt.Errorf("image %s does not contain runtime metadata label %s", image.Name(), RuntimeMetadataName)
+	}
+	err = json.Unmarshal([]byte(metadataString), &metadata)
+	if err != nil {
+		return nil, errors.Wrapf(err, "malformed runtime metadata file in %s", image.Name())
+	}
+
+	// Current CLI only supports host install runtime
+	if metadata.Runtime != "host_install" {
+		return nil, fmt.Errorf("unsupported runtime: %s\nPlease consult the release notes at %s for upgrade instructions", metadata.Runtime, c.GetReleaseNotesURL(image.Name()))
+	}
+
+	// Verify local containerd is new enough
+	localVersion, err := c.cclient.Version(ctx)
+	if err != nil {
+		return nil, err
+	}
+	if metadata.ContainerdMinVersion != "" {
+		lv, err := ver.NewVersion(localVersion.Version)
+		if err != nil {
+			return nil, err
+		}
+		mv, err := ver.NewVersion(metadata.ContainerdMinVersion)
+		if err != nil {
+			return nil, err
+		}
+		if lv.LessThan(mv) {
+			return nil, fmt.Errorf("local containerd is too old: %s - this engine version requires %s or newer.\nPlease consult the release notes at %s for upgrade instructions",
+				localVersion.Version, metadata.ContainerdMinVersion, c.GetReleaseNotesURL(image.Name()))
+		}
+	} // If omitted on metadata, no hard dependency on containerd version beyond 18.09 baseline
+
+	// All checks look OK, proceed with update
+	return &metadata, nil
+}
+
+// GetReleaseNotesURL returns a release notes url
+// If the image name does not contain a version tag, the base release notes URL is returned
+func (c *baseClient) GetReleaseNotesURL(imageName string) string {
+	versionTag := ""
+	distributionRef, err := reference.ParseNormalizedNamed(imageName)
+	if err == nil {
+		taggedRef, ok := distributionRef.(reference.NamedTagged)
+		if ok {
+			versionTag = taggedRef.Tag()
+		}
+	}
+	return fmt.Sprintf("%s/%s", ReleaseNotePrefix, versionTag)
 }