141 lines
		
	
	
		
			3.3 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			141 lines
		
	
	
		
			3.3 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
package main
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import (
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	"context"
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	"encoding/json"
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	"fmt"
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	"io/ioutil"
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	"os"
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	"strings"
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	contentapi "github.com/containerd/containerd/api/services/content"
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	rootfsapi "github.com/containerd/containerd/api/services/rootfs"
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	"github.com/containerd/containerd/content"
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	"github.com/containerd/containerd/log"
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	contentservice "github.com/containerd/containerd/services/content"
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	rootfsservice "github.com/containerd/containerd/services/rootfs"
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	digest "github.com/opencontainers/go-digest"
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	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
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	"github.com/urfave/cli"
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)
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var rootfsCommand = cli.Command{
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	Name:  "rootfs",
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	Usage: "rootfs setups a rootfs",
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	Subcommands: []cli.Command{
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		rootfsUnpackCommand,
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		rootfsPrepareCommand,
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	},
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}
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var rootfsUnpackCommand = cli.Command{
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	Name:      "unpack",
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	Usage:     "unpack applies layers from a manifest to a snapshot",
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	ArgsUsage: "[flags] <digest>",
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	Flags:     []cli.Flag{},
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	Action: func(clicontext *cli.Context) error {
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		ctx, cancel := appContext()
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		defer cancel()
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		dgst, err := digest.Parse(clicontext.Args().First())
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		if err != nil {
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			return err
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		}
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		log.G(ctx).Infof("unpacking layers from manifest %s", dgst.String())
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		conn, err := connectGRPC(clicontext)
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		if err != nil {
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			return err
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		}
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		provider := contentservice.NewProviderFromClient(contentapi.NewContentClient(conn))
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		m, err := resolveManifest(ctx, provider, dgst)
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		if err != nil {
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			return err
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		}
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		unpacker := rootfsservice.NewUnpackerFromClient(rootfsapi.NewRootFSClient(conn))
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		chainID, err := unpacker.Unpack(ctx, m.Layers)
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		if err != nil {
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			return err
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		}
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		log.G(ctx).Infof("chain ID: %s", chainID.String())
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		return nil
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	},
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}
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var rootfsPrepareCommand = cli.Command{
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	Name:      "prepare",
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	Usage:     "prepare gets mount commands for digest",
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	ArgsUsage: "[flags] <digest> <target>",
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	Flags:     []cli.Flag{},
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	Action: func(clicontext *cli.Context) error {
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		ctx, cancel := appContext()
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		defer cancel()
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		if clicontext.NArg() != 2 {
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			return cli.ShowSubcommandHelp(clicontext)
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		}
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		dgst, err := digest.Parse(clicontext.Args().Get(0))
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		if err != nil {
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			return err
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		}
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		target := clicontext.Args().Get(1)
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		log.G(ctx).Infof("preparing mounts %s", dgst.String())
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		conn, err := connectGRPC(clicontext)
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		if err != nil {
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			return err
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		}
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		rclient := rootfsapi.NewRootFSClient(conn)
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		ir := &rootfsapi.PrepareRequest{
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			Name:    target,
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			ChainID: dgst,
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		}
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		resp, err := rclient.Prepare(ctx, ir)
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		if err != nil {
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			return err
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		}
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		for _, m := range resp.Mounts {
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			fmt.Fprintf(os.Stdout, "mount -t %s %s %s -o %s\n", m.Type, m.Source, target, strings.Join(m.Options, ","))
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		}
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		return nil
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	},
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}
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func resolveManifest(ctx context.Context, provider content.Provider, dgst digest.Digest) (ocispec.Manifest, error) {
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	p, err := readAll(ctx, provider, dgst)
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	if err != nil {
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		return ocispec.Manifest{}, err
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	}
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	// TODO(stevvooe): This assumption that we get a manifest is unfortunate.
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	// Need to provide way to resolve what the type of the target is.
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	var manifest ocispec.Manifest
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	if err := json.Unmarshal(p, &manifest); err != nil {
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		return ocispec.Manifest{}, err
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	}
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	return manifest, nil
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}
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func readAll(ctx context.Context, provider content.Provider, dgst digest.Digest) ([]byte, error) {
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	rc, err := provider.Reader(ctx, dgst)
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	if err != nil {
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		return nil, err
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	}
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	defer rc.Close()
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	return ioutil.ReadAll(rc)
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}
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