github.com/mforkel/docker-ce-i386@v17.12.1-ce-rc2+incompatible/components/engine/distribution/pull_v2_windows.go (about)

     1  // +build windows
     2  
     3  package distribution
     4  
     5  import (
     6  	"fmt"
     7  	"net/http"
     8  	"os"
     9  	"runtime"
    10  	"sort"
    11  	"strings"
    12  
    13  	"github.com/docker/distribution"
    14  	"github.com/docker/distribution/context"
    15  	"github.com/docker/distribution/manifest/manifestlist"
    16  	"github.com/docker/distribution/manifest/schema2"
    17  	"github.com/docker/distribution/registry/client/transport"
    18  	"github.com/docker/docker/pkg/system"
    19  	"github.com/sirupsen/logrus"
    20  )
    21  
    22  var _ distribution.Describable = &v2LayerDescriptor{}
    23  
    24  func (ld *v2LayerDescriptor) Descriptor() distribution.Descriptor {
    25  	if ld.src.MediaType == schema2.MediaTypeForeignLayer && len(ld.src.URLs) > 0 {
    26  		return ld.src
    27  	}
    28  	return distribution.Descriptor{}
    29  }
    30  
    31  func (ld *v2LayerDescriptor) open(ctx context.Context) (distribution.ReadSeekCloser, error) {
    32  	blobs := ld.repo.Blobs(ctx)
    33  	rsc, err := blobs.Open(ctx, ld.digest)
    34  
    35  	if len(ld.src.URLs) == 0 {
    36  		return rsc, err
    37  	}
    38  
    39  	// We're done if the registry has this blob.
    40  	if err == nil {
    41  		// Seek does an HTTP GET.  If it succeeds, the blob really is accessible.
    42  		if _, err = rsc.Seek(0, os.SEEK_SET); err == nil {
    43  			return rsc, nil
    44  		}
    45  		rsc.Close()
    46  	}
    47  
    48  	// Find the first URL that results in a 200 result code.
    49  	for _, url := range ld.src.URLs {
    50  		logrus.Debugf("Pulling %v from foreign URL %v", ld.digest, url)
    51  		rsc = transport.NewHTTPReadSeeker(http.DefaultClient, url, nil)
    52  
    53  		// Seek does an HTTP GET.  If it succeeds, the blob really is accessible.
    54  		_, err = rsc.Seek(0, os.SEEK_SET)
    55  		if err == nil {
    56  			break
    57  		}
    58  		logrus.Debugf("Download for %v failed: %v", ld.digest, err)
    59  		rsc.Close()
    60  		rsc = nil
    61  	}
    62  	return rsc, err
    63  }
    64  
    65  func filterManifests(manifests []manifestlist.ManifestDescriptor, os string) []manifestlist.ManifestDescriptor {
    66  	osVersion := ""
    67  	if os == "windows" {
    68  		// TODO: Add UBR (Update Build Release) component after build
    69  		version := system.GetOSVersion()
    70  		osVersion = fmt.Sprintf("%d.%d.%d", version.MajorVersion, version.MinorVersion, version.Build)
    71  		logrus.Debugf("will prefer entries with version %s", osVersion)
    72  	}
    73  
    74  	var matches []manifestlist.ManifestDescriptor
    75  	for _, manifestDescriptor := range manifests {
    76  		// TODO: Consider filtering out greater versions, including only greater UBR
    77  		if manifestDescriptor.Platform.Architecture == runtime.GOARCH && manifestDescriptor.Platform.OS == os {
    78  			matches = append(matches, manifestDescriptor)
    79  			logrus.Debugf("found match for %s/%s with media type %s, digest %s", os, runtime.GOARCH, manifestDescriptor.MediaType, manifestDescriptor.Digest.String())
    80  		}
    81  	}
    82  	if os == "windows" {
    83  		sort.Stable(manifestsByVersion{osVersion, matches})
    84  	}
    85  	return matches
    86  }
    87  
    88  func versionMatch(actual, expected string) bool {
    89  	// Check whether the version matches up to the build, ignoring UBR
    90  	return strings.HasPrefix(actual, expected+".")
    91  }
    92  
    93  type manifestsByVersion struct {
    94  	version string
    95  	list    []manifestlist.ManifestDescriptor
    96  }
    97  
    98  func (mbv manifestsByVersion) Less(i, j int) bool {
    99  	// TODO: Split version by parts and compare
   100  	// TODO: Prefer versions which have a greater version number
   101  	// Move compatible versions to the top, with no other ordering changes
   102  	return versionMatch(mbv.list[i].Platform.OSVersion, mbv.version) && !versionMatch(mbv.list[j].Platform.OSVersion, mbv.version)
   103  }
   104  
   105  func (mbv manifestsByVersion) Len() int {
   106  	return len(mbv.list)
   107  }
   108  
   109  func (mbv manifestsByVersion) Swap(i, j int) {
   110  	mbv.list[i], mbv.list[j] = mbv.list[j], mbv.list[i]
   111  }