github.com/wulonghui/docker@v1.8.0-rc2/graph/export.go (about)

     1  package graph
     2  
     3  import (
     4  	"encoding/json"
     5  	"io"
     6  	"io/ioutil"
     7  	"os"
     8  	"path/filepath"
     9  
    10  	"github.com/Sirupsen/logrus"
    11  	"github.com/docker/docker/pkg/archive"
    12  	"github.com/docker/docker/pkg/parsers"
    13  	"github.com/docker/docker/registry"
    14  )
    15  
    16  // CmdImageExport exports all images with the given tag. All versions
    17  // containing the same tag are exported. The resulting output is an
    18  // uncompressed tar ball.
    19  // name is the set of tags to export.
    20  // out is the writer where the images are written to.
    21  type ImageExportConfig struct {
    22  	Names     []string
    23  	Outstream io.Writer
    24  }
    25  
    26  func (s *TagStore) ImageExport(imageExportConfig *ImageExportConfig) error {
    27  
    28  	// get image json
    29  	tempdir, err := ioutil.TempDir("", "docker-export-")
    30  	if err != nil {
    31  		return err
    32  	}
    33  	defer os.RemoveAll(tempdir)
    34  
    35  	rootRepoMap := map[string]Repository{}
    36  	addKey := func(name string, tag string, id string) {
    37  		logrus.Debugf("add key [%s:%s]", name, tag)
    38  		if repo, ok := rootRepoMap[name]; !ok {
    39  			rootRepoMap[name] = Repository{tag: id}
    40  		} else {
    41  			repo[tag] = id
    42  		}
    43  	}
    44  	for _, name := range imageExportConfig.Names {
    45  		name = registry.NormalizeLocalName(name)
    46  		logrus.Debugf("Serializing %s", name)
    47  		rootRepo := s.Repositories[name]
    48  		if rootRepo != nil {
    49  			// this is a base repo name, like 'busybox'
    50  			for tag, id := range rootRepo {
    51  				addKey(name, tag, id)
    52  				if err := s.exportImage(id, tempdir); err != nil {
    53  					return err
    54  				}
    55  			}
    56  		} else {
    57  			img, err := s.LookupImage(name)
    58  			if err != nil {
    59  				return err
    60  			}
    61  
    62  			if img != nil {
    63  				// This is a named image like 'busybox:latest'
    64  				repoName, repoTag := parsers.ParseRepositoryTag(name)
    65  
    66  				// check this length, because a lookup of a truncated has will not have a tag
    67  				// and will not need to be added to this map
    68  				if len(repoTag) > 0 {
    69  					addKey(repoName, repoTag, img.ID)
    70  				}
    71  				if err := s.exportImage(img.ID, tempdir); err != nil {
    72  					return err
    73  				}
    74  
    75  			} else {
    76  				// this must be an ID that didn't get looked up just right?
    77  				if err := s.exportImage(name, tempdir); err != nil {
    78  					return err
    79  				}
    80  			}
    81  		}
    82  		logrus.Debugf("End Serializing %s", name)
    83  	}
    84  	// write repositories, if there is something to write
    85  	if len(rootRepoMap) > 0 {
    86  		f, err := os.OpenFile(filepath.Join(tempdir, "repositories"), os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
    87  		if err != nil {
    88  			f.Close()
    89  			return err
    90  		}
    91  		if err := json.NewEncoder(f).Encode(rootRepoMap); err != nil {
    92  			return err
    93  		}
    94  		if err := f.Close(); err != nil {
    95  			return err
    96  		}
    97  	} else {
    98  		logrus.Debugf("There were no repositories to write")
    99  	}
   100  
   101  	fs, err := archive.Tar(tempdir, archive.Uncompressed)
   102  	if err != nil {
   103  		return err
   104  	}
   105  	defer fs.Close()
   106  
   107  	if _, err := io.Copy(imageExportConfig.Outstream, fs); err != nil {
   108  		return err
   109  	}
   110  	logrus.Debugf("End export image")
   111  	return nil
   112  }
   113  
   114  // FIXME: this should be a top-level function, not a class method
   115  func (s *TagStore) exportImage(name, tempdir string) error {
   116  	for n := name; n != ""; {
   117  		// temporary directory
   118  		tmpImageDir := filepath.Join(tempdir, n)
   119  		if err := os.Mkdir(tmpImageDir, os.FileMode(0755)); err != nil {
   120  			if os.IsExist(err) {
   121  				return nil
   122  			}
   123  			return err
   124  		}
   125  
   126  		var version = "1.0"
   127  		var versionBuf = []byte(version)
   128  
   129  		if err := ioutil.WriteFile(filepath.Join(tmpImageDir, "VERSION"), versionBuf, os.FileMode(0644)); err != nil {
   130  			return err
   131  		}
   132  
   133  		// serialize json
   134  		json, err := os.Create(filepath.Join(tmpImageDir, "json"))
   135  		if err != nil {
   136  			return err
   137  		}
   138  		imageInspectRaw, err := s.LookupRaw(n)
   139  		if err != nil {
   140  			return err
   141  		}
   142  		written, err := json.Write(imageInspectRaw)
   143  		if err != nil {
   144  			return err
   145  		}
   146  		if written != len(imageInspectRaw) {
   147  			logrus.Warnf("%d byes should have been written instead %d have been written", written, len(imageInspectRaw))
   148  		}
   149  
   150  		// serialize filesystem
   151  		fsTar, err := os.Create(filepath.Join(tmpImageDir, "layer.tar"))
   152  		if err != nil {
   153  			return err
   154  		}
   155  		if err := s.ImageTarLayer(n, fsTar); err != nil {
   156  			return err
   157  		}
   158  
   159  		// find parent
   160  		img, err := s.LookupImage(n)
   161  		if err != nil {
   162  			return err
   163  		}
   164  		n = img.Parent
   165  	}
   166  	return nil
   167  }