github.com/mheon/docker@v0.11.2-0.20150922122814-44f47903a831/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  // ImageExport exports list of images to a output stream specified in the
    17  // config. The exported images are archived into a tar when written to the
    18  // output stream. All images with the given tag and all versions containing the
    19  // same tag are exported. names is the set of tags to export, and outStream
    20  // is the writer which the images are written to.
    21  func (s *TagStore) ImageExport(names []string, outStream io.Writer) error {
    22  	// get image json
    23  	tempdir, err := ioutil.TempDir("", "docker-export-")
    24  	if err != nil {
    25  		return err
    26  	}
    27  	defer os.RemoveAll(tempdir)
    28  
    29  	rootRepoMap := map[string]Repository{}
    30  	addKey := func(name string, tag string, id string) {
    31  		logrus.Debugf("add key [%s:%s]", name, tag)
    32  		if repo, ok := rootRepoMap[name]; !ok {
    33  			rootRepoMap[name] = Repository{tag: id}
    34  		} else {
    35  			repo[tag] = id
    36  		}
    37  	}
    38  	for _, name := range names {
    39  		name = registry.NormalizeLocalName(name)
    40  		logrus.Debugf("Serializing %s", name)
    41  		rootRepo := s.Repositories[name]
    42  		if rootRepo != nil {
    43  			// this is a base repo name, like 'busybox'
    44  			for tag, id := range rootRepo {
    45  				addKey(name, tag, id)
    46  				if err := s.exportImage(id, tempdir); err != nil {
    47  					return err
    48  				}
    49  			}
    50  		} else {
    51  			img, err := s.LookupImage(name)
    52  			if err != nil {
    53  				return err
    54  			}
    55  
    56  			if img != nil {
    57  				// This is a named image like 'busybox:latest'
    58  				repoName, repoTag := parsers.ParseRepositoryTag(name)
    59  
    60  				// check this length, because a lookup of a truncated has will not have a tag
    61  				// and will not need to be added to this map
    62  				if len(repoTag) > 0 {
    63  					addKey(repoName, repoTag, img.ID)
    64  				}
    65  				if err := s.exportImage(img.ID, tempdir); err != nil {
    66  					return err
    67  				}
    68  
    69  			} else {
    70  				// this must be an ID that didn't get looked up just right?
    71  				if err := s.exportImage(name, tempdir); err != nil {
    72  					return err
    73  				}
    74  			}
    75  		}
    76  		logrus.Debugf("End Serializing %s", name)
    77  	}
    78  	// write repositories, if there is something to write
    79  	if len(rootRepoMap) > 0 {
    80  		f, err := os.OpenFile(filepath.Join(tempdir, "repositories"), os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
    81  		if err != nil {
    82  			f.Close()
    83  			return err
    84  		}
    85  		if err := json.NewEncoder(f).Encode(rootRepoMap); err != nil {
    86  			return err
    87  		}
    88  		if err := f.Close(); err != nil {
    89  			return err
    90  		}
    91  	} else {
    92  		logrus.Debugf("There were no repositories to write")
    93  	}
    94  
    95  	fs, err := archive.Tar(tempdir, archive.Uncompressed)
    96  	if err != nil {
    97  		return err
    98  	}
    99  	defer fs.Close()
   100  
   101  	if _, err := io.Copy(outStream, fs); err != nil {
   102  		return err
   103  	}
   104  	logrus.Debugf("End export image")
   105  	return nil
   106  }
   107  
   108  func (s *TagStore) exportImage(name, tempdir string) error {
   109  	for n := name; n != ""; {
   110  		// temporary directory
   111  		tmpImageDir := filepath.Join(tempdir, n)
   112  		if err := os.Mkdir(tmpImageDir, os.FileMode(0755)); err != nil {
   113  			if os.IsExist(err) {
   114  				return nil
   115  			}
   116  			return err
   117  		}
   118  
   119  		var version = "1.0"
   120  		var versionBuf = []byte(version)
   121  
   122  		if err := ioutil.WriteFile(filepath.Join(tmpImageDir, "VERSION"), versionBuf, os.FileMode(0644)); err != nil {
   123  			return err
   124  		}
   125  
   126  		// serialize json
   127  		json, err := os.Create(filepath.Join(tmpImageDir, "json"))
   128  		if err != nil {
   129  			return err
   130  		}
   131  		imageInspectRaw, err := s.lookupRaw(n)
   132  		if err != nil {
   133  			return err
   134  		}
   135  		written, err := json.Write(imageInspectRaw)
   136  		if err != nil {
   137  			return err
   138  		}
   139  		if written != len(imageInspectRaw) {
   140  			logrus.Warnf("%d byes should have been written instead %d have been written", written, len(imageInspectRaw))
   141  		}
   142  
   143  		// serialize filesystem
   144  		fsTar, err := os.Create(filepath.Join(tmpImageDir, "layer.tar"))
   145  		if err != nil {
   146  			return err
   147  		}
   148  		if err := s.ImageTarLayer(n, fsTar); err != nil {
   149  			return err
   150  		}
   151  
   152  		// find parent
   153  		img, err := s.LookupImage(n)
   154  		if err != nil {
   155  			return err
   156  		}
   157  		n = img.Parent
   158  	}
   159  	return nil
   160  }