github.com/Cloud-Foundations/Dominator@v0.3.4/cmd/imagetool/patchDirectory.go (about)

     1  package main
     2  
     3  import (
     4  	"errors"
     5  	"fmt"
     6  	"io"
     7  	"io/ioutil"
     8  	"os"
     9  	"path/filepath"
    10  	"syscall"
    11  	"time"
    12  
    13  	domlib "github.com/Cloud-Foundations/Dominator/dom/lib"
    14  	"github.com/Cloud-Foundations/Dominator/lib/filesystem/scanner"
    15  	"github.com/Cloud-Foundations/Dominator/lib/format"
    16  	"github.com/Cloud-Foundations/Dominator/lib/fsutil"
    17  	"github.com/Cloud-Foundations/Dominator/lib/hash"
    18  	"github.com/Cloud-Foundations/Dominator/lib/image"
    19  	"github.com/Cloud-Foundations/Dominator/lib/log"
    20  	"github.com/Cloud-Foundations/Dominator/lib/log/nulllogger"
    21  	"github.com/Cloud-Foundations/Dominator/lib/objectcache"
    22  	"github.com/Cloud-Foundations/Dominator/lib/objectserver"
    23  	"github.com/Cloud-Foundations/Dominator/lib/wsyscall"
    24  	subproto "github.com/Cloud-Foundations/Dominator/proto/sub"
    25  	sublib "github.com/Cloud-Foundations/Dominator/sub/lib"
    26  )
    27  
    28  func patchDirectorySubcommand(args []string, logger log.DebugLogger) error {
    29  	if err := patchDirectory(args[0], args[1], logger); err != nil {
    30  		return fmt.Errorf("error patching directory: %s", err)
    31  	}
    32  	return nil
    33  }
    34  
    35  func patchDirectory(imageName, dirName string, logger log.DebugLogger) error {
    36  	_, objectClient := getClients()
    37  	logger.Debugf(0, "getting image: %s\n", imageName)
    38  	img, imageName, err := getTypedImageAndName(imageName)
    39  	if err != nil {
    40  		return err
    41  	}
    42  	if err := img.FileSystem.RebuildInodePointers(); err != nil {
    43  		return err
    44  	}
    45  	img.FileSystem.BuildEntryMap()
    46  	rootDir, err := ioutil.TempDir("", "")
    47  	if err != nil {
    48  		return err
    49  	}
    50  	defer os.Remove(rootDir)
    51  	errorChannel := make(chan error)
    52  	go func() {
    53  		errorChannel <- patchRoot(img, objectClient, imageName, dirName,
    54  			rootDir, logger)
    55  	}()
    56  	return <-errorChannel
    57  }
    58  
    59  func patchRoot(img *image.Image, objectsGetter objectserver.ObjectsGetter,
    60  	imageName, dirName, rootDir string, logger log.DebugLogger) error {
    61  	if err := wsyscall.UnshareMountNamespace(); err != nil {
    62  		return fmt.Errorf("unable to unshare mount namesace: %s", err)
    63  	}
    64  	syscall.Unmount(rootDir, 0)
    65  	err := wsyscall.Mount(dirName, rootDir, "", wsyscall.MS_BIND, "")
    66  	if err != nil {
    67  		return fmt.Errorf("unable to bind mount %s to %s: %s",
    68  			dirName, rootDir, err)
    69  	}
    70  	logger.Debugf(0, "scanning directory: %s\n", dirName)
    71  	sfs, err := scanner.ScanFileSystem(rootDir, nil, img.Filter, nil, nil, nil)
    72  	if err != nil {
    73  		return err
    74  	}
    75  	fs := &sfs.FileSystem
    76  	if err := fs.RebuildInodePointers(); err != nil {
    77  		return err
    78  	}
    79  	fs.BuildEntryMap()
    80  	subObj := domlib.Sub{FileSystem: fs}
    81  	fetchMap, _ := domlib.BuildMissingLists(subObj, img, false, true,
    82  		logger)
    83  	objectsToFetch := objectcache.ObjectMapToCache(fetchMap)
    84  	subdDir := filepath.Join(rootDir, ".subd")
    85  	objectsDir := filepath.Join(subdDir, "objects")
    86  	defer os.RemoveAll(subdDir)
    87  	startTime := time.Now()
    88  	objectsReader, err := objectsGetter.GetObjects(objectsToFetch)
    89  	if err != nil {
    90  		return err
    91  	}
    92  	defer objectsReader.Close()
    93  	logger.Debugf(0, "fetching %d objects", len(objectsToFetch))
    94  	for _, hashVal := range objectsToFetch {
    95  		length, reader, err := objectsReader.NextObject()
    96  		if err != nil {
    97  			return err
    98  		}
    99  		err = readOne(objectsDir, hashVal, length, reader)
   100  		reader.Close()
   101  		if err != nil {
   102  			return err
   103  		}
   104  	}
   105  	logger.Debugf(0, "fetched %d objects in %s",
   106  		len(objectsToFetch), format.Duration(time.Since(startTime)))
   107  	subObj.ObjectCache = append(subObj.ObjectCache, objectsToFetch...)
   108  	var subRequest subproto.UpdateRequest
   109  	if domlib.BuildUpdateRequest(subObj, img, &subRequest, false, true,
   110  		nulllogger.New()) {
   111  		return errors.New("failed building update: missing computed files")
   112  	}
   113  	subRequest.ImageName = imageName
   114  	subRequest.Triggers = nil
   115  	logger.Debugln(0, "starting update")
   116  	_, _, err = sublib.Update(subRequest, rootDir, objectsDir, nil, nil, nil,
   117  		logger)
   118  	if err != nil {
   119  		return err
   120  	}
   121  	return nil
   122  }
   123  
   124  func readOne(objectsDir string, hashVal hash.Hash, length uint64,
   125  	reader io.Reader) error {
   126  	filename := filepath.Join(objectsDir, objectcache.HashToFilename(hashVal))
   127  	dirname := filepath.Dir(filename)
   128  	if err := os.MkdirAll(dirname, fsutil.DirPerms); err != nil {
   129  		return err
   130  	}
   131  	return fsutil.CopyToFile(filename, fsutil.PrivateFilePerms, reader, length)
   132  }