github.com/moby/docker@v26.1.3+incompatible/pkg/archive/example_changes.go (about)

     1  //go:build ignore
     2  
     3  // Simple tool to create an archive stream from an old and new directory
     4  //
     5  // By default it will stream the comparison of two temporary directories with junk files
     6  package main
     7  
     8  import (
     9  	"flag"
    10  	"fmt"
    11  	"io"
    12  	"os"
    13  	"path"
    14  
    15  	"github.com/containerd/log"
    16  	"github.com/docker/docker/pkg/archive"
    17  )
    18  
    19  var (
    20  	flDebug  = flag.Bool("D", false, "debugging output")
    21  	flNewDir = flag.String("newdir", "", "")
    22  	flOldDir = flag.String("olddir", "", "")
    23  	log      = log.G(ctx).New()
    24  )
    25  
    26  func main() {
    27  	flag.Usage = func() {
    28  		fmt.Println("Produce a tar from comparing two directory paths. By default a demo tar is created of around 200 files (including hardlinks)")
    29  		fmt.Printf("%s [OPTIONS]\n", os.Args[0])
    30  		flag.PrintDefaults()
    31  	}
    32  	flag.Parse()
    33  	log.Out = os.Stderr
    34  	if (len(os.Getenv("DEBUG")) > 0) || *flDebug {
    35  		log.G(ctx).SetLevel(logrus.DebugLevel)
    36  	}
    37  	var newDir, oldDir string
    38  
    39  	if len(*flNewDir) == 0 {
    40  		var err error
    41  		newDir, err = os.MkdirTemp("", "docker-test-newDir")
    42  		if err != nil {
    43  			log.Fatal(err)
    44  		}
    45  		defer os.RemoveAll(newDir)
    46  		if _, err := prepareUntarSourceDirectory(100, newDir, true); err != nil {
    47  			log.Fatal(err)
    48  		}
    49  	} else {
    50  		newDir = *flNewDir
    51  	}
    52  
    53  	if len(*flOldDir) == 0 {
    54  		oldDir, err := os.MkdirTemp("", "docker-test-oldDir")
    55  		if err != nil {
    56  			log.Fatal(err)
    57  		}
    58  		defer os.RemoveAll(oldDir)
    59  	} else {
    60  		oldDir = *flOldDir
    61  	}
    62  
    63  	changes, err := archive.ChangesDirs(newDir, oldDir)
    64  	if err != nil {
    65  		log.Fatal(err)
    66  	}
    67  
    68  	a, err := archive.ExportChanges(newDir, changes)
    69  	if err != nil {
    70  		log.Fatal(err)
    71  	}
    72  	defer a.Close()
    73  
    74  	i, err := io.Copy(os.Stdout, a)
    75  	if err != nil && err != io.EOF {
    76  		log.Fatal(err)
    77  	}
    78  	fmt.Fprintf(os.Stderr, "wrote archive of %d bytes", i)
    79  }
    80  
    81  func prepareUntarSourceDirectory(numberOfFiles int, targetPath string, makeLinks bool) (int, error) {
    82  	fileData := []byte("fooo")
    83  	for n := 0; n < numberOfFiles; n++ {
    84  		fileName := fmt.Sprintf("file-%d", n)
    85  		if err := os.WriteFile(path.Join(targetPath, fileName), fileData, 0o700); err != nil {
    86  			return 0, err
    87  		}
    88  		if makeLinks {
    89  			if err := os.Link(path.Join(targetPath, fileName), path.Join(targetPath, fileName+"-link")); err != nil {
    90  				return 0, err
    91  			}
    92  		}
    93  	}
    94  	totalSize := numberOfFiles * len(fileData)
    95  	return totalSize, nil
    96  }