103 lines
2.4 KiB
Go
103 lines
2.4 KiB
Go
package remotecontext // import "github.com/docker/docker/builder/remotecontext"
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import (
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"encoding/hex"
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"os"
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"path/filepath"
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"runtime"
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"strings"
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"github.com/docker/docker/builder"
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"github.com/docker/docker/pkg/pools"
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"github.com/pkg/errors"
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)
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// NewLazySource creates a new LazyContext. LazyContext defines a hashed build
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// context based on a root directory. Individual files are hashed first time
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// they are asked. It is not safe to call methods of LazyContext concurrently.
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func NewLazySource(root string) (builder.Source, error) {
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return &lazySource{
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root: root,
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sums: make(map[string]string),
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}, nil
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}
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type lazySource struct {
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root string
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sums map[string]string
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}
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func (c *lazySource) Root() string {
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return c.root
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}
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func (c *lazySource) Close() error {
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return nil
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}
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func (c *lazySource) Hash(path string) (string, error) {
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cleanPath, fullPath, err := normalize(path, c.root)
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if err != nil {
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return "", err
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}
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relPath, err := Rel(c.root, fullPath)
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if err != nil {
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return "", errors.WithStack(convertPathError(err, cleanPath))
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}
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fi, err := os.Lstat(fullPath)
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if err != nil {
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// Backwards compatibility: a missing file returns a path as hash.
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// This is reached in the case of a broken symlink.
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return relPath, nil
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}
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sum, ok := c.sums[relPath]
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if !ok {
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sum, err = c.prepareHash(relPath, fi)
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if err != nil {
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return "", err
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}
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}
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return sum, nil
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}
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func (c *lazySource) prepareHash(relPath string, fi os.FileInfo) (string, error) {
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p := filepath.Join(c.root, relPath)
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h, err := NewFileHash(p, relPath, fi)
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if err != nil {
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return "", errors.Wrapf(err, "failed to create hash for %s", relPath)
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}
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if fi.Mode().IsRegular() && fi.Size() > 0 {
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f, err := os.Open(p)
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if err != nil {
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return "", errors.Wrapf(err, "failed to open %s", relPath)
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}
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defer f.Close()
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if _, err := pools.Copy(h, f); err != nil {
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return "", errors.Wrapf(err, "failed to copy file data for %s", relPath)
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}
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}
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sum := hex.EncodeToString(h.Sum(nil))
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c.sums[relPath] = sum
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return sum, nil
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}
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// Rel makes a path relative to base path. Same as `filepath.Rel` but can also
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// handle UUID paths in windows.
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func Rel(basepath string, targpath string) (string, error) {
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// filepath.Rel can't handle UUID paths in windows
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if runtime.GOOS == "windows" {
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pfx := basepath + `\`
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if strings.HasPrefix(targpath, pfx) {
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p := strings.TrimPrefix(targpath, pfx)
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if p == "" {
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p = "."
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}
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return p, nil
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}
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}
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return filepath.Rel(basepath, targpath)
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}
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