e0ef11a4c2
This patch creates interfaces in builder/ for building Docker images. It is a first step in a series of patches to remove the daemon dependency on builder and later allow a client-side Dockerfile builder as well as potential builder plugins. It is needed because we cannot remove the /build API endpoint, so we need to keep the server-side Dockerfile builder, but we also want to reuse the same Dockerfile parser and evaluator for both server-side and client-side. builder/dockerfile/ and api/server/builder.go contain implementations of those interfaces as a refactoring of the current code. Signed-off-by: Tibor Vass <tibor@docker.com>
165 lines
4.2 KiB
Go
165 lines
4.2 KiB
Go
package builder
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import (
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"fmt"
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"io"
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"os"
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"path/filepath"
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"strings"
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"github.com/docker/docker/pkg/archive"
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"github.com/docker/docker/pkg/chrootarchive"
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"github.com/docker/docker/pkg/ioutils"
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"github.com/docker/docker/pkg/symlink"
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"github.com/docker/docker/pkg/tarsum"
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)
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type tarSumContext struct {
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root string
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sums tarsum.FileInfoSums
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}
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func (c *tarSumContext) Close() error {
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return os.RemoveAll(c.root)
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}
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func convertPathError(err error, cleanpath string) error {
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if err, ok := err.(*os.PathError); ok {
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err.Path = cleanpath
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return err
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}
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return err
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}
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func (c *tarSumContext) Open(path string) (io.ReadCloser, error) {
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cleanpath, fullpath, err := c.normalize(path)
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if err != nil {
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return nil, err
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}
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r, err := os.Open(fullpath)
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if err != nil {
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return nil, convertPathError(err, cleanpath)
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}
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return r, nil
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}
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func (c *tarSumContext) Stat(path string) (fi FileInfo, err error) {
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cleanpath, fullpath, err := c.normalize(path)
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if err != nil {
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return nil, err
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}
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st, err := os.Lstat(fullpath)
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if err != nil {
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return nil, convertPathError(err, cleanpath)
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}
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fi = PathFileInfo{st, fullpath}
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// we set sum to path by default for the case where GetFile returns nil.
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// The usual case is if cleanpath is empty.
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sum := path
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if tsInfo := c.sums.GetFile(cleanpath); tsInfo != nil {
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sum = tsInfo.Sum()
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}
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fi = &HashedFileInfo{fi, sum}
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return fi, nil
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}
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// MakeTarSumContext returns a build Context from a tar stream.
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//
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// It extracts the tar stream to a temporary folder that is deleted as soon as
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// the Context is closed.
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// As the extraction happens, a tarsum is calculated for every file, and the set of
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// all those sums then becomes the source of truth for all operations on this Context.
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//
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// Closing tarStream has to be done by the caller.
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func MakeTarSumContext(tarStream io.Reader) (ModifiableContext, error) {
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root, err := ioutils.TempDir("", "docker-builder")
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if err != nil {
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return nil, err
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}
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tsc := &tarSumContext{root: root}
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// Make sure we clean-up upon error. In the happy case the caller
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// is expected to manage the clean-up
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defer func() {
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if err != nil {
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tsc.Close()
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}
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}()
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decompressedStream, err := archive.DecompressStream(tarStream)
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if err != nil {
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return nil, err
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}
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sum, err := tarsum.NewTarSum(decompressedStream, true, tarsum.Version1)
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if err != nil {
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return nil, err
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}
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if err := chrootarchive.Untar(sum, root, nil); err != nil {
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return nil, err
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}
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tsc.sums = sum.GetSums()
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return tsc, nil
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}
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func (c *tarSumContext) normalize(path string) (cleanpath, fullpath string, err error) {
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cleanpath = filepath.Clean(string(os.PathSeparator) + path)[1:]
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fullpath, err = symlink.FollowSymlinkInScope(filepath.Join(c.root, path), c.root)
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if err != nil {
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return "", "", fmt.Errorf("Forbidden path outside the build context: %s (%s)", path, fullpath)
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}
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_, err = os.Stat(fullpath)
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if err != nil {
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return "", "", convertPathError(err, path)
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}
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return
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}
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func (c *tarSumContext) Walk(root string, walkFn WalkFunc) error {
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for _, tsInfo := range c.sums {
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path := tsInfo.Name()
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path, fullpath, err := c.normalize(path)
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if err != nil {
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return err
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}
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// Any file in the context that starts with the given path will be
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// picked up and its hashcode used. However, we'll exclude the
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// root dir itself. We do this for a coupel of reasons:
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// 1 - ADD/COPY will not copy the dir itself, just its children
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// so there's no reason to include it in the hash calc
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// 2 - the metadata on the dir will change when any child file
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// changes. This will lead to a miss in the cache check if that
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// child file is in the .dockerignore list.
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if rel, err := filepath.Rel(root, path); err != nil {
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return err
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} else if rel == "." || strings.HasPrefix(rel, ".."+string(os.PathSeparator)) {
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continue
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}
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info, err := os.Lstat(fullpath)
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if err != nil {
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return convertPathError(err, path)
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}
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// TODO check context breakout?
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fi := &HashedFileInfo{PathFileInfo{info, fullpath}, tsInfo.Sum()}
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if err := walkFn(path, fi, nil); err != nil {
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return err
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}
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}
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return nil
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}
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func (c *tarSumContext) Remove(path string) error {
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_, fullpath, err := c.normalize(path)
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if err != nil {
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return err
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}
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return os.RemoveAll(fullpath)
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}
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