distributedCache: allow local dir as a cache transport

Allowing local directory as transport enables users to make distributed
caching more flexible by making sure.

* Allows end users to move cache sources and destination manually.
* Allows storing cache on an `NFS` or various mount sources.
* Allows end users to distribute cache without registry setup.

[NO NEW TESTS NEEDED]
[NO TESTS NEEDED]
// Will add test in final commit

Signed-off-by: Aditya R <[email protected]>

define/build.go

@@ -5,7 +5,6 @@ import (
 	"time"
 
 	nettypes "github.com/containers/common/libnetwork/types"
-	"github.com/containers/image/v5/docker/reference"
 	"github.com/containers/image/v5/types"
 	encconfig "github.com/containers/ocicrypt/config"
 	"github.com/containers/storage/pkg/archive"
@@ -141,10 +140,10 @@ type BuildOptions struct {
 	TransientMounts []string
 	// CacheFrom specifies any remote repository which can be treated as
 	// potential cache source.
-	CacheFrom []reference.Named
+	CacheFrom []types.ImageReference
 	// CacheTo specifies any remote repository which can be treated as
 	// potential cache destination.
-	CacheTo []reference.Named
+	CacheTo []types.ImageReference
 	// CacheTTL specifies duration, if specified using `--cache-ttl` then
 	// cache intermediate images under this duration will be considered as
 	// valid cache sources and images outside this duration will be ignored.

imagebuildah/executor.go

@@ -61,8 +61,8 @@ var builtinAllowedBuildArgs = map[string]bool{
 // interface.  It coordinates the entire build by using one or more
 // StageExecutors to handle each stage of the build.
 type Executor struct {
-	cacheFrom                      []reference.Named
-	cacheTo                        []reference.Named
+	cacheFrom                      []types.ImageReference
+	cacheTo                        []types.ImageReference
 	cacheTTL                       time.Duration
 	containerSuffix                string
 	logger                         *logrus.Logger

imagebuildah/stage_executor.go

@@ -24,6 +24,7 @@ import (
 	"github.com/containers/buildah/util"
 	config "github.com/containers/common/pkg/config"
 	cp "github.com/containers/image/v5/copy"
+	imagedirectory "github.com/containers/image/v5/directory"
 	imagedocker "github.com/containers/image/v5/docker"
 	"github.com/containers/image/v5/docker/reference"
 	"github.com/containers/image/v5/manifest"
@@ -985,10 +986,16 @@ func (s *StageExecutor) Execute(ctx context.Context, base string) (imgID string,
 	}
 	// logCachePulled produces build log for cases when `--cache-from`
 	// is used and a valid intermediate image is pulled from remote source.
-	logCachePulled := func(cacheKey string, remote reference.Named) {
+	logCachePulled := func(cacheKey string, remote types.ImageReference) {
 		if !s.executor.quiet {
 			cachePullMessage := "--> Cache pulled from remote"
-			fmt.Fprintf(s.executor.out, "%s %s\n", cachePullMessage, fmt.Sprintf("%s:%s", remote.String(), cacheKey))
+			repo := ""
+			if remote.Transport().Name() == imagedocker.Transport.Name() {
+				repo = remote.DockerReference().String()
+			} else {
+				repo = remote.StringWithinTransport()
+			}
+			fmt.Fprintf(s.executor.out, "%s %s\n", cachePullMessage, fmt.Sprintf("%s:%s", repo, cacheKey))
 		}
 	}
 	// logCachePush produces build log for cases when `--cache-to`
@@ -1782,18 +1789,29 @@ func (s *StageExecutor) generateCacheKey(ctx context.Context, currNode *parser.N
 
 // cacheImageReference is internal function which generates ImageReference from Named repo sources
 // and a tag.
-func cacheImageReferences(repos []reference.Named, cachekey string) ([]types.ImageReference, error) {
+func cacheImageReferences(repos []types.ImageReference, cachekey string) ([]types.ImageReference, error) {
 	var result []types.ImageReference
 	for _, repo := range repos {
-		tagged, err := reference.WithTag(repo, cachekey)
-		if err != nil {
-			return nil, fmt.Errorf("failed generating tagged reference for %q: %w", repo, err)
-		}
-		dest, err := imagedocker.NewReference(tagged)
-		if err != nil {
-			return nil, fmt.Errorf("failed generating docker reference for %q: %w", tagged, err)
+		if repo.Transport().Name() == imagedocker.Transport.Name() {
+			ref := repo.DockerReference()
+			tagged, err := reference.WithTag(ref, cachekey)
+			if err != nil {
+				return nil, fmt.Errorf("failed generating tagged reference for %q: %w", repo, err)
+			}
+			dest, err := imagedocker.NewReference(tagged)
+			if err != nil {
+				return nil, fmt.Errorf("failed generating docker reference for %q: %w", tagged, err)
+			}
+			result = append(result, dest)
+		} else if repo.Transport().Name() == imagedirectory.Transport.Name() {
+			dirPath := repo.StringWithinTransport()
+			tagged := filepath.Join(dirPath, cachekey)
+			dest, err := imagedirectory.NewReference(tagged)
+			if err != nil {
+				return nil, fmt.Errorf("failed generating directory reference for %q: %w", tagged, err)
+			}
+			result = append(result, dest)
 		}
-		result = append(result, dest)
 	}
 	return result, nil
 }
@@ -1833,7 +1851,7 @@ func (s *StageExecutor) pushCache(ctx context.Context, src, cacheKey string) err
 // or a newer version of cache was found in the upstream repo. If new
 // image was pulled function returns image id otherwise returns empty
 // string "" or error if any error was encontered while pulling the cache.
-func (s *StageExecutor) pullCache(ctx context.Context, cacheKey string) (reference.Named, string, error) {
+func (s *StageExecutor) pullCache(ctx context.Context, cacheKey string) (types.ImageReference, string, error) {
 	srcList, err := cacheImageReferences(s.executor.cacheFrom, cacheKey)
 	if err != nil {
 		return nil, "", err
@@ -1851,14 +1869,20 @@ func (s *StageExecutor) pullCache(ctx context.Context, cacheKey string) (referen
 			ReportWriter:        nil,
 			PullPolicy:          define.PullIfNewer,
 		}
-		id, err := buildah.Pull(ctx, src.DockerReference().String(), options)
+		srcString := ""
+		if src.Transport().Name() == imagedocker.Transport.Name() {
+			srcString = src.DockerReference().String()
+		} else if src.Transport().Name() == imagedirectory.Transport.Name() {
+			srcString = "dir://" + src.StringWithinTransport()
+		}
+		id, err := buildah.Pull(ctx, srcString, options)
 		if err != nil {
 			logrus.Debugf("failed pulling cache from source %s: %v", src, err)
 			continue // failed pulling this one try next
 			//return "", fmt.Errorf("failed while pulling cache from %q: %w", src, err)
 		}
 		logrus.Debugf("successfully pulled cache from repo %s: %s", src, id)
-		return src.DockerReference(), id, nil
+		return src, id, nil
 	}
 	return nil, "", fmt.Errorf("failed pulling cache from all available sources %q", srcList)
 }

pkg/cli/build.go

@@ -17,7 +17,6 @@ import (
 	"github.com/containers/buildah/pkg/parse"
 	"github.com/containers/buildah/pkg/util"
 	"github.com/containers/common/pkg/auth"
-	"github.com/containers/image/v5/docker/reference"
 	"github.com/containers/image/v5/types"
 	"github.com/opencontainers/runtime-spec/specs-go"
 	"github.com/sirupsen/logrus"
@@ -296,8 +295,8 @@ func GenBuildOptions(c *cobra.Command, inputArgs []string, iopts BuildOptions) (
 			iopts.Quiet = true
 		}
 	}
-	var cacheTo []reference.Named
-	var cacheFrom []reference.Named
+	var cacheTo []types.ImageReference
+	var cacheFrom []types.ImageReference
 	cacheTo = nil
 	cacheFrom = nil
 	if c.Flag("cache-to").Changed {

pkg/parse/parse.go

@@ -21,7 +21,9 @@ import (
 	"github.com/containers/buildah/pkg/sshagent"
 	"github.com/containers/common/pkg/config"
 	"github.com/containers/common/pkg/parse"
+	imagedocker "github.com/containers/image/v5/docker"
 	"github.com/containers/image/v5/docker/reference"
+	"github.com/containers/image/v5/transports/alltransports"
 	"github.com/containers/image/v5/types"
 	"github.com/containers/storage/pkg/idtools"
 	"github.com/containers/storage/pkg/unshare"
@@ -53,15 +55,21 @@ const (
 )
 
 // RepoNamesToNamedReferences parse the raw string to Named reference
-func RepoNamesToNamedReferences(destList []string) ([]reference.Named, error) {
-	var result []reference.Named
+func RepoNamesToNamedReferences(destList []string) ([]types.ImageReference, error) {
+	var result []types.ImageReference
 	for _, dest := range destList {
-		named, err := reference.ParseNormalizedNamed(dest)
+		if t := alltransports.TransportFromImageName(dest); t == nil {
+			// assume no default transport provided in such case append docker
+			dest = "docker://" + dest
+		}
+		named, err := alltransports.ParseImageName(dest)
 		if err != nil {
 			return nil, fmt.Errorf("invalid repo %q: must contain registry and repository: %w", dest, err)
 		}
-		if !reference.IsNameOnly(named) {
-			return nil, fmt.Errorf("repository must contain neither a tag nor digest: %v", named)
+		if named.Transport().Name() == imagedocker.Transport.Name() {
+			if !reference.IsNameOnly(named.DockerReference()) {
+				return nil, fmt.Errorf("repository must contain neither a tag nor digest: %v", named)
+			}
 		}
 		result = append(result, named)
 	}