Implement same_tag versioning mode

internal/pkg/registry/cache.go

@@ -1,31 +1,35 @@
 package registry
 
 import (
+	"fmt"
+	"net/http"
+
+	l "hulthe.net/lookbuilding/internal/pkg/logging"
 	"hulthe.net/lookbuilding/internal/pkg/semver"
 
 	"github.com/heroku/docker-registry-client/registry"
-	"github.com/opencontainers/go-digest"
+	d "github.com/opencontainers/go-digest"
 	"github.com/pkg/errors"
 )
 
 type tagListReq struct {
 	repository string
-	responder chan<- tagListResp
+	responder  chan<- tagListResp
 }
 
 type tagListResp struct {
-	Data []Tag
+	Data  []Tag
 	Error error
 }
 
 type digestReq struct {
 	repository string
-	tag string
-	responder chan<- digestResp
+	tag        string
+	responder  chan<- digestResp
 }
 
 type digestResp struct {
-	Data digest.Digest
+	Data  d.Digest
 	Error error
 }
 
@@ -33,23 +37,68 @@ type repoCache struct {
 	Tags []Tag
 
 	// Map tags to digests
-	Digests map[string]digest.Digest
+	Digests map[string]d.Digest
 }
 
 type cache struct {
 	TagListReq chan<- tagListReq
-	DigestReq chan<- digestReq
+	DigestReq  chan<- digestReq
 }
 
 func newCache(registry registry.Registry) cache {
 	tagListReq := make(chan tagListReq)
 	digestReq := make(chan digestReq)
+	cache := cache{
+		tagListReq,
+		digestReq,
+	}
 
 	store := map[string]repoCache{}
 
 	go func() {
 		for {
 			select {
+			case req := <-digestReq:
+				repo, isPresent := store[req.repository]
+				if !isPresent {
+					req.responder <- digestResp{Error: errors.Errorf(
+						`repo "%s" not present in cache, can't fetch digest'`, req.repository,
+					)}
+				}
+
+				digest, isPresent := repo.Digests[req.tag]
+				if isPresent {
+					req.responder <- digestResp{Data: digest}
+				} else {
+					url := fmt.Sprintf("%s/v2/%s/manifests/%s", registry.URL, req.repository, req.tag)
+					l.Logger.Infof("registry.manifest.head url=%s repository=%s reference=%s", url, req.repository, req.tag)
+
+					httpReq, _ := http.NewRequest("HEAD", url, nil)
+					httpReq.Header.Add("Accept", "application/vnd.docker.distribution.manifest.v2+json")
+					resp, err := registry.Client.Do(httpReq)
+					if resp != nil {
+						defer resp.Body.Close()
+					}
+					if err != nil {
+						req.responder <- digestResp{Error: errors.Wrapf(
+							err, "failed to get digest for repo=%s tag=%s", req.repository, req.tag,
+						)}
+					}
+					digest, err := d.Parse(resp.Header.Get("Docker-Content-Digest"))
+
+					/*
+						digest, err := registry.ManifestDigest(req.repository, req.tag)
+						if err != nil {
+							req.responder <- digestResp{Error: errors.Wrapf(
+									err, `failed to get digest for repo=%s tag=%s`, req.repository, req.tag,
+								)}
+						}
+					*/
+
+					repo.Digests[req.tag] = digest
+					req.responder <- digestResp{Data: digest}
+				}
+
 			case req := <-tagListReq:
 				repo, isPresent := store[req.repository]
 
@@ -71,50 +120,26 @@ func newCache(registry registry.Registry) cache {
 					var tags []Tag
 					for _, tagName := range tagNames {
 						tags = append(tags, Tag{
-							Name:   tagName,
-							SemVer: semver.ParseTagAsSemVer(tagName),
+							Name:       tagName,
+							SemVer:     semver.ParseTagAsSemVer(tagName),
+							repository: req.repository,
+							cache:      cache,
 						})
 					}
 
 					// store result in cache
 					store[req.repository] = repoCache{
 						Tags:    tags,
-						Digests: map[string]digest.Digest{},
+						Digests: map[string]d.Digest{},
 					}
 
 					req.responder <- tagListResp{
 						Data: tags,
 					}
 				}
-
-			case req := <-digestReq:
-				repo, isPresent := store[req.repository]
-				if !isPresent {
-					req.responder <- digestResp{Error: errors.Errorf(
-						`repo "%s" not present in cache, can't fetch digest'`, req.repository,
-					)}
-				}
-
-				digest, isPresent := repo.Digests[req.tag]
-				if isPresent {
-					req.responder <- digestResp{Data: digest}
-				} else {
-					digest, err := registry.ManifestDigest(req.repository, req.tag)
-					if err != nil {
-						req.responder <- digestResp{Error: errors.Wrapf(
-							err, `failed to get digest for repo=%s tag=%s`, req.repository, req.tag,
-						)}
-					}
-
-					repo.Digests[req.tag] = digest
-					req.responder <- digestResp{Data: digest}
-				}
 			}
 		}
 	}()
 
-	return cache {
-		tagListReq,
-		digestReq,
-	}
-}
+	return cache
+}