Support chainguard tag history extension

Author: jonjohnsonjr

internal/explore/explore.go

@@ -178,6 +178,9 @@ func (h *handler) errHandler(hfe HandleFuncE) http.HandlerFunc {
 func (h *handler) renderResponse(w http.ResponseWriter, r *http.Request) error {
 	qs := r.URL.Query()
 
+	if image := qs.Get("history"); image != "" {
+		return h.renderHistory(w, r, strings.TrimPrefix(strings.TrimSpace(image), "https://"))
+	}
 	if image := qs.Get("image"); image != "" {
 		return h.renderManifest(w, r, strings.TrimPrefix(strings.TrimSpace(image), "https://"))
 	}
@@ -572,6 +575,105 @@ func (h *handler) renderManifest(w http.ResponseWriter, r *http.Request, image s
 	return nil
 }
 
+func (h *handler) tagHistory(w http.ResponseWriter, r *http.Request, ref name.Reference, u string) ([]byte, error) {
+	repo := ref.Context().String()
+
+	auth := authn.Anonymous
+	if h.keychain != nil {
+		ref, err := name.NewRepository(repo)
+		if err == nil {
+			maybeAuth, err := h.keychain.Resolve(ref)
+			if err == nil {
+				auth = maybeAuth
+			} else {
+				logs.Debug.Printf("Resolve(%q) = %v", repo, err)
+			}
+		} else {
+			logs.Debug.Printf("NewRepository(%q) = %v", repo, err)
+		}
+	}
+	tr, err := h.transportFromCookie(w, r, repo, auth)
+	if err != nil {
+		return nil, err
+	}
+
+	req, err := http.NewRequest(http.MethodGet, u, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	req.Header.Set("User-Agent", h.userAgent)
+
+	resp, err := tr.RoundTrip(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("unexpected status: %d", resp.StatusCode)
+	}
+
+	return io.ReadAll(resp.Body)
+}
+
+// Render CGR history.
+func (h *handler) renderHistory(w http.ResponseWriter, r *http.Request, image string) error {
+	ref, err := name.ParseReference(image, name.WeakValidation)
+	if err != nil {
+		return err
+	}
+
+	if ref.Context().RegistryStr() != "cgr.dev" {
+		return fmt.Errorf("not a cgr.dev image: %s", image)
+	}
+
+	u := fmt.Sprintf("https://%s/v2/%s/_chainguard/history/%s", ref.Context().Registry, ref.Context().RepositoryStr(), ref.Identifier())
+
+	// TODO: Do we need to cache this?
+	th, err := h.tagHistory(w, r, ref, u)
+	if err != nil {
+		return err
+	}
+
+	header := HeaderData{
+		Repo:      ref.Context().String(),
+		Reference: ref.String(),
+		JQ:        `curl -H "$(crane auth token -H ` + ref.Context().String() + `)" ` + u,
+	}
+
+	if err := headerTmpl.Execute(w, TitleData{image}); err != nil {
+		return fmt.Errorf("headerTmpl: %w", err)
+	}
+
+	copied := *r.URL
+	output := &jsonOutputter{
+		w:     w,
+		u:     &copied,
+		fresh: []bool{},
+		repo:  ref.Context().String(),
+		mt:    r.URL.Query().Get("mt"),
+	}
+
+	// Mutates header for bodyTmpl.
+	b, err := h.jq(output, th, r, &header)
+	if err != nil {
+		return fmt.Errorf("h.jq: %w", err)
+	}
+
+	if err := bodyTmpl.Execute(w, header); err != nil {
+		return fmt.Errorf("bodyTmpl: %w", err)
+	}
+
+	if err := h.renderContent(w, r, ref, b, output, copied); err != nil {
+		return err
+	}
+
+	fmt.Fprintf(w, footer)
+
+	return nil
+}
+
 func (h *handler) renderReferrers(w http.ResponseWriter, r *http.Request, src string) error {
 	ref, err := name.NewDigest(src)
 	if err != nil {
@@ -1444,6 +1546,12 @@ func headerData(ref name.Reference, desc v1.Descriptor) *HeaderData {
 	if strings.Contains(handler, "?") {
 		sep = "&"
 	}
+
+	if _, ok := ref.(name.Tag); ok {
+		if ref.Context().RegistryStr() == "cgr.dev" {
+			handler = "?history="
+		}
+	}
 	return &HeaderData{
 		Repo:             ref.Context().String(),
 		Reference:        ref.String(),

internal/explore/render.go

@@ -545,27 +545,34 @@ func renderMap(w *jsonOutputter, o map[string]interface{}, raw *json.RawMessage)
 				}
 			}
 		case "digest":
-			if mt, ok := o["mediaType"]; ok {
-				if s, ok := mt.(string); ok {
-					h := v1.Hash{}
-					if err := json.Unmarshal(v, &h); err != nil {
-						log.Printf("Unmarshal digest %q: %v", string(v), err)
-					} else {
-						size := int64(0)
-						if sz, ok := o["size"]; ok {
-							if i64, ok := sz.(int64); ok {
-								size = i64
-							} else if f64, ok := sz.(float64); ok {
-								size = int64(f64)
-							}
-						}
-
-						w.Linkify(s, h, size)
+			h := v1.Hash{}
+			if err := json.Unmarshal(v, &h); err != nil {
+				log.Printf("Unmarshal digest %q: %v", string(v), err)
+			} else {
+				size := int64(0)
+				if sz, ok := o["size"]; ok {
+					if i64, ok := sz.(int64); ok {
+						size = i64
+					} else if f64, ok := sz.(float64); ok {
+						size = int64(f64)
+					}
+				}
 
-						// Don't fall through to renderRaw.
-						continue
+				mediaType := w.u.Query().Get("mt")
+				if mt, ok := o["mediaType"]; ok {
+					if s, ok := mt.(string); ok {
+						mediaType = s
 					}
 				}
+
+				if mediaType == "" && w.u.Query().Get("history") != "" {
+					mediaType = string(types.OCIImageIndex)
+				}
+
+				w.Linkify(mediaType, h, size)
+
+				// Don't fall through to renderRaw.
+				continue
 			}
 			if name, ok := o["name"]; ok {
 				// Set this for DSSE digest.name