add docker image search api

Signed-off-by: soulseen <sunzhu@yunify.com>

pkg/models/registries/blob.go

@@ -0,0 +1,48 @@
+package registries
+
+import (
+	"encoding/json"
+	"fmt"
+	"github.com/docker/distribution/manifest/schema2"
+	log "github.com/golang/glog"
+	"net/http"
+)
+
+// Digest returns the digest for an image.
+func (r *Registry) ImageBlob(image Image, token string) (*ImageBlob, error) {
+
+	url := r.GetBlobUrl(image)
+	log.Info("registry.blobs.get url=" + url)
+
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	req.Header.Add("Accept", schema2.MediaTypeManifest)
+	if token != "" {
+		req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", token))
+	}
+	resp, err := r.Client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	respBody, _ := GetRespBody(resp)
+
+	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusNotFound {
+		log.Info("got response: " + string(resp.StatusCode) + string(respBody))
+		return nil, fmt.Errorf("got response: %s", respBody)
+	}
+
+	imageBlob := &ImageBlob{}
+	json.Unmarshal(respBody, imageBlob)
+
+	return imageBlob, nil
+}
+
+func (r *Registry) GetBlobUrl(image Image) string {
+	url := r.url("/v2/%s/blobs/%s", image.Path, image.Digest)
+	return url
+}