update vendor

Signed-off-by: Jess Frazelle <acidburn@microsoft.com>

vendor/github.com/docker/distribution/registry/proxy/proxyauth.go

@@ -0,0 +1,83 @@
+package proxy
+
+import (
+	"net/http"
+	"net/url"
+	"strings"
+
+	"github.com/docker/distribution/context"
+	"github.com/docker/distribution/registry/client/auth"
+	"github.com/docker/distribution/registry/client/auth/challenge"
+)
+
+const challengeHeader = "Docker-Distribution-Api-Version"
+
+type userpass struct {
+	username string
+	password string
+}
+
+type credentials struct {
+	creds map[string]userpass
+}
+
+func (c credentials) Basic(u *url.URL) (string, string) {
+	up := c.creds[u.String()]
+
+	return up.username, up.password
+}
+
+func (c credentials) RefreshToken(u *url.URL, service string) string {
+	return ""
+}
+
+func (c credentials) SetRefreshToken(u *url.URL, service, token string) {
+}
+
+// configureAuth stores credentials for challenge responses
+func configureAuth(username, password, remoteURL string) (auth.CredentialStore, error) {
+	creds := map[string]userpass{}
+
+	authURLs, err := getAuthURLs(remoteURL)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, url := range authURLs {
+		context.GetLogger(context.Background()).Infof("Discovered token authentication URL: %s", url)
+		creds[url] = userpass{
+			username: username,
+			password: password,
+		}
+	}
+
+	return credentials{creds: creds}, nil
+}
+
+func getAuthURLs(remoteURL string) ([]string, error) {
+	authURLs := []string{}
+
+	resp, err := http.Get(remoteURL + "/v2/")
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	for _, c := range challenge.ResponseChallenges(resp) {
+		if strings.EqualFold(c.Scheme, "bearer") {
+			authURLs = append(authURLs, c.Parameters["realm"])
+		}
+	}
+
+	return authURLs, nil
+}
+
+func ping(manager challenge.Manager, endpoint, versionHeader string) error {
+	resp, err := http.Get(endpoint)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	return manager.AddResponse(resp)
+}