feat: add retry support to the auth client (#838)

Signed-off-by: Soule BA <[email protected]>

cmd/oras/internal/option/remote.go

@@ -30,6 +30,7 @@ import (
 	"github.com/spf13/pflag"
 	"oras.land/oras-go/v2/registry/remote"
 	"oras.land/oras-go/v2/registry/remote/auth"
+	"oras.land/oras-go/v2/registry/remote/retry"
 	"oras.land/oras/internal/credential"
 	"oras.land/oras/internal/crypto"
 	onet "oras.land/oras/internal/net"
@@ -205,22 +206,25 @@ func (opts *Remote) authClient(registry string, debug bool) (client *auth.Client
 			return dialer.DialContext
 		}
 	}
+	// default value are derived from http.DefaultTransport
+	baseTransport := &http.Transport{
+		Proxy: http.ProxyFromEnvironment,
+		DialContext: resolveDialContext(&net.Dialer{
+			Timeout:   30 * time.Second,
+			KeepAlive: 30 * time.Second,
+		}),
+		ForceAttemptHTTP2:     true,
+		MaxIdleConns:          100,
+		IdleConnTimeout:       90 * time.Second,
+		TLSHandshakeTimeout:   10 * time.Second,
+		ExpectContinueTimeout: 1 * time.Second,
+		TLSClientConfig:       config,
+	}
 	client = &auth.Client{
 		Client: &http.Client{
-			// default value are derived from http.DefaultTransport
-			Transport: &http.Transport{
-				Proxy: http.ProxyFromEnvironment,
-				DialContext: resolveDialContext(&net.Dialer{
-					Timeout:   30 * time.Second,
-					KeepAlive: 30 * time.Second,
-				}),
-				ForceAttemptHTTP2:     true,
-				MaxIdleConns:          100,
-				IdleConnTimeout:       90 * time.Second,
-				TLSHandshakeTimeout:   10 * time.Second,
-				ExpectContinueTimeout: 1 * time.Second,
-				TLSClientConfig:       config,
-			},
+			// http.RoundTripper with a retry using the DefaultPolicy
+			// see: https://pkg.go.dev/oras.land/oras-go/v2/registry/remote/retry#Policy
+			Transport: retry.NewTransport(baseTransport),
 		},
 		Cache:  auth.NewCache(),
 		Header: opts.headers,

cmd/oras/internal/option/remote_test.go

@@ -23,6 +23,7 @@ import (
 	"encoding/json"
 	"encoding/pem"
 	"fmt"
+	"net/http"
 	nhttp "net/http"
 	"net/http/httptest"
 	"net/url"
@@ -415,3 +416,53 @@ func TestRemote_parseCustomHeaders(t *testing.T) {
 		})
 	}
 }
+
+func TestRemote_NewRepository_Retry(t *testing.T) {
+	caPath := filepath.Join(t.TempDir(), "oras-test.pem")
+	if err := os.WriteFile(caPath, pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: ts.Certificate().Raw}), 0644); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	retries, count := 3, 0
+	ts := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		count++
+		if count < retries {
+			http.Error(w, "error", http.StatusTooManyRequests)
+			return
+		}
+		json.NewEncoder(w).Encode(testTagList)
+	}))
+	defer ts.Close()
+
+	opts := struct {
+		Remote
+		Common
+	}{
+		Remote{
+			CACertFilePath: caPath,
+		},
+		Common{},
+	}
+
+	uri, err := url.ParseRequestURI(ts.URL)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	repo, err := opts.NewRepository(uri.Host+"/"+testRepo, opts.Common)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if err = repo.Tags(context.Background(), "", func(got []string) error {
+		want := []string{"tag"}
+		if len(got) != len(testTagList.Tags) || !reflect.DeepEqual(got, want) {
+			return fmt.Errorf("expect: %v, got: %v", testTagList.Tags, got)
+		}
+		return nil
+	}); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	if count != retries {
+		t.Errorf("expected %d retries, got %d", retries, count)
+	}
+}