GC retries failed upstream revocations for a while, but not forever

internal/controller/supervisorstorage/garbage_collector.go

@@ -121,13 +121,26 @@ func (c *garbageCollectorController) Sync(ctx controllerlib.Context) error {
 			continue
 		}
 
-		if garbageCollectAfterTime.Before(frozenClock.Now()) {
+		if !garbageCollectAfterTime.Before(frozenClock.Now()) {
+			// not old enough yet
+			continue
+		}
+
 		storageType, isSessionStorage := secret.Labels[crud.SecretLabelKey]
 		if isSessionStorage {
 			err := c.maybeRevokeUpstreamOIDCRefreshToken(ctx.Context, storageType, secret)
 			if err != nil {
 				// Log the error for debugging purposes, but still carry on to delete the Secret despite the error.
 				plog.WarningErr("garbage collector could not revoke upstream refresh token", err, logKV(secret))
+				// If the error is of a type that is worth retrying, then not delete the Secret right away.
+				// A future call to Sync will try revocation again for that secret. However, if the Secret is
+				// getting too old, then just delete it anyway. We don't want to extend the lifetime of these
+				// session Secrets by too much time, since the garbage collector is the only thing that is
+				// cleaning them out of etcd storage.
+				fourHoursAgo := frozenClock.Now().Add(-4 * time.Hour)
+				if errors.As(err, &retryableRevocationError{}) && garbageCollectAfterTime.After(fourHoursAgo) {
+					continue
+				}
 			}
 		}
 
@@ -143,7 +156,6 @@ func (c *garbageCollectorController) Sync(ctx controllerlib.Context) error {
 		}
 		plog.Info("storage garbage collector deleted resource", logKV(secret))
 	}
-	}
 
 	return nil
 }
@@ -222,6 +234,7 @@ func (c *garbageCollectorController) revokeUpstreamOIDCRefreshToken(ctx context.
 	for _, p := range c.idpCache.GetOIDCIdentityProviders() {
 		if p.GetName() == customSessionData.ProviderName && p.GetResourceUID() == customSessionData.ProviderUID {
 			foundOIDCIdentityProviderI = p
+			break
 		}
 	}
 	if foundOIDCIdentityProviderI == nil {
@@ -231,13 +244,29 @@ func (c *garbageCollectorController) revokeUpstreamOIDCRefreshToken(ctx context.
 	// Revoke the upstream refresh token. This is a noop if the upstream provider does not offer a revocation endpoint.
 	err := foundOIDCIdentityProviderI.RevokeRefreshToken(ctx, customSessionData.OIDC.UpstreamRefreshToken)
 	if err != nil {
-		return err
+		// This could be a network failure, a 503 result which we should retry
+		// (see https://datatracker.ietf.org/doc/html/rfc7009#section-2.2.1),
+		// or any other non-200 response from the revocation endpoint.
+		// Regardless of which, it is probably worth retrying.
+		return retryableRevocationError{wrapped: err}
 	}
 
 	plog.Trace("garbage collector successfully revoked upstream OIDC refresh token (or provider has no revocation endpoint)", logKV(secret))
 	return nil
 }
 
+type retryableRevocationError struct {
+	wrapped error
+}
+
+func (e retryableRevocationError) Error() string {
+	return fmt.Sprintf("retryable revocation error: %v", e.wrapped)
+}
+
+func (e retryableRevocationError) Unwrap() error {
+	return e.wrapped
+}
+
 func logKV(secret *v1.Secret) []interface{} {
 	return []interface{}{
 		"secretName", secret.Name,

internal/controller/supervisorstorage/garbage_collector_test.go

@@ -625,7 +625,7 @@ func TestGarbageCollectorControllerSync(t *testing.T) {
 			})
 		})
 
-		when("there is a valid, expired authcode secret but the upstream revocation fails", func() {
+		when("there is a valid, recently expired authcode secret but the upstream revocation fails", func() {
 			it.Before(func() {
 				activeOIDCAuthcodeSession := &authorizationcode.Session{
 					Version: "2",
@@ -654,7 +654,8 @@ func TestGarbageCollectorControllerSync(t *testing.T) {
 						UID:             "uid-123",
 						ResourceVersion: "rv-123",
 						Annotations: map[string]string{
-							"storage.pinniped.dev/garbage-collect-after": frozenNow.Add(-time.Second).Format(time.RFC3339),
+							// expired almost 4 hours ago, but not quite 4 hours
+							"storage.pinniped.dev/garbage-collect-after": frozenNow.Add((-time.Hour * 4) + time.Second).Format(time.RFC3339),
 						},
 						Labels: map[string]string{
 							"storage.pinniped.dev/type": authorizationcode.TypeLabelValue,
@@ -672,7 +673,7 @@ func TestGarbageCollectorControllerSync(t *testing.T) {
 				r.NoError(kubeClient.Tracker().Add(activeOIDCAuthcodeSessionSecret))
 			})
 
-			it("should remove the secret anyway because it has expired", func() {
+			it("keeps the secret for a while longer so the revocation can be retried on a future sync", func() {
 				happyOIDCUpstream := oidctestutil.NewTestUpstreamOIDCIdentityProviderBuilder().
 					WithName("upstream-oidc-provider-name").
 					WithResourceUID("upstream-oidc-provider-uid").
@@ -691,7 +692,79 @@ func TestGarbageCollectorControllerSync(t *testing.T) {
 					},
 				)
 
-				// The authcode session secrets is still deleted because it is expired.
+				// The authcode session secrets is not deleted.
+				r.Empty(kubeClient.Actions())
+			})
+		})
+
+		when("there is a valid, long-since expired authcode secret but the upstream revocation fails", func() {
+			it.Before(func() {
+				activeOIDCAuthcodeSession := &authorizationcode.Session{
+					Version: "2",
+					Active:  true,
+					Request: &fosite.Request{
+						ID:     "request-id-1",
+						Client: &clientregistry.Client{},
+						Session: &psession.PinnipedSession{
+							Custom: &psession.CustomSessionData{
+								ProviderUID:  "upstream-oidc-provider-uid",
+								ProviderName: "upstream-oidc-provider-name",
+								ProviderType: psession.ProviderTypeOIDC,
+								OIDC: &psession.OIDCSessionData{
+									UpstreamRefreshToken: "fake-upstream-refresh-token",
+								},
+							},
+						},
+					},
+				}
+				activeOIDCAuthcodeSessionJSON, err := json.Marshal(activeOIDCAuthcodeSession)
+				r.NoError(err)
+				activeOIDCAuthcodeSessionSecret := &corev1.Secret{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:            "activeOIDCAuthcodeSession",
+						Namespace:       installedInNamespace,
+						UID:             "uid-123",
+						ResourceVersion: "rv-123",
+						Annotations: map[string]string{
+							// expired just over 4 hours ago
+							"storage.pinniped.dev/garbage-collect-after": frozenNow.Add((-time.Hour * 4) - time.Second).Format(time.RFC3339),
+						},
+						Labels: map[string]string{
+							"storage.pinniped.dev/type": authorizationcode.TypeLabelValue,
+						},
+					},
+					Data: map[string][]byte{
+						"pinniped-storage-data":    activeOIDCAuthcodeSessionJSON,
+						"pinniped-storage-version": []byte("1"),
+					},
+					Type: "storage.pinniped.dev/" + authorizationcode.TypeLabelValue,
+				}
+				_, err = authorizationcode.ReadFromSecret(activeOIDCAuthcodeSessionSecret)
+				r.NoError(err, "the test author accidentally formed an invalid authcode secret")
+				r.NoError(kubeInformerClient.Tracker().Add(activeOIDCAuthcodeSessionSecret))
+				r.NoError(kubeClient.Tracker().Add(activeOIDCAuthcodeSessionSecret))
+			})
+
+			it("deletes the secret because it has probably been retrying revocation for hours without success", func() {
+				happyOIDCUpstream := oidctestutil.NewTestUpstreamOIDCIdentityProviderBuilder().
+					WithName("upstream-oidc-provider-name").
+					WithResourceUID("upstream-oidc-provider-uid").
+					WithRevokeRefreshTokenError(errors.New("some upstream revocation error")) // the upstream revocation will fail
+				idpListerBuilder := oidctestutil.NewUpstreamIDPListerBuilder().WithOIDC(happyOIDCUpstream.Build())
+
+				startInformersAndController(idpListerBuilder.Build())
+				r.NoError(controllerlib.TestSync(t, subject, *syncContext))
+
+				// Tried to revoke it, although this revocation will fail.
+				idpListerBuilder.RequireExactlyOneCallToRevokeRefreshToken(t,
+					"upstream-oidc-provider-name",
+					&oidctestutil.RevokeRefreshTokenArgs{
+						Ctx:          syncContext.Context,
+						RefreshToken: "fake-upstream-refresh-token",
+					},
+				)
+
+				// The authcode session secrets is deleted.
 				r.ElementsMatch(
 					[]kubetesting.Action{
 						kubetesting.NewDeleteAction(secretsGVR, installedInNamespace, "activeOIDCAuthcodeSession"),