flyteorg
diff --git a/‎flytectl/cmd/core/cmd.go
+4-4 b/‎flytectl/cmd/core/cmd.go
+4-4
diff --git a/‎flytectl/pkg/pkce/token_cache_keyring.go
+80-6 b/‎flytectl/pkg/pkce/token_cache_keyring.go
+80-6
diff --git a/‎flyteidl/clients/go/admin/auth_interceptor.go
+45-7 b/‎flyteidl/clients/go/admin/auth_interceptor.go
+45-7
@@ -73,10 +73,10 @@ func generateCommandFunc(cmdEntry CommandEntry) func(cmd *cobra.Command, args []
 		cmdCtx := NewCommandContextNoClient(cmd.OutOrStdout())
 		if !cmdEntry.DisableFlyteClient {
 			clientSet, err := admin.ClientSetBuilder().WithConfig(admin.GetConfig(ctx)).
-				WithTokenCache(pkce.TokenCacheKeyringProvider{
-					ServiceUser: fmt.Sprintf("%s:%s", adminCfg.Endpoint.String(), pkce.KeyRingServiceUser),
-					ServiceName: pkce.KeyRingServiceName,
-				}).Build(ctx)
+				WithTokenCache(pkce.NewTokenCacheKeyringProvider(
+					pkce.KeyRingServiceName,
+					fmt.Sprintf("%s:%s", adminCfg.Endpoint.String(), pkce.KeyRingServiceUser),
+				)).Build(ctx)
 			if err != nil {
 				return err
 			}
 
@@ -1,25 +1,88 @@
 package pkce
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
+	"sync"
+
+	"github.com/flyteorg/flyte/flyteidl/clients/go/admin/cache"
+	"github.com/flyteorg/flyte/flytestdlib/logger"
 
 	"github.com/zalando/go-keyring"
 	"golang.org/x/oauth2"
 )
 
+const (
+	KeyRingServiceUser = "flytectl-user"
+	KeyRingServiceName = "flytectl"
+)
+
 // TokenCacheKeyringProvider wraps the logic to save and retrieve tokens from the OS's keyring implementation.
 type TokenCacheKeyringProvider struct {
 	ServiceName string
 	ServiceUser string
+	mu          *sync.Mutex
+	condLocker  *cache.NoopLocker
+	cond        *sync.Cond
 }
 
-const (
-	KeyRingServiceUser = "flytectl-user"
-	KeyRingServiceName = "flytectl"
-)
+func (t *TokenCacheKeyringProvider) PurgeIfEquals(existing *oauth2.Token) (bool, error) {
+	if existingBytes, err := json.Marshal(existing); err != nil {
+		return false, fmt.Errorf("unable to marshal token to save in cache due to %w", err)
+	} else if tokenJSON, err := keyring.Get(t.ServiceName, t.ServiceUser); err != nil {
+		logger.Warnf(context.Background(), "unable to read token from cache but not failing the purge as the token might not have been saved at all. Error: %v", err)
+		return true, nil
+	} else if tokenJSON != string(existingBytes) {
+		return false, nil
+	}
+
+	_ = keyring.Delete(t.ServiceName, t.ServiceUser)
+	return true, nil
+}
 
-func (t TokenCacheKeyringProvider) SaveToken(token *oauth2.Token) error {
+func (t *TokenCacheKeyringProvider) Lock() {
+	t.mu.Lock()
+}
+
+func (t *TokenCacheKeyringProvider) Unlock() {
+	t.mu.Unlock()
+}
+
+// TryLock the cache.
+func (t *TokenCacheKeyringProvider) TryLock() bool {
+	return t.mu.TryLock()
+}
+
+// CondWait  adds the current go routine to the condition waitlist and waits for another go routine to notify using CondBroadcast
+// The current usage is that one who was able to acquire the lock using TryLock is the one who gets a valid token and notifies all the waitlist requesters so that they can use the new valid token.
+// It also locks the Locker in the condition variable as the semantics of Wait is that it unlocks the Locker after adding
+// the consumer to the waitlist and before blocking on notification.
+// We use the condLocker which is noOp locker to get added to waitlist for notifications.
+// The underlying notifcationList doesn't need to be guarded as it implementation is atomic and is thread safe
+// Refer https://go.dev/src/runtime/sema.go
+// Following is the function and its comments
+// notifyListAdd adds the caller to a notify list such that it can receive
+// notifications. The caller must eventually call notifyListWait to wait for
+// such a notification, passing the returned ticket number.
+//
+//	func notifyListAdd(l *notifyList) uint32 {
+//		// This may be called concurrently, for example, when called from
+//		// sync.Cond.Wait while holding a RWMutex in read mode.
+//		return l.wait.Add(1) - 1
+//	}
+func (t *TokenCacheKeyringProvider) CondWait() {
+	t.condLocker.Lock()
+	t.cond.Wait()
+	t.condLocker.Unlock()
+}
+
+// CondBroadcast broadcasts the condition.
+func (t *TokenCacheKeyringProvider) CondBroadcast() {
+	t.cond.Broadcast()
+}
+
+func (t *TokenCacheKeyringProvider) SaveToken(token *oauth2.Token) error {
 	var tokenBytes []byte
 	if token.AccessToken == "" {
 		return fmt.Errorf("cannot save empty token with expiration %v", token.Expiry)
@@ -38,7 +101,7 @@ func (t TokenCacheKeyringProvider) SaveToken(token *oauth2.Token) error {
 	return nil
 }
 
-func (t TokenCacheKeyringProvider) GetToken() (*oauth2.Token, error) {
+func (t *TokenCacheKeyringProvider) GetToken() (*oauth2.Token, error) {
 	// get saved token
 	tokenJSON, err := keyring.Get(t.ServiceName, t.ServiceUser)
 	if len(tokenJSON) == 0 {
@@ -56,3 +119,14 @@ func (t TokenCacheKeyringProvider) GetToken() (*oauth2.Token, error) {
 
 	return &token, nil
 }
+
+func NewTokenCacheKeyringProvider(serviceName, serviceUser string) *TokenCacheKeyringProvider {
+	condLocker := &cache.NoopLocker{}
+	return &TokenCacheKeyringProvider{
+		mu:          &sync.Mutex{},
+		condLocker:  condLocker,
+		cond:        sync.NewCond(condLocker),
+		ServiceName: serviceName,
+		ServiceUser: serviceUser,
+	}
+}
@@ -20,7 +20,8 @@ const ProxyAuthorizationHeader = "proxy-authorization"
 
 // MaterializeCredentials will attempt to build a TokenSource given the anonymously available information exposed by the server.
 // Once established, it'll invoke PerRPCCredentialsFuture.Store() on perRPCCredentials to populate it with the appropriate values.
-func MaterializeCredentials(ctx context.Context, cfg *Config, tokenCache cache.TokenCache, perRPCCredentials *PerRPCCredentialsFuture, proxyCredentialsFuture *PerRPCCredentialsFuture) error {
+func MaterializeCredentials(ctx context.Context, cfg *Config, tokenCache cache.TokenCache,
+	perRPCCredentials *PerRPCCredentialsFuture, proxyCredentialsFuture *PerRPCCredentialsFuture) error {
 	authMetadataClient, err := InitializeAuthMetadataClient(ctx, cfg, proxyCredentialsFuture)
 	if err != nil {
 		return fmt.Errorf("failed to initialized Auth Metadata Client. Error: %w", err)
@@ -42,11 +43,17 @@ func MaterializeCredentials(ctx context.Context, cfg *Config, tokenCache cache.T
 
 	tokenSource, err := tokenSourceProvider.GetTokenSource(ctx)
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to get token source. Error: %w", err)
+	}
+
+	_, err = tokenSource.Token()
+	if err != nil {
+		return fmt.Errorf("failed to issue token. Error: %w", err)
 	}
 
 	wrappedTokenSource := NewCustomHeaderTokenSource(tokenSource, cfg.UseInsecureConnection, authorizationMetadataKey)
 	perRPCCredentials.Store(wrappedTokenSource)
+
 	return nil
 }
 
@@ -134,19 +141,50 @@ func NewAuthInterceptor(cfg *Config, tokenCache cache.TokenCache, credentialsFut
 	return func(ctx context.Context, method string, req, reply interface{}, cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
 		ctx = setHTTPClientContext(ctx, cfg, proxyCredentialsFuture)
 
+		// If there is already a token in the cache (e.g. key-ring), we should use it immediately...
+		t, _ := tokenCache.GetToken()
+		if t != nil {
+			err := MaterializeCredentials(ctx, cfg, tokenCache, credentialsFuture, proxyCredentialsFuture)
+			if err != nil {
+				return fmt.Errorf("failed to materialize credentials. Error: %v", err)
+			}
+		}
+
 		err := invoker(ctx, method, req, reply, cc, opts...)
 		if err != nil {
 			logger.Debugf(ctx, "Request failed due to [%v]. If it's an unauthenticated error, we will attempt to establish an authenticated context.", err)
 
 			if st, ok := status.FromError(err); ok {
 				// If the error we receive from executing the request expects
 				if shouldAttemptToAuthenticate(st.Code()) {
-					logger.Debugf(ctx, "Request failed due to [%v]. Attempting to establish an authenticated connection and trying again.", st.Code())
-					newErr := MaterializeCredentials(ctx, cfg, tokenCache, credentialsFuture, proxyCredentialsFuture)
-					if newErr != nil {
-						return fmt.Errorf("authentication error! Original Error: %v, Auth Error: %w", err, newErr)
+					err = func() error {
+						if !tokenCache.TryLock() {
+							tokenCache.CondWait()
+							return nil
+						}
+
+						defer tokenCache.Unlock()
+						_, err := tokenCache.PurgeIfEquals(t)
+						if err != nil && !errors.Is(err, cache.ErrNotFound) {
+							logger.Errorf(ctx, "Failed to purge cache. Error [%v]", err)
+							return fmt.Errorf("failed to purge cache. Error: %w", err)
+						}
+
+						logger.Debugf(ctx, "Request failed due to [%v]. Attempting to establish an authenticated connection and trying again.", st.Code())
+						newErr := MaterializeCredentials(ctx, cfg, tokenCache, credentialsFuture, proxyCredentialsFuture)
+						if newErr != nil {
+							errString := fmt.Sprintf("authentication error! Original Error: %v, Auth Error: %v", err, newErr)
+							logger.Errorf(ctx, errString)
+							return fmt.Errorf(errString)
+						}
+
+						tokenCache.CondBroadcast()
+						return nil
+					}()
+
+					if err != nil {
+						return err
 					}
-
 					return invoker(ctx, method, req, reply, cc, opts...)
 				}
 			}