Migrate AWS Cassandra (Keyspaces) authenticator initialization to AWS…

… SDK V2 (#51147)

* refactor(cassandra): use aws sdk v2 for creating keyspaces signer

* refactor(cassandra): only use external id for one assume role

lib/srv/db/cassandra/engine.go

@@ -309,8 +309,8 @@ func (e *Engine) getAuth(sessionCtx *common.Session) (handshakeHandler, error) {
 	switch {
 	case sessionCtx.Database.IsAWSHosted():
 		return &authAWSSigV4Auth{
-			cloudClients: e.CloudClients,
-			ses:          sessionCtx,
+			ses:       sessionCtx,
+			awsConfig: e.AWSConfigProvider,
 		}, nil
 	default:
 		return &basicHandshake{ses: sessionCtx}, nil

lib/srv/db/cassandra/handshake.go

@@ -28,7 +28,7 @@ import (
 	"github.com/gocql/gocql"
 	"github.com/gravitational/trace"
 
-	"github.com/gravitational/teleport/lib/cloud"
+	"github.com/gravitational/teleport/lib/cloud/awsconfig"
 	"github.com/gravitational/teleport/lib/srv/db/cassandra/protocol"
 	"github.com/gravitational/teleport/lib/srv/db/common"
 	awsutils "github.com/gravitational/teleport/lib/utils/aws"
@@ -190,8 +190,8 @@ func sendAuthenticationErrorMessage(authErr error, clientConn *protocol.Conn, in
 
 // authHandler is a handler that performs the Cassandra authentication flow.
 type authAWSSigV4Auth struct {
-	ses          *common.Session
-	cloudClients cloud.Clients
+	ses       *common.Session
+	awsConfig awsconfig.Provider
 }
 
 func (a *authAWSSigV4Auth) getSigV4Authenticator(ctx context.Context) (gocql.Authenticator, error) {
@@ -200,25 +200,22 @@ func (a *authAWSSigV4Auth) getSigV4Authenticator(ctx context.Context) (gocql.Aut
 	if err != nil {
 		return nil, trace.Wrap(err)
 	}
-	baseSession, err := a.cloudClients.GetAWSSession(ctx, meta.Region,
-		cloud.WithAssumeRoleFromAWSMeta(meta),
-		cloud.WithAmbientCredentials(),
-	)
-	if err != nil {
-		return nil, trace.Wrap(err)
-	}
-	var externalID string
+	// ExternalID should only be used in one of the assumed roles. If the
+	// configuration doesn't specify the AssumeRoleARN, it should be used for
+	// the database role.
+	var dbRoleExternalID string
 	if meta.AssumeRoleARN == "" {
-		externalID = meta.ExternalID
+		dbRoleExternalID = meta.ExternalID
 	}
-	session, err := a.cloudClients.GetAWSSession(ctx, meta.Region,
-		cloud.WithChainedAssumeRole(baseSession, roleARN, externalID),
-		cloud.WithAmbientCredentials(),
+	awsCfg, err := a.awsConfig.GetConfig(ctx, meta.Region,
+		awsconfig.WithAssumeRole(meta.AssumeRoleARN, meta.ExternalID),
+		awsconfig.WithAssumeRole(roleARN, dbRoleExternalID),
+		awsconfig.WithAmbientCredentials(),
 	)
 	if err != nil {
 		return nil, trace.Wrap(err)
 	}
-	cred, err := session.Config.Credentials.GetWithContext(ctx)
+	cred, err := awsCfg.Credentials.Retrieve(ctx)
 	if err != nil {
 		return nil, trace.Wrap(err)
 	}