public Builder withBase64Auth(
        String authMethod,
        String hadoopUsername,
        String encodedKrbKeytab,
        String encodedKrbConf,
        String krbPrincipal) {
      this.disableAuth = false;
      byte[] keytab = null;
      if (encodedKrbKeytab != null) {
        keytab = Base64.getDecoder().decode(encodedKrbKeytab);
      }
      byte[] krbConf = null;
      if (krbPrincipal != null) {
        krbConf = Base64.getDecoder().decode(encodedKrbConf);
      }
      return withAuth(authMethod, hadoopUsername, keytab, krbConf, krbPrincipal);
    }
Login with configured catalog user and create a proxy user ugi. Then the operations are
performed within the doAs method of this proxy user ugi.
amoro-common/src/main/java/org/apache/amoro/table/TableMetaStore.java