public Optional get()

in core/src/main/java/com/google/cloud/sql/core/DefaultAccessTokenSupplier.java [71:136]
49 lines of code
9 McCabe index (conditional complexity)

  public Optional<AccessToken> get() throws IOException {
    if (credentialFactory == null) {
      return Optional.empty();
    }

    RetryingCallable<Optional<AccessToken>> retries =
        new RetryingCallable<>(
            () -> {
              final GoogleCredentials credentials = credentialFactory.getCredentials();
              try {
                refreshIfRequired(credentials);
              } catch (IllegalStateException e) {
                throw new IllegalStateException("Error refreshing credentials " + credentials, e);
              }

              if (isAccessTokenEmpty(credentials)) {

                String errorMessage = "Access Token has length of zero";
                logger.debug(errorMessage);

                throw new IllegalStateException(errorMessage);
              }

              validateAccessTokenExpiration(credentials.getAccessToken());

              // Now, attempt to down-scope and refresh credentials
              GoogleCredentials downscoped = getDownscopedCredentials(credentials);

              // For some implementations of GoogleCredentials, particularly
              // ImpersonatedCredentials, down-scoped credentials are not
              // initialized with a token and need to be explicitly refreshed.
              if (isAccessTokenEmpty(downscoped)) {
                try {
                  downscoped.refresh();
                } catch (Exception e) {
                  throw new IllegalStateException(
                      "Error refreshing downscoped credentials " + credentials, e);
                }

                // After attempting to refresh once, if the downscoped credentials do not have
                // an access token after attempting to refresh, then throw an IllegalStateException
                if (isAccessTokenEmpty(downscoped)) {
                  String errorMessage = "Downscoped access token has length of zero";
                  logger.debug(errorMessage);

                  throw new IllegalStateException(
                      errorMessage
                          + ": "
                          + downscoped.getClass().getName()
                          + " from "
                          + credentials.getClass().getName());
                }
                validateAccessTokenExpiration(downscoped.getAccessToken());
              }

              return Optional.of(downscoped.getAccessToken());
            });

    try {
      return retries.call();
    } catch (IOException | RuntimeException e) {
      throw e;
    } catch (Exception e) {
      throw new RuntimeException("Unexpected exception refreshing authentication token", e);
    }
  }