protected void failoverWriter()

in wrapper/src/main/java/software/amazon/jdbc/plugin/failover2/FailoverConnectionPlugin.java [514:609]
82 lines of code
10 McCabe index (conditional complexity)

  protected void failoverWriter() throws SQLException {
    TelemetryFactory telemetryFactory = this.pluginService.getTelemetryFactory();
    TelemetryContext telemetryContext = telemetryFactory.openTelemetryContext(
        TELEMETRY_WRITER_FAILOVER, TelemetryTraceLevel.NESTED);
    this.failoverWriterTriggeredCounter.inc();

    long failoverStartTimeNano = System.nanoTime();

    try {
      LOGGER.info(() -> Messages.get("Failover.startWriterFailover"));

      // It's expected that this method synchronously returns when topology is stabilized,
      // i.e. when cluster control plane has already chosen a new writer.
      if (!this.pluginService.forceRefreshHostList(true, this.failoverTimeoutMsSetting)) {
        this.failoverWriterFailedCounter.inc();
        LOGGER.severe(Messages.get("Failover.unableToRefreshHostList"));
        throw new FailoverFailedSQLException(Messages.get("Failover.unableToRefreshHostList"));
      }

      final List<HostSpec> updatedHosts = this.pluginService.getAllHosts();

      Connection writerCandidateConn;
      final HostSpec writerCandidate = updatedHosts.stream()
          .filter(x -> x.getRole() == HostRole.WRITER)
          .findFirst()
          .orElse(null);

      if (writerCandidate == null) {
        this.failoverWriterFailedCounter.inc();
        String message = Utils.logTopology(updatedHosts, Messages.get("Failover.noWriterHost"));
        LOGGER.severe(message);
        throw new FailoverFailedSQLException(message);
      }

      final List<HostSpec> allowedHosts = this.pluginService.getHosts();
      if (!Utils.containsUrl(allowedHosts, writerCandidate.getUrl())) {
        this.failoverWriterFailedCounter.inc();
        String topologyString = Utils.logTopology(allowedHosts, "");
        LOGGER.severe(Messages.get("Failover.newWriterNotAllowed",
            new Object[] {writerCandidate.getUrl(), topologyString}));
        throw new FailoverFailedSQLException(
            Messages.get("Failover.newWriterNotAllowed",
                new Object[] {writerCandidate.getUrl(), topologyString}));
      }

      try {
        writerCandidateConn = this.pluginService.connect(writerCandidate, this.properties, this);
      } catch (SQLException ex) {
        this.failoverWriterFailedCounter.inc();
        LOGGER.severe(
            Messages.get("Failover.exceptionConnectingToWriter", new Object[]{writerCandidate.getHost()}));
        throw new FailoverFailedSQLException(
            Messages.get("Failover.exceptionConnectingToWriter", new Object[]{writerCandidate.getHost()}), ex);
      }

      HostRole role = this.pluginService.getHostRole(writerCandidateConn);
      if (role != HostRole.WRITER) {
        try {
          writerCandidateConn.close();
        } catch (SQLException ex) {
          // do nothing
        }
        this.failoverWriterFailedCounter.inc();
        LOGGER.severe(
            Messages.get("Failover.unexpectedReaderRole", new Object[]{writerCandidate.getHost(), role}));
        throw new FailoverFailedSQLException(
            Messages.get("Failover.unexpectedReaderRole", new Object[]{writerCandidate.getHost(), role}));
      }

      this.pluginService.setCurrentConnection(writerCandidateConn, writerCandidate);

      LOGGER.fine(
          () -> Messages.get(
              "Failover.establishedConnection",
              new Object[]{this.pluginService.getCurrentHostSpec()}));
      throwFailoverSuccessException();
    } catch (FailoverSuccessSQLException ex) {
      this.failoverWriterSuccessCounter.inc();
      telemetryContext.setSuccess(true);
      telemetryContext.setException(ex);
      throw ex;
    } catch (Exception ex) {
      telemetryContext.setSuccess(false);
      telemetryContext.setException(ex);
      this.failoverWriterFailedCounter.inc();
      throw ex;
    } finally {
      LOGGER.finest(() -> Messages.get(
          "Failover.writerFailoverElapsed",
          new Object[]{TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - failoverStartTimeNano)}));
      telemetryContext.closeContext();
      if (this.telemetryFailoverAdditionalTopTraceSetting) {
        telemetryFactory.postCopy(telemetryContext, TelemetryTraceLevel.FORCE_TOP_LEVEL);
      }
    }
  }