protected void nativeProtocolHealthCheck()

in server/src/main/java/org/apache/cassandra/sidecar/cluster/CassandraAdapterDelegate.java [242:290]
42 lines of code
5 McCabe index (conditional complexity)

    protected void nativeProtocolHealthCheck()
    {
        Session activeSession;
        try
        {
            activeSession = cqlSessionProvider.get();
        }
        catch (CassandraUnavailableException cue)
        {
            LOGGER.info("No local CQL session is available for cassandraInstanceId={}. " +
                        "Cassandra instance is down presumably.", cassandraInstanceId);
            markNativeDownAndMaybeNotifyDisconnection();
            return;
        }

        maybeRegisterHostListener(activeSession);

        try
        {
            // NOTE: We cannot use `executeLocal` here as there may be no adapter yet.
            SimpleStatement healthCheckStatement = new SimpleStatement("SELECT release_version FROM system.local");
            Metadata metadata = activeSession.getCluster().getMetadata();
            host = getHost(metadata);
            if (host == null)
            {
                LOGGER.warn("Could not find host in cluster metadata by address and port {}",
                            localNativeTransportAddress);
                return;
            }
            healthCheckStatement.setHost(host);
            healthCheckStatement.setConsistencyLevel(ConsistencyLevel.ONE);
            Row row = activeSession.execute(healthCheckStatement).one();
            // This should never happen but added for completeness
            Preconditions.checkArgument(row != null, "Session execution result should never be null");

            if (isNativeUp.compareAndSet(false, true))
            {
                notifyNativeConnection();
            }
        }
        catch (IllegalArgumentException | NoHostAvailableException e)
        {
            LOGGER.debug("Unexpected error querying Cassandra instance {}", cassandraInstanceId, e);
            // The cassandra native protocol connection to the node is down.
            markNativeDownAndMaybeNotifyDisconnection();
            // Unregister the host listener.
            maybeUnregisterHostListener(activeSession);
        }
    }