public void stop()

in priam/src/main/java/com/netflix/priam/defaultimpl/CassandraProcessManager.java [143:217]
61 lines of code
12 McCabe index (conditional complexity)

    public void stop(boolean force) throws IOException {
        logger.info("Stopping cassandra server ....");
        List<String> command = Lists.newArrayList();
        if (config.useSudo()) {
            logger.info("Configured to use sudo to stop C*");

            if (!"root".equals(System.getProperty("user.name"))) {
                command.add(SUDO_STRING);
                command.add("-n");
                command.add("-E");
            }
        }
        for (String param : config.getCassStopScript().split(" ")) {
            if (StringUtils.isNotBlank(param)) command.add(param);
        }
        ProcessBuilder stopCass = new ProcessBuilder(command);
        stopCass.directory(new File("/"));
        stopCass.redirectErrorStream(true);

        instanceState.setShouldCassandraBeAlive(false);
        if (!force && config.getGracefulDrainHealthWaitSeconds() >= 0) {
            ExecutorService executor = Executors.newSingleThreadExecutor();
            Future drainFuture =
                    executor.submit(
                            () -> {
                                // As the node has been marked as shutting down above in
                                // setShouldCassandraBeAlive, we wait this
                                // duration to allow external healthcheck systems time to pick up
                                // the state change.
                                try {
                                    Thread.sleep(config.getGracefulDrainHealthWaitSeconds() * 1000);
                                } catch (InterruptedException e) {
                                    return;
                                }

                                try {
                                    JMXNodeTool nodetool = JMXNodeTool.instance(config);
                                    nodetool.drain();
                                } catch (InterruptedException
                                        | IOException
                                        | ExecutionException e) {
                                    logger.error(
                                            "Exception draining Cassandra, could not drain. Proceeding with shutdown.",
                                            e);
                                }
                                // Once Cassandra is drained the thrift/native servers are shutdown
                                // and there is no need to wait to
                                // stop Cassandra. Just stop it now.
                            });

            // In case drain hangs, timeout the future and continue stopping anyways. Give drain 30s
            // always
            // In production we frequently see servers that do not want to drain
            try {
                drainFuture.get(config.getGracefulDrainHealthWaitSeconds() + 30, TimeUnit.SECONDS);
            } catch (ExecutionException | TimeoutException | InterruptedException e) {
                logger.error(
                        "Waited 30s for drain but it did not complete, continuing to shutdown", e);
            }
        }
        Process stopper = stopCass.start();
        try {
            int code = stopper.waitFor();
            if (code == 0) {
                logger.info("Cassandra server has been stopped");
                this.cassMonitorMetrics.incCassStop();
                instanceState.setCassandraProcessAlive(false);
            } else {
                logger.error("Unable to stop cassandra server. Error code: {}", code);
                logProcessOutput(stopper);
            }
        } catch (Exception e) {
            logger.warn("couldn't shut down cassandra correctly", e);
        }
    }