public static void main()

in deployer/src/main/java/com/alibaba/otter/canal/deployer/CanalLauncher.java [34:134]
87 lines of code
11 McCabe index (conditional complexity)

    public static void main(String[] args) {
        try {
            logger.info("## set default uncaught exception handler");
            setGlobalUncaughtExceptionHandler();

            // 支持rocketmq client 配置日志路径
            System.setProperty("rocketmq.client.logUseSlf4j","true");

            logger.info("## load canal configurations");
            String conf = System.getProperty("canal.conf", "classpath:canal.properties");
            Properties properties = new Properties();
            if (conf.startsWith(CLASSPATH_URL_PREFIX)) {
                conf = StringUtils.substringAfter(conf, CLASSPATH_URL_PREFIX);
                properties.load(CanalLauncher.class.getClassLoader().getResourceAsStream(conf));
            } else {
                properties.load(new FileInputStream(conf));
            }

            final CanalStarter canalStater = new CanalStarter(properties);
            String managerAddress = CanalController.getProperty(properties, CanalConstants.CANAL_ADMIN_MANAGER);
            if (StringUtils.isNotEmpty(managerAddress)) {
                String user = CanalController.getProperty(properties, CanalConstants.CANAL_ADMIN_USER);
                String passwd = CanalController.getProperty(properties, CanalConstants.CANAL_ADMIN_PASSWD);
                if (StringUtils.isEmpty(passwd)) {
                    throw new IllegalArgumentException(
                        "canal.admin.passwd is empty , pls check https://github.com/alibaba/canal/issues/4941");
                }
                String adminPort = CanalController.getProperty(properties, CanalConstants.CANAL_ADMIN_PORT, "11110");
                boolean autoRegister = BooleanUtils.toBoolean(CanalController.getProperty(properties,
                    CanalConstants.CANAL_ADMIN_AUTO_REGISTER));
                String autoCluster = CanalController.getProperty(properties, CanalConstants.CANAL_ADMIN_AUTO_CLUSTER);
                String name = CanalController.getProperty(properties, CanalConstants.CANAL_ADMIN_REGISTER_NAME);
                if (StringUtils.isEmpty(name)) {
                    name = AddressUtils.getHostName();
                }

                String registerIp = CanalController.getProperty(properties, CanalConstants.CANAL_REGISTER_IP);
                if (StringUtils.isEmpty(registerIp)) {
                    registerIp = AddressUtils.getHostIp();
                }
                final PlainCanalConfigClient configClient = new PlainCanalConfigClient(managerAddress,
                    user,
                    passwd,
                    registerIp,
                    Integer.parseInt(adminPort),
                    autoRegister,
                    autoCluster,
                    name);
                PlainCanal canalConfig = configClient.findServer(null);
                if (canalConfig == null) {
                    throw new IllegalArgumentException("managerAddress:" + managerAddress
                                                       + " can't not found config for [" + registerIp + ":" + adminPort
                                                       + "]");
                }
                Properties managerProperties = canalConfig.getProperties();
                // merge local
                managerProperties.putAll(properties);
                int scanIntervalInSecond = Integer.valueOf(CanalController.getProperty(managerProperties,
                    CanalConstants.CANAL_AUTO_SCAN_INTERVAL,
                    "5"));
                executor.scheduleWithFixedDelay(new Runnable() {

                    private PlainCanal lastCanalConfig;

                    public void run() {
                        try {
                            if (lastCanalConfig == null) {
                                lastCanalConfig = configClient.findServer(null);
                            } else {
                                PlainCanal newCanalConfig = configClient.findServer(lastCanalConfig.getMd5());
                                if (newCanalConfig != null) {
                                    // 远程配置canal.properties修改重新加载整个应用
                                    canalStater.stop();
                                    Properties managerProperties = newCanalConfig.getProperties();
                                    // merge local
                                    managerProperties.putAll(properties);
                                    canalStater.setProperties(managerProperties);
                                    canalStater.start();

                                    lastCanalConfig = newCanalConfig;
                                }
                            }

                        } catch (Throwable e) {
                            logger.error("scan failed", e);
                        }
                    }

                }, 0, scanIntervalInSecond, TimeUnit.SECONDS);
                canalStater.setProperties(managerProperties);
            } else {
                canalStater.setProperties(properties);
            }

            canalStater.start();
            runningLatch.await();
            executor.shutdownNow();
        } catch (Throwable e) {
            logger.error("## Something goes wrong when starting up the canal Server:", e);
        }
    }