diamond源码阅读-获取服务器列表

serverAddressProcessor

public synchronized void start() {
        if (isRun) {
            return;
        }
        isRun = true;
        initHttpClient();//初始化HttpClient
        if (this.diamondConfigure.isLocalFirst()) {
            acquireServerAddressFromLocal();//如果是本地，从本地获取服务器列表
        }
        else {
            synAcquireServerAddress();
            //如果不再异步每隔一段通过域名时间去取diamondIpList，注释掉下面这行
            //asynAcquireServerAddress();
            asynAcquireServerAddress();
        }

1 initHttpClinet()

private void initHttpClient() {
        HostConfiguration hostConfiguration = new HostConfiguration();

        SimpleHttpConnectionManager connectionManager = new SimpleHttpConnectionManager();
        connectionManager.closeIdleConnections(5000L);//空闲时间

        HttpConnectionManagerParams params = new HttpConnectionManagerParams();
        params.setStaleCheckingEnabled(diamondConfigure.isConnectionStaleCheckingEnabled());
        params.setConnectionTimeout(diamondConfigure.getConnectionTimeout());
        connectionManager.setParams(params);

        configHttpClient = new HttpClient(connectionManager);
        configHttpClient.setHostConfiguration(hostConfiguration);
    }

2 acquireServerAddressFromLocal

protected void acquireServerAddressFromLocal() {
        if (!isRun) {
            throw new RuntimeException("ServerAddressProcessor不在运行状态，无法同步获取服务器地址列表");
        }
        if (MockServer.isTestMode()) {
            diamondConfigure.addDomainName("测试模式，没有使用的真实服务器");
            return;
        }

        int acquireCount = 0;
        if (diamondConfigure.getDomainNameList().size() == 0) {
            reloadServerAddresses();
            if (diamondConfigure.getDomainNameList().size() == 0) {
                if (!acquireServerAddressOnce(acquireCount)) {//从本地获取 发送http请求
                    acquireCount++;
                    if (acquireServerAddressOnce(acquireCount)) {//从服务器获取
                        // 存入本地文件
                        storeServerAddressesToLocal();
                        log.info("在同步获取服务器列表时，向日常ConfigServer服务器获取到了服务器列表");
                    }
                    else {
                        throw new RuntimeException("当前没有可用的服务器列表");
                    }
                }
                else {
                    log.info("在同步获取服务器列表时，向线上ConfigServer服务器获取到了服务器列表");
                    // 存入本地文件
                    storeServerAddressesToLocal();
                }
            }
            else {
                log.info("在同步获取服务器列表时，由于本地指定了服务器列表，不向ConfigServer服务器同步获取服务器列表");
            }
        }
    }

3 类似第2步

protected void synAcquireServerAddress() {
        if (!isRun) {
            throw new RuntimeException("ServerAddressProcessor不在运行状态，无法同步获取服务器地址列表");
        }
        if (MockServer.isTestMode()) {
            diamondConfigure.addDomainName("测试模式，没有使用的真实服务器");
            return;
        }

        if (reloadServerAddresses()) {
			log.info("成功从本地获取Diamond地址列表");
			return ;
		}
        
        int acquireCount = 0;
        
        if (diamondConfigure.getDomainNameList().size() == 0) {
            if (!acquireServerAddressOnce(acquireCount)) {
                acquireCount++;
                if (acquireServerAddressOnce(acquireCount)) {
                    // 存入本地文件
                    storeServerAddressesToLocal();
                    log.info("在同步获取服务器列表时，向日常ConfigServer服务器获取到了服务器列表");
                }
                else {
                    log.info("从本地获取Diamond地址列表");
                    reloadServerAddresses();
                    if (diamondConfigure.getDomainNameList().size() == 0)
                        throw new RuntimeException("当前没有可用的服务器列表");
                }
            }
            else {
                log.info("在同步获取服务器列表时，向线上ConfigServer服务器获取到了服务器列表");
                // 存入本地文件
                storeServerAddressesToLocal();
            }
        }
        if (diamondConfigure.getDomainNameList().size() == 0) {
			throw new RuntimeException("当前没有可用的服务器列表");
		}
    }

4 开线程获取服务器地址列表

protected void asynAcquireServerAddress() {
        if (MockServer.isTestMode()) {
            return;
        }
        this.scheduledExecutor.schedule(new Runnable() {
            public void run() {
                if (!isRun) {
                    log.warn("ServerAddressProcessor不在运行状态，无法异步获取服务器地址列表");
                    return;
                }
                int acquireCount = 0;
                if (!acquireServerAddressOnce(acquireCount)) {
                    acquireCount++;
                    if (acquireServerAddressOnce(acquireCount)) {
                        // 存入本地文件
                        storeServerAddressesToLocal();
                    }
                }
                else {
                    // 存入本地文件
                    storeServerAddressesToLocal();
                }

                asynAcquireServerAddress();
            }
        }, asynAcquireIntervalInSec, TimeUnit.SECONDS);
    }

5 获取到服务器列表后

this.diamondConfigure.setDomainNameList(newDomainNameList);