应用系统定制开发本文在前一篇文章的基应用系统定制开发础上来继续分析的核心内容。

RibbonClientConfiguration

  RibbonClientConfiguration应用系统定制开发是一个非常中的Ribbon配置类，应用系统定制开发在第一个发起Ribbon请求的时候会完成对应的初始化操作。会完成多个相关的默认设置。

@Bean    @ConditionalOnMissingBean    public IClientConfig ribbonClientConfig() {        DefaultClientConfigImpl config = new DefaultClientConfigImpl();        config.loadProperties(this.name);        config.set(CommonClientConfigKey.ConnectTimeout, 1000);        config.set(CommonClientConfigKey.ReadTimeout, 1000);        config.set(CommonClientConfigKey.GZipPayload, true);        return config;    }    @Bean    @ConditionalOnMissingBean    public IRule ribbonRule(IClientConfig config) {        if (this.propertiesFactory.isSet(IRule.class, this.name)) {            return (IRule)this.propertiesFactory.get(IRule.class, config, this.name);        } else {            ZoneAvoidanceRule rule = new ZoneAvoidanceRule();            rule.initWithNiwsConfig(config);            return rule;        }    }    @Bean    @ConditionalOnMissingBean    public IPing ribbonPing(IClientConfig config) {        return (IPing)(this.propertiesFactory.isSet(IPing.class, this.name) ? (IPing)this.propertiesFactory.get(IPing.class, config, this.name) : new DummyPing());    }    @Bean    @ConditionalOnMissingBean    public ServerList<Server> ribbonServerList(IClientConfig config) {        if (this.propertiesFactory.isSet(ServerList.class, this.name)) {            return (ServerList)this.propertiesFactory.get(ServerList.class, config, this.name);        } else {            ConfigurationBasedServerList serverList = new ConfigurationBasedServerList();            serverList.initWithNiwsConfig(config);            return serverList;        }    }    @Bean    @ConditionalOnMissingBean    public ServerListUpdater ribbonServerListUpdater(IClientConfig config) {        return new PollingServerListUpdater(config);    }    @Bean    @ConditionalOnMissingBean    public ILoadBalancer ribbonLoadBalancer(IClientConfig config, ServerList<Server> serverList, ServerListFilter<Server> serverListFilter, IRule rule, IPing ping, ServerListUpdater serverListUpdater) {        return (ILoadBalancer)(this.propertiesFactory.isSet(ILoadBalancer.class, this.name) ? (ILoadBalancer)this.propertiesFactory.get(ILoadBalancer.class, config, this.name) : new ZoneAwareLoadBalancer(config, rule, ping, serverList, serverListFilter, serverListUpdater));
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51

  在众多的默认实现中比较重要的是【ILoadBalancer】对象的实现。即【ZoneAwareLoadBalancer】的实现。实现的原理图为：

在【ZoneAwareLoadBalancer】里面完成了服务地址动态获取和服务地址更新定时任务的配置。首先会进入【ZoneAwareLoadBalancer】的构造方法中

public ZoneAwareLoadBalancer(IClientConfig clientConfig, IRule rule,                                 IPing ping, ServerList<T> serverList, ServerListFilter<T> filter,                                 ServerListUpdater serverListUpdater) {        super(clientConfig, rule, ping, serverList, filter, serverListUpdater);    }
1
2
3
4
5

  通过源码能够发现会调用父类中的构造方法。

    public DynamicServerListLoadBalancer(IClientConfig clientConfig, IRule rule, IPing ping,                                         ServerList<T> serverList, ServerListFilter<T> filter,                                         ServerListUpdater serverListUpdater) {        // 继续调用父类中的方法        super(clientConfig, rule, ping);        this.serverListImpl = serverList;        this.filter = filter;        this.serverListUpdater = serverListUpdater;        if (filter instanceof AbstractServerListFilter) {            ((AbstractServerListFilter) filter).setLoadBalancerStats(getLoadBalancerStats());        }        // 完成相关的初始操作  服务地址获取和更新        restOfInit(clientConfig);    }
1
2
3
4
5
6
7
8
9
10
11
12
13
14

  在上面的源码中我们先继续跟踪父类中的方法。

    void initWithConfig(IClientConfig clientConfig, IRule rule, IPing ping, LoadBalancerStats stats) {        this.config = clientConfig;        String clientName = clientConfig.getClientName();        this.name = clientName;        // 设置了定时任务的间隔时间为30秒。        int pingIntervalTime = Integer.parseInt(""                + clientConfig.getProperty(                        CommonClientConfigKey.NFLoadBalancerPingInterval,                        Integer.parseInt("30")));        int maxTotalPingTime = Integer.parseInt(""                + clientConfig.getProperty(                        CommonClientConfigKey.NFLoadBalancerMaxTotalPingTime,                        Integer.parseInt("2")));        setPingInterval(pingIntervalTime);        setMaxTotalPingTime(maxTotalPingTime);        // cross associate with each other        // i.e. Rule,Ping meet your container LB        // LB, these are your Ping and Rule guys ...        setRule(rule);        setPing(ping);        setLoadBalancerStats(stats);        rule.setLoadBalancer(this);        if (ping instanceof AbstractLoadBalancerPing) {            ((AbstractLoadBalancerPing) ping).setLoadBalancer(this);        }        logger.info("Client: {} instantiated a LoadBalancer: {}", name, this);        boolean enablePrimeConnections = clientConfig.get(                CommonClientConfigKey.EnablePrimeConnections, DefaultClientConfigImpl.DEFAULT_ENABLE_PRIME_CONNECTIONS);        if (enablePrimeConnections) {            this.setEnablePrimingConnections(true);            PrimeConnections primeConnections = new PrimeConnections(                    this.getName(), clientConfig);            this.setPrimeConnections(primeConnections);        }        init();    }
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41

  在initWithConfig方法中比较中的就是设置了定时任务的间隔时间。然后我们再回到restOfInit方法中。

    void restOfInit(IClientConfig clientConfig) {        boolean primeConnection = this.isEnablePrimingConnections();        // turn this off to avoid duplicated asynchronous priming done in BaseLoadBalancer.setServerList()        this.setEnablePrimingConnections(false);        // 设置定时任务        enableAndInitLearnNewServersFeature();		// 获取并更新服务地址        updateListOfServers();        if (primeConnection && this.getPrimeConnections() != null) {            this.getPrimeConnections()                    .primeConnections(getReachableServers());        }        this.setEnablePrimingConnections(primeConnection);        LOGGER.info("DynamicServerListLoadBalancer for client {} initialized: {}", clientConfig.getClientName(), this.toString());    }
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

  先看enableAndInitLearnNewServersFeature方法

    public void enableAndInitLearnNewServersFeature() {        LOGGER.info("Using serverListUpdater {}", serverListUpdater.getClass().getSimpleName());        serverListUpdater.start(updateAction);    }
1
2
3
4

  start方法的实现有多种，根据我们的服务选择对应的选择即可。比如本地就使用PollingServerListUpdater,如果是Eureka注册中心就选择EurekaNotificationServerListUpdater.

以本地为例：

@Override    public synchronized void start(final UpdateAction updateAction) {        if (isActive.compareAndSet(false, true)) {            // 定时任务的  任务体            final Runnable wrapperRunnable = new Runnable() {                @Override                public void run() {                    if (!isActive.get()) {                        if (scheduledFuture != null) {                            scheduledFuture.cancel(true);                        }                        return;                    }                    try {                        // doUpdate()的方法体要注意                        updateAction.doUpdate();                        lastUpdated = System.currentTimeMillis();                    } catch (Exception e) {                        logger.warn("Failed one update cycle", e);                    }                }            };			// 设置定时任务 10秒开始第一次检查，间隔时间是30秒            scheduledFuture = getRefreshExecutor().scheduleWithFixedDelay(                    wrapperRunnable,                    initialDelayMs,                    refreshIntervalMs,                    TimeUnit.MILLISECONDS            );        } else {            logger.info("Already active, no-op");        }    }
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

  此处要注意定时任务的具体内容，以本地为例。

 所以定时任务执行的方法也就是【updateListOfServers】方法，也就是：

emsp; 所以我们继续来看看【updateListOfServers】方法中的逻辑

    @VisibleForTesting    public void updateListOfServers() {        List<T> servers = new ArrayList<T>();        if (serverListImpl != null) {            // 从本地或者Eureka或者Nacos等各个配置中心中获取对应的服务地址信息            servers = serverListImpl.getUpdatedListOfServers();            LOGGER.debug("List of Servers for {} obtained from Discovery client: {}",                    getIdentifier(), servers);            if (filter != null) {                servers = filter.getFilteredListOfServers(servers);                LOGGER.debug("Filtered List of Servers for {} obtained from Discovery client: {}",                        getIdentifier(), servers);            }        }        // 更新服务地址信息        updateAllServerList(servers);    }
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18

  上面代码中重要的方法是【getUpdatedListOfServers】和【updateAllServerList】，先来看【getUpdatedListOfServers】方法

  查看本地的逻辑，Eureka的自行查看

	@Override	public List<Server> getUpdatedListOfServers() {        // 从本地配置中获取        String listOfServers = clientConfig.get(CommonClientConfigKey.ListOfServers);        return derive(listOfServers);	}
1
2
3
4
5
6

  然后就是【updateAllServerList】方法

    protected void updateAllServerList(List<T> ls) {        // other threads might be doing this - in which case, we pass        // 通过CAS保证操作的原子性        if (serverListUpdateInProgress.compareAndSet(false, true)) {            try {                for (T s : ls) {                    s.setAlive(true); // set so that clients can start using these                                      // servers right away instead                                      // of having to wait out the ping cycle.                }                // 更新服务地址信息                setServersList(ls);                // 强制ping服务地址                super.forceQuickPing();            } finally {                serverListUpdateInProgress.set(false);            }        }    }
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19

以上的操作流程图为：

好了~【RibbonClientConfiguration】这个配置类的内容就给大家介绍到这里，欢迎大家一键三连!!!