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本文主要研究一下canal的CanalAdapterService
CanalAdapterService
canal-1.1.4/client-adapter/launcher/src/main/java/com/alibaba/otter/canal/adapter/launcher/loader/CanalAdapterService.java
@Component
@RefreshScope
public class CanalAdapterService {
private static final Logger logger = LoggerFactory.getLogger(CanalAdapterService.class);
private CanalAdapterLoader adapterLoader;
@Resource
private ContextRefresher contextRefresher;
@Resource
private AdapterCanalConfig adapterCanalConfig;
@Resource
private Environment env;
// 注入bean保证优先注册
@Resource
private SpringContext springContext;
@Resource
private SyncSwitch syncSwitch;
private volatile boolean running = false;
@PostConstruct
public synchronized void init() {
if (running) {
return;
}
try {
logger.info("## start the canal client adapters.");
adapterLoader = new CanalAdapterLoader(adapterCanalConfig);
adapterLoader.init();
running = true;
logger.info("## the canal client adapters are running now ......");
} catch (Exception e) {
logger.error("## something goes wrong when starting up the canal client adapters:", e);
}
}
@PreDestroy
public synchronized void destroy() {
if (!running) {
return;
}
try {
running = false;
logger.info("## stop the canal client adapters");
if (adapterLoader != null) {
adapterLoader.destroy();
adapterLoader = null;
}
for (DruidDataSource druidDataSource : DatasourceConfig.DATA_SOURCES.values()) {
try {
druidDataSource.close();
} catch (Exception e) {
logger.error(e.getMessage(), e);
}
}
DatasourceConfig.DATA_SOURCES.clear();
} catch (Throwable e) {
logger.warn("## something goes wrong when stopping canal client adapters:", e);
} finally {
logger.info("## canal client adapters are down.");
}
}
}
- CanalAdapterService提供了init及destroy方法；其init方法会使用adapterCanalConfig创建CanalAdapterLoader，然后执行adapterLoader.init()；其destroy方法会执行adapterLoader.destroy()，然后遍历DatasourceConfig.DATA_SOURCES执行druidDataSource.close()，最后清空DatasourceConfig.DATA_SOURCES
CanalAdapterLoader
canal-1.1.4/client-adapter/launcher/src/main/java/com/alibaba/otter/canal/adapter/launcher/loader/CanalAdapterLoader.java
public class CanalAdapterLoader {
private static final Logger logger = LoggerFactory.getLogger(CanalAdapterLoader.class);
private CanalClientConfig canalClientConfig;
private Map<String, CanalAdapterWorker> canalWorkers = new HashMap<>();
private Map<String, AbstractCanalAdapterWorker> canalMQWorker = new HashMap<>();
private ExtensionLoader<OuterAdapter> loader;
public CanalAdapterLoader(CanalClientConfig canalClientConfig){
this.canalClientConfig = canalClientConfig;
}
/**
* 初始化canal-client
*/
public void init() {
loader = ExtensionLoader.getExtensionLoader(OuterAdapter.class);
String canalServerHost = this.canalClientConfig.getCanalServerHost();
SocketAddress sa = null;
if (canalServerHost != null) {
String[] ipPort = canalServerHost.split(":");
sa = new InetSocketAddress(ipPort[0], Integer.parseInt(ipPort[1]));
}
String zkHosts = this.canalClientConfig.getZookeeperHosts();
if ("tcp".equalsIgnoreCase(canalClientConfig.getMode())) {
// 初始化canal-client的适配器
for (CanalClientConfig.CanalAdapter canalAdapter : canalClientConfig.getCanalAdapters()) {
List<List<OuterAdapter>> canalOuterAdapterGroups = new ArrayList<>();
for (CanalClientConfig.Group connectorGroup : canalAdapter.getGroups()) {
List<OuterAdapter> canalOutConnectors = new ArrayList<>();
for (OuterAdapterConfig c : connectorGroup.getOuterAdapters()) {
loadAdapter(c, canalOutConnectors);
}
canalOuterAdapterGroups.add(canalOutConnectors);
}
CanalAdapterWorker worker;
if (sa != null) {
worker = new CanalAdapterWorker(canalClientConfig,
canalAdapter.getInstance(),
sa,
canalOuterAdapterGroups);
} else if (zkHosts != null) {
worker = new CanalAdapterWorker(canalClientConfig,
canalAdapter.getInstance(),
zkHosts,
canalOuterAdapterGroups);
} else {
throw new RuntimeException("No canal server connector found");
}
canalWorkers.put(canalAdapter.getInstance(), worker);
worker.start();
logger.info("Start adapter for canal instance: {} succeed", canalAdapter.getInstance());
}
} else if ("kafka".equalsIgnoreCase(canalClientConfig.getMode())) {
// 初始化canal-client-kafka的适配器
for (CanalClientConfig.CanalAdapter canalAdapter : canalClientConfig.getCanalAdapters()) {
for (CanalClientConfig.Group group : canalAdapter.getGroups()) {
List<List<OuterAdapter>> canalOuterAdapterGroups = new ArrayList<>();
List<OuterAdapter> canalOuterAdapters = new ArrayList<>();
for (OuterAdapterConfig config : group.getOuterAdapters()) {
loadAdapter(config, canalOuterAdapters);
}
canalOuterAdapterGroups.add(canalOuterAdapters);
CanalAdapterKafkaWorker canalKafkaWorker = new CanalAdapterKafkaWorker(canalClientConfig,
canalClientConfig.getMqServers(),
canalAdapter.getInstance(),
group.getGroupId(),
canalOuterAdapterGroups,
canalClientConfig.getFlatMessage());
canalMQWorker.put(canalAdapter.getInstance() + "-kafka-" + group.getGroupId(), canalKafkaWorker);
canalKafkaWorker.start();
logger.info("Start adapter for canal-client mq topic: {} succeed",
canalAdapter.getInstance() + "-" + group.getGroupId());
}
}
} else if ("rocketMQ".equalsIgnoreCase(canalClientConfig.getMode())) {
// 初始化canal-client-rocketMQ的适配器
for (CanalClientConfig.CanalAdapter canalAdapter : canalClientConfig.getCanalAdapters()) {
for (CanalClientConfig.Group group : canalAdapter.getGroups()) {
List<List<OuterAdapter>> canalOuterAdapterGroups = new ArrayList<>();
List<OuterAdapter> canalOuterAdapters = new ArrayList<>();
for (OuterAdapterConfig config : group.getOuterAdapters()) {
loadAdapter(config, canalOuterAdapters);
}
canalOuterAdapterGroups.add(canalOuterAdapters);
CanalAdapterRocketMQWorker rocketMQWorker = new CanalAdapterRocketMQWorker(canalClientConfig,
canalClientConfig.getMqServers(),
canalAdapter.getInstance(),
group.getGroupId(),
canalOuterAdapterGroups,
canalClientConfig.getAccessKey(),
canalClientConfig.getSecretKey(),
canalClientConfig.getFlatMessage(),
canalClientConfig.isEnableMessageTrace(),
canalClientConfig.getCustomizedTraceTopic(),
canalClientConfig.getAccessChannel(),
canalClientConfig.getNamespace());
canalMQWorker.put(canalAdapter.getInstance() + "-rocketmq-" + group.getGroupId(), rocketMQWorker);
rocketMQWorker.start();
logger.info("Start adapter for canal-client mq topic: {} succeed",
canalAdapter.getInstance() + "-" + group.getGroupId());
}
}
}
}
private void loadAdapter(OuterAdapterConfig config, List<OuterAdapter> canalOutConnectors) {
try {
OuterAdapter adapter;
adapter = loader.getExtension(config.getName(), StringUtils.trimToEmpty(config.getKey()));
ClassLoader cl = Thread.currentThread().getContextClassLoader();
// 替换ClassLoader
Thread.currentThread().setContextClassLoader(adapter.getClass().getClassLoader());
Environment env = (Environment) SpringContext.getBean(Environment.class);
Properties evnProperties = null;
if (env instanceof StandardEnvironment) {
evnProperties = new Properties();
for (PropertySource<?> propertySource : ((StandardEnvironment) env).getPropertySources()) {
if (propertySource instanceof EnumerablePropertySource) {
String[] names = ((EnumerablePropertySource<?>) propertySource).getPropertyNames();
for (String name : names) {
Object val = propertySource.getProperty(name);
if (val != null) {
evnProperties.put(name, val);
}
}
}
}
}
adapter.init(config, evnProperties);
Thread.currentThread().setContextClassLoader(cl);
canalOutConnectors.add(adapter);
logger.info("Load canal adapter: {} succeed", config.getName());
} catch (Exception e) {
logger.error("Load canal adapter: {} failed", config.getName(), e);
}
}
/**
* 销毁所有适配器 为防止canal实例太多造成销毁阻塞, 并行销毁
*/
public void destroy() {
if (!canalWorkers.isEmpty()) {
ExecutorService stopExecutorService = Executors.newFixedThreadPool(canalWorkers.size());
for (CanalAdapterWorker canalAdapterWorker : canalWorkers.values()) {
stopExecutorService.execute(canalAdapterWorker::stop);
}
stopExecutorService.shutdown();
try {
while (!stopExecutorService.awaitTermination(1, TimeUnit.SECONDS)) {
// ignore
}
} catch (InterruptedException e) {
// ignore
}
}
if (!canalMQWorker.isEmpty()) {
ExecutorService stopMQWorkerService = Executors.newFixedThreadPool(canalMQWorker.size());
for (AbstractCanalAdapterWorker canalAdapterMQWorker : canalMQWorker.values()) {
stopMQWorkerService.execute(canalAdapterMQWorker::stop);
}
stopMQWorkerService.shutdown();
try {
while (!stopMQWorkerService.awaitTermination(1, TimeUnit.SECONDS)) {
// ignore
}
} catch (InterruptedException e) {
// ignore
}
}
logger.info("All canal adapters destroyed");
}
}
- CanalAdapterLoader的init方法通过ExtensionLoader.getExtensionLoader(OuterAdapter.class)获取OuterAdapter的loader，之后根据不同的canalClientConfig.getMode()进行不同的初始化，这里有tcp、kafka、rocketMQ三种模式；tcp模式创建CanalAdapterWorker，然后添加到canalWorkers之后执行worker.start方法；kafka模式创建CanalAdapterKafkaWorker，然后添加到canalMQWorker之后执行worker.start方法；rocketMQ创建CanalAdapterRocketMQWorker，然后添加到canalMQWorker之后执行worker.start方法；其destroy方法会遍历canalWorkers.values()及canalMQWorker.values()，提交异步线程执行其stop方法
小结
CanalAdapterService提供了init及destroy方法；其init方法会使用adapterCanalConfig创建CanalAdapterLoader，然后执行adapterLoader.init()；其destroy方法会执行adapterLoader.destroy()，然后遍历DatasourceConfig.DATA_SOURCES执行druidDataSource.close()，最后清空DatasourceConfig.DATA_SOURCES
doc
来源：oschina
链接：https://my.oschina.net/go4it/blog/3219280