erosaConnection = buildErosaConnection();
erosaConnection.connect();// 链接
// 2. 获取最后的位置信息
final EntryPosition startPosition = findStartPosition(erosaConnection);
if (startPosition == null) {
throw new CanalParseException("can't find start position for " + destination);
}
logger.info("find start position : {}", startPosition.toString());
// 重新链接，因为在找position过程中可能有状态，需要断开后重建
erosaConnection.reconnect();
// 3. 执行dump前的准备工作
preDump(erosaConnection);
final SinkFunction sinkHandler = new SinkFunction<EVENT>() {
private LogPosition lastPosition;
public boolean sink(EVENT event) {
try {
CanalEntry.Entry entry = parseAndProfilingIfNecessary(event);
if (!running) {
return false;
}
if (entry != null) {
transactionBuffer.add(entry);
// 记录一下对应的positions
this.lastPosition = buildLastPosition(entry);
}
return running;
} catch (TableIdNotFoundException e) {
throw e;
} catch (Exception e) {
processError(e, this.lastPosition, startPosition.getJournalName(),
startPosition.getPosition());
// 走到这一步，说明出错了
return false;
}
}
};
// 4. 开始dump数据
if (StringUtils.isEmpty(startPosition.getJournalName()) && startPosition.getTimestamp() != null) {
erosaConnection.dump(startPosition.getTimestamp(), sinkHandler);
} else {
erosaConnection.dump(startPosition.getJournalName(), startPosition.getPosition(),
sinkHandler);
}
} catch (TableIdNotFoundException e) {
// 特殊处理TableIdNotFound异常,出现这样的异常，一种可能就是起始的position是一个事务当中，导致tablemap Event时间没解析过
needTransactionPosition.compareAndSet(false, true);
logger.error(String.format("dump address %s has an error, retrying. caused by ",
runningInfo.getAddress().toString()), e);
} catch (Throwable e) {
if (!running) {
if (!(e instanceof java.nio.channels.ClosedByInterruptException || e.getCause() instanceof java.nio.channels.ClosedByInterruptException)) {
throw new CanalParseException(String.format("dump address %s has an error, retrying. ",
runningInfo.getAddress().toString()), e);
}
} else {
logger.error(String.format("dump address %s has an error, retrying. caused by ",
runningInfo.getAddress().toString()), e);
sendAlarm(destination, ExceptionUtils.getFullStackTrace(e));
}
} finally {
// 关闭一下链接
afterDump(erosaConnection);
try {
if (erosaConnection != null) {
erosaConnection.disconnect();
}
} catch (IOException e1) {
if (!running) {
throw new CanalParseException(
String.format(
"disconnect address %s has an error, retrying. ",
runningInfo.getAddress().toString()), e1);
} else {
logger.error("disconnect address {} has an error, retrying., caused by ",