public void subscribe(String filter) throws CanalClientException {
waitClientRunning();
try {
writeWithHeader(
channel,
Packet.newBuilder()
.setType(PacketType.SUBSCRIPTION)
.setBody(
Sub.newBuilder()
.setDestination(clientIdentity.getDestination())
.setClientId(String.valueOf(clientIdentity.getClientId()))
.setFilter(filter)
.build()
.toByteString())
.build()
.toByteArray());
//
Packet p = Packet.parseFrom(readNextPacket(channel));
Ack ack = Ack.parseFrom(p.getBody());
if (ack.getErrorCode() > 0) {
throw new CanalClientException("failed to subscribe with reason: " + ack.getErrorMessage());
}
clientIdentity.setFilter(filter);
} catch (IOException e) {
throw new CanalClientException(e);
}
}
public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
logger.info("message receives in session handler...");
ChannelBuffer buffer = (ChannelBuffer) e.getMessage();
Packet packet = Packet.parseFrom(buffer.readBytes(buffer.readableBytes()).array());
ClientIdentity clientIdentity = null;
try {
switch (packet.getType()) {
case SUBSCRIPTION:
Sub sub = Sub.parseFrom(packet.getBody());
if (StringUtils.isNotEmpty(sub.getDestination())
&& StringUtils.isNotEmpty(sub.getClientId())) {
clientIdentity =
new ClientIdentity(
sub.getDestination(), Short.valueOf(sub.getClientId()), sub.getFilter());
MDC.put("destination", clientIdentity.getDestination());
embededServer.subscribe(clientIdentity);
// 尝试启动，如果已经启动，忽略
if (!embededServer.isStart(clientIdentity.getDestination())) {
ServerRunningMonitor runningMonitor =
ServerRunningMonitors.getRunningMonitor(clientIdentity.getDestination());
if (!runningMonitor.isStart()) {
runningMonitor.start();
}
}
ctx.setAttachment(clientIdentity); // 设置状态数据
NettyUtils.ack(ctx.getChannel(), null);
} else {
NettyUtils.error(
401,
MessageFormatter.format("destination or clientId is null", sub.toString())
.getMessage(),
ctx.getChannel(),
null);
}
break;
case UNSUBSCRIPTION:
Unsub unsub = Unsub.parseFrom(packet.getBody());
if (StringUtils.isNotEmpty(unsub.getDestination())
&& StringUtils.isNotEmpty(unsub.getClientId())) {
clientIdentity =
new ClientIdentity(
unsub.getDestination(), Short.valueOf(unsub.getClientId()), unsub.getFilter());
MDC.put("destination", clientIdentity.getDestination());
embededServer.unsubscribe(clientIdentity);
stopCanalInstanceIfNecessary(clientIdentity); // 尝试关闭
NettyUtils.ack(ctx.getChannel(), null);
} else {
NettyUtils.error(
401,
MessageFormatter.format("destination or clientId is null", unsub.toString())
.getMessage(),
ctx.getChannel(),
null);
}
break;
case GET:
Get get = CanalPacket.Get.parseFrom(packet.getBody());
if (StringUtils.isNotEmpty(get.getDestination())
&& StringUtils.isNotEmpty(get.getClientId())) {
clientIdentity =
new ClientIdentity(get.getDestination(), Short.valueOf(get.getClientId()));
MDC.put("destination", clientIdentity.getDestination());
Message message = embededServer.getWithoutAck(clientIdentity, get.getFetchSize());
Packet.Builder packetBuilder = CanalPacket.Packet.newBuilder();
packetBuilder.setType(PacketType.MESSAGES);
Messages.Builder messageBuilder = CanalPacket.Messages.newBuilder();
messageBuilder.setBatchId(message.getId());
if (message.getId() != -1 && !CollectionUtils.isEmpty(message.getEntries())) {
for (Entry entry : message.getEntries()) {
messageBuilder.addMessages(entry.toByteString());
}
}
packetBuilder.setBody(messageBuilder.build().toByteString());
NettyUtils.write(ctx.getChannel(), packetBuilder.build().toByteArray(), null); // 输出数据
} else {
NettyUtils.error(
401,
MessageFormatter.format("destination or clientId is null", get.toString())
.getMessage(),
ctx.getChannel(),
null);
}
break;
case CLIENTACK:
ClientAck ack = CanalPacket.ClientAck.parseFrom(packet.getBody());
MDC.put("destination", ack.getDestination());
if (StringUtils.isNotEmpty(ack.getDestination())
&& StringUtils.isNotEmpty(ack.getClientId())) {
if (ack.getBatchId() == 0L) {
NettyUtils.error(
402,
MessageFormatter.format("batchId should assign value", ack.toString())
.getMessage(),
ctx.getChannel(),
null);
} else if (ack.getBatchId() == -1L) { // -1代表上一次get没有数据，直接忽略之
// donothing
} else {
clientIdentity =
new ClientIdentity(ack.getDestination(), Short.valueOf(ack.getClientId()));
embededServer.ack(clientIdentity, ack.getBatchId());
}
} else {
NettyUtils.error(
401,
MessageFormatter.format("destination or clientId is null", ack.toString())
.getMessage(),
ctx.getChannel(),
null);
}
break;
case CLIENTROLLBACK:
ClientRollback rollback = CanalPacket.ClientRollback.parseFrom(packet.getBody());
MDC.put("destination", rollback.getDestination());
if (StringUtils.isNotEmpty(rollback.getDestination())
&& StringUtils.isNotEmpty(rollback.getClientId())) {
clientIdentity =
new ClientIdentity(
rollback.getDestination(), Short.valueOf(rollback.getClientId()));
if (rollback.getBatchId() == 0L) {
embededServer.rollback(clientIdentity); // 回滚所有批次
} else {
embededServer.rollback(clientIdentity, rollback.getBatchId()); // 只回滚单个批次
}
} else {
NettyUtils.error(
401,
MessageFormatter.format("destination or clientId is null", rollback.toString())
.getMessage(),
ctx.getChannel(),
null);
}
break;
default:
NettyUtils.error(
400,
MessageFormatter.format("packet type={} is NOT supported!", packet.getType())
.getMessage(),
ctx.getChannel(),
null);
break;
}
} catch (Throwable exception) {
NettyUtils.error(
400,
MessageFormatter.format(
"something goes wrong with channel:{}, exception={}",
ctx.getChannel(),
ExceptionUtils.getStackTrace(exception))
.getMessage(),
ctx.getChannel(),
null);
} finally {
MDC.remove("destination");
}
}