/**
* Retry the given RPC.
*
* @param rpc an RPC to retry or fail
* @param exception an exception to propagate with the RPC
*/
private void failOrRetryRpc(final KuduRpc<?> rpc, final ConnectionResetException exception) {
AsyncKuduClient.RemoteTablet tablet = rpc.getTablet();
// Note As of the time of writing (03/11/16), a null tablet doesn't make sense, if we see a null
// tablet it's because we didn't set it properly before calling sendRpc().
if (tablet == null) { // Can't retry, dunno where this RPC should go.
rpc.errback(exception);
} else {
kuduClient.handleRetryableError(rpc, exception);
}
}
/**
* Provides different handling for various kinds of master errors: re-uses the mechanisms already
* in place for handling tablet server errors as much as possible.
*
* @param rpc The original RPC call that triggered the error.
* @param error The error the master sent.
* @return An exception if we couldn't dispatch the error, or null.
*/
private Exception dispatchMasterErrorOrReturnException(KuduRpc rpc, Master.MasterErrorPB error) {
WireProtocol.AppStatusPB.ErrorCode code = error.getStatus().getCode();
MasterErrorException ex = new MasterErrorException(uuid, error);
if (error.getCode() == Master.MasterErrorPB.Code.NOT_THE_LEADER) {
kuduClient.handleNotLeader(rpc, ex, this);
} else if (code == WireProtocol.AppStatusPB.ErrorCode.SERVICE_UNAVAILABLE
&& (!(rpc instanceof GetMasterRegistrationRequest))) {
// TODO: This is a crutch until we either don't have to retry RPCs going to the
// same server or use retry policies.
kuduClient.handleRetryableError(rpc, ex);
} else {
return ex;
}
return null;
}
/**
* Takes care of a few kinds of TS errors that we handle differently, like tablets or leaders
* moving. Builds and returns an exception if we don't know what to do with it.
*
* @param rpc The original RPC call that triggered the error.
* @param error The error the TS sent.
* @return An exception if we couldn't dispatch the error, or null.
*/
private Exception dispatchTSErrorOrReturnException(
KuduRpc rpc, Tserver.TabletServerErrorPB error) {
WireProtocol.AppStatusPB.ErrorCode code = error.getStatus().getCode();
TabletServerErrorException ex = new TabletServerErrorException(uuid, error.getStatus());
if (error.getCode() == Tserver.TabletServerErrorPB.Code.TABLET_NOT_FOUND) {
kuduClient.handleTabletNotFound(rpc, ex, this);
// we're not calling rpc.callback() so we rely on the client to retry that RPC
} else if (code == WireProtocol.AppStatusPB.ErrorCode.SERVICE_UNAVAILABLE) {
kuduClient.handleRetryableError(rpc, ex);
// The following two error codes are an indication that the tablet isn't a leader.
} else if (code == WireProtocol.AppStatusPB.ErrorCode.ILLEGAL_STATE
|| code == WireProtocol.AppStatusPB.ErrorCode.ABORTED) {
kuduClient.handleNotLeader(rpc, ex, this);
} else {
return ex;
}
return null;
}
/**
* The reason we are suppressing the unchecked conversions is because the KuduRpc is coming from a
* collection that has RPCs with different generics, and there's no way to get "decoded" casted
* correctly. The best we can do is to rely on the RPC to decode correctly, and to not pass an
* Exception in the callback.
*/
@Override
@SuppressWarnings("unchecked")
protected Object decode(
ChannelHandlerContext ctx, Channel chan, ChannelBuffer buf, VoidEnum voidEnum) {
final long start = System.nanoTime();
final int rdx = buf.readerIndex();
LOG.debug("------------------>> ENTERING DECODE >>------------------");
try {
buf = secureRpcHelper.handleResponse(buf, chan);
} catch (SaslException e) {
String message = getPeerUuidLoggingString() + "Couldn't complete the SASL handshake";
LOG.error(message);
throw new NonRecoverableException(message, e);
}
if (buf == null) {
return null;
}
CallResponse response = new CallResponse(buf);
RpcHeader.ResponseHeader header = response.getHeader();
if (!header.hasCallId()) {
final int size = response.getTotalResponseSize();
final String msg =
getPeerUuidLoggingString()
+ "RPC response (size: "
+ size
+ ") doesn't"
+ " have a call ID: "
+ header
+ ", buf="
+ Bytes.pretty(buf);
LOG.error(msg);
throw new NonRecoverableException(msg);
}
final int rpcid = header.getCallId();
@SuppressWarnings("rawtypes")
final KuduRpc rpc = rpcs_inflight.get(rpcid);
if (rpc == null) {
final String msg =
getPeerUuidLoggingString()
+ "Invalid rpcid: "
+ rpcid
+ " found in "
+ buf
+ '='
+ Bytes.pretty(buf);
LOG.error(msg);
// The problem here is that we don't know which Deferred corresponds to
// this RPC, since we don't have a valid ID. So we're hopeless, we'll
// never be able to recover because responses are not framed, we don't
// know where the next response will start... We have to give up here
// and throw this outside of our Netty handler, so Netty will call our
// exception handler where we'll close this channel, which will cause
// all RPCs in flight to be failed.
throw new NonRecoverableException(msg);
}
Pair<Object, Object> decoded = null;
Exception exception = null;
KuduException retryableHeaderException = null;
if (header.hasIsError() && header.getIsError()) {
RpcHeader.ErrorStatusPB.Builder errorBuilder = RpcHeader.ErrorStatusPB.newBuilder();
KuduRpc.readProtobuf(response.getPBMessage(), errorBuilder);
RpcHeader.ErrorStatusPB error = errorBuilder.build();
if (error.getCode().equals(RpcHeader.ErrorStatusPB.RpcErrorCodePB.ERROR_SERVER_TOO_BUSY)) {
// We can't return right away, we still need to remove ourselves from 'rpcs_inflight', so we
// populate 'retryableHeaderException'.
retryableHeaderException = new TabletServerErrorException(uuid, error);
} else {
String message =
getPeerUuidLoggingString() + "Tablet server sent error " + error.getMessage();
exception = new NonRecoverableException(message);
LOG.error(message); // can be useful
}
} else {
try {
decoded = rpc.deserialize(response, this.uuid);
} catch (Exception ex) {
exception = ex;
}
}
if (LOG.isDebugEnabled()) {
LOG.debug(
getPeerUuidLoggingString()
+ "rpcid="
+ rpcid
+ ", response size="
+ (buf.readerIndex() - rdx)
+ " bytes"
+ ", "
+ actualReadableBytes()
+ " readable bytes left"
+ ", rpc="
+ rpc);
}
{
final KuduRpc<?> removed = rpcs_inflight.remove(rpcid);
if (removed == null) {
// The RPC we were decoding was cleaned up already, give up.
throw new NonRecoverableException("RPC not found");
}
}
// This check is specifically for the ERROR_SERVER_TOO_BUSY case above.
if (retryableHeaderException != null) {
kuduClient.handleRetryableError(rpc, retryableHeaderException);
return null;
}
// We can get this Message from within the RPC's expected type,
// so convert it into an exception and nullify decoded so that we use the errback route.
// Have to do it for both TS and Master errors.
if (decoded != null) {
if (decoded.getSecond() instanceof Tserver.TabletServerErrorPB) {
Tserver.TabletServerErrorPB error = (Tserver.TabletServerErrorPB) decoded.getSecond();
exception = dispatchTSErrorOrReturnException(rpc, error);
if (exception == null) {
// It was taken care of.
return null;
} else {
// We're going to errback.
decoded = null;
}
} else if (decoded.getSecond() instanceof Master.MasterErrorPB) {
Master.MasterErrorPB error = (Master.MasterErrorPB) decoded.getSecond();
exception = dispatchMasterErrorOrReturnException(rpc, error);
if (exception == null) {
// Exception was taken care of.
return null;
} else {
decoded = null;
}
}
}
try {
if (decoded != null) {
assert !(decoded.getFirst() instanceof Exception);
if (kuduClient.isStatisticsEnabled()) {
rpc.updateStatistics(kuduClient.getStatistics(), decoded.getFirst());
}
rpc.callback(decoded.getFirst());
} else {
if (kuduClient.isStatisticsEnabled()) {
rpc.updateStatistics(kuduClient.getStatistics(), null);
}
rpc.errback(exception);
}
} catch (Exception e) {
LOG.debug(
getPeerUuidLoggingString()
+ "Unexpected exception while handling RPC #"
+ rpcid
+ ", rpc="
+ rpc
+ ", buf="
+ Bytes.pretty(buf),
e);
}
if (LOG.isDebugEnabled()) {
LOG.debug(
"------------------<< LEAVING DECODE <<------------------"
+ " time elapsed: "
+ ((System.nanoTime() - start) / 1000)
+ "us");
}
return null; // Stop processing here. The Deferred does everything else.
}