/**
* Return the list of the children of the node of the given path.
*
* <p>If the watch is non-null and the call is successful (no exception is thrown), a watch will
* be left on the node with the given path. The watch willbe triggered by a successful operation
* that deletes the node of the given path or creates/delete a child under the node.
*
* <p>The list of children returned is not sorted and no guarantee is provided as to its natural
* or lexical order.
*
* <p>A KeeperException with error code KeeperException.NoNode will be thrown if no node with the
* given path exists.
*
* @param path
* @param watcher explicit watcher
* @return an unordered array of children of the node with the given path
* @throws InterruptedException If the server transaction is interrupted.
* @throws KeeperException If the server signals an error with a non-zero error code.
* @throws IllegalArgumentException if an invalid path is specified
*/
public List<String> getChildren(final String path, Watcher watcher)
throws KeeperException, InterruptedException {
final String clientPath = path;
PathUtils.validatePath(clientPath);
// the watch contains the un-chroot path
WatchRegistration wcb = null;
if (watcher != null) {
wcb = new ChildWatchRegistration(watcher, clientPath);
}
final String serverPath = prependChroot(clientPath);
RequestHeader h = new RequestHeader();
h.setType(ZooDefs.OpCode.getChildren);
GetChildrenRequest request = new GetChildrenRequest();
request.setPath(serverPath);
request.setWatch(watcher != null);
GetChildrenResponse response = new GetChildrenResponse();
ReplyHeader r = cnxn.submitRequest(h, request, response, wcb);
if (r.getErr() != 0) {
throw KeeperException.create(KeeperException.Code.get(r.getErr()), clientPath);
}
return response.getChildren();
}
/**
* The Asynchronous version of getChildren. The request doesn't actually until the asynchronous
* callback is called.
*
* @see #getChildren(String, Watcher)
*/
public void getChildren(final String path, Watcher watcher, ChildrenCallback cb, Object ctx) {
final String clientPath = path;
PathUtils.validatePath(clientPath);
// the watch contains the un-chroot path
WatchRegistration wcb = null;
if (watcher != null) {
wcb = new ChildWatchRegistration(watcher, clientPath);
}
final String serverPath = prependChroot(clientPath);
RequestHeader h = new RequestHeader();
h.setType(ZooDefs.OpCode.getChildren);
GetChildrenRequest request = new GetChildrenRequest();
request.setPath(serverPath);
request.setWatch(watcher != null);
GetChildrenResponse response = new GetChildrenResponse();
cnxn.queuePacket(h, new ReplyHeader(), request, response, cb, clientPath, serverPath, ctx, wcb);
}
public void processRequest(Request request) {
if (LOG.isDebugEnabled()) {
LOG.debug("Processing request:: " + request);
}
// request.addRQRec(">final");
long traceMask = ZooTrace.CLIENT_REQUEST_TRACE_MASK;
if (request.type == OpCode.ping) {
traceMask = ZooTrace.SERVER_PING_TRACE_MASK;
}
if (LOG.isTraceEnabled()) {
ZooTrace.logRequest(LOG, traceMask, 'E', request, "");
}
ProcessTxnResult rc = null;
synchronized (zks.outstandingChanges) {
while (!zks.outstandingChanges.isEmpty()
&& zks.outstandingChanges.get(0).zxid <= request.zxid) {
ChangeRecord cr = zks.outstandingChanges.remove(0);
if (cr.zxid < request.zxid) {
LOG.warn("Zxid outstanding " + cr.zxid + " is less than current " + request.zxid);
}
if (zks.outstandingChangesForPath.get(cr.path) == cr) {
zks.outstandingChangesForPath.remove(cr.path);
}
}
if (request.hdr != null) {
TxnHeader hdr = request.hdr;
Record txn = request.txn;
rc = zks.processTxn(hdr, txn);
}
// do not add non quorum packets to the queue.
if (Request.isQuorum(request.type)) {
zks.getZKDatabase().addCommittedProposal(request);
}
}
if (request.hdr != null && request.hdr.getType() == OpCode.closeSession) {
ServerCnxnFactory scxn = zks.getServerCnxnFactory();
// this might be possible since
// we might just be playing diffs from the leader
if (scxn != null && request.cnxn == null) {
// calling this if we have the cnxn results in the client's
// close session response being lost - we've already closed
// the session/socket here before we can send the closeSession
// in the switch block below
scxn.closeSession(request.sessionId);
return;
}
}
if (request.cnxn == null) {
return;
}
ServerCnxn cnxn = request.cnxn;
String lastOp = "NA";
zks.decInProcess();
Code err = Code.OK;
Record rsp = null;
boolean closeSession = false;
try {
if (request.hdr != null && request.hdr.getType() == OpCode.error) {
throw KeeperException.create(KeeperException.Code.get(((ErrorTxn) request.txn).getErr()));
}
KeeperException ke = request.getException();
if (ke != null && request.type != OpCode.multi) {
throw ke;
}
if (LOG.isDebugEnabled()) {
LOG.debug("{}", request);
}
switch (request.type) {
case OpCode.ping:
{
zks.serverStats().updateLatency(request.createTime);
lastOp = "PING";
cnxn.updateStatsForResponse(
request.cxid, request.zxid, lastOp, request.createTime, System.currentTimeMillis());
cnxn.sendResponse(
new ReplyHeader(-2, zks.getZKDatabase().getDataTreeLastProcessedZxid(), 0),
null,
"response");
return;
}
case OpCode.createSession:
{
zks.serverStats().updateLatency(request.createTime);
lastOp = "SESS";
cnxn.updateStatsForResponse(
request.cxid, request.zxid, lastOp, request.createTime, System.currentTimeMillis());
zks.finishSessionInit(request.cnxn, true);
return;
}
case OpCode.multi:
{
lastOp = "MULT";
rsp = new MultiResponse();
for (ProcessTxnResult subTxnResult : rc.multiResult) {
OpResult subResult;
switch (subTxnResult.type) {
case OpCode.check:
subResult = new CheckResult();
break;
case OpCode.create:
subResult = new CreateResult(subTxnResult.path);
break;
case OpCode.delete:
subResult = new DeleteResult();
break;
case OpCode.setData:
subResult = new SetDataResult(subTxnResult.stat);
break;
case OpCode.error:
subResult = new ErrorResult(subTxnResult.err);
break;
default:
throw new IOException("Invalid type of op");
}
((MultiResponse) rsp).add(subResult);
}
break;
}
case OpCode.create:
{
lastOp = "CREA";
rsp = new CreateResponse(rc.path);
err = Code.get(rc.err);
break;
}
case OpCode.delete:
{
lastOp = "DELE";
err = Code.get(rc.err);
break;
}
case OpCode.setData:
{
lastOp = "SETD";
rsp = new SetDataResponse(rc.stat);
err = Code.get(rc.err);
break;
}
case OpCode.setACL:
{
lastOp = "SETA";
rsp = new SetACLResponse(rc.stat);
err = Code.get(rc.err);
break;
}
case OpCode.closeSession:
{
lastOp = "CLOS";
closeSession = true;
err = Code.get(rc.err);
break;
}
case OpCode.sync:
{
lastOp = "SYNC";
SyncRequest syncRequest = new SyncRequest();
ByteBufferInputStream.byteBuffer2Record(request.request, syncRequest);
rsp = new SyncResponse(syncRequest.getPath());
break;
}
case OpCode.check:
{
lastOp = "CHEC";
rsp = new SetDataResponse(rc.stat);
err = Code.get(rc.err);
break;
}
case OpCode.exists:
{
lastOp = "EXIS";
// TODO we need to figure out the security requirement for this!
ExistsRequest existsRequest = new ExistsRequest();
ByteBufferInputStream.byteBuffer2Record(request.request, existsRequest);
String path = existsRequest.getPath();
if (path.indexOf('\0') != -1) {
throw new KeeperException.BadArgumentsException();
}
Stat stat = zks.getZKDatabase().statNode(path, existsRequest.getWatch() ? cnxn : null);
rsp = new ExistsResponse(stat);
break;
}
case OpCode.getData:
{
lastOp = "GETD";
GetDataRequest getDataRequest = new GetDataRequest();
ByteBufferInputStream.byteBuffer2Record(request.request, getDataRequest);
DataNode n = zks.getZKDatabase().getNode(getDataRequest.getPath());
if (n == null) {
throw new KeeperException.NoNodeException();
}
Long aclL;
synchronized (n) {
aclL = n.acl;
}
PrepRequestProcessor.checkACL(
zks, zks.getZKDatabase().convertLong(aclL), ZooDefs.Perms.READ, request.authInfo);
Stat stat = new Stat();
byte b[] =
zks.getZKDatabase()
.getData(
getDataRequest.getPath(), stat, getDataRequest.getWatch() ? cnxn : null);
rsp = new GetDataResponse(b, stat);
break;
}
case OpCode.setWatches:
{
lastOp = "SETW";
SetWatches setWatches = new SetWatches();
// XXX We really should NOT need this!!!!
request.request.rewind();
ByteBufferInputStream.byteBuffer2Record(request.request, setWatches);
long relativeZxid = setWatches.getRelativeZxid();
zks.getZKDatabase()
.setWatches(
relativeZxid,
setWatches.getDataWatches(),
setWatches.getExistWatches(),
setWatches.getChildWatches(),
cnxn);
break;
}
case OpCode.getACL:
{
lastOp = "GETA";
GetACLRequest getACLRequest = new GetACLRequest();
ByteBufferInputStream.byteBuffer2Record(request.request, getACLRequest);
Stat stat = new Stat();
List<ACL> acl = zks.getZKDatabase().getACL(getACLRequest.getPath(), stat);
rsp = new GetACLResponse(acl, stat);
break;
}
case OpCode.getChildren:
{
lastOp = "GETC";
GetChildrenRequest getChildrenRequest = new GetChildrenRequest();
ByteBufferInputStream.byteBuffer2Record(request.request, getChildrenRequest);
DataNode n = zks.getZKDatabase().getNode(getChildrenRequest.getPath());
if (n == null) {
throw new KeeperException.NoNodeException();
}
Long aclG;
synchronized (n) {
aclG = n.acl;
}
PrepRequestProcessor.checkACL(
zks, zks.getZKDatabase().convertLong(aclG), ZooDefs.Perms.READ, request.authInfo);
List<String> children =
zks.getZKDatabase()
.getChildren(
getChildrenRequest.getPath(),
null,
getChildrenRequest.getWatch() ? cnxn : null);
rsp = new GetChildrenResponse(children);
break;
}
case OpCode.getChildren2:
{
lastOp = "GETC";
GetChildren2Request getChildren2Request = new GetChildren2Request();
ByteBufferInputStream.byteBuffer2Record(request.request, getChildren2Request);
Stat stat = new Stat();
DataNode n = zks.getZKDatabase().getNode(getChildren2Request.getPath());
if (n == null) {
throw new KeeperException.NoNodeException();
}
Long aclG;
synchronized (n) {
aclG = n.acl;
}
PrepRequestProcessor.checkACL(
zks, zks.getZKDatabase().convertLong(aclG), ZooDefs.Perms.READ, request.authInfo);
List<String> children =
zks.getZKDatabase()
.getChildren(
getChildren2Request.getPath(),
stat,
getChildren2Request.getWatch() ? cnxn : null);
rsp = new GetChildren2Response(children, stat);
break;
}
}
} catch (SessionMovedException e) {
// session moved is a connection level error, we need to tear
// down the connection otw ZOOKEEPER-710 might happen
// ie client on slow follower starts to renew session, fails
// before this completes, then tries the fast follower (leader)
// and is successful, however the initial renew is then
// successfully fwd/processed by the leader and as a result
// the client and leader disagree on where the client is most
// recently attached (and therefore invalid SESSION MOVED generated)
cnxn.sendCloseSession();
return;
} catch (KeeperException e) {
err = e.code();
} catch (Exception e) {
// log at error level as we are returning a marshalling
// error to the user
LOG.error("Failed to process " + request, e);
StringBuilder sb = new StringBuilder();
ByteBuffer bb = request.request;
bb.rewind();
while (bb.hasRemaining()) {
sb.append(Integer.toHexString(bb.get() & 0xff));
}
LOG.error("Dumping request buffer: 0x" + sb.toString());
err = Code.MARSHALLINGERROR;
}
long lastZxid = zks.getZKDatabase().getDataTreeLastProcessedZxid();
ReplyHeader hdr = new ReplyHeader(request.cxid, lastZxid, err.intValue());
zks.serverStats().updateLatency(request.createTime);
cnxn.updateStatsForResponse(
request.cxid, lastZxid, lastOp, request.createTime, System.currentTimeMillis());
try {
cnxn.sendResponse(hdr, rsp, "response");
if (closeSession) {
cnxn.sendCloseSession();
}
} catch (IOException e) {
LOG.error("FIXMSG", e);
}
}