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arangodb/arangod/Cluster/ClusterComm.cpp

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////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
/// http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Max Neunhoeffer
////////////////////////////////////////////////////////////////////////////////
#include "Cluster/ClusterComm.h"
#include "Logger/Logger.h"
#include "Basics/ConditionLocker.h"
#include "Basics/HybridLogicalClock.h"
#include "Basics/StringUtils.h"
#include "Cluster/ClusterInfo.h"
#include "Cluster/ServerState.h"
#include "Dispatcher/DispatcherThread.h"
#include "Rest/FakeRequest.h"
#include "SimpleHttpClient/ConnectionManager.h"
#include "SimpleHttpClient/SimpleHttpClient.h"
#include "Utils/Transaction.h"
#include "VocBase/ticks.h"
using namespace arangodb;
////////////////////////////////////////////////////////////////////////////////
/// @brief global callback for asynchronous REST handler
////////////////////////////////////////////////////////////////////////////////
void arangodb::ClusterCommRestCallback(std::string& coordinator,
GeneralResponse* response) {
ClusterComm::instance()->asyncAnswer(coordinator, response);
}
////////////////////////////////////////////////////////////////////////////////
/// @brief routine to set the destination
////////////////////////////////////////////////////////////////////////////////
void ClusterCommResult::setDestination(std::string const& dest,
bool logConnectionErrors) {
// This sets result.shardId, result.serverId and result.endpoint,
// depending on what dest is. Note that if a shardID is given, the
// responsible server is looked up, if a serverID is given, the endpoint
// is looked up, both can fail and immediately lead to a CL_COMM_ERROR
// state.
if (dest.substr(0, 6) == "shard:") {
shardID = dest.substr(6);
{
std::shared_ptr<std::vector<ServerID>> resp =
ClusterInfo::instance()->getResponsibleServer(shardID);
if (!resp->empty()) {
serverID = (*resp)[0];
} else {
serverID = "";
status = CL_COMM_BACKEND_UNAVAILABLE;
if (logConnectionErrors) {
LOG(ERR) << "cannot find responsible server for shard '" << shardID
<< "'";
} else {
LOG(INFO) << "cannot find responsible server for shard '" << shardID
<< "'";
}
return;
}
}
LOG(DEBUG) << "Responsible server: " << serverID;
} else if (dest.substr(0, 7) == "server:") {
shardID = "";
serverID = dest.substr(7);
} else if (dest.substr(0, 6) == "tcp://" || dest.substr(0, 6) == "ssl://") {
shardID = "";
serverID = "";
endpoint = dest;
return; // all good
} else {
shardID = "";
serverID = "";
endpoint = "";
status = CL_COMM_BACKEND_UNAVAILABLE;
errorMessage = "did not understand destination'" + dest + "'";
if (logConnectionErrors) {
LOG(ERR) << "did not understand destination '" << dest << "'";
} else {
LOG(INFO) << "did not understand destination '" << dest << "'";
}
return;
}
// Now look up the actual endpoint:
auto ci = ClusterInfo::instance();
endpoint = ci->getServerEndpoint(serverID);
if (endpoint.empty()) {
status = CL_COMM_BACKEND_UNAVAILABLE;
errorMessage = "did not find endpoint of server '" + serverID + "'";
if (logConnectionErrors) {
LOG(ERR) << "did not find endpoint of server '" << serverID << "'";
} else {
LOG(INFO) << "did not find endpoint of server '" << serverID << "'";
}
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief ClusterComm constructor
////////////////////////////////////////////////////////////////////////////////
ClusterComm::ClusterComm()
: _backgroundThread(nullptr), _logConnectionErrors(false) {}
////////////////////////////////////////////////////////////////////////////////
/// @brief ClusterComm destructor
////////////////////////////////////////////////////////////////////////////////
ClusterComm::~ClusterComm() {
if (_backgroundThread != nullptr) {
_backgroundThread->beginShutdown();
delete _backgroundThread;
_backgroundThread = nullptr;
}
cleanupAllQueues();
}
////////////////////////////////////////////////////////////////////////////////
/// @brief getter for our singleton instance
////////////////////////////////////////////////////////////////////////////////
ClusterComm* ClusterComm::instance() {
static ClusterComm* Instance = new ClusterComm();
return Instance;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief initialize the cluster comm singleton object
////////////////////////////////////////////////////////////////////////////////
void ClusterComm::initialize() {
auto* i = instance();
i->startBackgroundThread();
}
////////////////////////////////////////////////////////////////////////////////
/// @brief cleanup function to call once when shutting down
////////////////////////////////////////////////////////////////////////////////
void ClusterComm::cleanup() {
auto i = instance();
TRI_ASSERT(i != nullptr);
delete i;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief start the communication background thread
////////////////////////////////////////////////////////////////////////////////
void ClusterComm::startBackgroundThread() {
_backgroundThread = new ClusterCommThread();
if (!_backgroundThread->start()) {
LOG(FATAL) << "ClusterComm background thread does not work";
FATAL_ERROR_EXIT();
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief produces an operation ID which is unique in this process
////////////////////////////////////////////////////////////////////////////////
OperationID ClusterComm::getOperationID() { return TRI_NewTickServer(); }
////////////////////////////////////////////////////////////////////////////////
/// @brief submit an HTTP request to a shard asynchronously.
///
/// This function queues a single HTTP request, usually to one of the
/// DBServers to be sent by ClusterComm in the background thread. If
/// `singleRequest` is false, as is the default, this request actually
/// orders an answer, which is an HTTP request sent from the target
/// DBServer back to us. Therefore ClusterComm also creates an entry in
/// a list of expected answers. One either has to use a callback for
/// the answer, or poll for it, or drop it to prevent memory leaks.
/// This call never returns a result directly, rather, it returns an
/// operation ID under which one can query the outcome with a wait() or
/// enquire() call (see below).
///
/// Use @ref enquire below to get information about the progress. The
/// actual answer is then delivered either in the callback or via
/// poll. If `singleRequest` is set to `true`, then the destination
/// can be an arbitrary server, the functionality can also be used in
/// single-Server mode, and the operation is complete when the single
/// request is sent and the corresponding answer has been received. We
/// use this functionality for the agency mode of ArangoDB.
/// The library takes ownerships of the pointer `headerFields` by moving
/// the unique_ptr to its own storage, this is necessary since this
/// method sometimes has to add its own headers. The library retains shared
/// ownership of `callback`. We use a shared_ptr for the body string
/// such that it is possible to use the same body in multiple requests.
///
/// Arguments: `clientTransactionID` is a string coming from the
/// client and describing the transaction the client is doing,
/// `coordTransactionID` is a number describing the transaction the
/// coordinator is doing, `destination` is a string that either starts
/// with "shard:" followed by a shardID identifying the shard this
/// request is sent to, actually, this is internally translated into a
/// server ID. It is also possible to specify a DB server ID directly
/// here in the form of "server:" followed by a serverID. Furthermore,
/// it is possible to specify the target endpoint directly using
/// "tcp://..." or "ssl://..." endpoints, if `singleRequest` is true.
///
/// There are two timeout arguments. `timeout` is the globale timeout
/// specifying after how many seconds the complete operation must be
/// completed. `initTimeout` is a second timeout, which is used to
/// limit the time to send the initial request away. If `initTimeout`
/// is negative (as for example in the default value), then `initTimeout`
/// is taken to be the same as `timeout`. The idea behind the two timeouts
/// is to be able to specify correct behaviour for automatic failover.
/// The idea is that if the initial request cannot be sent within
/// `initTimeout`, one can retry after a potential failover.
////////////////////////////////////////////////////////////////////////////////
OperationID ClusterComm::asyncRequest(
ClientTransactionID const clientTransactionID,
CoordTransactionID const coordTransactionID, std::string const& destination,
arangodb::GeneralRequest::RequestType reqtype, std::string const& path,
std::shared_ptr<std::string const> body,
std::unique_ptr<std::unordered_map<std::string, std::string>>& headerFields,
std::shared_ptr<ClusterCommCallback> callback, ClusterCommTimeout timeout,
bool singleRequest, ClusterCommTimeout initTimeout) {
TRI_ASSERT(headerFields.get() != nullptr);
auto op = std::make_unique<ClusterCommOperation>();
op->result.clientTransactionID = clientTransactionID;
op->result.coordTransactionID = coordTransactionID;
OperationID opId = 0;
do {
opId = getOperationID();
} while (opId == 0); // just to make sure
op->result.operationID = opId;
op->result.status = CL_COMM_SUBMITTED;
op->result.single = singleRequest;
op->reqtype = reqtype;
op->path = path;
op->body = body;
op->headerFields = std::move(headerFields);
op->callback = callback;
double now = TRI_microtime();
op->endTime = timeout == 0.0 ? now + 24 * 60 * 60.0 : now + timeout;
if (initTimeout <= 0.0) {
op->initEndTime = op->endTime;
} else {
op->initEndTime = now + initTimeout;
}
op->result.setDestination(destination, logConnectionErrors());
if (op->result.status == CL_COMM_BACKEND_UNAVAILABLE) {
// We put it into the received queue right away for error reporting:
ClusterCommResult const resCopy(op->result);
LOG(DEBUG) << "In asyncRequest, putting failed request "
<< resCopy.operationID << " directly into received queue.";
CONDITION_LOCKER(locker, somethingReceived);
received.push_back(op.get());
op.release();
auto q = received.end();
receivedByOpID[opId] = --q;
if (nullptr != callback) {
op.reset(*q);
if ((*callback.get())(&(op->result))) {
auto i = receivedByOpID.find(opId);
receivedByOpID.erase(i);
received.erase(q);
} else {
op.release();
}
}
somethingReceived.broadcast();
return opId;
}
if (destination.substr(0, 6) == "shard:") {
if (arangodb::Transaction::_makeNolockHeaders != nullptr) {
// LOCKING-DEBUG
// std::cout << "Found Nolock header\n";
auto it =
arangodb::Transaction::_makeNolockHeaders->find(op->result.shardID);
if (it != arangodb::Transaction::_makeNolockHeaders->end()) {
// LOCKING-DEBUG
// std::cout << "Found our shard\n";
(*op->headerFields)["X-Arango-Nolock"] = op->result.shardID;
}
}
}
if (singleRequest == false) {
// Add the header fields for asynchronous mode:
(*op->headerFields)["X-Arango-Async"] = "store";
(*op->headerFields)["X-Arango-Coordinator"] =
ServerState::instance()->getId() + ":" +
basics::StringUtils::itoa(op->result.operationID) + ":" +
clientTransactionID + ":" +
basics::StringUtils::itoa(coordTransactionID);
(*op->headerFields)["Authorization"] =
ServerState::instance()->getAuthentication();
}
TRI_voc_tick_t timeStamp = TRI_HybridLogicalClock();
(*op->headerFields)[StaticStrings::HLCHeader] =
arangodb::basics::HybridLogicalClock::encodeTimeStamp(timeStamp);
#ifdef DEBUG_CLUSTER_COMM
#ifdef ARANGODB_ENABLE_MAINTAINER_MODE
#if ARANGODB_ENABLE_BACKTRACE
std::string bt;
TRI_GetBacktrace(bt);
std::replace(bt.begin(), bt.end(), '\n', ';'); // replace all '\n' to ';'
(*op->headerFields)["X-Arango-BT-A-SYNC"] = bt;
#endif
#endif
#endif
// LOCKING-DEBUG
// std::cout << "asyncRequest: sending " <<
// arangodb::rest::HttpRequest::translateMethod(reqtype) << " request to DB
// server '" << op->serverID << ":" << path << "\n" << *(body.get()) << "\n";
// for (auto& h : *(op->headerFields)) {
// std::cout << h.first << ":" << h.second << std::endl;
// }
// std::cout << std::endl;
{
CONDITION_LOCKER(locker, somethingToSend);
toSend.push_back(op.get());
TRI_ASSERT(nullptr != op.get());
op.release();
std::list<ClusterCommOperation*>::iterator i = toSend.end();
toSendByOpID[opId] = --i;
}
LOG(DEBUG) << "In asyncRequest, put into queue " << opId;
somethingToSend.signal();
return opId;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief submit a single HTTP request to a shard synchronously.
///
/// This function does an HTTP request synchronously, waiting for the
/// result. Note that the result has `status` field set to `CL_COMM_SENT`
/// and the field `result` is set to the HTTP response. The field `answer`
/// is unused in this case. In case of a timeout the field `status` is
/// `CL_COMM_TIMEOUT` and the field `result` points to an HTTP response
/// object that only says "timeout". Note that the ClusterComm library
/// does not keep a record of this operation, in particular, you cannot
/// use @ref enquire to ask about it.
///
/// Arguments: `clientTransactionID` is a string coming from the client
/// and describing the transaction the client is doing, `coordTransactionID`
/// is a number describing the transaction the coordinator is doing,
/// shardID is a string that identifies the shard this request is sent to,
/// actually, this is internally translated into a server ID. It is also
/// possible to specify a DB server ID directly here.
////////////////////////////////////////////////////////////////////////////////
std::unique_ptr<ClusterCommResult> ClusterComm::syncRequest(
ClientTransactionID const& clientTransactionID,
CoordTransactionID const coordTransactionID, std::string const& destination,
arangodb::GeneralRequest::RequestType reqtype, std::string const& path,
std::string const& body,
std::unordered_map<std::string, std::string> const& headerFields,
ClusterCommTimeout timeout) {
std::unordered_map<std::string, std::string> headersCopy(headerFields);
auto res = std::make_unique<ClusterCommResult>();
res->clientTransactionID = clientTransactionID;
res->coordTransactionID = coordTransactionID;
do {
res->operationID = getOperationID();
} while (res->operationID == 0); // just to make sure
res->status = CL_COMM_SENDING;
double currentTime = TRI_microtime();
double endTime =
timeout == 0.0 ? currentTime + 24 * 60 * 60.0 : currentTime + timeout;
res->setDestination(destination, logConnectionErrors());
if (res->status == CL_COMM_BACKEND_UNAVAILABLE) {
return res;
}
if (destination.substr(0, 6) == "shard:") {
if (arangodb::Transaction::_makeNolockHeaders != nullptr) {
// LOCKING-DEBUG
// std::cout << "Found Nolock header\n";
auto it = arangodb::Transaction::_makeNolockHeaders->find(res->shardID);
if (it != arangodb::Transaction::_makeNolockHeaders->end()) {
// LOCKING-DEBUG
// std::cout << "Found our shard\n";
headersCopy["X-Arango-Nolock"] = res->shardID;
}
}
}
httpclient::ConnectionManager* cm = httpclient::ConnectionManager::instance();
httpclient::ConnectionManager::SingleServerConnection* connection =
cm->leaseConnection(res->endpoint);
if (nullptr == connection) {
res->status = CL_COMM_BACKEND_UNAVAILABLE;
res->errorMessage =
"cannot create connection to server '" + res->serverID + "'";
if (logConnectionErrors()) {
LOG(ERR) << "cannot create connection to server '" << res->serverID
<< "' at endpoint '" << res->endpoint << "'";
} else {
LOG(INFO) << "cannot create connection to server '" << res->serverID
<< "' at endpoint '" << res->endpoint << "'";
}
} else {
LOG(DEBUG) << "sending " << arangodb::HttpRequest::translateMethod(reqtype)
<< " request to DB server '" << res->serverID
<< "' at endpoint '" << res->endpoint << "': " << body;
// LOCKING-DEBUG
// std::cout << "syncRequest: sending " <<
// arangodb::rest::HttpRequest::translateMethod(reqtype) << " request to
// DB server '" << res->serverID << ":" << path << "\n" << body << "\n";
// for (auto& h : headersCopy) {
// std::cout << h.first << ":" << h.second << std::endl;
// }
// std::cout << std::endl;
auto client = std::make_unique<arangodb::httpclient::SimpleHttpClient>(
connection->_connection, endTime - currentTime, false);
client->keepConnectionOnDestruction(true);
headersCopy["Authorization"] = ServerState::instance()->getAuthentication();
TRI_voc_tick_t timeStamp = TRI_HybridLogicalClock();
headersCopy[StaticStrings::HLCHeader] =
arangodb::basics::HybridLogicalClock::encodeTimeStamp(timeStamp);
#ifdef DEBUG_CLUSTER_COMM
#ifdef ARANGODB_ENABLE_MAINTAINER_MODE
#if ARANGODB_ENABLE_BACKTRACE
std::string bt;
TRI_GetBacktrace(bt);
std::replace(bt.begin(), bt.end(), '\n', ';'); // replace all '\n' to ';'
headersCopy["X-Arango-BT-SYNC"] = bt;
#endif
#endif
#endif
res->result.reset(
client->request(reqtype, path, body.c_str(), body.size(), headersCopy));
if (res->result == nullptr || !res->result->isComplete()) {
res->errorMessage = client->getErrorMessage();
if (res->errorMessage == "Request timeout reached") {
res->status = CL_COMM_TIMEOUT;
} else {
res->status = CL_COMM_BACKEND_UNAVAILABLE;
}
cm->brokenConnection(connection);
client->invalidateConnection();
} else {
cm->returnConnection(connection);
if (res->result->wasHttpError()) {
res->status = CL_COMM_ERROR;
res->errorMessage = client->getErrorMessage();
}
}
}
if (res->status == CL_COMM_SENDING) {
// Everything was OK
res->status = CL_COMM_SENT;
}
return res;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief internal function to match an operation:
////////////////////////////////////////////////////////////////////////////////
bool ClusterComm::match(ClientTransactionID const& clientTransactionID,
CoordTransactionID const coordTransactionID,
ShardID const& shardID, ClusterCommOperation* op) {
return ((clientTransactionID == "" ||
clientTransactionID == op->result.clientTransactionID) &&
(0 == coordTransactionID ||
coordTransactionID == op->result.coordTransactionID) &&
(shardID == "" || shardID == op->result.shardID));
}
////////////////////////////////////////////////////////////////////////////////
/// @brief check on the status of an operation
///
/// This call never blocks and returns information about a specific operation
/// given by `operationID`. Note that if the `status` is >= `CL_COMM_SENT`,
/// then the `result` field in the returned object is set, if the `status`
/// is `CL_COMM_RECEIVED`, then `answer` is set. However, in both cases
/// the ClusterComm library retains the operation in its queues! Therefore,
/// you have to use @ref wait or @ref drop to dequeue. Do not delete
/// `result` and `answer` before doing this! However, you have to delete
/// the ClusterCommResult pointer you get, it will automatically refrain
/// from deleting `result` and `answer`.
////////////////////////////////////////////////////////////////////////////////
ClusterCommResult const ClusterComm::enquire(OperationID const operationID) {
IndexIterator i;
ClusterCommOperation* op = nullptr;
// First look into the send queue:
{
CONDITION_LOCKER(locker, somethingToSend);
i = toSendByOpID.find(operationID);
if (i != toSendByOpID.end()) {
op = *(i->second);
return op->result;
}
}
// Note that operations only ever move from the send queue to the
// receive queue and never in the other direction. Therefore it is
// OK to use two different locks here, since we look first in the
// send queue and then in the receive queue; we can never miss
// an operation that is actually there.
// If the above did not give anything, look into the receive queue:
{
CONDITION_LOCKER(locker, somethingReceived);
i = receivedByOpID.find(operationID);
if (i != receivedByOpID.end()) {
op = *(i->second);
return op->result;
}
}
ClusterCommResult res;
res.operationID = operationID;
res.status = CL_COMM_DROPPED;
return res;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief wait for one answer matching the criteria
///
/// If clientTransactionID is empty, then any answer with any
/// clientTransactionID matches. If coordTransactionID is 0, then any
/// answer with any coordTransactionID matches. If shardID is empty,
/// then any answer from any ShardID matches. If operationID is 0, then
/// any answer with any operationID matches. This function returns
/// a result structure with status CL_COMM_DROPPED if no operation
/// matches. If `timeout` is given, the result can be a result structure
/// with status CL_COMM_TIMEOUT indicating that no matching answer was
/// available until the timeout was hit.
////////////////////////////////////////////////////////////////////////////////
ClusterCommResult const ClusterComm::wait(
ClientTransactionID const& clientTransactionID,
CoordTransactionID const coordTransactionID, OperationID const operationID,
ShardID const& shardID, ClusterCommTimeout timeout) {
IndexIterator i;
QueueIterator q;
double endtime;
double timeleft;
if (0.0 == timeout) {
endtime = TRI_microtime() +
24.0 * 60.0 * 60.0; // this is the Sankt Nimmerleinstag
} else {
endtime = TRI_microtime() + timeout;
}
// tell Dispatcher that we are waiting:
auto dt = arangodb::rest::DispatcherThread::current();
if (dt != nullptr) {
dt->block();
}
if (0 != operationID) {
// In this case we only have to look into at most one operation.
CONDITION_LOCKER(locker, somethingReceived);
while (true) { // will be left by return or break on timeout
i = receivedByOpID.find(operationID);
if (i == receivedByOpID.end()) {
// It could be that the operation is still in the send queue:
CONDITION_LOCKER(sendLocker, somethingToSend);
i = toSendByOpID.find(operationID);
if (i == toSendByOpID.end()) {
// Nothing known about this operation, return with failure:
ClusterCommResult res;
res.operationID = operationID;
res.status = CL_COMM_DROPPED;
// tell Dispatcher that we are back in business
if (dt != nullptr) {
dt->unblock();
}
return res;
}
} else {
// It is in the receive queue, now look at the status:
q = i->second;
if ((*q)->result.status >= CL_COMM_TIMEOUT ||
((*q)->result.single && (*q)->result.status == CL_COMM_SENT)) {
std::unique_ptr<ClusterCommOperation> op(*q);
// It is done, let's remove it from the queue and return it:
try {
receivedByOpID.erase(i);
received.erase(q);
} catch (...) {
op.release();
throw;
}
// tell Dispatcher that we are back in business
if (dt != nullptr) {
dt->unblock();
}
return op->result;
}
// It is in the receive queue but still waiting, now wait actually
}
// Here it could either be in the receive or the send queue, let's wait
timeleft = endtime - TRI_microtime();
if (timeleft <= 0) {
break;
}
somethingReceived.wait(uint64_t(timeleft * 1000000.0));
}
// This place is only reached on timeout
} else {
// here, operationID == 0, so we have to do matching, we are only
// interested, if at least one operation matches, if it is ready,
// we return it immediately, otherwise, we report an error or wait.
CONDITION_LOCKER(locker, somethingReceived);
while (true) { // will be left by return or break on timeout
bool found = false;
for (q = received.begin(); q != received.end(); q++) {
if (match(clientTransactionID, coordTransactionID, shardID, *q)) {
found = true;
if ((*q)->result.status >= CL_COMM_TIMEOUT ||
((*q)->result.single && (*q)->result.status == CL_COMM_SENT)) {
ClusterCommOperation* op = *q;
// It is done, let's remove it from the queue and return it:
i = receivedByOpID.find(op->result.operationID); // cannot fail!
TRI_ASSERT(i != receivedByOpID.end());
TRI_ASSERT(i->second == q);
receivedByOpID.erase(i);
received.erase(q);
std::unique_ptr<ClusterCommOperation> opPtr(op);
ClusterCommResult res = op->result;
// tell Dispatcher that we are back in business
if (dt != nullptr) {
dt->unblock();
}
return res;
}
}
}
// If we found nothing, we have to look through the send queue:
if (!found) {
CONDITION_LOCKER(sendLocker, somethingToSend);
for (q = toSend.begin(); q != toSend.end(); q++) {
if (match(clientTransactionID, coordTransactionID, shardID, *q)) {
found = true;
break;
}
}
}
if (!found) {
// Nothing known about this operation, return with failure:
ClusterCommResult res;
res.clientTransactionID = clientTransactionID;
res.coordTransactionID = coordTransactionID;
res.operationID = operationID;
res.shardID = shardID;
res.status = CL_COMM_DROPPED;
// tell Dispatcher that we are back in business
if (dt != nullptr) {
dt->unblock();
}
return res;
}
// Here it could either be in the receive or the send queue, let's wait
timeleft = endtime - TRI_microtime();
if (timeleft <= 0) {
break;
}
somethingReceived.wait(uint64_t(timeleft * 1000000.0));
}
// This place is only reached on timeout
}
// Now we have to react on timeout:
ClusterCommResult res;
res.clientTransactionID = clientTransactionID;
res.coordTransactionID = coordTransactionID;
res.operationID = operationID;
res.shardID = shardID;
res.status = CL_COMM_TIMEOUT;
// tell Dispatcher that we are back in business
if (dt != nullptr) {
dt->unblock();
}
return res;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief ignore and drop current and future answers matching
///
/// If clientTransactionID is empty, then any answer with any
/// clientTransactionID matches. If coordTransactionID is 0, then
/// any answer with any coordTransactionID matches. If shardID is
/// empty, then any answer from any ShardID matches. If operationID
/// is 0, then any answer with any operationID matches. If there
/// is already an answer for a matching operation, it is dropped and
/// freed. If not, any future answer coming in is automatically dropped.
/// This function can be used to automatically delete all information about an
/// operation, for which @ref enquire reported successful completion.
////////////////////////////////////////////////////////////////////////////////
void ClusterComm::drop(ClientTransactionID const& clientTransactionID,
CoordTransactionID const coordTransactionID,
OperationID const operationID, ShardID const& shardID) {
QueueIterator q;
QueueIterator nextq;
IndexIterator i;
// First look through the send queue:
{
CONDITION_LOCKER(sendLocker, somethingToSend);
for (q = toSend.begin(); q != toSend.end();) {
ClusterCommOperation* op = *q;
if ((0 != operationID && operationID == op->result.operationID) ||
match(clientTransactionID, coordTransactionID, shardID, op)) {
if (op->result.status == CL_COMM_SENDING) {
op->result.dropped = true;
q++;
} else {
nextq = q;
nextq++;
i = toSendByOpID.find(op->result.operationID); // cannot fail
TRI_ASSERT(i != toSendByOpID.end());
TRI_ASSERT(q == i->second);
toSendByOpID.erase(i);
toSend.erase(q);
q = nextq;
}
} else {
q++;
}
}
}
// Now look through the receive queue:
{
CONDITION_LOCKER(locker, somethingReceived);
for (q = received.begin(); q != received.end();) {
ClusterCommOperation* op = *q;
if ((0 != operationID && operationID == op->result.operationID) ||
match(clientTransactionID, coordTransactionID, shardID, op)) {
nextq = q;
nextq++;
i = receivedByOpID.find(op->result.operationID); // cannot fail
if (i != receivedByOpID.end() && q == i->second) {
receivedByOpID.erase(i);
}
received.erase(q);
delete op;
q = nextq;
} else {
q++;
}
}
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief send an answer HTTP request to a coordinator
///
/// This is only called in a DBServer node and never in a coordinator
/// node.
////////////////////////////////////////////////////////////////////////////////
void ClusterComm::asyncAnswer(std::string& coordinatorHeader,
GeneralResponse* response) {
// FIXME - generalize for VPP
HttpResponse* responseToSend = dynamic_cast<HttpResponse*>(response);
if (responseToSend == nullptr) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_INTERNAL);
}
// First take apart the header to get the coordinatorID:
ServerID coordinatorID;
size_t start = 0;
size_t pos;
LOG(DEBUG) << "In asyncAnswer, seeing " << coordinatorHeader;
pos = coordinatorHeader.find(":", start);
if (pos == std::string::npos) {
LOG(ERR) << "Could not find coordinator ID in X-Arango-Coordinator";
return;
}
coordinatorID = coordinatorHeader.substr(start, pos - start);
// Now find the connection to which the request goes from the coordinatorID:
httpclient::ConnectionManager* cm = httpclient::ConnectionManager::instance();
std::string endpoint =
ClusterInfo::instance()->getServerEndpoint(coordinatorID);
if (endpoint == "") {
if (logConnectionErrors()) {
LOG(ERR) << "asyncAnswer: cannot find endpoint for server '"
<< coordinatorID << "'";
} else {
LOG(INFO) << "asyncAnswer: cannot find endpoint for server '"
<< coordinatorID << "'";
}
return;
}
httpclient::ConnectionManager::SingleServerConnection* connection =
cm->leaseConnection(endpoint);
if (nullptr == connection) {
LOG(ERR) << "asyncAnswer: cannot create connection to server '"
<< coordinatorID << "'";
return;
}
std::unordered_map<std::string, std::string> headers =
responseToSend->headers();
headers["X-Arango-Coordinator"] = coordinatorHeader;
headers["X-Arango-Response-Code"] =
responseToSend->responseString(responseToSend->responseCode());
headers["Authorization"] = ServerState::instance()->getAuthentication();
TRI_voc_tick_t timeStamp = TRI_HybridLogicalClock();
headers[StaticStrings::HLCHeader] =
arangodb::basics::HybridLogicalClock::encodeTimeStamp(timeStamp);
char const* body = responseToSend->body().c_str();
size_t len = responseToSend->body().length();
LOG(DEBUG) << "asyncAnswer: sending PUT request to DB server '"
<< coordinatorID << "'";
auto client = std::make_unique<arangodb::httpclient::SimpleHttpClient>(
connection->_connection, 3600.0, false);
client->keepConnectionOnDestruction(true);
// We add this result to the operation struct without acquiring
// a lock, since we know that only we do such a thing:
std::unique_ptr<httpclient::SimpleHttpResult> result(
client->request(GeneralRequest::RequestType::PUT, "/_api/shard-comm",
body, len, headers));
if (result.get() == nullptr || !result->isComplete()) {
cm->brokenConnection(connection);
client->invalidateConnection();
} else {
cm->returnConnection(connection);
}
// We cannot deal with a bad result here, so forget about it in any case.
}
////////////////////////////////////////////////////////////////////////////////
/// @brief process an answer coming in on the HTTP socket
///
/// this is called for a request, which is actually an answer to one of
/// our earlier requests, return value of "" means OK and nonempty is
/// an error. This is only called in a coordinator node and not in a
/// DBServer node.
////////////////////////////////////////////////////////////////////////////////
std::string ClusterComm::processAnswer(std::string& coordinatorHeader,
GeneralRequest* answer) {
if (answer == nullptr) {
THROW_ARANGO_EXCEPTION(TRI_ERROR_INTERNAL);
}
TRI_ASSERT(answer != nullptr);
// First take apart the header to get the operaitonID:
OperationID operationID;
size_t start = 0;
size_t pos;
LOG(DEBUG) << "In processAnswer, seeing " << coordinatorHeader;
pos = coordinatorHeader.find(":", start);
if (pos == std::string::npos) {
return std::string(
"could not find coordinator ID in 'X-Arango-Coordinator'");
}
// coordinatorID = coordinatorHeader.substr(start,pos-start);
start = pos + 1;
pos = coordinatorHeader.find(":", start);
if (pos == std::string::npos) {
return std::string("could not find operationID in 'X-Arango-Coordinator'");
}
operationID = basics::StringUtils::uint64(coordinatorHeader.substr(start));
// Finally find the ClusterCommOperation record for this operation:
{
CONDITION_LOCKER(locker, somethingReceived);
ClusterComm::IndexIterator i;
i = receivedByOpID.find(operationID);
if (i != receivedByOpID.end()) {
TRI_ASSERT(answer != nullptr);
ClusterCommOperation* op = *(i->second);
op->result.answer.reset(answer);
op->result.answer_code = GeneralResponse::responseCode(
answer->header("x-arango-response-code"));
op->result.status = CL_COMM_RECEIVED;
// Do we have to do a callback?
if (nullptr != op->callback.get()) {
if ((*op->callback.get())(&op->result)) {
// This is fully processed, so let's remove it from the queue:
QueueIterator q = i->second;
std::unique_ptr<ClusterCommOperation> o(op);
receivedByOpID.erase(i);
received.erase(q);
return std::string("");
}
}
} else {
// We have to look in the send queue as well, as it might not yet
// have been moved to the received queue. Note however that it must
// have been fully sent, so this is highly unlikely, but not impossible.
CONDITION_LOCKER(sendLocker, somethingToSend);
i = toSendByOpID.find(operationID);
if (i != toSendByOpID.end()) {
TRI_ASSERT(answer != nullptr);
ClusterCommOperation* op = *(i->second);
op->result.answer.reset(answer);
op->result.answer_code = GeneralResponse::responseCode(
answer->header("x-arango-response-code"));
op->result.status = CL_COMM_RECEIVED;
if (nullptr != op->callback) {
if ((*op->callback)(&op->result)) {
// This is fully processed, so let's remove it from the queue:
QueueIterator q = i->second;
std::unique_ptr<ClusterCommOperation> o(op);
toSendByOpID.erase(i);
toSend.erase(q);
return std::string("");
}
}
} else {
// Nothing known about the request, get rid of it:
delete answer;
return std::string("operation was already dropped by sender");
}
}
}
// Finally tell the others:
somethingReceived.broadcast();
return std::string("");
}
////////////////////////////////////////////////////////////////////////////////
/// @brief move an operation from the send to the receive queue
////////////////////////////////////////////////////////////////////////////////
bool ClusterComm::moveFromSendToReceived(OperationID operationID) {
LOG(DEBUG) << "In moveFromSendToReceived " << operationID;
CONDITION_LOCKER(locker, somethingReceived);
CONDITION_LOCKER(sendLocker, somethingToSend);
IndexIterator i = toSendByOpID.find(operationID); // cannot fail
// TRI_ASSERT(i != toSendByOpID.end());
// KV: Except the operation has been dropped in the meantime
QueueIterator q = i->second;
ClusterCommOperation* op = *q;
TRI_ASSERT(op->result.operationID == operationID);
toSendByOpID.erase(i);
toSend.erase(q);
std::unique_ptr<ClusterCommOperation> opPtr(op);
if (op->result.dropped) {
return false;
}
if (op->result.status == CL_COMM_SENDING) {
// Note that in the meantime the status could have changed to
// CL_COMM_ERROR, CL_COMM_TIMEOUT or indeed to CL_COMM_RECEIVED in
// these cases, we do not want to overwrite this result
op->result.status = CL_COMM_SENT;
}
received.push_back(op);
opPtr.release();
q = received.end();
q--;
receivedByOpID[operationID] = q;
somethingReceived.broadcast();
return true;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief cleanup all queues
////////////////////////////////////////////////////////////////////////////////
void ClusterComm::cleanupAllQueues() {
{
CONDITION_LOCKER(locker, somethingToSend);
for (auto& it : toSend) {
delete it;
}
toSendByOpID.clear();
toSend.clear();
}
{
CONDITION_LOCKER(locker, somethingReceived);
for (auto& it : received) {
delete it;
}
receivedByOpID.clear();
received.clear();
}
}
ClusterCommThread::ClusterCommThread() : Thread("ClusterComm") {}
ClusterCommThread::~ClusterCommThread() { shutdown(); }
////////////////////////////////////////////////////////////////////////////////
/// @brief begin shutdown sequence
////////////////////////////////////////////////////////////////////////////////
void ClusterCommThread::beginShutdown() {
Thread::beginShutdown();
ClusterComm* cc = ClusterComm::instance();
if (cc != nullptr) {
CONDITION_LOCKER(guard, cc->somethingToSend);
guard.signal();
}
}
////////////////////////////////////////////////////////////////////////////////
/// @brief this method performs the given requests described by the vector
/// of ClusterCommRequest structs in the following way: all requests are
/// tried and the result is stored in the result component. Each request is
/// done with asyncRequest and the given timeout. If a request times out
/// it is considered to be a failure. If a connection cannot be created,
/// a retry is done with exponential backoff, that is, first after 1 second,
/// then after another 2 seconds, 4 seconds and so on, until the overall
/// timeout has been reached. A request that can connect and produces a
/// result is simply reported back with no retry, even in an error case.
/// The method returns the number of successful requests and puts the
/// number of finished ones in nrDone. Thus, the timeout was triggered
/// if and only if nrDone < requests.size().
////////////////////////////////////////////////////////////////////////////////
size_t ClusterComm::performRequests(std::vector<ClusterCommRequest>& requests,
ClusterCommTimeout timeout, size_t& nrDone,
arangodb::LogTopic const& logTopic) {
if (requests.size() == 0) {
nrDone = 0;
return 0;
}
if (requests.size() == 1) {
return performSingleRequest(requests, timeout, nrDone, logTopic);
}
CoordTransactionID coordinatorTransactionID = TRI_NewTickServer();
ClusterCommTimeout startTime = TRI_microtime();
ClusterCommTimeout now = startTime;
ClusterCommTimeout endTime = startTime + timeout;
std::vector<ClusterCommTimeout> dueTime;
for (size_t i = 0; i < requests.size(); ++i) {
dueTime.push_back(startTime);
}
nrDone = 0;
size_t nrGood = 0;
std::unordered_map<OperationID, size_t> opIDtoIndex;
try {
while (now <= endTime) {
if (nrDone >= requests.size()) {
// All good, report
return nrGood;
}
// First send away what is due:
for (size_t i = 0; i < requests.size(); i++) {
if (!requests[i].done && now >= dueTime[i]) {
if (requests[i].headerFields.get() == nullptr) {
requests[i].headerFields = std::make_unique<
std::unordered_map<std::string, std::string>>();
}
LOG_TOPIC(TRACE, logTopic)
<< "ClusterComm::performRequests: sending request to "
<< requests[i].destination << ":" << requests[i].path
<< "body:" << requests[i].body;
double localInitTimeout =
(std::min)((std::max)(1.0, now - startTime), 10.0);
double localTimeout = endTime - now;
dueTime[i] = endTime + 10; // no retry unless ordered elsewhere
if (localInitTimeout > localTimeout) {
localInitTimeout = localTimeout;
}
OperationID opId = asyncRequest(
"", coordinatorTransactionID, requests[i].destination,
requests[i].requestType, requests[i].path, requests[i].body,
requests[i].headerFields, nullptr, localTimeout, false,
localInitTimeout);
opIDtoIndex.insert(std::make_pair(opId, i));
// It is possible that an error occurs right away, we will notice
// below after wait(), though, and retry in due course.
}
}
// Now see how long we can afford to wait:
ClusterCommTimeout actionNeeded = endTime;
for (size_t i = 0; i < dueTime.size(); i++) {
if (!requests[i].done && dueTime[i] < actionNeeded) {
actionNeeded = dueTime[i];
}
}
// Now wait for results:
while (true) {
now = TRI_microtime();
if (now >= actionNeeded) {
break;
}
auto res =
wait("", coordinatorTransactionID, 0, "", actionNeeded - now);
if (res.status == CL_COMM_TIMEOUT && res.operationID == 0) {
// Did not receive any result until the timeout (of wait) was hit.
break;
}
if (res.status == CL_COMM_DROPPED) {
// Nothing in flight, simply wait:
now = TRI_microtime();
if (now >= actionNeeded) {
break;
}
usleep((std::min)(500000,
static_cast<int>((actionNeeded - now) * 1000000)));
continue;
}
auto it = opIDtoIndex.find(res.operationID);
if (it == opIDtoIndex.end()) {
// Ooops, we got a response to which we did not send the request
LOG(ERR)
<< "Received ClusterComm response for a request we did not send!";
continue;
}
size_t index = it->second;
if (res.status == CL_COMM_RECEIVED) {
requests[index].result = res;
requests[index].done = true;
nrDone++;
if (res.answer_code == GeneralResponse::ResponseCode::OK ||
res.answer_code == GeneralResponse::ResponseCode::CREATED ||
res.answer_code == GeneralResponse::ResponseCode::ACCEPTED) {
nrGood++;
}
LOG_TOPIC(TRACE, logTopic)
<< "ClusterComm::performRequests: "
<< "got answer from " << requests[index].destination << ":"
<< requests[index].path << " with return code "
<< (int)res.answer_code;
} else if (res.status == CL_COMM_BACKEND_UNAVAILABLE ||
(res.status == CL_COMM_TIMEOUT && !res.sendWasComplete)) {
requests[index].result = res;
// In this case we will retry:
dueTime[index] =
(std::min)(10.0, (std::max)(0.2, 2 * (now - startTime))) +
startTime;
if (dueTime[index] >= endTime) {
requests[index].done = true;
nrDone++;
}
if (dueTime[index] < actionNeeded) {
actionNeeded = dueTime[index];
}
LOG_TOPIC(TRACE, logTopic)
<< "ClusterComm::performRequests: "
<< "got BACKEND_UNAVAILABLE or TIMEOUT from "
<< requests[index].destination << ":" << requests[index].path;
} else { // a "proper error"
requests[index].result = res;
requests[index].done = true;
nrDone++;
LOG_TOPIC(TRACE, logTopic)
<< "ClusterComm::performRequests: "
<< "got no answer from " << requests[index].destination << ":"
<< requests[index].path << " with error " << res.status;
}
if (nrDone >= requests.size()) {
// We are done, all results are in!
return nrGood;
}
}
}
} catch (...) {
LOG_TOPIC(ERR, logTopic) << "ClusterComm::performRequests: "
<< "caught exception, ignoring...";
}
// We only get here if the global timeout was triggered, not all
// requests are marked by done!
LOG_TOPIC(DEBUG, logTopic) << "ClusterComm::performRequests: "
<< "got timeout, this will be reported...";
// Forget about
drop("", coordinatorTransactionID, 0, "");
return nrGood;
}
//////////////////////////////////////////////////////////////////////////////
/// @brief this is the fast path method for performRequests for the case
/// of only a single request in the vector. In this case we can use a single
/// syncRequest, which saves a network roundtrip. This is an important
/// optimization for the single document operation case.
/// Exact same semantics as performRequests.
//////////////////////////////////////////////////////////////////////////////
size_t ClusterComm::performSingleRequest(
std::vector<ClusterCommRequest>& requests, ClusterCommTimeout timeout,
size_t& nrDone, arangodb::LogTopic const& logTopic) {
CoordTransactionID coordinatorTransactionID = TRI_NewTickServer();
ClusterCommRequest& req(requests[0]);
if (req.headerFields.get() == nullptr) {
req.headerFields =
std::make_unique<std::unordered_map<std::string, std::string>>();
}
if (req.body == nullptr) {
req.result = *syncRequest("", coordinatorTransactionID, req.destination,
req.requestType, req.path, "",
*(req.headerFields), timeout);
} else {
req.result = *syncRequest("", coordinatorTransactionID, req.destination,
req.requestType, req.path, *(req.body),
*(req.headerFields), timeout);
}
req.result.status = CL_COMM_RECEIVED; // a fake, but a good one
req.done = true;
nrDone = 1;
// This was it, except for a small problem: syncRequest reports back in
// req.result.result of type httpclient::SimpleHttpResult rather than
// req.result.answer of type GeneralRequest, so we have to translate.
// Additionally, GeneralRequest is a virtual base class, so we actually
// have to create an HttpRequest instance:
GeneralRequest::ContentType type = GeneralRequest::ContentType::JSON;
// Add correct recognition of content type later.
basics::StringBuffer& buffer = req.result.result->getBody();
auto answer = new FakeRequest(type, buffer.c_str(),
static_cast<int64_t>(buffer.length()));
answer->setHeaders(req.result.result->getHeaderFields());
auto answer = new HttpRequest::createFakeRequest(
type, buffer.c_str(), static_cast<int64_t>(buffer.length()),
req.result.result->getHeaderFields());
req.result.answer.reset(static_cast<GeneralRequest*>(answer));
req.result.answer_code = static_cast<GeneralResponse::ResponseCode>(
req.result.result->getHttpReturnCode());
return (req.result.answer_code == GeneralResponse::ResponseCode::OK ||
req.result.answer_code == GeneralResponse::ResponseCode::CREATED ||
req.result.answer_code == GeneralResponse::ResponseCode::ACCEPTED)
? 1
: 0;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief ClusterComm main loop
////////////////////////////////////////////////////////////////////////////////
void ClusterCommThread::run() {
ClusterComm::QueueIterator q;
ClusterComm::IndexIterator i;
ClusterCommOperation* op;
ClusterComm* cc = ClusterComm::instance();
LOG(DEBUG) << "starting ClusterComm thread";
while (!isStopping()) {
// First check the sending queue, as long as it is not empty, we send
// a request via SimpleHttpClient:
while (true) { // left via break when there is no job in send queue
if (isStopping()) {
break;
}
{
CONDITION_LOCKER(locker, cc->somethingToSend);
if (cc->toSend.empty()) {
break;
} else {
LOG(DEBUG) << "Noticed something to send";
op = cc->toSend.front();
TRI_ASSERT(op->result.status == CL_COMM_SUBMITTED);
op->result.status = CL_COMM_SENDING;
}
}
// We release the lock, if the operation is dropped now, the
// `dropped` flag is set. We find out about this after we have
// sent the request (happens in moveFromSendToReceived).
// Have we already reached the timeout?
double currentTime = TRI_microtime();
if (op->initEndTime <= currentTime) {
op->result.status = CL_COMM_TIMEOUT;
} else {
// We know that op->result.endpoint is nonempty here, otherwise
// the operation would not have been in the send queue!
httpclient::ConnectionManager* cm =
httpclient::ConnectionManager::instance();
httpclient::ConnectionManager::SingleServerConnection* connection =
cm->leaseConnection(op->result.endpoint);
if (nullptr == connection) {
op->result.status = CL_COMM_BACKEND_UNAVAILABLE;
op->result.errorMessage = "cannot create connection to server: ";
op->result.errorMessage += op->result.serverID;
if (cc->logConnectionErrors()) {
LOG(ERR) << "cannot create connection to server '"
<< op->result.serverID << "' at endpoint '"
<< op->result.endpoint << "'";
} else {
LOG(INFO) << "cannot create connection to server '"
<< op->result.serverID << "' at endpoint '"
<< op->result.endpoint << "'";
}
} else {
if (nullptr != op->body.get()) {
LOG(DEBUG) << "sending "
<< arangodb::HttpRequest::translateMethod(op->reqtype)
.c_str() << " request to DB server '"
<< op->result.serverID << "' at endpoint '"
<< op->result.endpoint << "': " << op->body->c_str();
} else {
LOG(DEBUG) << "sending "
<< arangodb::HttpRequest::translateMethod(op->reqtype)
.c_str() << " request to DB server '"
<< op->result.serverID << "' at endpoint '"
<< op->result.endpoint << "'";
}
auto client =
std::make_unique<arangodb::httpclient::SimpleHttpClient>(
connection->_connection, op->initEndTime - currentTime,
false);
client->keepConnectionOnDestruction(true);
// We add this result to the operation struct without acquiring
// a lock, since we know that only we do such a thing:
if (nullptr != op->body.get()) {
op->result.result.reset(
client->request(op->reqtype, op->path, op->body->c_str(),
op->body->size(), *(op->headerFields)));
} else {
op->result.result.reset(client->request(
op->reqtype, op->path, nullptr, 0, *(op->headerFields)));
}
if (op->result.result.get() == nullptr ||
!op->result.result->isComplete()) {
if (client->getErrorMessage() == "Request timeout reached") {
op->result.status = CL_COMM_TIMEOUT;
op->result.errorMessage = "timeout";
auto r = op->result.result->getResultType();
op->result.sendWasComplete =
(r == arangodb::httpclient::SimpleHttpResult::READ_ERROR) ||
(r == arangodb::httpclient::SimpleHttpResult::UNKNOWN);
} else {
op->result.status = CL_COMM_BACKEND_UNAVAILABLE;
op->result.errorMessage = client->getErrorMessage();
op->result.sendWasComplete = false;
}
cm->brokenConnection(connection);
client->invalidateConnection();
} else {
cm->returnConnection(connection);
op->result.sendWasComplete = true;
if (op->result.result->wasHttpError()) {
op->result.status = CL_COMM_ERROR;
op->result.errorMessage = "HTTP error, status ";
op->result.errorMessage += arangodb::basics::StringUtils::itoa(
op->result.result->getHttpReturnCode());
}
}
}
}
if (op->result.single) {
// For single requests this is it, either it worked and is ready
// or there was an error (timeout or other). If there is a callback,
// we have to call it now:
if (nullptr != op->callback.get()) {
if (op->result.status == CL_COMM_SENDING) {
op->result.status = CL_COMM_SENT;
}
if ((*op->callback.get())(&op->result)) {
// This is fully processed, so let's remove it from the queue:
CONDITION_LOCKER(locker, cc->somethingToSend);
auto i = cc->toSendByOpID.find(op->result.operationID);
TRI_ASSERT(i != cc->toSendByOpID.end());
auto q = i->second;
cc->toSendByOpID.erase(i);
cc->toSend.erase(q);
delete op;
continue; // do not move to the received queue but forget it
}
}
}
cc->moveFromSendToReceived(op->result.operationID);
// Potentially it was dropped in the meantime, then we forget about it.
}
// Now the send queue is empty (at least was empty, when we looked
// just now, so we can check on our receive queue to detect timeouts:
{
double currentTime = TRI_microtime();
CONDITION_LOCKER(locker, cc->somethingReceived);
ClusterComm::QueueIterator q;
for (q = cc->received.begin(); q != cc->received.end();) {
bool deleted = false;
op = *q;
if (op->result.status == CL_COMM_SENT) {
if (op->endTime < currentTime) {
op->result.status = CL_COMM_TIMEOUT;
if (nullptr != op->callback.get()) {
if ((*op->callback.get())(&op->result)) {
// This is fully processed, so let's remove it from the queue:
auto i = cc->receivedByOpID.find(op->result.operationID);
TRI_ASSERT(i != cc->receivedByOpID.end());
cc->receivedByOpID.erase(i);
std::unique_ptr<ClusterCommOperation> o(op);
auto qq = q++;
cc->received.erase(qq);
deleted = true;
}
}
}
}
if (!deleted) {
++q;
}
}
}
// Finally, wait for some time or until something happens using
// the condition variable:
{
CONDITION_LOCKER(locker, cc->somethingToSend);
locker.wait(100000);
}
}
LOG(DEBUG) << "stopped ClusterComm thread";
}
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