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arangodb/arangod/Cluster/ClusterComm.cpp

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////////////////////////////////////////////////////////////////////////////////
/// @brief Library for intra-cluster communications
///
/// @file ClusterComm.cpp
///
/// DISCLAIMER
///
/// Copyright 2014 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
/// @author Copyright 2014, ArangoDB GmbH, Cologne, Germany
/// @author Copyright 2013, triagens GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////
#include "Cluster/ClusterComm.h"
#include "Basics/logging.h"
#include "Basics/WriteLocker.h"
#include "Basics/ConditionLocker.h"
#include "Basics/StringUtils.h"
#include "SimpleHttpClient/ConnectionManager.h"
#include "Dispatcher/DispatcherThread.h"
#include "Utils/Transaction.h"
#include "VocBase/server.h"
using namespace std;
using namespace triagens::arango;
// -----------------------------------------------------------------------------
// --SECTION-- ClusterComm connection options
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief global callback for asynchronous REST handler
////////////////////////////////////////////////////////////////////////////////
void triagens::arango::ClusterCommRestCallback(string& coordinator,
triagens::rest::HttpResponse* response) {
ClusterComm::instance()->asyncAnswer(coordinator, response);
}
// -----------------------------------------------------------------------------
// --SECTION-- ClusterComm class
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief ClusterComm constructor
////////////////////////////////////////////////////////////////////////////////
ClusterComm::ClusterComm () :
_backgroundThread(nullptr),
_logConnectionErrors(false) {
}
////////////////////////////////////////////////////////////////////////////////
/// @brief ClusterComm destructor
////////////////////////////////////////////////////////////////////////////////
ClusterComm::~ClusterComm () {
if (_backgroundThread != nullptr) {
_backgroundThread->stop();
_backgroundThread->shutdown();
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 (nullptr == _backgroundThread) {
LOG_FATAL_AND_EXIT("unable to start ClusterComm background thread");
}
if (! _backgroundThread->init() || ! _backgroundThread->start()) {
LOG_FATAL_AND_EXIT("ClusterComm background thread does not work");
}
}
////////////////////////////////////////////////////////////////////////////////
/// @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 is only called when arangod is in coordinator mode. It
/// queues a single HTTP request to one of the DBServers to be sent by
/// ClusterComm in the background thread. 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. The result of
/// this call is just a record that the initial HTTP request has been
/// queued (`status` is CL_COMM_SUBMITTED). Use @ref enquire below to get
/// information about the progress. The actual answer is then delivered
/// either in the callback or via poll. The caller has to call delete on
/// the resulting ClusterCommResult*. The library takes ownerships of
/// the pointers `headerFields` and `callback` and releases
/// the memory when the operation has been finished. If `freeBody`
/// is `true`, then the library takes ownership of the pointer `body`
/// as well and deletes it at the end. If `freeBody` is `false, it
/// is the caller's responsibility to ensure that the object object
/// to which `body` points is retained until the full asynchronous
/// operation is finished and has been reported back to the caller
/// and that the object is destructed after the operation has finally
/// terminated.
///
/// 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.
////////////////////////////////////////////////////////////////////////////////
ClusterCommResult* ClusterComm::asyncRequest (
ClientTransactionID const clientTransactionID,
CoordTransactionID const coordTransactionID,
string const& destination,
triagens::rest::HttpRequest::HttpRequestType reqtype,
string const path,
string const* body,
bool freeBody,
map<string, string>* headerFields,
ClusterCommCallback* callback,
ClusterCommTimeout timeout) {
ClusterCommOperation* op = new ClusterCommOperation();
op->clientTransactionID = clientTransactionID;
op->coordTransactionID = coordTransactionID;
do {
op->operationID = getOperationID();
}
while (op->operationID == 0); // just to make sure
if (destination.substr(0, 6) == "shard:") {
op->shardID = destination.substr(6);
op->serverID = ClusterInfo::instance()->getResponsibleServer(op->shardID);
LOG_DEBUG("Responsible server: %s", op->serverID.c_str());
if (triagens::arango::Transaction::_makeNolockHeaders != nullptr) {
// LOCKING-DEBUG
// std::cout << "Found Nolock header\n";
auto it = triagens::arango::Transaction::_makeNolockHeaders->find(op->shardID);
if (it != triagens::arango::Transaction::_makeNolockHeaders->end()) {
// LOCKING-DEBUG
// std::cout << "Found our shard\n";
(*headerFields)["X-Arango-Nolock"] = op->shardID;
}
}
}
else if (destination.substr(0, 7) == "server:") {
op->shardID = "";
op->serverID = destination.substr(7);
}
else {
op->shardID = "";
op->serverID = "";
}
// Add the header fields for asynchronous mode:
(*headerFields)["X-Arango-Async"] = "store";
(*headerFields)["X-Arango-Coordinator"] = ServerState::instance()->getId() +
":" + basics::StringUtils::itoa(op->operationID) +
":" + clientTransactionID + ":" +
basics::StringUtils::itoa(coordTransactionID);
(*headerFields)["Authorization"] = ServerState::instance()->getAuthentication();
#ifdef DEBUG_CLUSTER_COMM
#ifdef TRI_ENABLE_MAINTAINER_MODE
#if HAVE_BACKTRACE
std::string bt;
TRI_GetBacktrace(bt);
std::replace( bt.begin(), bt.end(), '\n', ';'); // replace all '\n' to ';'
(*headerFields)["X-Arango-BT-A-SYNC"] = bt;
#endif
#endif
#endif
op->status = CL_COMM_SUBMITTED;
op->reqtype = reqtype;
op->path = path;
op->body = body;
op->freeBody = freeBody;
op->headerFields = headerFields;
op->callback = callback;
op->endTime = timeout == 0.0 ? TRI_microtime() + 24 * 60 * 60.0
: TRI_microtime() + timeout;
// LOCKING-DEBUG
// std::cout << "asyncRequest: sending " << triagens::rest::HttpRequest::translateMethod(reqtype) << " request to DB server '" << op->serverID << ":" << path << "\n" << body << "\n";
// for (auto& h : *headerFields) {
// std::cout << h.first << ":" << h.second << std::endl;
// }
// std::cout << std::endl;
ClusterCommResult* res = new ClusterCommResult();
*res = *static_cast<ClusterCommResult*>(op);
{
CONDITION_LOCKER(locker, somethingToSend);
toSend.push_back(op);
TRI_ASSERT(nullptr != op);
list<ClusterCommOperation*>::iterator i = toSend.end();
toSendByOpID[op->operationID] = --i;
}
LOG_DEBUG("In asyncRequest, put into queue %llu",
(unsigned long long) op->operationID);
somethingToSend.signal();
return res;
}
////////////////////////////////////////////////////////////////////////////////
/// @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.
////////////////////////////////////////////////////////////////////////////////
ClusterCommResult* ClusterComm::syncRequest (
ClientTransactionID const& clientTransactionID,
CoordTransactionID const coordTransactionID,
string const& destination,
triagens::rest::HttpRequest::HttpRequestType reqtype,
string const& path,
string const& body,
map<string, string> const& headerFields,
ClusterCommTimeout timeout) {
map<string, string> headersCopy(headerFields);
ClusterCommResult* res = new 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;
if (destination.substr(0, 6) == "shard:") {
res->shardID = destination.substr(6);
res->serverID = ClusterInfo::instance()->getResponsibleServer(res->shardID);
LOG_DEBUG("Responsible server: %s", res->serverID.c_str());
if (res->serverID.empty()) {
res->status = CL_COMM_ERROR;
return res;
}
if (triagens::arango::Transaction::_makeNolockHeaders != nullptr) {
// LOCKING-DEBUG
// std::cout << "Found Nolock header\n";
auto it = triagens::arango::Transaction::_makeNolockHeaders->find(res->shardID);
if (it != triagens::arango::Transaction::_makeNolockHeaders->end()) {
// LOCKING-DEBUG
// std::cout << "Found this shard: " << res->shardID << std::endl;
headersCopy["X-Arango-Nolock"] = res->shardID;
}
}
}
else if (destination.substr(0, 7) == "server:") {
res->shardID = "";
res->serverID = destination.substr(7);
}
else {
res->status = CL_COMM_ERROR;
return res;
}
// We need a connection to this server:
string endpoint = ClusterInfo::instance()->getServerEndpoint(res->serverID);
if (endpoint.empty()) {
res->status = CL_COMM_ERROR;
if (logConnectionErrors()) {
LOG_ERROR("cannot find endpoint of server '%s'", res->serverID.c_str());
}
else {
LOG_INFO("cannot find endpoint of server '%s'", res->serverID.c_str());
}
}
else {
httpclient::ConnectionManager* cm = httpclient::ConnectionManager::instance();
httpclient::ConnectionManager::SingleServerConnection* connection
= cm->leaseConnection(endpoint);
if (nullptr == connection) {
res->status = CL_COMM_ERROR;
if (logConnectionErrors()) {
LOG_ERROR("cannot create connection to server '%s'", res->serverID.c_str());
}
else {
LOG_INFO("cannot create connection to server '%s'", res->serverID.c_str());
}
}
else {
LOG_DEBUG("sending %s request to DB server '%s': %s",
triagens::rest::HttpRequest::translateMethod(reqtype).c_str(),
res->serverID.c_str(), body.c_str());
// LOCKING-DEBUG
// std::cout << "syncRequest: sending " << triagens::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;
std::unique_ptr<triagens::httpclient::SimpleHttpClient> client(
new triagens::httpclient::SimpleHttpClient(
connection->_connection,
endTime - currentTime, false)
);
client->keepConnectionOnDestruction(true);
headersCopy["Authorization"] = ServerState::instance()->getAuthentication();
#ifdef DEBUG_CLUSTER_COMM
#ifdef TRI_ENABLE_MAINTAINER_MODE
#if HAVE_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 = 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_ERROR;
}
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->clientTransactionID) &&
(0 == coordTransactionID ||
coordTransactionID == op->coordTransactionID) &&
(shardID == "" ||
shardID == op->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;
ClusterCommResult* res;
// First look into the send queue:
{
CONDITION_LOCKER(locker, somethingToSend);
i = toSendByOpID.find(operationID);
if (i != toSendByOpID.end()) {
res = new ClusterCommResult();
op = *(i->second);
*res = *static_cast<ClusterCommResult*>(op);
res->doNotDeleteOnDestruction();
return res;
}
}
// 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()) {
res = new ClusterCommResult();
op = *(i->second);
*res = *static_cast<ClusterCommResult*>(op);
res->doNotDeleteOnDestruction();
return res;
}
}
res = new ClusterCommResult();
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. The caller has to delete the
/// result.
////////////////////////////////////////////////////////////////////////////////
ClusterCommResult* ClusterComm::wait (
ClientTransactionID const& clientTransactionID,
CoordTransactionID const coordTransactionID,
OperationID const operationID,
ShardID const& shardID,
ClusterCommTimeout timeout) {
IndexIterator i;
QueueIterator q;
ClusterCommOperation* op = nullptr;
ClusterCommResult* res = nullptr;
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:
if (triagens::rest::DispatcherThread::currentDispatcherThread != nullptr) {
triagens::rest::DispatcherThread::currentDispatcherThread->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:
res = new ClusterCommResult();
res->operationID = operationID;
res->status = CL_COMM_DROPPED;
// tell Dispatcher that we are back in business
if (triagens::rest::DispatcherThread::currentDispatcherThread != nullptr) {
triagens::rest::DispatcherThread::currentDispatcherThread->unblock();
}
return res;
}
}
else {
// It is in the receive queue, now look at the status:
q = i->second;
op = *q;
if (op->status >= CL_COMM_TIMEOUT) {
// It is done, let's remove it from the queue and return it:
receivedByOpID.erase(i);
received.erase(q);
res = static_cast<ClusterCommResult*>(op);
// tell Dispatcher that we are back in business
if (triagens::rest::DispatcherThread::currentDispatcherThread != nullptr) {
triagens::rest::DispatcherThread::currentDispatcherThread->unblock();
}
return res;
}
// 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++) {
op = *q;
if (match(clientTransactionID, coordTransactionID, shardID, op)) {
found = true;
if (op->status >= CL_COMM_TIMEOUT) {
// It is done, let's remove it from the queue and return it:
i = receivedByOpID.find(op->operationID); // cannot fail!
TRI_ASSERT(i != receivedByOpID.end());
TRI_ASSERT(i->second == q);
receivedByOpID.erase(i);
received.erase(q);
res = static_cast<ClusterCommResult*>(op);
// tell Dispatcher that we are back in business
if (triagens::rest::DispatcherThread::currentDispatcherThread != nullptr) {
triagens::rest::DispatcherThread::currentDispatcherThread->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++) {
op = *q;
if (match(clientTransactionID, coordTransactionID, shardID, op)) {
found = true;
break;
}
}
}
if (! found) {
// Nothing known about this operation, return with failure:
res = new ClusterCommResult();
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 (triagens::rest::DispatcherThread::currentDispatcherThread != nullptr) {
triagens::rest::DispatcherThread::currentDispatcherThread->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:
res = new ClusterCommResult();
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 (triagens::rest::DispatcherThread::currentDispatcherThread != nullptr) {
triagens::rest::DispatcherThread::currentDispatcherThread->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;
ClusterCommOperation* op;
// First look through the send queue:
{
CONDITION_LOCKER(sendLocker, somethingToSend);
for (q = toSend.begin(); q != toSend.end(); ) {
op = *q;
if ((0 != operationID && operationID == op->operationID) ||
match(clientTransactionID, coordTransactionID, shardID, op)) {
if (op->status == CL_COMM_SENDING) {
op->dropped = true;
q++;
}
else {
nextq = q;
nextq++;
i = toSendByOpID.find(op->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(); ) {
op = *q;
if ((0 != operationID && operationID == op->operationID) ||
match(clientTransactionID, coordTransactionID, shardID, op)) {
nextq = q;
nextq++;
i = receivedByOpID.find(op->operationID); // cannot fail
TRI_ASSERT(i != receivedByOpID.end());
TRI_ASSERT(q == i->second);
receivedByOpID.erase(i);
received.erase(q);
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 (string& coordinatorHeader,
triagens::rest::HttpResponse* responseToSend) {
// First take apart the header to get the coordinatorID:
ServerID coordinatorID;
size_t start = 0;
size_t pos;
LOG_DEBUG("In asyncAnswer, seeing %s", coordinatorHeader.c_str());
pos = coordinatorHeader.find(":",start);
if (pos == string::npos) {
LOG_ERROR("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();
string endpoint = ClusterInfo::instance()->getServerEndpoint(coordinatorID);
if (endpoint == "") {
if (logConnectionErrors()) {
LOG_ERROR("asyncAnswer: cannot find endpoint for server '%s'",
coordinatorID.c_str());
}
else {
LOG_INFO("asyncAnswer: cannot find endpoint for server '%s'",
coordinatorID.c_str());
}
return;
}
httpclient::ConnectionManager::SingleServerConnection* connection
= cm->leaseConnection(endpoint);
if (nullptr == connection) {
LOG_ERROR("asyncAnswer: cannot create connection to server '%s'",
coordinatorID.c_str());
return;
}
map<string, string> headers = responseToSend->headers();
headers["X-Arango-Coordinator"] = coordinatorHeader;
headers["X-Arango-Response-Code"] = responseToSend->responseString(responseToSend->responseCode());
headers["Authorization"] = ServerState::instance()->getAuthentication();
char const* body = responseToSend->body().c_str();
size_t len = responseToSend->body().length();
LOG_DEBUG("asyncAnswer: sending PUT request to DB server '%s'",
coordinatorID.c_str());
std::unique_ptr<triagens::httpclient::SimpleHttpClient> client(
new triagens::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:
httpclient::SimpleHttpResult* result =
client->request(rest::HttpRequest::HTTP_REQUEST_PUT,
"/_api/shard-comm", body, len, headers);
if (result == 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.
delete result;
}
////////////////////////////////////////////////////////////////////////////////
/// @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.
////////////////////////////////////////////////////////////////////////////////
string ClusterComm::processAnswer (string& coordinatorHeader,
triagens::rest::HttpRequest* answer) {
// First take apart the header to get the operaitonID:
OperationID operationID;
size_t start = 0;
size_t pos;
LOG_DEBUG("In processAnswer, seeing %s", coordinatorHeader.c_str());
pos = coordinatorHeader.find(":", start);
if (pos == string::npos) {
return 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 == string::npos) {
return
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()) {
ClusterCommOperation* op = *(i->second);
op->answer = answer;
op->answer_code = rest::HttpResponse::responseCode(
answer->header("x-arango-response-code"));
op->status = CL_COMM_RECEIVED;
// Do we have to do a callback?
if (nullptr != op->callback) {
if ((*op->callback)(static_cast<ClusterCommResult*>(op))) {
// This is fully processed, so let's remove it from the queue:
QueueIterator q = i->second;
receivedByOpID.erase(i);
received.erase(q);
delete op;
}
}
}
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()) {
ClusterCommOperation* op = *(i->second);
op->answer = answer;
op->answer_code = rest::HttpResponse::responseCode(
answer->header("x-arango-response-code"));
op->status = CL_COMM_RECEIVED;
if (nullptr != op->callback) {
if ((*op->callback)(static_cast<ClusterCommResult*>(op))) {
// This is fully processed, so let's remove it from the queue:
QueueIterator q = i->second;
toSendByOpID.erase(i);
toSend.erase(q);
delete op;
}
}
}
else {
// Nothing known about the request, get rid of it:
delete answer;
return string("operation was already dropped by sender");
}
}
}
// Finally tell the others:
somethingReceived.broadcast();
return string("");
}
////////////////////////////////////////////////////////////////////////////////
/// @brief move an operation from the send to the receive queue
////////////////////////////////////////////////////////////////////////////////
bool ClusterComm::moveFromSendToReceived (OperationID operationID) {
LOG_DEBUG("In moveFromSendToReceived %llu", (unsigned long long) operationID);
CONDITION_LOCKER(locker, somethingReceived);
CONDITION_LOCKER(sendLocker, somethingToSend);
IndexIterator i = toSendByOpID.find(operationID); // cannot fail
TRI_ASSERT(i != toSendByOpID.end());
QueueIterator q = i->second;
ClusterCommOperation* op = *q;
TRI_ASSERT(op->operationID == operationID);
toSendByOpID.erase(i);
toSend.erase(q);
if (op->dropped) {
return false;
}
if (op->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->status = CL_COMM_SENT;
}
received.push_back(op);
q = received.end();
q--;
receivedByOpID[operationID] = q;
somethingReceived.broadcast();
return true;
}
////////////////////////////////////////////////////////////////////////////////
/// @brief cleanup all queues
////////////////////////////////////////////////////////////////////////////////
void ClusterComm::cleanupAllQueues() {
QueueIterator i;
{
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();
}
}
// -----------------------------------------------------------------------------
// --SECTION-- ClusterCommThread
// -----------------------------------------------------------------------------
// -----------------------------------------------------------------------------
// --SECTION-- constructors and destructors
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief constructs a ClusterCommThread
////////////////////////////////////////////////////////////////////////////////
ClusterCommThread::ClusterCommThread ()
: Thread("ClusterComm"),
_agency(),
_condition(),
_stop(0) {
allowAsynchronousCancelation();
}
////////////////////////////////////////////////////////////////////////////////
/// @brief destroys a ClusterCommThread
////////////////////////////////////////////////////////////////////////////////
ClusterCommThread::~ClusterCommThread () {
}
// -----------------------------------------------------------------------------
// --SECTION-- ClusterCommThread methods
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @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 (0 == _stop) {
// 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 (0 != _stop) {
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->status == CL_COMM_SUBMITTED);
op->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->endTime <= currentTime) {
op->status = CL_COMM_TIMEOUT;
}
else {
if (op->serverID == "") {
op->status = CL_COMM_ERROR;
}
else {
// We need a connection to this server:
string endpoint
= ClusterInfo::instance()->getServerEndpoint(op->serverID);
if (endpoint == "") {
op->status = CL_COMM_ERROR;
if (cc->logConnectionErrors()) {
LOG_ERROR("cannot find endpoint for server '%s'",
op->serverID.c_str());
}
else {
LOG_INFO("cannot find endpoint for server '%s'",
op->serverID.c_str());
}
}
else {
httpclient::ConnectionManager* cm
= httpclient::ConnectionManager::instance();
httpclient::ConnectionManager::SingleServerConnection* connection
= cm->leaseConnection(endpoint);
if (nullptr == connection) {
op->status = CL_COMM_ERROR;
if (cc->logConnectionErrors()) {
LOG_ERROR("cannot create connection to server '%s'", op->serverID.c_str());
}
else {
LOG_INFO("cannot create connection to server '%s'", op->serverID.c_str());
}
}
else {
if (nullptr != op->body) {
LOG_DEBUG("sending %s request to DB server '%s': %s",
triagens::rest::HttpRequest::translateMethod(op->reqtype)
.c_str(), op->serverID.c_str(), op->body->c_str());
}
else {
LOG_DEBUG("sending %s request to DB server '%s'",
triagens::rest::HttpRequest::translateMethod(op->reqtype)
.c_str(), op->serverID.c_str());
}
std::unique_ptr<triagens::httpclient::SimpleHttpClient> client(
new triagens::httpclient::SimpleHttpClient(
connection->_connection,
op->endTime-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) {
op->result = client->request(op->reqtype, op->path,
op->body->c_str(), op->body->size(),
*(op->headerFields));
}
else {
op->result = client->request(op->reqtype, op->path,
nullptr, 0, *(op->headerFields));
}
if (op->result == nullptr || ! op->result->isComplete()) {
if (client->getErrorMessage() == "Request timeout reached") {
op->status = CL_COMM_TIMEOUT;
}
else {
op->status = CL_COMM_ERROR;
}
cm->brokenConnection(connection);
client->invalidateConnection();
}
else {
cm->returnConnection(connection);
if (op->result->wasHttpError()) {
op->status = CL_COMM_ERROR;
}
}
}
}
}
}
if (! cc->moveFromSendToReceived(op->operationID)) {
// It was dropped in the meantime, so forget about it:
delete op;
}
}
// 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(); ++q) {
op = *q;
if (op->status == CL_COMM_SENT) {
if (op->endTime < currentTime) {
op->status = CL_COMM_TIMEOUT;
}
}
}
}
// Finally, wait for some time or until something happens using
// the condition variable:
{
CONDITION_LOCKER(locker, cc->somethingToSend);
locker.wait(100000);
}
}
// another thread is waiting for this value to shut down properly
_stop = 2;
LOG_DEBUG("stopped ClusterComm thread");
}
// -----------------------------------------------------------------------------
// --SECTION-- public methods
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief initializes the cluster comm background thread
////////////////////////////////////////////////////////////////////////////////
bool ClusterCommThread::init () {
return true;
}
// -----------------------------------------------------------------------------
// --SECTION-- END-OF-FILE
// -----------------------------------------------------------------------------
// Local Variables:
// mode: outline-minor
// outline-regexp: "/// @brief\\|/// {@inheritDoc}\\|/// @page\\|// --SECTION--\\|/// @\\}"
// End:
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