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arangodb/arangod/Cluster/ClusterComm.cpp

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////////////////////////////////////////////////////////////////////////////////
/// @brief Library for intra-cluster communications
///
/// @file ClusterComm.cpp
///
/// DISCLAIMER
///
/// Copyright 2010-2013 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 triAGENS GmbH, Cologne, Germany
///
/// @author Max Neunhoeffer
/// @author Copyright 2013, triagens GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////
#include "Cluster/ClusterComm.h"
#include "BasicsC/logging.h"
#include "Basics/WriteLocker.h"
#include "Basics/ConditionLocker.h"
#include "VocBase/server.h"
using namespace triagens::arango;
// -----------------------------------------------------------------------------
// --SECTION-- ClusterComm connection options
// -----------------------------------------------------------------------------
ClusterCommOptions ClusterComm::_globalConnectionOptions = {
15.0, // connectTimeout
3.0, // requestTimeout
3, // numRetries,
5.0 // singleRequestTimeout
};
// -----------------------------------------------------------------------------
// --SECTION-- ClusterComm class
// -----------------------------------------------------------------------------
ClusterComm::ClusterComm () {
_backgroundThread = new ClusterCommThread();
if (0 == _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");
}
}
ClusterComm::~ClusterComm () {
// FIXME: Delete all stuff in queues, close all connections
_backgroundThread->stop();
_backgroundThread = 0;
}
ClusterComm* ClusterComm::_theinstance = 0;
ClusterComm* ClusterComm::instance () {
// This does not have to be thread-safe, because we guarantee that
// this is called very early in the startup phase when there is still
// a single thread.
if (0 == _theinstance) {
_theinstance = new ClusterComm( ); // this now happens exactly once
}
return _theinstance;
}
void ClusterComm::initialise () {
}
OperationID ClusterComm::getOperationID () {
return TRI_NewTickServer();
}
ClusterComm::SingleServerConnection::~SingleServerConnection () {
delete connection;
delete endpoint;
lastUsed = 0;
serverID = "";
}
ClusterComm::ServerConnections::~ServerConnections () {
vector<SingleServerConnection*>::iterator i;
WRITE_LOCKER(lock);
unused.clear();
for (i = connections.begin();i != connections.end();++i) {
delete *i;
}
connections.clear();
}
ClusterComm::SingleServerConnection*
ClusterComm::getConnection(ServerID& serverID) {
map<ServerID,ServerConnections*>::iterator i;
ServerConnections* s;
SingleServerConnection* c;
// First find a collections list:
{
WRITE_LOCKER(allLock);
i = allConnections.find(serverID);
if (i != allConnections.end()) {
s = i->second;
}
else {
s = new ServerConnections();
allConnections[serverID] = s;
}
}
// Now get an unused one:
{
WRITE_LOCKER(s->lock);
if (!s->unused.empty()) {
c = s->unused.back();
s->unused.pop_back();
return c;
}
}
// We need to open a new one:
string a = ClusterState::instance()->getServerEndpoint(serverID);
if (a == "") {
// Unknown server address, probably not yet connected
return 0;
}
triagens::rest::Endpoint* e = triagens::rest::Endpoint::clientFactory(a);
if (0 == e) {
return 0;
}
triagens::httpclient::GeneralClientConnection*
g = triagens::httpclient::GeneralClientConnection::factory(
e,
_globalConnectionOptions._requestTimeout,
_globalConnectionOptions._connectTimeout,
_globalConnectionOptions._connectRetries);
if (0 == g) {
delete e;
return 0;
}
c = new SingleServerConnection(g,e,serverID);
if (0 == c) {
delete g;
delete e;
return 0;
}
// Now put it into our administration:
{
WRITE_LOCKER(s->lock);
s->connections.push_back(c);
}
c->lastUsed = time(0);
return c;
}
void ClusterComm::returnConnection(SingleServerConnection* c) {
map<ServerID,ServerConnections*>::iterator i;
ServerConnections* s;
// First find the collections list:
{
WRITE_LOCKER(allLock);
i = allConnections.find(c->serverID);
if (i != allConnections.end()) {
s = i->second;
}
else {
// How strange! We just destroy the connection in despair!
delete c;
return;
}
}
c->lastUsed = time(0);
// Now mark it as unused:
{
WRITE_LOCKER(s->lock);
s->unused.push_back(c);
}
}
void ClusterComm::brokenConnection(SingleServerConnection* c) {
map<ServerID,ServerConnections*>::iterator i;
ServerConnections* s;
// First find the collections list:
{
WRITE_LOCKER(allLock);
i = allConnections.find(c->serverID);
if (i != allConnections.end()) {
s = i->second;
}
else {
// How strange! We just destroy the connection in despair!
delete c;
return;
}
}
// Now find it to get rid of it:
{
WRITE_LOCKER(s->lock);
vector<SingleServerConnection*>::iterator i;
for (i = s->connections.begin(); i != s->connections.end(); ++i) {
if (*i == c) {
// Got it, now remove it:
s->connections.erase(i);
delete c;
return;
}
}
}
// How strange! We should have known this one!
delete c;
}
void ClusterComm::closeUnusedConnections () {
WRITE_LOCKER(allLock);
map<ServerID,ServerConnections*>::iterator s;
list<SingleServerConnection*>::iterator i;
list<SingleServerConnection*>::iterator prev;
ServerConnections* sc;
time_t t;
bool haveprev;
t = time(0);
for (s = allConnections.begin(); s != allConnections.end(); ++s) {
sc = s->second;
{
WRITE_LOCKER(sc->lock);
haveprev = false;
for (i = sc->unused.begin(); i != sc->unused.end(); ) {
if (t - (*i)->lastUsed > 120) {
vector<SingleServerConnection*>::iterator j;
for (j = sc->connections.begin(); j != sc->connections.end(); j++) {
if (*j == *i) {
sc->connections.erase(j);
break;
}
}
delete (*i);
sc->unused.erase(i);
if (haveprev) {
i = prev; // will be incremented in next iteration
i++;
haveprev = false;
}
else {
i = sc->unused.begin();
}
}
else {
prev = i;
i++;
haveprev = true;
}
}
}
}
}
ClusterCommResult* ClusterComm::asyncRequest (
ClientTransactionID const clientTransactionID,
CoordTransactionID const coordTransactionID,
ShardID const shardID,
rest::HttpRequest::HttpRequestType reqtype,
string const path,
char const* body,
size_t const bodyLength,
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
op->shardID = shardID;
op->serverID = ClusterState::instance()->getResponsibleServer(
shardID);
op->status = CL_COMM_SUBMITTED;
op->path = path;
op->body = body;
op->bodyLength = bodyLength;
op->headerFields = headerFields;
op->callback = callback;
op->timeout = timeout;
ClusterCommResult* res = new ClusterCommResult();
*res = *static_cast<ClusterCommResult*>(op);
{
basics::ConditionLocker locker(&somethingToSend);
toSend.push_back(op);
list<ClusterCommOperation*>::iterator i = toSend.end();
toSendByOpID[op->operationID] = --i;
}
somethingToSend.signal();
return res;
}
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) );
}
ClusterCommResult* ClusterComm::enquire (OperationID const operationID) {
IndexIterator i;
ClusterCommOperation* op = 0;
ClusterCommResult* res;
// First look into the send queue:
{
basics::ConditionLocker locker(&somethingToSend);
i = toSendByOpID.find(operationID);
if (i != toSendByOpID.end()) {
res = new ClusterCommResult();
if (0 == res) {
return 0;
}
op = *(i->second);
*res = *static_cast<ClusterCommResult*>(op);
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:
{
basics::ConditionLocker locker(&somethingReceived);
i = receivedByOpID.find(operationID);
if (i != toSendByOpID.end()) {
res = new ClusterCommResult();
if (0 == res) {
return 0;
}
op = *(i->second);
*res = *static_cast<ClusterCommResult*>(op);
return res;
}
}
return 0;
}
ClusterCommResult* ClusterComm::wait (
ClientTransactionID const& clientTransactionID,
CoordTransactionID const coordTransactionID,
OperationID const operationID,
ShardID const& shardID,
ClusterCommTimeout timeout) {
IndexIterator i;
QueueIterator q;
ClusterCommOperation* op = 0;
ClusterCommResult* res = 0;
double endtime;
double timeleft;
bool found;
if (0.0 == timeout) {
endtime = 1.0e50; // this is the Sankt Nimmerleinstag
}
else {
endtime = now() + timeout;
}
if (0 != operationID) {
// In this case we only have to look into at most one operation.
basics::ConditionLocker 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:
basics::ConditionLocker 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;
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);
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 - now();
if (timeleft <= 0) break;
somethingReceived.wait(uint64_t(timeleft * 1000.0));
}
// 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.
basics::ConditionLocker locker(&somethingReceived);
while (true) { // will be left by return or break on timeout
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!
assert(i != receivedByOpID.end());
assert(i->second == q);
receivedByOpID.erase(i);
received.erase(q);
res = static_cast<ClusterCommResult*>(op);
return res;
}
}
}
// If we found nothing, we have to look through the send queue:
if (!found) {
basics::ConditionLocker 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;
return res;
}
// Here it could either be in the receive or the send queue, let's wait
timeleft = endtime - now();
if (timeleft <= 0) break;
somethingReceived.wait(uint64_t(timeleft * 1000.0));
}
// 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;
return res;
}
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:
{
basics::ConditionLocker sendlocker(&somethingToSend);
for (q = toSend.begin(); q != toSend.end(); ) {
op = *q;
if ((0 != operationID && operationID == op->operationID) ||
match(clientTransactionID, coordTransactionID, shardID, op)) {
nextq = q;
nextq++;
i = toSendByOpID.find(op->operationID); // cannot fail
assert(i != toSendByOpID.end());
assert(q == i->second);
receivedByOpID.erase(i);
toSend.erase(q);
q = nextq;
}
else {
q++;
}
}
}
// Now look through the receive queue:
{
basics::ConditionLocker 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
assert(i != receivedByOpID.end());
assert(q == i->second);
receivedByOpID.erase(i);
toSend.erase(q);
q = nextq;
}
else {
q++;
}
}
}
}
int ClusterComm::processAnswer(rest::HttpRequest* answer) {
// find matching operation, report if found, otherwise drop
return TRI_ERROR_NO_ERROR;
}
// Move an operation from the send to the receive queue:
bool ClusterComm::moveFromSendToReceived (OperationID operationID) {
QueueIterator q;
IndexIterator i;
ClusterCommOperation* op;
basics::ConditionLocker locker(&somethingReceived);
basics::ConditionLocker sendlocker(&somethingToSend);
i = toSendByOpID.find(operationID); // cannot fail
assert(i != toSendByOpID.end());
q = i->second;
op = *q;
assert(op->operationID == operationID);
toSendByOpID.erase(i);
toSend.erase(q);
if (CL_COMM_DROPPING == op->status) {
return false;
}
op->status = CL_COMM_SENT;
received.push_back(op);
q = received.end();
q--;
receivedByOpID[operationID] = q;
return true;
}
// -----------------------------------------------------------------------------
// --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_TRACE("starting ClusterComm thread");
while (! _stop) {
LOG_DEBUG("ClusterComm alive");
// First check the sending queue, as long as it is not empty, we send
// a request via SimpleHttpClient:
while (true) { // will be left by break when queue is empty
{
basics::ConditionLocker locker(&cc->somethingToSend);
if (cc->toSend.empty()) {
break;
}
op = cc->toSend.front();
assert(op->status == CL_COMM_SUBMITTED);
op->status = CL_COMM_SENDING;
}
// We release the lock, if it is dropped now, the status just goes
// to CL_COMM_DROPPING, we find out about this after we have sent
// the request.
LOG_DEBUG("ClusterComm faking a send");
if (!cc->moveFromSendToReceived(op->operationID)) {
// It was dropped in the meantime, so forget about it:
delete op;
}
}
// Now wait for the condition variable, but use a timeout to notice
// a request to terminate the thread:
{
basics::ConditionLocker locker(&cc->somethingToSend);
locker.wait(100);
}
}
// another thread is waiting for this value to shut down properly
_stop = 2;
LOG_TRACE("stopped ClusterComm thread");
}
// -----------------------------------------------------------------------------
// --SECTION-- public methods
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief initialises the heartbeat
////////////////////////////////////////////////////////////////////////////////
bool ClusterCommThread::init () {
return true;
}
// -----------------------------------------------------------------------------
// --SECTION-- private methods
// -----------------------------------------------------------------------------
// Local Variables:
// mode: outline-minor
// outline-regexp: "^\\(/// @brief\\|/// {@inheritDoc}\\|/// @addtogroup\\|// --SECTION--\\|/// @\\}\\)"
// End:
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