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/**
* Copyright (C) 2020-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kTest
#include "mongo/platform/basic.h"
#include <functional>
#include <iostream>
#include <memory>
#include "mongo/bson/timestamp.h"
#include "mongo/bson/util/bson_extract.h"
#include "mongo/db/repl/is_master_response.h"
#include "mongo/db/repl/replication_coordinator.h"
#include "mongo/db/repl/replication_coordinator_impl.h"
#include "mongo/db/repl/replication_coordinator_test_fixture.h"
#include "mongo/db/repl/topology_version_observer.h"
#include "mongo/unittest/unittest.h"
#include "mongo/util/assert_util.h"
#include "mongo/util/clock_source.h"
#include "mongo/util/fail_point.h"
#include "mongo/util/time_support.h"
namespace mongo {
namespace repl {
namespace {
/**
* Sets up and tears down the test environment for `TopologyVersionObserver`
*/
class TopologyVersionObserverTest : public ReplCoordTest {
protected:
BSONObj getConfigObj() {
BSONObjBuilder configBuilder;
configBuilder << "_id"
<< "mySet";
configBuilder << "version" << 1;
configBuilder << "members"
<< BSON_ARRAY(BSON("_id" << 1 << "host"
<< "node1:12345")
<< BSON("_id" << 2 << "host"
<< "node2:12345"));
configBuilder << "protocolVersion" << 1;
return configBuilder.obj();
}
public:
virtual void setUp() {
auto configObj = getConfigObj();
assertStartSuccess(configObj, HostAndPort("node1", 12345));
ReplSetConfig config = assertMakeRSConfig(configObj);
replCoord = getReplCoord();
ASSERT_OK(replCoord->setFollowerMode(MemberState::RS_SECONDARY));
replCoordSetMyLastAppliedOpTime(OpTime(Timestamp(100, 1), 1), Date_t() + Seconds(100));
replCoordSetMyLastDurableOpTime(OpTime(Timestamp(100, 1), 1), Date_t() + Seconds(100));
simulateSuccessfulV1Election();
ASSERT(replCoord->getMemberState().primary());
getNet()->enterNetwork();
getNet()->advanceTime(Date_t::now() + sleepTime);
getNet()->exitNetwork();
auto serviceContext = getServiceContext();
observer = std::make_unique<TopologyVersionObserver>();
observer->init(serviceContext, replCoord);
}
virtual void tearDown() {
observer->shutdown();
ASSERT(observer->isShutdown());
observer.reset();
}
auto getObserverCache() {
// Wait for observer to initialize its cache. Due to the unpredictable nature of thread
// scheduling, do not change the following to a fixed-wait.
auto cache = observer->getCached();
while (!cache) {
sleepFor(sleepTime);
cache = observer->getCached();
}
return cache;
}
protected:
ReplicationCoordinatorImpl* replCoord;
const Milliseconds sleepTime = Milliseconds(100);
std::unique_ptr<TopologyVersionObserver> observer;
};
TEST_F(TopologyVersionObserverTest, PopulateCache) {
auto cachedResponse = getObserverCache();
ASSERT(cachedResponse);
auto opCtx = makeOperationContext();
auto expectedResponse =
replCoord->awaitHelloResponse(opCtx.get(), {}, boost::none, boost::none);
ASSERT_EQ(cachedResponse->toBSON().toString(), expectedResponse->toBSON().toString());
}
TEST_F(TopologyVersionObserverTest, UpdateCache) {
auto cachedResponse = getObserverCache();
ASSERT(cachedResponse);
// Force an election to advance topology version
auto opCtx = makeOperationContext();
auto electionTimeoutWhen = getReplCoord()->getElectionTimeout_forTest();
simulateSuccessfulV1ElectionWithoutExitingDrainMode(electionTimeoutWhen, opCtx.get());
// Wait for the observer to update its cache
while (observer->getCached()->getTopologyVersion()->getCounter() ==
cachedResponse->getTopologyVersion()->getCounter()) {
sleepFor(sleepTime);
}
auto newResponse = observer->getCached();
ASSERT(newResponse && newResponse->getTopologyVersion());
ASSERT(newResponse->getTopologyVersion()->getCounter() >
cachedResponse->getTopologyVersion()->getCounter());
auto expectedResponse =
replCoord->awaitHelloResponse(opCtx.get(), {}, boost::none, boost::none);
ASSERT(expectedResponse && expectedResponse->getTopologyVersion());
ASSERT_EQ(newResponse->getTopologyVersion()->getCounter(),
expectedResponse->getTopologyVersion()->getCounter());
}
TEST_F(TopologyVersionObserverTest, HandleDBException) {
auto cachedResponse = getObserverCache();
ASSERT(cachedResponse);
Client* observerClient = nullptr;
{
auto cur = ServiceContext::LockedClientsCursor(getGlobalServiceContext());
while (auto client = cur.next()) {
if (client->desc() == kTopologyVersionObserverName) {
observerClient = client;
break;
}
}
}
// The client should not go out-of-scope as it is attached to the observer thread.
ASSERT(observerClient);
auto tryKillOperation = [&] {
stdx::lock_guard clientLock(*observerClient);
if (auto opCtx = observerClient->getOperationContext()) {
observerClient->getServiceContext()->killOperation(clientLock, opCtx);
return true;
}
return false;
};
{
// Set the failpoint here so that if there is no opCtx we catch the next one.
FailPointEnableBlock failBlock("topologyVersionObserverExpectsInterruption");
// Kill the operation waiting on the `isMaster` future to make it throw
if (!tryKillOperation()) {
// If we weren't able to kill, then block until there is an opCtx again.
failBlock->waitForTimesEntered(failBlock.initialTimesEntered() + 1);
// Try again to kill now that we've waited for the failpoint.
ASSERT(tryKillOperation()) << "Unable to acquire and kill observer OpCtx";
}
}
// Observer thread must handle the exception and fetch the most recent IMR
auto newResponse = getObserverCache();
ASSERT(newResponse->getTopologyVersion()->getCounter() ==
cachedResponse->getTopologyVersion()->getCounter());
}
TEST_F(TopologyVersionObserverTest, HandleQuiesceMode) {
// Start out as a secondary to transition to quiesce mode easily.
ASSERT_OK(getReplCoord()->setFollowerMode(MemberState::RS_SECONDARY));
auto cachedResponse = getObserverCache();
ASSERT(cachedResponse);
// Set a failpoint so we can observe the background thread shutting down.
FailPointEnableBlock failBlock("topologyVersionObserverExpectsShutdown");
{
// Enter quiesce mode in the replication coordinator to make shutdown errors come from
// awaitHelloResponseFuture()/getHelloResponseFuture().
auto opCtx = makeOperationContext();
getReplCoord()->enterQuiesceModeIfSecondary(Milliseconds(0));
getNet()->enterNetwork();
getNet()->advanceTime(getNet()->now() + sleepTime);
getNet()->exitNetwork();
ASSERT_THROWS_CODE(replCoord->getHelloResponseFuture({}, boost::none).get(opCtx.get()),
AssertionException,
ErrorCodes::ShutdownInProgress);
}
// Wait for the background thread to fully shutdown.
failBlock->waitForTimesEntered(failBlock.initialTimesEntered() + 1);
// In quiescence, the observer should be shutdown and have nothing in cache.
ASSERT(!observer->getCached());
ASSERT(observer->isShutdown());
}
} // namespace
} // namespace repl
} // namespace mongo
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