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zkutil: added state to LeaderElection [#METR-10190]

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This commit is contained in:
Pavel Kartavyy 2014-04-16 13:51:12 +04:00
parent 4c7dd4e269
commit 16d8fe8ab0
1 changed files with 36 additions and 1 deletions
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37
libs/libzkutil/include/zkutil/LeaderElection.h
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@ -19,7 +19,7 @@ public:
*/
LeaderElection(const std::string & path_, ZooKeeper & zookeeper_, LeadershipHandler handler_, const std::string & identifier_ = "")
: path(path_), zookeeper(zookeeper_), handler(handler_), identifier(identifier_),
shutdown(false), log(&Logger::get("LeaderElection"))
shutdown(false), state(WAITING_LEADERSHIP), log(&Logger::get("LeaderElection"))
{
node = EphemeralNodeHolder::createSequential(path + "/leader_election-", zookeeper, identifier);
@ -29,6 +29,38 @@ public:
thread = std::thread(&LeaderElection::threadFunction, this);
}
enum State
{
WAITING_LEADERSHIP,
LEADER,
LEADERSHIP_LOST
};
/// если возвращает LEADER, то еще sessionTimeoutMs мы будем лидером, даже если порвется соединение с zookeeper
State state()
{
if (state == LEADER)
{
try
{
/// возможно, если сессия разорвалась и заново был вызван init
if (!zookeeper.exists(node->getPath()))
{
LOG_WARNING(log, "Leadership lost. Node " << node->getPath() << " doesn't exist.");
state = LEADERSHIP_LOST;
}
}
catch (const KeeperException & e)
{
LOG_WARNING(log, "Leadership lost. e.message() = " << e.message());
state = LEADERSHIP_LOST;
}
}
return state;
}
~LeaderElection()
{
shutdown = true;
@ -47,6 +79,8 @@ private:
std::thread thread;
volatile bool shutdown;
State state;
Logger * log;
void threadFunction()
@ -63,6 +97,7 @@ private:
if (it == children.begin())
{
state = LEADER;
handler();
return;
}