listeners on Leader Latch?

[Eric Tschetter]

Hi guys,

I'm looking at using Leader Latch and I noticed it only has polling mechanisms for figuring out if you are the leader.  I was wondering if there is a reason to not have a callback mechanism that you can register with two methods:

startBeingMaster();

stopBeingMaster();

Basically, any time setLeadership() is called with a value other than what it was, it would cause either startBeingMaster() to be called or stopBeingMaster() to be called.

I can effect this using an extra thread and the polling mechanisms that are there, but am wondering if I'm the only one that would prefer to interact with it in this way or if others would also prefer to have access to this type of API?

(Btw, for anyone wondering, I'm currently swapping out an old zookeeper client library for Curator and that's why I have all of these random questions about APIs and stuff)

--Eric

[Jordan Zimmerman]

Look at LeaderSelector. It is a leader recipe that has a callback mechanism. 

====================

Jordan Zimmerman

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[Eric Tschetter]

You and your super-secret undocumented recipes!  Checking it out.

[Eric Tschetter]

Oh, that's the Leader Election recipe.

I don't really like that abstraction either because it makes me worry about too much:

1) Losing connection, etc.

2) "Relinquishing" leadership

I just want to either be the leader or not be the leader and have that choice be completely external.  That is, I want something to tell me that I became the leader or that I lost leadership.  I assume that I can always give up my leadership by just closing the thing down.

--Eric

[Eric Tschetter]

Just submitted a pull request for this, hopefully it doesn't go completely against your sensibilities.

https://github.com/Netflix/curator/pull/272

--Eric