Write-though API for CuratorCache (is read-my-writes semantics possible) ?

[Enrico Olivelli <eo...@gmail.com>]

Hello folks,
I was discussing with a colleague of mine, who is starting to use Curator
for a brand new project.

I suggested using a CuratorCache in order to have a Cache over a subtree of
ZK as usual.

I am missing some part of the story.

If I use a CuratorCache and I update a znode, then I am not guaranteed to
immediately see the result of my write reflected into the local
CuratorCache, because the Cache will be only eventually updated with the
new value.
So I cannot implement "read-my-writes" semantics....

Shall we add some "write-through" API to CuratorCache ? or add some
plumbing in CuratorClient in a way that the writes using the client are
automatically applied to every CuratorCache registered in the Client ?


Best regards
Enrico

Re: Write-though API for CuratorCache (is read-my-writes semantics possible) ?

[Jordan Zimmerman <jo...@jordanzimmerman.com>]

All Curator caches have had that problem. I guess what's needed is a way to listen for writes so that the cache can subscribe. Or, add some kind of write semantics to the CuratorCache API?

-Jordan

> On Jul 27, 2021, at 7:27 AM, Enrico Olivelli <eo...@gmail.com> wrote:
> 
> Hello folks,
> I was discussing with a colleague of mine, who is starting to use Curator
> for a brand new project.
> 
> I suggested using a CuratorCache in order to have a Cache over a subtree of
> ZK as usual.
> 
> I am missing some part of the story.
> 
> If I use a CuratorCache and I update a znode, then I am not guaranteed to
> immediately see the result of my write reflected into the local
> CuratorCache, because the Cache will be only eventually updated with the
> new value.
> So I cannot implement "read-my-writes" semantics....
> 
> Shall we add some "write-through" API to CuratorCache ? or add some
> plumbing in CuratorClient in a way that the writes using the client are
> automatically applied to every CuratorCache registered in the Client ?
> 
> 
> Best regards
> Enrico