Mailing-List: contact zookeeper-dev-help@hadoop.apache.org; run by ezmlm
Precedence: bulk
Reply-To: zookeeper-dev@hadoop.apache.org
Received-SPF: pass (athena.apache.org: domain of chris87@gmail.com designates
 209.85.132.245 as permitted sender)
DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=message-id:date:from:to:subject:in-reply-to:mime-version
         :content-type:content-transfer-encoding:content-disposition
         :references;
        b=GghUfvKLFtVtEmTtTW+Mrgi47OI76WF+HOqTxFxOFxuwpucpxSo6aX1evVM5esx5Ll
         rjgCU/TD4SDFX616NSyu8zOnQu0qprSmWV8/qjlQAINRDhZICabMSFq5j27RiCnc8aDd
         UDLJehPvCRvswAhuqRievgaGNJSZ8OvW4J87c=
Message-ID: <6b12e470807220324o40a83bf6q31ffc47e2fa63efc@mail.gmail.com>
Date: Tue, 22 Jul 2008 11:24:30 +0100
From: "Chris Smith" <chris87@gmail.com>
To: zookeeper-dev@hadoop.apache.org
Subject: Re: Thrift interface
In-Reply-To: <487D6F4B.1060004@yahoo-inc.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
References: <6b12e470807141036l1795071du70137ddba8165952@mail.gmail.com>
	 <487D6F4B.1060004@yahoo-inc.com>

I've now got a working stand-alone 'proxy' that acts as a Thrift
server and a ZK client. Is this something you guys would want/accept
as a contrib module? I appreciate that you already have SWIG and FUSE
bindings, but I think the Thrift interface makes more sense in
environments where [most] other services are already exposed using
Thrift.

At present the code is not hugely nice, as it has to convert between
Thrift-generated objects and Jute-generated ones; if you did switch to
using Thrift RPC for ZK's serialisation layer it'd make this a lot
more tidy. Also, it doesn't support watches at the minute, although I
can think of several ways this could be done if needed (I don't think
we actually need them for what we're going to be using the Thrift
interface for).

- Chris

On Wed, Jul 16, 2008 at 4:47 AM, Benjamin Reed <breed@yahoo-inc.com> wrote:
> Hi Chris,
>
> We have talked about using Thrift for our serialization layer (I thought
> we had a Jira opened for it, but I cannot find it). Thrift RPC is a
> different story. You would lose watch callbacks. I think it would also
> be hard to support sessions and thus ephemeral nodes. Finally, your
> client and server throughput would be quite low since clients wouldn't
> be able to pipeline requests (it appears you can only have one request
> outstanding at a time) and servers have to dedicate a thread to service
> a request.
>
> ZooKeeper clients are more than simple RPC dispatchers they also do
> session maintenance and completion processing, so you need something a
> bit more sophisticated at the client.
>
> I assume you want this to get bindings for other languages. We have SWIG
> and FUSE bindings for this.
>
> If you really want thrift, I think there is a combo solution: implement
> a standalone service, thrift server and zk client, and run it on each
> ZooKeeper server.
>
> ben
>
> Chris Smith wrote:
>>
>> Hi,
>>
>> I'm currently thinking about implementing a Thrift interface for
>> ZooKeeper, and wanted to get some opinions on it before I start. I can
>> basically see two possible ways to implement it:
>>
>>  * A standalone service which implements both a ZooKeeper client and a
>> Thrift server, and basically acts as a proxy between the two
>>  * Integrate the Thrift server with the ZooKeeper server, so that ZK
>> servers themselves handle the Thrift connections
>>
>> I think the former is probably nicer from a development stand-point,
>> but the latter seems better from an end-user stand-point. Has anyone
>> else thought about doing this (or actually done it!), and does anyone
>> have any preferences/comments with regard to the above options?
>>
>> Cheers,
>>
>> Chris Smith
>>
>
>