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From Alexey Popov <tank2.a...@gmail.com>
Subject RE: Thin Client Protocol documentation
Date Fri, 01 Dec 2017 10:38:09 GMT
Pavel,

I believe ClientListenerNioListener.onHandshake() could support more than one Handshake request
format (be backward compatible), for instance, if we will have a new handshake code = 0xABCD
that differs from 0x01 byte. 

It is a design vs architecture question.

I can’t understand why the legacy Handshake format should be used for a new protocol. If
this protocol is supposed to be public it should have no exceptions for message formats.

Thank you,
Alexey

From: Pavel Tupitsyn
Sent: Thursday, November 30, 2017 12:11 PM
To: dev@ignite.apache.org
Subject: Re: Thin Client Protocol documentation

Hi Alexey,

1,2,3 are related only to handshake. All other operations are consistent.

Handshake request format is dictated by existing client connector that is
shared with ODBC and JDBC clients (see
ClientListenerNioListener.onHandshake).
so we can't add magic numbers or change operation code.

But yes, we can add server version to the handshake response, and I think
this makes sense.

> 4. The same comments for success flag (1 byte) and status code (4 bytes)
in responses. Let's leave only status code.
We don't have a success flag in responses, there is just a 4-byte status
code, 0 indicates success, everything else is an error.

Thanks,
Pavel

On Thu, Nov 30, 2017 at 12:01 PM, Alexey Popov <tank2.alex@gmail.com> wrote:

> Hi Pavel,
>
> Let me add my 5 cents.
>
> 1. It would be great if both Handshake request & response have some
> "magic" number (2 or 4 bytes) inside their msg body. That will simplify
> handling situations when non-Ignite client connects to Ignite server and
> vice versa.
>
> 2. It makes sense to add server version to successful Handshake response
> as well. It will help to understand & debug possible backward compatibility
> issues in the field by *.pcap logs analysis & etc.
>
> 3. Can we have a more strict header for all message types?
> As far as I understand,
> Handshake request has:
> 1) length - 4 byte
> 2) Handshake code - 1 byte
> 3) body - (length - 1) bytes
>
> while OP_CACHE_GET request has:
> 1) length - 4 byte
> 2) OP_CACHE_GET code - 2 bytes
> 3) request id - 4 bytes
> 4) body - (length - 2 - 4) bytes
>
> Why some messages have Operation code with 1 byte while others - 2 bytes?
> Why some requests/responses have request-id while others don't? Let's
> simplify parser work )
>
> 4. The same comments for success flag (1 byte) and status code (4 bytes)
> in responses. Let's leave only status code.
>
> Thank you,
> Alexey
>
> From: Pavel Tupitsyn
> Sent: Wednesday, November 22, 2017 4:04 PM
> To: dev@ignite.apache.org
> Subject: Thin Client Protocol documentation
>
> Igniters,
>
> I've put together a detailed description of our Thin Client protocol
> in form of IEP on wiki:
> https://cwiki.apache.org/confluence/display/IGNITE/IEP-
> 9+Thin+Client+Protocol
>
>
> To clarify:
> - Protocol implementation is in master (see ClientMessageParser class)
> - Protocol has not been released yet, so we are free to change anything
> - Protocol is only used by .NET Thin Client for now, but is supposed to be
> used from other languages by third party contributors
> - More operations will be added in future, this is a first set of them,
> cache-related
>
>
> Please review the document and let me know your thoughts.
> Is there anything missing or wrong?
>
> We should make sure that the foundation is solid and extensible.
>
>
> Thanks,
> Pavel
>
>


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