Re: [i2rs] Call for Input from WG: I2RS error handling simplification for initial I2RS protocol

Joe: 

Joe:

Great questions - see below. 

-----Original Message-----
From: i2rs [mailto:i2rs-bounces@ietf.org] On Behalf Of Joe Clarke
Sent: Thursday, October 15, 2015 11:06 AM
To: Susan Hares; i2rs@ietf.org
Cc: jhaas@pfrc.org; 'Alia Atlas'
Subject: Re: [i2rs] Call for Input from WG: I2RS error handling
simplification for initial I2RS protocol

On 10/14/15 23:20, Susan Hares wrote:
>> Joe:
>>
>> There will be some groups of data model have dependencies between
objects.
>> Some Client interactions will be orthogonal to each other.   If there are
>> groupings, then the dependencies may leave the I2RS agent and routing 
>> system in an unknown state.

>Sure.

>>
>> The "all-or-nothing" is the normal case for NETCONF/RESTCONF. If 
>> clients are based on the Netconf/RESTCONF code base, this will be the 
>> simple upward change.

>RESTCONF does do all-or-none, but typically operations apply to one data
element at a time.  >Clients would need to include multiple sub-operations
for a, say, a PATCH.  So, if I understand >correctly, there would be burden
on the Client that uses RESTCONF and multi-messages for a >single
"transaction" to handle the backout?

Yes - multiple sub-operation in RESTCONF requires a PATCH, and the burden is
on the client to handle the backing out of data in RESTCONF.  You have hit
upon the challenge.  The I2RS client is bearing the burden of this back-out
instead of the I2RS agent (Netconf "server" concept).  

Do you think this is reasonable to keep the I2RS agents simple? Will it make
the I2RS clients unworkable? 

>Joe

>
> The I2RS agent needs to provide notification for error on writing for
> priority conflict, and for other errors.   The Stop-on-error would also
need
> to provide this input.
>
> Sue
>
> -----Original Message-----
> From: Joe Clarke [mailto:jclarke@cisco.com]
> Sent: Tuesday, October 13, 2015 8:56 AM
> To: Susan Hares; i2rs@ietf.org
> Cc: jhaas@pfrc.org; 'Alia Atlas'
> Subject: Re: [i2rs] Call for Input from WG: I2RS error handling
> simplification for initial I2RS protocol
>
> On 10/13/15 04:57, Susan Hares wrote:
>> Currently the I2RS requirements have error handling having three parts:
>>
>> 1)"all-or-nothing",
>>
>> 2)"continue-on-error", and
>>
>> 3)"stop-on-error".
>>
>> To provide an easier first step for the I2RS Agent for the first
>> implementation of an I2RS protocol,  the I2RS protocol design team
>> suggests reduce this to the "all-or-nothing" for the initial version.
>> Later versions of the I2RS protocol can provide the "continue-on-error"
>> or "stop-on-error" error handling.  The earlier decision in the I2RS
>> architecture was to support all 3 error handling pieces.
>
> It seems to me the latter two would be easier to implement as the Client
> continues to fire (until not told to do so in the stop-on-error case) and
> the Agent wouldn't have to track all operations for rollback.
>
> Is the assumption that most I2RS transactions will have mutual
dependencies,
> and this is the most common error case?
>
> Joe
>

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