[Engine-devel] REST-API: Exposing correlation-ID

[Itamar Heim]

On 05/03/2012 06:15 PM, Eoghan Glynn wrote:
>
>
>> Correlation-ID feature allows 'tagging' a call to a Backend command
>> with a String ID, and this ID will be appended to all log messages
>> that result from this command.
>>
>> http://www.ovirt.org/wiki/Features/TaskManagerDetailed
>>
>> In REST-API, we would like to enable the user to pass a
>> correlation-ID
>> when he activates actions.
>>
>> I have two questions:
>>
>> 1) what's the name you'd give this parameter? job-id? batch-id?
>> flow-id? command-id? correlation-id???
>>
>> 2) I've already implemented this as a url parameter. Are there
>> objections?
>> The only viable alternative I see is as an http header, which doesn't
>> feel
>> right. It's not an option to pass it in the XML body, because
>> sometimes
>> there is no body, for example, in DELETE commands.
>
> Hi Ori,
>
> Is the intent here to allow correlation between multiple backend actions
> initiated from a single restapi call, or an over-arching correlation
> across multiple restapi calls?
>
> If the former, then I'd agree with Yaniv, just generate the ID internally
> and return it as a response header.
>
> If the latter, then allowing it to be optionally set via a request header,
> seems more natural to me than a URL parameter because this is additional
> out-of-band data that aids in log interpretation, as opposed to something
> directly germane to the interaction with the target resource.

both.
engine auto-generates this if not provided and domain is single command.
but client can pass this to see all events or multiple commands running 
in parallel as part of same single client logical action.