Redfish EventService Implementation

[RAJESWARAN THILLAIGOVINDAN]

ApparaRao.

As you have shown interest in this feature and submitted the design 
document, do you have any opinion on this? Do you see any merit in using 
D-Bus match in bmcweb to create event logs for life cycle events?  
Please feel free to weigh in.

Thanks,
Rajes

On 01-02-2020 02:23, RAJESWARAN THILLAIGOVINDAN wrote:
> Hi,
>
> I am going through the bmcweb code for implementing Redfish 
> EventService based on the design document 
> https://gerrit.openbmc-project.xyz/c/openbmc/docs/+/24749. This design 
> is hooked to the journal based Redfish Event Logging. For life cycle 
> events(ResourceAdded, ResourceRemoved, ResourceUpdated),  using D-Bus 
> match, bmcweb can create an event log. This requires a JSON 
> dictionary, comprising an array of Redfish Resource Name and the D-Bus 
> path. This approach works only in case of one to one mapping of 
> Redfish Resource Name and the D-Bus path. For propertiesChanged 
> events, if the Redfish Resource property is not on the same D-Bus path 
> or the Redfish Resource property name is different from the D-Bus 
> property name, then an additional JSON dictionary to maintain this 
> information is required. With D-Bus match alone in the bmcweb, Redfish 
> EventService can't be fully supported. For the Message Registers and 
> the Resource Types that are supported, the relevant OpenBMC 
> application must create an event log in the journal using either the 
> phosphor::logging::entry or sd_journal_send() command.
>
> After realizing that with D-Bus match in the bmcweb alone can't help 
> to fully implement EventService, I prefer to avoid using D-Bus match 
> in bmcweb. Instead, I prefer to modify the OpenBMC application that 
> generated the event to create an event log in the journal. Do you see 
> any advantage of using combination of D-Bus match in the bmcweb 
> wherever it is possible and changes to OpenBMC application in other 
> cases to create an event log ?
>
> Your views are highly appreciated.
>
> Thanks,
> Rajes