[bmcweb] Device Level Logging Services

[Bills, Jason M]

On 5/26/2021 1:50 PM, Willy Tu wrote:
> Hi all,
> 
> Main discussion: 
> https://lore.kernel.org/openbmc/CAHwn2XknKWyv6Bsq48tkvA52rHKZRFoEJgUuZUmMj6uZb584JQ@mail.gmail.com/ (a 
> bit outdated)
> 
> This will be a sub-thread about logging services that will be used to 
> support Drive (and could support others).
> 
> For bmcweb, I am wondering if we can support custom logging services 
> other than the static ones that we have in 
> https://github.com/openbmc/bmcweb/blob/master/redfish-core/lib/log_services.hpp.
> 
> I am thinking about supporting custom log service at a device level that 
> can be exported by different hardwares log entries that are more 
> specific. Then at each device resource can link  the Status.Condition to 
> the LogEntries.
> 
> Initial Idea,
> 
> For example, I want to have log entries for Drive devices.
> 
> ComputerSystemId could still be system or bmc and the Redfish 
> endpoint will be something like.
> 
> ```
> /redfish/v1/Systems/system/LogServices/Drive0LogService/Entries
> ```
Specifically regarding the endpoint, we have considered a similar 
approach for publishing a LogService for a memory device.  I don't know 
if we have finalized our proposal to the DMTF yet, but we were thinking 
it would be better to add a LogService to the individual resource rather 
than keep everything under Systems/system.

If the same idea is applied for your drive devices, each drive resource 
in Redfish would also contain its own LogService.

> 
> On the D-bus side, the service exporting the log can add log entry 
> <https://github.com/openbmc/phosphor-dbus-interfaces/blob/master/xyz/openbmc_project/Logging/Entry.interface.yaml> under.
> 
> We can have
> ```
> /xyz/openbmc_project/logging/device/drive_0
> |__/xyz/openbmc_project/logging/device/drive_0/entry/...
> ```
> 
> We can parse the `xyz.openbmc_project.ObjectMapper` at 
> `/xyz/openbmc_project/logging/device` with depth of 1 to get all the new 
> device log services and so on.
> 
> Please let me know if there are any questions about it. If no one is 
> against it, I'll work on implementing it.
> 
> Best,
> 
> Willy Tu
> 
> 
> 
> 
> Best,
> 
> Willy Tu