Ed, Venture, 

Could you confirm if the "/xyz/openbmc_project/host/post/1" that we talked here contains a list of post code for one cycle? 

From my understanding, it should be like:
/xyz/openbmc_project/host/post/current (objpath)
->xyz.openbmc_project.Host.State.Boot.Raw (intf)
---->Value (a list of POST code for current POST) (property)
/xyz/openbmc_project/host/post/1
->xyz.openbmc_project.Host.State.Boot.Raw
---->Value (a list of POST code for previous POST)
/xyz/openbmc_project/host/post/2
->xyz.openbmc_project.Host.State.Boot.Raw
---->Value (a list of POST code for the time before previous)

Is that correct?

The reason I am asking is that the orginal post code interface only keep *one* post code. Even if one DC cycle could generate 30~40 post code, it just keep latest and previous one.
I assume the objpath /xyz/openbmc_project/host/post/1 contains a list.   Otherwise, it will just represent one post code in one cycle.  In the latter case, we will have /xyz/openbmc_project/host/post/[0~40] objects for one cycle and it looks ugly. 

chunhui.jia
 
From: Tanous, Ed
Date: 2018-08-25 03:33
To: Patrick Venture
CC: Wang, Kuiying; Mihm, James; Nguyen, Hai V; Feist, James; Jia, Chunhui; OpenBMC Maillist; Li, Yong B; Yang, Cheng C; Brad Bishop; Xu, Qiang; kun.yi.731@gmail.com; geissonator@yahoo.com
Subject: RE: Proposal for caching/buffering POST codes list for one boot process.
>
> I like this approach, but one would need to enumerate the tree to know how
> many there are cached available.  Albeit, maybe that's trivial :D
 
A DBus call to Objectmapper  would tell you how many objects you have.
GetSubtree  path:/xyz/openbmc_project/host/post depth: 0 interfaces ["xyz.openbmc_project.Host.State.Boot.Raw"] would get you a list of all Post code interfaces
Depending on the context you might also be able to get away with just GetSubtreePaths.
 
I wouldn't call it trivial, but it falls in the category of doable.
 
Alternatively, if you know you need all of them for whatever response you're building, GetManagedObjects to the Post code daemon directly would save you a round trip through DBus.