xref: /openbmc/bmcweb/DBUS_USAGE.md (revision dfa3fdc3)
1The following are guidelines for bmcweb's use of DBus to construct Redfish
2schemas:
3
4- Do not require (ie set 500 internal error on) an implementation present a
5  property that wasn't in the first commit of the interface unless it can be
6  verified that _all_ OpenBMC implementers of the interface support that
7  property.
8- If an implementation presents a property that doesn't match the type specified
9  by the interface at any version, it shall be repored as a 500 error.
10- If the DBus interface definition has an "unknown" or "unspecified" value,
11  detecting these will omit the property from the Redfish tree, in line with the
12  Redfish specification.
13- All DBus interfaces on all object paths are optional. An object missing an
14  interface is never an error, and shall simply omit the relevant properties
15  and/or actions from that Redfish Resource.
16- bmcweb will code to the DBus interface itself. This means that daemons are
17  expected to handle functionally bad, but DBus-correct input in their own
18  process, and return appropriate return codes. This is done to reduce the
19  duplication in input processing between the various user-facing daemons.
20- There are interfaces for which there is an expectation that there will only
21  ever be one producer in the project (ex bmc networking, user management). In
22  these cases, it is desirable to call the daemon by well known name directly.
23  Bmcweb APIs should call the mapper in cases where it's reasonably expected
24  that multiple implementations exist (ex, CPU management, Sensors).
25