commit 7962944f072b54e22075e8290e1e6708bdb30c38
author Chau Ly <chaul@amperecomputing.com> Wed Aug 20 10:27:20 2025 +0000
committer ChauLy-Vietnam <chaul@amperecomputing.com> Thu Sep 25 02:46:19 2025 +0000
tree 96e1f6423e4e77baf197b3a95656643068cecff4
parent dbef7168ac42e87d14faec6908d96e392afa7387

entity-manager: Handle left-over template vars

With current implementations for template variable replacement, if a
variable does not exist on D-Bus, it will be left as is and will appear
in the final configuration. However, if the string is intended to be
replaced and not handled properly after a replacement failure, the
variable itself will possibly be shown to users via Redfish/IPMI if the
consuming properties are used by those.

After performing the template variable replacement, a post-processing
step is added to check for any leftover template variables. These
leftovers may occur if the probed property is not available on D-Bus.
Any such variables are replaced with an empty string to avoid
unresolved placeholders.

The boundary of a template var is decided to be from the character "$"
to before a " " character, or the end of the keyPair's value string.
This conforms to the implicit rules currently applied to template
variable configuration that a template variable should not be
immediately followed by an arbitrary string without a space separating
them. This pattern can also be found in how the math configurations are
extracted, which looks for a math operator at the position that is one
character away from the end of the template variable [1].

The unit tests are also updated to test the new function that handles
left-over template variables.

[1]: https://github.com/openbmc/entity-manager/blob/3911d80afb6956b17c4f4b9a76c7eb45bb76e3b9/src/entity_manager/utils.cpp#L134

Tested: Unit tests pass

Tested with real configuration:

`$PRODUCT_PRODUCT_KK_NAME`, `$PRODUCT_KK_VERSION` and
`$PRODUCT_SERIAL_KK_NUMBER` are non-existent probed property on D-Bus.

```
{
        "Exposes": [
	...
	],
	"Name": "Mt.Mitchell_Motherboard",
        "Probe": [
            "xyz.openbmc_project.FruDevice({'BOARD_PRODUCT_NAME': 'MB'})",
            "AND",
            "FOUND('Mt.Mitchell_DCSCM_BMC')"
        ],
        "Type": "Board",
        "xyz.openbmc_project.Common.UUID": {
            "UUID": "$MULTIRECORD_UUID"
        },
        "xyz.openbmc_project.Inventory.Decorator.Asset": {
            "BuildDate": "$BOARD_MANUFACTURE_DATE",
            "Manufacturer": "$PRODUCT_MANUFACTURER",
            "Model": "$PRODUCT_PRODUCT_KK_NAME $PRODUCT_KK_VERSION",
            "PartNumber": "$PRODUCT_PART_NUMBER",
            "SerialNumber": "$PRODUCT_SERIAL_KK_NUMBER"
        }
}
```

D-Bus results after the configuration is processed:

- `Model` has a space character which is the space between
`$PRODUCT_PRODUCT_KK_NAME` and `$PRODUCT_KK_VERSION` in the
configuration.

- SerialNumber is empty.

```
$ busctl introspect xyz.openbmc_project.EntityManager \
/xyz/openbmc_project/inventory/system/board/Mt_Mitchell_Motherboard

xyz.openbmc_project.Common.UUID       interface -         -
.UUID                                 property  s         "xx-xx"
xyz.openbmc_project.Inventory.Decorator.Asset      interface -         -
.BuildDate                            property  s         "20221018Z"
.Manufacturer                         property  s         "NULL"
.Model                                property  s         " "
.PartNumber                           property  s         "ProductPN"
.SerialNumber                         property  s         ""

Change-Id: I4499baf3ebe9560e13932a49e324d1c8b0255623
Signed-off-by: Chau Ly <chaul@amperecomputing.com>