control: action to override a single fan in a zone - Action class

This change contains the OverrideFanTarget class to create the Action
from a json config. A very basic events.json would look like t

control: action to override a single fan in a zone - Action class

This change contains the OverrideFanTarget class to create the Action
from a json config. A very basic events.json would look like this:

[
{
"name": "test",
"groups": [
{ "name": "fan0 sensor inventory", "interface": "xyz.openbmc_project.State.Decorator.OperationalStatus",
"property": { "name": "Functional" } }
],
"triggers": [
{ "class": "init", "method": "get_properties" },
{ "class": "signal", "signal": "properties_changed" }
],
"actions": [ {
"name": "override_fan_target",
"count": 1,
"state": false,
"fans": [ "fan0", "fan2" ],
"target": 9999
} ]
}
]

When the tach sensor for fan0 is set to non-funtional:

root@p10bmc:~# busctl set-property xyz.openbmc_project.Inventory.Manager
/xyz/openbmc_project/inventory/system/chassis/motherboard/fan0/fan0_0
xyz.openbmc_project.State.Decorator.OperationalStatus Functional b false

the run() method for the Action is called and all registered fans will
be locked at the "target" value given in the json "actions" section.

...
<output trimmed>
...
FAN TARGET(RPM) FEEDBACKS(RPMS) PRESENT FUNCTIONAL
===============================================================
fan0 9999 7019/9999 true true
fan1 10000 7020/10000 true true
fan2 9999 7019/9999 true true
...

When the inventory registers the sensor back to functional, the override
lock is lifted and the fan is restored to its zone's current target.

Signed-off-by: Mike Capps <mikepcapps@gmail.com>
Change-Id: I6bf5bd55fd6eac2131aec02775a64ad287d3b3b0

show more ...