tree 0457aa6693101465fdc9a007aa95beb0ececc7d8
parent 65dfe1ead04c90e799f487ae041b870b4ea87d20
author Matt Spinler <spinler@us.ibm.com> 1635455384 -0500
committer Matt Spinler <spinler@us.ibm.com> 1635885439 -0500

control: Timer trigger can preload groups

The timer trigger is used to run actions when it expires.  This commit
adds the ability for it to preload group properties so the latest values
are in the cache before it runs the actions.

This means that there doesn't need to be propertiesChanged triggers for
the groups, instead the load just reads them straight from D-Bus.

One reason to use this is so an action can be run on a slower cadence than
propertiesChanged signals would be sent.  An example is a virtual sensor
that has component sensors spread out across multiple daemons.  Even if
the daemons all use the same poll rates, they can be staggered between
them so virtual sensor changes could occur faster then any component
sensor read interval.

The trade off is there will be D-Bus traffic every timer interval, even
in the case the group property values don't change.

To enable this, use the following in the trigger JSON:
    "preload_groups": true

Signed-off-by: Matt Spinler <spinler@us.ibm.com>
Change-Id: I1a92007c10fdd8017c1a89d15983ae50134c852a