26. Property Datum Filter¶

The Property Datum Filter provides a way to remove properties of datum. This can help if some component generates properties that you don't actually need to use.

For example you might have a plugin that collects data from an AC power meter that capture power, energy, quality, and other properties each time a sample is taken. If you are only interested in capturing the power and energy properties you could use this component to remove all the others.

This component can also throttle individual properties over time, so that individual properties are posted less frequently than the rate the whole datum it is a part of is sampled at. For example a plugin for an AC power meter might collect datum once per minute, and you want to collect the energy properties of the datum every minute but the quality properties only once every 10 minutes.

The general idea for filtering properties is to configure rules that define which datum sources you want to filter, along with a list of properties to include and/or a list to exclude. All matching is done using regular expressions, which can help make your rules concise.

This filter is provided by the Standard Datum Filters plugin.

26.1 Settings¶

Each filter configuration contains the following overall settings:

Setting	Description
Service Name	A unique ID for the filter, to be referenced by other components.
Service Group	An optional service group name to assign.
Source ID	A case-insensitive pattern to match the input source ID(s) to filter. If omitted then datum for all source ID values will be filtered, otherwise only datum with matching source ID values will be filtered.
Required Mode	If configured, an operational mode that must be active for this filter to be applied.
Required Tag	Only apply the filter on datum with the given tag. A tag may be prefixed with `!` to invert the logic so that the filter only applies to datum without the given tag. Multiple tags can be defined using a `,` delimiter, in which case at least one of the configured tags must match to apply the filter.
Property Includes	A list of property names to include, removing all others. This is a list of case-insensitive patterns to match against datum property names. If any inclusion patterns are configured then only properties matching one of these patterns will be included in datum. Any property name that does not match one of these patterns will be removed.
Property Excludes	A list of property names to exclude. This is a list of case-insensitive patterns to match against datum property names. If any exclusion expressions are configured then any property that matches one of these expressions will be removed. Exclusion epxressions are processed after inclusion expressions when both are configured.

Use the + and - buttons to add/remove property include/exclude patterns.

Each property inclusion setting contains the following settings:

Setting	Description
Name	The property name pattern to include.
Limit Seconds	A throttle limit, in seconds, to apply to included properties. The minimum number of seconds to limit properties that match the configured property inclusion pattern. If properties are produced faster than this rate, they will be filtered out. Leave empty (or `0`) for no throttling.