Chart Variables

Chart variables serve as configuration parameters that can be read from the chart’s code and are used to promote reusability of charts across Composer data sources. There are two types of chart variables in Composer:

• Query Variables

• Constant Variables

Query Variables

These variables drive the type of query that executes against the backend database. For example, a chart with a single query variable of type Group aggregates the data based on the configured field and uses count as the aggregation function. If the developer additionally adds a query variable of type Multi-Metric, the data includes the aggregated values of the configured metrics based on the aggregation functions specified.

Constant Variables

These variables are useful for chart settings specified as numeric, text, or list values. For example, a custom chart might use a service that requires an API key. A chart developer can create a string constant variable for the API key to allow users to specify a different key per data source.

Supported Variable Types

A list of the various variable types supported by Composer custom charts and their configurations can be found here.