conditional

type Config struct {
	// Condition to produce metric
	// See syntax here: https://expr-lang.org/docs/language-definition
	Condition string `toml:"condition"`
}

type Expression interface {
	// Match test if the event match the conditional expression
	Match(event events.Event) bool
	// String returns condition as text
	String() string
}

type Output interface {
	// SetCondition sets the condition expression for the interface.
	SetCondition(condition Expression)
}