// createMetricNamespace returns metric namespace based on given `ns` which is used as a prefix; all dynamic elements
// in the `metricName` are defined based on content of map `dynamicElements`
func (creator *nsCreator) createMetricNamespace(ns core.Namespace, metricName string) (core.Namespace, error) {
metricName = strings.TrimSpace(metricName)
if len(metricName) == 0 {
return nil, errors.New("Cannot create metric namespace: empty metric name")
}
elements := strings.Split(metricName, "/")
// check if metricName contains only static elements
if !strings.Contains(metricName, "*") {
ns = ns.AddStaticElements(elements...)
return ns, nil
}
// when metric name contains dynamic element iterate over elements
for index, element := range elements {
if element == "*" {
// the following element is dynamic
dynamicElement, ok := creator.dynamicElements[elements[index-1]]
// check if this dynamic element is supported (name and description are available)
if !ok {
return nil, fmt.Errorf("Unknown dynamic element in metric `%s` under index %d", metricName, index)
}
// add recognize dynamic element (define its name and description)
ns = ns.AddDynamicElement(dynamicElement.name, dynamicElement.description)
if len(elements)-1 == index {
// in case when an asterisk is the last element, add `value` at the end of ns
ns = ns.AddStaticElement("value")
}
} else {
// the following element is static
ns = ns.AddStaticElement(element)
}
}
if len(ns) == 0 {
return nil, fmt.Errorf("Cannot create metric namespace for metric %s", metricName)
}
return ns, nil
}
