metricDescriptor property

The metric descriptor associated with the logs-based metric.

If unspecified, it uses a default metric descriptor with a DELTA metric kind, INT64 value type, with no labels and a unit of "1". Such a metric counts the number of log entries matching the filter expression.The name, type, and description fields in the metric_descriptor are output only, and is constructed using the name and description field in the LogMetric.To create a logs-based metric that records a distribution of log values, a DELTA metric kind with a DISTRIBUTION value type must be used along with a value_extractor expression in the LogMetric.Each label in the metric descriptor must have a matching label name as the key and an extractor expression as the value in the label_extractors map.The metric_kind and value_type fields in the metric_descriptor cannot be updated once initially configured. New labels can be added in the metric_descriptor, but existing labels cannot be modified except for their description.

Optional.