This extension exposes for collection by a Prometheus server (https://prometheus.io/). Emitter is enabled by setting druid.emitter=prometheus or include prometheus in the composing emitter list.

Configuration

All metric names and labels are reformatted to match Prometheus standards.

• For labels: all characters which are not alphanumeric or underscores (matching ) are replaced with _

Metric mapping

For metrics which are emitted from multiple services with different dimensions, the metric name is prefixed with the service name. e.g. "coordinator-segment/count" : { "dimensions" : ["dataSource"], "type" : "gauge" }, "historical-segment/count" : { "dimensions" : ["dataSource", "tier", "priority"], "type" : "gauge" }