StatsD Emitter
- Introduction
- Configuration
  - Druid to StatsD Event Converter

StatsD Emitter

To use this Apache Druid extension, include statsd-emitter in the extensions load list.

Introduction

This extension emits druid metrics to a StatsD server. (https://github.com/etsy/statsd) (https://github.com/armon/statsite)

Configuration

All the configuration parameters for the StatsD emitter are under druid.emitter.statsd.

property	description	required?	default
`druid.emitter.statsd.hostname`	The hostname of the StatsD server.	yes	none
`druid.emitter.statsd.port`	The port of the StatsD server.	yes	none
`druid.emitter.statsd.prefix`	Optional metric name prefix.	no	“”
`druid.emitter.statsd.separator`	Metric name separator	no	.
`druid.emitter.statsd.includeHost`	Flag to include the hostname as part of the metric name.	no	false
`druid.emitter.statsd.dimensionMapPath`	JSON file defining the StatsD type, and desired dimensions for every Druid metric	no	Default mapping provided. See below.
`druid.emitter.statsd.blankHolder`	The blank character replacement as StatsD does not support path with blank character	no	“-“
`druid.emitter.statsd.dogstatsd`	Flag to enable DogStatsD support. Causes dimensions to be included as tags, not as a part of the metric name. `convertRange` fields will be ignored.	no	false
`druid.emitter.statsd.dogstatsdConstantTags`	If `druid.emitter.statsd.dogstatsd` is true, the tags in the JSON list of strings will be sent with every event.	no	[]
`druid.emitter.statsd.dogstatsdServiceAsTag`	If `druid.emitter.statsd.dogstatsd` and `druid.emitter.statsd.dogstatsdServiceAsTag` are true, druid service (e.g. `druid/broker`, `druid/coordinator`, etc) is reported as a tag (e.g. `druid_service:druid/broker`) instead of being included in metric name (e.g. `druid.broker.query.time`) and `druid` is used as metric prefix (e.g. `druid.query.time`).	no	false
`druid.emitter.statsd.dogstatsdEvents`	If `druid.emitter.statsd.dogstatsd` and `druid.emitter.statsd.dogstatsdEvents` are true, Alert events are reported to DogStatsD.	no	false

Druid to StatsD Event Converter

Each metric sent to StatsD must specify a type, one of [timer, counter, guage]. StatsD Emitter expects this mapping to be provided as a JSON file. Additionally, this mapping specifies which dimensions should be included for each metric. StatsD expects that metric values be integers. Druid emits some metrics with values between the range 0 and 1. To accommodate these metrics they are converted into the range 0 to 100. This conversion can be enabled by setting the optional “convertRange” field true in the JSON mapping file. If the user does not specify their own JSON file, a default mapping is used. All metrics are expected to be mapped. Metrics which are not mapped will log an error. StatsD metric path is organized using the following schema: <druid metric name> : { "dimensions" : <dimension list>, "type" : <StatsD type>, "convertRange" : true/false} e.g. query/time" : { "dimensions" : ["dataSource", "type"], "type" : "timer"}

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" }

For most use-cases, the default mapping is sufficient.