StatsD Emitter
To use this Apache Druid extension, make sure to include statsd-emitter extension.
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.