Graphite Emitter

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

Introduction

This extension emits druid metrics to a graphite carbon server. Metrics can be sent by using plaintext or pickle protocol. The pickle protocol is more efficient and supports sending batches of metrics (plaintext protocol send only one metric) in one request; batch size is configurable.

Configuration

All the configuration parameters for graphite emitter are under druid.emitter.graphite.

property	description	required?	default
druid.emitter.graphite.hostname	The hostname of the graphite server.	yes	none
druid.emitter.graphite.port	The port of the graphite server.	yes	none
druid.emitter.graphite.batchSize	Number of events to send as one batch (only for pickle protocol)	no	100
druid.emitter.graphite.protocol	Graphite protocol; available protocols: pickle, plaintext.	no	pickle
druid.emitter.graphite.eventConverter	Filter and converter of druid events to graphite event (please see next section).	yes	none
druid.emitter.graphite.flushPeriod	Queue flushing period in milliseconds.	no	1 minute
druid.emitter.graphite.maxQueueSize	Maximum size of the queue used to buffer events.	no	MAX_INT
druid.emitter.graphite.alertEmitters	List of emitters where alerts will be forwarded to. This is a JSON list of emitter names, e.g. ["logging", "http"]	no	empty list (no forwarding)
druid.emitter.graphite.requestLogEmitters	List of emitters where request logs (i.e., query logging events sent to emitters when druid.request.logging.type is set to emitter) will be forwarded to. This is a JSON list of emitter names, e.g. ["logging", "http"]	no	empty list (no forwarding)
druid.emitter.graphite.emitWaitTime	wait time in milliseconds to try to send the event otherwise emitter will throwing event.	no	0
druid.emitter.graphite.waitForEventTime	waiting time in milliseconds if necessary for an event to become available.	no	1000 (1 sec)

Supported event types

The graphite emitter only emits service metric events to graphite (See Druid Metrics for a list of metrics).

Alerts and request logs are not sent to graphite. These event types are not well represented in Graphite, which is more suited for timeseries views on numeric metrics, vs. storing non-numeric log events.

Instead, alerts and request logs are optionally forwarded to other emitter implementations, specified by druid.emitter.graphite.alertEmitters and druid.emitter.graphite.requestLogEmitters respectively.

Druid to Graphite Event Converter

Graphite Event Converter defines a mapping between druid metrics name plus dimensions to a Graphite metric path. Graphite metric path is organized using the following schema: <namespacePrefix>.[<druid service name>].[<druid hostname>].<druid metrics dimensions>.<druid metrics name> Properly naming the metrics is critical to avoid conflicts, confusing data and potentially wrong interpretation later on.

Example druid.historical.hist-host1_yahoo_com:8080.MyDataSourceName.GroupBy.query/time:

• druid -> namespace prefix
• historical -> service name
• hist-host1.yahoo.com:8080 -> druid hostname
• MyDataSourceName -> dimension value
• GroupBy -> dimension value
• query/time -> metric name

We have two different implementation of event converter:

Send-All converter

The first implementation called all, will send all the druid service metrics events. The path will be in the form <namespacePrefix>.[<druid service name>].[<druid hostname>].<dimensions values ordered by dimension's name>.<metric> User has control of <namespacePrefix>.[<druid service name>].[<druid hostname>].

You can omit the hostname by setting ignoreHostname=true druid.SERVICE_NAME.dataSourceName.queryType.query/time

You can omit the service name by setting ignoreServiceName=true druid.HOSTNAME.dataSourceName.queryType.query/time

Elements in metric name by default are separated by "/", so graphite will create all metrics on one level. If you want to have metrics in the tree structure, you have to set replaceSlashWithDot=true Original: druid.HOSTNAME.dataSourceName.queryType.query/time Changed: druid.HOSTNAME.dataSourceName.queryType.query.time

druid.emitter.graphite.eventConverter={"type":"all", "namespacePrefix": "druid.test", "ignoreHostname":true, "ignoreServiceName":true}

White-list based converter

The second implementation called whiteList, will send only the white listed metrics and dimensions. Same as for the all converter user has control of <namespacePrefix>.[<druid service name>].[<druid hostname>]. White-list based converter comes with the following default white list map located under resources in ./src/main/resources/defaultWhiteListMap.json

Although user can override the default white list map by supplying a property called mapPath. This property is a String containing the path for the file containing white list map JSON object. For example the following converter will read the map from the file /pathPrefix/fileName.json.

druid.emitter.graphite.eventConverter={"type":"whiteList", "namespacePrefix": "druid.test", "ignoreHostname":true, "ignoreServiceName":true, "mapPath":"/pathPrefix/fileName.json"}

Druid emits a huge number of metrics we highly recommend to use the whiteList converter