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Druid Firehoses
Firehoses describe the data stream source. They are pluggable and thus the configuration schema can and will vary based on the type
of the firehose.
Field | Type | Description | Required |
---|---|---|---|
type | String | Specifies the type of firehose. Each value will have its own configuration schema, firehoses packaged with Druid are described below. | yes |
We describe the configuration of the Kafka firehose example, but there are other types available in Druid (see below).
consumerProps
is a map of properties for the Kafka consumer. The JSON object is converted into a Properties object and passed along to the Kafka consumer.feed
is the feed that the Kafka consumer should read from.
Available Firehoses
There are several firehoses readily available in Druid, some are meant for examples, others can be used directly in a production environment.
KafkaFirehose
This firehose acts as a Kafka consumer and ingests data from Kafka.
StaticS3Firehose
This firehose ingests events from a predefined list of S3 objects.
TwitterSpritzerFirehose
See Examples. This firehose connects directly to the twitter spritzer data stream.
RandomFirehose
See Examples. This firehose creates a stream of random numbers.
RabbitMqFirehose
This firehose ingests events from a define rabbit-mq queue.
LocalFirehose
This Firehose can be used to read the data from files on local disk. It can be used for POCs to ingest data on disk. A sample local firehose spec is shown below:
{
"type" : "local",
"filter" : "*.csv",
"baseDir" : "/data/directory"
}
property | description | required? |
---|---|---|
type | This should be "local". | yes |
filter | A wildcard filter for files. See here for more information. | yes |
baseDir | location of baseDirectory containing files to be ingested. | yes |
IngestSegmentFirehose
This Firehose can be used to read the data from existing druid segments. It can be used ingest existing druid segments using a new schema and change the name, dimensions, metrics, rollup, etc. of the segment. A sample ingest firehose spec is shown below -
{
"type" : "ingestSegment",
"dataSource" : "wikipedia",
"interval" : "2013-01-01/2013-01-02"
}
property | description | required? |
---|---|---|
type | ingestSegment. Type of firehose | yes |
dataSource | A String defining the data source to fetch rows from, very similar to a table in a relational database | yes |
interval | A String representing ISO-8601 Interval. This defines the time range to fetch the data over. | yes |
dimensions | The list of dimensions to select. If left empty, no dimensions are returned. If left null or not defined, all dimensions are returned. | no |
metrics | The list of metrics to select. If left empty, no metrics are returned. If left null or not defined, all metrics are selected. | no |
filter | See Filters | yes |
CombiningFirehose
This firehose can be used to combine and merge data from a list of different firehoses. This can be used to merge data from more than one firehoses.
{
"type" : "combining",
"delegates" : [ { firehose1 }, { firehose2 }, ..... ]
}
property | description | required? |
---|---|---|
type | combining | yes |
delegates | list of firehoses to combine data from | yes |
EventReceiverFirehose
EventReceiverFirehoseFactory can be used to ingest events using http endpoint.
when using this firehose druid.realtime.chathandler.type
needs to be set to announce
in runtime.properties.
{
"type": "receiver",
"serviceName": "eventReceiverServiceName",
"bufferSize": 10000
}
when using above firehose the events can be sent via submitting a POST request to the http endpoint -
http://<peonHost>:<port>/druid/worker/v1/chat/<eventReceiverServiceName>/push-events/
property | description | required? |
---|---|---|
type | receiver | yes |
serviceName | name used to announce the event receiver service endpoint | yes |
bufferSize | size of buffer used by firehose to store events | no default(100000) |