Skip to content
Branch: master
Find file History
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Type Name Latest commit message Commit time
Failed to load latest commit information.

Kafka Sink

The Kafka sink allows flushing of metrics or spans to to a Kafka topic.


See the various kafka_* keys in example.yaml for all available configuration options. This sink supports the following features:


This sink is stable. Some some encoding or options may change. This sink is in active development.


  • Uses the async client, but doesn't currently do anything on failure.

  • Does not currently handle writes of events or checks

  • batching

  • ack requirements

  • publishing of Protobuf or JSON formatted messages

Span Sampling

The Kafka sink supports span sampling! By default, setting kafka_span_sample_rate_percent less than 100 will sample based off of traceId (meaning that if one span with a particular traceId is selected, all spans with that traceId will be selected), but that behavior can be configured to use a tag instead via kafka_span_sample_tag. For example,

kafka_span_sample_tag: "request_id"
kafka_span_sample_rate_percent: 75

With this configuration, spans without the "request_id" tag will be rejected, and spans with the "request_id" will be sampled at 75%, based off of a hash of their "request_id" value; in this way, you can sample all values relevant to a particular tag value.


Metrics are published in JSON in the form of:

  "name": "some.metric",
  "timestamp": 1234567, // unix time
  "value": 1.0,
  "tags": [ "tag:value", … ],
  "type": "gauge" // counter, etc

Spans are published in one of JSON or Protobuf. The form is defined in SSF's protobuf and codegen output. Note that it has a version field for compatibility in the future.

You can’t perform that action at this time.