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xk6-output-kafka

This extension is extracted from the k6 kafka output so it can be used with xk6.

Build

To build a k6 binary with this extension, first ensure you have the prerequisites:

  1. Build with xk6:
xk6 build --with github.com/grafana/xk6-output-kafka

This will result in a k6 binary in the current directory.

  1. Run with the just built k6:
./k6 run -o xk6-kafka <script.js>

Instructions

You can configure the broker (or multiple ones), topic, and message format directly from the command line parameter like this:

./k6 run --out xk6-kafka=brokers=broker_host:9092,topic=k6

or if you want multiple brokers:

./k6 --out xk6-kafka=brokers={broker1,broker2},topic=k6,format=json

You can also specify the message format k6 will use. By default, it will be the same as the JSON output, but you can also use the InfluxDB line protocol for direct "consumption" by InfluxDB:

./k6 --out xk6-kafka=brokers=someBroker,topic=someTopic,format=influxdb

You can even modify some of the format settings such as tagsAsFields:

./k6 --out xk6-kafka=brokers=someBroker,topic=someTopic,format=influxdb,influxdb.tagsAsFields={url,myCustomTag}

Testing Locally

This repo includes a docker-compose.yml file that starts local Kafka environment with several dependencies and utilities baked-in. See lensesio/fast-data-dev for more information.

:warning: Be sure that you've already compiled your custom k6 binary as described in the Build section!

We'll use this environment to run some examples.

  1. Start the docker compose environment.

    docker compose up -d

    Once you see the following, you should be ready.

     [+] Running 2/2
 ⠿ Network xk6-output-kafka_default       Created
 ⠿ Container xk6-output-kafka-lensesio-1  Started

    Next, we'll use the k6 binary we compiled in the Build section above.

  2. Open http://localhost:3030/ to display the landing page for your local Kafka Development environment provided by the docker image. From there, you can select the Kafka Topics UI.

  3. Using our custom k6 binary, we can execute our example script outputting test metrics to kafka.

    ./k6 run --out xk6-kafka=brokers={localhost:9092},topic=k6-metrics examples/simple.js

    Refreshing your browser should now list the k6-metrics topic. Clicking into the topic will now show messages for real-time metrics published during the k6 test execution.

See also