pg

README

xk6-kafka

This is a k6 extension using the xk6 system.

❗ This is a proof of concept, isn't supported by the k6 team, and may break in the future. USE AT YOUR OWN RISK!

This project is a k6 extension that can be used to load test Kafka, using a producer. Per each connection to Kafka, many messages can be sent. These messages are an array of objects containing a key and a value. There is also a consumer for testing purposes, i.e. to make sure you send the correct data to Kafka. The consumer is not meant to be used for testing Kafka under load. The extension supports producing and consuming messages in Avro format, given a schema for key and/or value.

The real purpose of this extension is not only to test Apache Kafka, but also the system you've designed that uses Apache Kafka. So, you can test your consumers, and hence your system, by auto-generating messages and sending them to your system via Apache Kafka.

In order to build the source, you should have the latest version of Go (go1.15) installed. I recommend you to have gvm installed.

Build

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

• gvm
• Git

Then, install xk6 and build your custom k6 binary with the Kafka extension:

1. Install xk6:

$ go get -u github.com/k6io/xk6/cmd/xk6

1. Build the binary:

$ xk6 build v0.29.0 --with github.com/mostafa/xk6-kafka

Run & Test

First, you need to have your Kafka development environment setup. I recommend you to use Lenses.io fast-data-dev Docker image, which is a complete Kafka setup for development that includes: Kafka, Zookeeper, Schema Registry, Kafka-Connect, Landoop Tools, 20+ connectors. It is fairly easy to setup, if you have Docker installed. Just make sure to monitor Docker logs to have a working setup, before attempting to test. Initial setup, leader election and test data ingestion takes time.

Development Environment

After running the following commands, visit localhost:3030 to get into the fast-data-dev environment.

$ sudo docker run -d --rm --name lensesio --net=host lensesio/fast-data-dev
$ sudo docker logs -f lensesio

k6 Test

The following k6 test script is used to test this extension and Apache Kafka in turn. The script is available as test.js with more code and commented sections. The script has 4 parts:

1. The imports at the top shows the exposed functions that are imported from k6 and the extension, check from k6 and the writer, produce, reader, consume from the extension using the k6/x/kafka extension loading convention.
2. The Avro schema defines a value schema that is used by both producer and consumer, according to the Avro schema specification.
3. The Avro message producer:
   1. The writer function is used to open a connection to the bootstrap servers. The first argument is an array of strings that signifies the bootstrap server addresses and the second is the topic you want to write to. You can reuse this writer object to produce as many messages as you want.
   2. The produce function is used to send a list of messages to Kafka. The first argument is the producer object, the second is the list of messages (with key and value), the third and the fourth are the key schema and value schema in Avro format. If the schema are not passed to the function, the values are treated as normal strings, as in the key schema, where an empty string, "", is passed. The produce function returns an error if it fails. The check is optional, but error being undefined means that produce function successfully sent the message.
   3. The producer.close() function closes the producer object.
4. The Avro message consumer:
   1. The reader function is used to open a connection to the bootstrap servers. The first argument is an array of strings that signifies the bootstrap server addresses and the second is the topic you want to reader from.
   2. The consume function is used to read a list of messages from Kafka. The first argument is the consumer object, the second is the number of messages to read in one go, the third and the fourth are the key schema and value schema in Avro format. If the schema are not passed to the function, the values are treated as normal strings, as in the key schema, where an empty string, "", is passed. The consume function returns an empty array if it fails. The check is optional, but it checks to see if the length of the message array is exactly 10.
   3. The consumer.close() function closes the consumer object.

import { check } from 'k6';
import { writer, produce, reader, consume } from 'k6/x/kafka';  // import kafka extension

// Avro value schema
const value_schema = JSON.stringify({
    "type": "record",
    "name": "ModuleValue",
    "fields": [
        { "name": "name", "type": "string" },
        { "name": "version", "type": "string" },
        { "name": "author", "type": "string" },
        { "name": "description", "type": "string" }
    ]
});

export default function () {
    // Avro message producer
    const producer = writer(
        ["localhost:9092"],  // bootstrap servers
        "test-k6-extension-topic",  // Kafka topic
    )

    for (let index = 0; index < 100; index++) {
        let error = produce(producer,
            [{
                key: "DA KEY!",
                value: JSON.stringify({
                    "name": "k6-extension-kafka",
                    "version": "0.0.1",
                    "author": "Mostafa Moradian",
                    "description": "k6 Extension to Load Test Apache Kafka"
                })
            }], "", value_schema);

        check(error, {
            "is sent": err => err == undefined
        });
    }
    producer.close();

    // Avro message consumer
    const consumer = reader(
        ["localhost:9092"],  // bootstrap servers
        "test-k6-extension-topic",  // Kafka topic
    )

    // Read 10 messages only
    let messages = consume(consumer, 10, "", value_schema);
    check(messages, {
        "10 messages returned": msgs => msgs.length == 10
    })

    consumer.close();
}

You can run k6 with the Kafka extension using the following command:

$ ./k6 run --vus 50 --duration 60s test.js

And here's the test result output:

          /\      |‾‾| /‾‾/   /‾‾/
     /\  /  \     |  |/  /   /  /
    /  \/    \    |     (   /   ‾‾\
   /          \   |  |\  \ |  (‾)  |
  / __________ \  |__| \__\ \_____/ .io

  execution: local
     script: test.js
     output: -

  scenarios: (100.00%) 1 scenario, 50 max VUs, 1m30s max duration (incl. graceful stop):
           * default: 50 looping VUs for 1m0s (gracefulStop: 30s)


running (1m00.4s), 00/50 VUs, 6554 complete and 0 interrupted iterations
default ✓ [======================================] 50 VUs  1m0s

    ✓ is sent
    ✓ 10 messages returned

    checks.........................: 100.00% ✓ 661954 ✗ 0
    data_received..................: 0 B     0 B/s
    data_sent......................: 0 B     0 B/s
    iteration_duration.............: avg=459.31ms min=188.19ms med=456.26ms max=733.67ms p(90)=543.22ms p(95)=572.76ms
    iterations.....................: 6554    108.563093/s
    kafka.reader.dial.count........: 6554    108.563093/s
    kafka.reader.error.count.......: 0       0/s
    kafka.reader.fetches.count.....: 6554    108.563093/s
    kafka.reader.message.bytes.....: 6.4 MB  106 kB/s
    kafka.reader.message.count.....: 77825   1289.124612/s
    kafka.reader.rebalance.count...: 0       0/s
    kafka.reader.timeouts.count....: 0       0/s
    kafka.writer.dial.count........: 6554    108.563093/s
    kafka.writer.error.count.......: 0       0/s
    kafka.writer.message.bytes.....: 54 MB   890 kB/s
    kafka.writer.message.count.....: 655400  10856.309293/s
    kafka.writer.rebalance.count...: 6554    108.563093/s
    kafka.writer.write.count.......: 655400  10856.309293/s
    vus............................: 50      min=50   max=50
    vus_max........................: 50      min=50   max=50

Documentation

Index

• type PG
  • func (*PG) Close(client *sql.DB)
  • func (*PG) Get(client *sql.DB, query string) (*sql.Rows, error)
  • func (*PG) Insert(client *sql.DB, query string)
  • func (*PG) NewClient(conninfo string) (*sql.DB, error)

Types

type PG

type PG struct{}

PG is the k6 extension for a PG connection.

func (*PG) Close

func (*PG) Close(client *sql.DB)

Close closes the db connection

func (*PG) Get

func (*PG) Get(client *sql.DB, query string) (*sql.Rows, error)

Get returns the value for the given key.

func (*PG) Insert

func (*PG) Insert(client *sql.DB, query string)

Insert the given key with the given value and expiration time.

func (*PG) NewClient

func (*PG) NewClient(conninfo string) (*sql.DB, error)

NewClient creates a new PG client with the provided options.