README.md

go-kafka-checker

An Apache Kafka checker for InVisionApp go-health.

How it works

The Apache Kafka checker implements a simple roundtrip check that sends a random message to a specific topic and checks that the message is received within the time specified in the configuration.

Installation

go get github.com/3rs4lg4d0/go-kafka-checker

Usage

// Create a new health instance.
h := health.New()

// Create a kafka check skipping the first three consumer timeouts (as maximum) if any.
kafkaCheck, err := kafka.NewKafka(kafka.KafkaConfig{
	BootstrapServers:     "localhost:19092",
	SkipConsumerTimeouts: 3,
})

You have a complete example here.

Configuration

You can configure the checker using the KafkaConfig struct.

type KafkaConfig struct {
    BootstrapServers     string
    Topic                string
    PollTimeout          time.Duration
    CheckTimeout         time.Duration
    SkipConsumerTimeouts int
    ConsumerConfig       map[string]any
    ProducerConfig       map[string]any
}

Property	Type	Default value	Description
BootstrapServers	string	-	Coma separated list of kafka brokers. This property is mandatory.
Topic	string	health-checks	Topic to connect to (make sure it exists).
PollTimeout	time.Duration	200 ms	The maximum time spent fetching data from the topic.
CheckTimeout	time.Duration	1000 ms	The maximum time to wait for the check to complete.
SkipConsumerTimeouts	int	0	Maximum number of check timeouts to skip at the beginning when consuming messages.
ConsumerConfig	map[string]any	0	Consumer configuration (see librdkafka/CONFIGURATION.md).
ProducerConfig	map[string]any	0	Producer configuration (see librdkafka/CONFIGURATION.md).

SkipConsumerTimeouts can be a useful property to avoid some unhealthy results because joining to a consumer group and receiving a partition assignment can take some time. So if you provide a value for this property greater than zero, for the first n checks (as maximum), if any timeout happens when consuming messages, you will see an output like this:

{
  "details": {
    "kafka-check": {
      "name": "kafka-check",
      "status": "ok",
      "fatal": true,
      "details": {
        "info": "skipped check timeout (2 remaining)"
      },
      "check_time": "2023-10-17T00:48:57.51717+02:00",
      "num_failures": 0,
      "first_failure_at": "0001-01-01T00:00:00Z"
    }
  },
  "status": "ok"
}

If another type of error happens during the first checks (e.g. a Kafka error), even if you set this property to a value greater than zero, SkipConsumerTimeouts is internally set to zero. This also happens as soon as a check completes successfully.

With ConsumerConfig and ProducerConfig you can provide specific configuration (e.g. security) but the following properties will be ignored (because they are internally set by the Kafka checker):

• bootstrap.servers
• group.id
• auto.offset.reset