= Kafka Health Check

This library provides a kafka health check for spring boot actuator.

== Usage

Add the following dependency to your `pom.xml`

[source,xml]
....
<dependency>
    <groupId>com.deviceinsight.kafka</groupId>
    <artifactId>kafka-health-check</artifactId>
    <version>0.1.0-SNAPSHOT</version>
</dependency>
....

In the same maven module you can configure the topic, poll timeouts, subscription timeouts and the receive timeouts
in the `application.yml`

An example for an `application.yaml` is:

[source,yaml]
....
kafka:
  health:
    topic: health-checks
    sendReceiveTimeoutMs: 2500
    pollTimeoutMs: 200
    subscriptionTimeoutMs: 5000
....

The values shown are the defaults.

IMPORTANT: Make sure the configured health check topic exists!

[source,java]
....
@Bean
@ConfigurationProperties("kafka.health")
public KafkaHealthProperties kafkaHealthProperties() {
    return new KafkaHealthProperties();
}
....

[source,java]
....
@Bean
public KafkaConsumingHealthIndicator kafkaConsumingHealthIndicator(KafkaHealthProperties kafkaProperties,
        KafkaProperties processingProperties) {
    return new KafkaConsumingHealthIndicator(kafkaHealthProperties, kafkaProperties.buildConsumerProperties(),
            kafkaProperties.buildProducerProperties());
}
....

Now if you call the actuator endpoint `actuator/health` you should see the following output:

[source,json]
....
{
   "status" : "UP",
   "details" : {
      "kafkaConsuming" : {
         "status" : "UP"
      }
   }
}
....

== Configuration

|===
|Property |Default |Description

|kafka.health.topic |`health-checks` | Topic to subscribe to
|kafka.health.sendReceiveTimeoutMs |2500 | The maximum time, in milliseconds, to wait for sending and receiving the message
|kafka.health.pollTimeoutMs |200 | The time, in milliseconds, spent fetching the data from the topic
|kafka.health.subscriptionTimeoutMs |5000 | The maximum time, in milliseconds, to wait for subscribing to topic

|===

== Releasing

Creating a new release involves the following steps:

. `./mvnw -DenableSshAgent=true jgitflow:release-start jgitflow:release-finish` +
[NOTE]
The `-DenableSshAgent=true` is only necessary, if you cloned the repository via SSH.
. `git push origin master`
. `git push --tags`
. `git push origin develop`

In order to deploy the release to Maven Central, you need to create an account at https://issues.sonatype.org and
configure your account in `~/.m2/settings.xml`:

[source,xml]
....
<settings>
  <servers>
    <server>
      <id>ossrh</id>
      <username>your-jira-id</username>
      <password>your-jira-pwd</password>
    </server>
  </servers>
</settings>
....

The account also needs access to the project on Maven Central. This can be requested by another project member.

Then check out the release you want to deploy (`git checkout x.y.z`) and run `./mvnw deploy -Prelease`.