/*
* Copyright 2019 Jack Henry & Associates, Inc.®
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.banno.kafka.metrics.prometheus
import cats.effect.Sync
import cats.implicits._
import org.apache.kafka.clients.consumer.ConsumerRecord
import io.prometheus.client._
import scala.math.max
object CurrentOffsetCounter {
def apply[F[_]](cr: CollectorRegistry, prefix: String, clientId: String)(
implicit F: Sync[F]
): F[ConsumerRecord[_, _] => F[Unit]] =
F.delay {
Counter
.build()
.name(prefix + "_current_offset")
.help("Counter for last consumed (not necessarily committed) offset of topic partition.")
.labelNames("client_id", "topic", "partition")
.register(cr)
}
.map { counter => (record: ConsumerRecord[_, _]) =>
for {
value <- F.delay(counter.labels(clientId, record.topic, record.partition.toString).get)
delta = max(0, record.offset.toDouble - value)
_ <- F.delay(counter.labels(clientId, record.topic, record.partition.toString).inc(delta))
} yield ()
}
}
