/
metrics.scala
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/
metrics.scala
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/*
* Copyright 2018 http4s.org
*
* 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 org.http4s
package metrics
import cats.Applicative
import cats.effect.Sync
import cats.syntax.applicative._
import com.codahale.metrics.MetricRegistry
import com.codahale.metrics.json.MetricsModule
import com.fasterxml.jackson.databind.ObjectMapper
import java.util.concurrent.TimeUnit
package object dropwizard {
private val defaultMapper = {
val module = new MetricsModule(TimeUnit.SECONDS, TimeUnit.SECONDS, true)
new ObjectMapper().registerModule(module)
}
/** Encodes a metric registry in JSON format */
def metricRegistryEncoder[F[_]](
mapper: ObjectMapper = defaultMapper): EntityEncoder[F, MetricRegistry] =
EntityEncoder[F, String].contramap { metricRegistry =>
val writer = mapper.writerWithDefaultPrettyPrinter()
writer.writeValueAsString(metricRegistry)
}
/** Returns an OK response with a JSON dump of a MetricRegistry */
def metricsResponse[F[_]: Applicative](
registry: MetricRegistry,
mapper: ObjectMapper = defaultMapper): F[Response[F]] = {
implicit val encoder: EntityEncoder[F, MetricRegistry] = metricRegistryEncoder[F](mapper)
Response[F](Status.Ok).withEntity[MetricRegistry](registry).pure[F]
}
/** Returns an OK response with a JSON dump of a MetricRegistry */
def metricsService[F[_]: Sync](
registry: MetricRegistry,
mapper: ObjectMapper = defaultMapper): HttpRoutes[F] =
HttpRoutes.of {
case req if req.method == Method.GET => metricsResponse(registry, mapper)
}
}