feral.lambda.natchez.TracedLambda.scala Maven / Gradle / Ivy

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/*
 * Copyright 2021 Typelevel
 *
 * 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 feral.lambda.natchez

import cats.effect.kernel.MonadCancelThrow
import cats.syntax.all._
import feral.lambda.Lambda
import natchez.EntryPoint
import natchez.Span
import natchez.Trace

object TracedLambda {

  def apply[F[_]: MonadCancelThrow, G[_], Event: HasKernel, Result](entryPoint: EntryPoint[F])(
      lambda: Trace[G] => Lambda[G, Event, Result]
  )(implicit lift: LiftTrace[F, G]): Lambda[F, Event, Result] =
    viaSpan(entryPoint) { span => (event, context) =>
      lift.run(span)(lambda(_)(event, context.mapK(lift.liftK)))
    }

  def viaSpan[F[_]: MonadCancelThrow, Event: HasKernel, Result](entryPoint: EntryPoint[F])(
      lambda: Span[F] => Lambda[F, Event, Result]): Lambda[F, Event, Result] = {
    (event, context) =>
      val kernel = HasKernel[Event].extract(event)
      entryPoint.continueOrElseRoot(context.functionName, kernel).use { span =>
        span.put(
          Tags.arn(context.invokedFunctionArn),
          Tags.requestId(context.awsRequestId)
        ) >> lambda(span)(event, context)
      }
  }

}