ZIO learning - using zio logging great features with log4j2 / published by https://github.com/dacr/code-examples-manager #fc148a1e-4e3a-461c-b4fe-24e8a2cf4c0d/4e6bdd90842b259197f6c51bd461448c33d7711e

zio-learning-logging-3-features-with-log4j2.sc

// summary : ZIO learning - using zio logging great features with log4j2
// keywords : scala, zio, learning, logging, pure-functional, log4j2, mdc, @testable
// publish : gist
// authors : David Crosson
// license : Apache NON-AI License Version 2.0 (https://raw.githubusercontent.com/non-ai-licenses/non-ai-licenses/main/NON-AI-APACHE2)
// id : fc148a1e-4e3a-461c-b4fe-24e8a2cf4c0d
// created-on : 2023-05-09T07:33:28+02:00
// managed-by : https://github.com/dacr/code-examples-manager
// run-with : scala-cli $file

// ---------------------
//> using scala "3.4.2"
//> using dep "dev.zio::zio:2.0.13"
//> using dep "dev.zio::zio-logging:2.1.13"
//> using dep "dev.zio::zio-logging-slf4j2:2.1.13"
//> using dep "org.apache.logging.log4j:log4j-api:2.20.0"
//> using dep "org.apache.logging.log4j:log4j-core:2.20.0"
//> using dep "org.apache.logging.log4j:log4j-slf4j2-impl:2.20.0"
// ---------------------

import zio.*
import zio.logging.*
import ZIOAspect.*
import zio.logging.{LogFormat, removeDefaultLoggers}
import zio.logging.backend.{SLF4J}

// =====================================================================================================================

object LogBackHelpers {

  import org.slf4j.{Logger, LoggerFactory}
  import org.apache.logging.log4j.{LogManager, Level}
  import org.apache.logging.log4j.core.config.*

  def configureLogBack(xmlConfig: String): Unit = {
    val configStream = new java.io.ByteArrayInputStream(xmlConfig.getBytes)
    val source       = new ConfigurationSource(configStream);
    Configurator.initialize(null, source);
  }
}

val logConfig =
  """<?xml version="1.0" encoding="UTF-8"?>
    |<Configuration>
    |  <Appenders>
    |     <Console name="ConsoleOut">
    |       <PatternLayout>
    |           <!--<pattern>%highlight{%m - %MDC%n}{STYLE=Logback}</pattern>-->
    |           <pattern>%highlight{%d{ISO8601}{GMT+0}Z [%t] %level %logger{18} func:%M - L:%L - %m - %MDC%n}{STYLE=Logback}</pattern>
    |    <!--   <pattern>%highlight{%d{ISO8601}{GMT+0}Z [%t] %level %logger{18} func:%M - L:%L - %m - %MAP%n}{STYLE=Logback}</pattern> -->
    |       </PatternLayout>
    |     </Console>
    |  </Appenders>
    |  <Loggers>
    |      <Logger name="com.example" level="info"/>
    |      <Root level="info">
    |          <AppenderRef ref="ConsoleOut"/>
    |      </Root>
    |  </Loggers>
    |</Configuration>
    |""".stripMargin

import LogBackHelpers._
configureLogBack(logConfig)

// =====================================================================================================================

object Encapsulated extends ZIOAppDefault {

  override val bootstrap = removeDefaultLoggers ++ SLF4J.slf4j

  val doThat =
    ZIO.logSpan("doThat") {
      ZIO.succeed(true) @@ logged("result")
    }

  val getIt =
    ZIO.logSpan("processThat") {
      for {
        x <- ZIO.succeed(42)
        _ <- doThat
        _ <- ZIO.logInfo(s"$x has been received")
      } yield x
    }

  val myapp =
    ZIO.logSpan("myapp") {
      for {
        _      <- ZIO.logInfo("Application has started")
        _      <- ZIO.logWarning("Configuration is wrong")
        userId <- Random.nextUUID
        result <- getIt @@ annotated("userId" -> userId.toString) @@ logged("getIt result") // The result is appended :) Great !!!
        _      <- ZIO.logInfo("Application has finished")
      } yield ()
    }

  def run = myapp
}

Encapsulated.main(Array.empty)