Merge pull request #553 from yadavan88/scala-logging

Scala logging

Author: dominiqueplante

build.sbt

@@ -7,7 +7,7 @@ ThisBuild / organizationName := "core-scala"
 val jUnitInterface = "com.novocode" % "junit-interface" % "0.11" % "test"
 val catsEffect = "org.typelevel" %% "cats-effect" % "3.4.5"
 val scalaReflection = "org.scala-lang" % "scala-reflect" % scalaV
-val logback = "ch.qos.logback" % "logback-classic" % "1.2.3"
+val logback = "ch.qos.logback" % "logback-classic" % "1.3.5"
 
 val scalaTestDeps = Seq(
   "org.scalatest" %% "scalatest" % "3.2.15" % Test,
@@ -156,7 +156,7 @@ lazy val scala_test = (project in file("scala-test"))
 
 lazy val scala_akka_dependencies: Seq[ModuleID] = Seq(
   "com.typesafe.akka" %% "akka-actor-typed" % "2.6.19",
-  logback,
+  "ch.qos.logback" % "logback-classic" % "1.2.3",
   "com.typesafe.akka" %% "akka-actor-testkit-typed" % "2.6.19" % Test,
   "com.lightbend.akka" %% "akka-stream-alpakka-mongodb" % "2.0.1",
   "com.typesafe.akka" %% "akka-stream" % "2.6.19",
@@ -328,7 +328,9 @@ lazy val scala_libraries_4 = (project in file("scala-libraries-4"))
       scalaReflection % Provided,
       "org.tpolecat" %% "skunk-core" % "0.3.2",
       sparkSqlDep,
-      sparkCoreDep
+      sparkCoreDep,
+      logback,
+      "com.typesafe.scala-logging" %% "scala-logging" % "3.9.5"
     ),
     libraryDependencies ++= Seq(
       "com.clever-cloud.pulsar4s" %% "pulsar4s-core" % "2.9.0",

scala-libraries-4/src/main/resources/logback.xml

@@ -0,0 +1,10 @@
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} -%kvp- %msg%n</pattern>
+        </encoder>
+    </appender>
+    <root level="trace">
+        <appender-ref ref="STDOUT"/>
+    </root>
+</configuration>

scala-libraries-4/src/main/scala/com/baeldung/scala/logging/ScalaLoggingSample.scala

@@ -0,0 +1,61 @@
+package com.baeldung.scala.logging
+
+import com.typesafe.scalalogging.{CanLog, LazyLogging, Logger, StrictLogging}
+import org.slf4j.LoggerFactory
+
+class ScalaLoggingSample {
+
+  val loggerV1 = Logger("BaeldungLogger")
+  val loggerV2 = Logger(getClass.getName)
+  val loggerV3 = Logger(classOf[ScalaLoggingSample])
+  val loggerV4 = Logger[ScalaLoggingSample]
+  val loggerV5 = Logger(LoggerFactory.getLogger("FromSlf4jLogger"))
+
+}
+case class RequestId(id: String)
+
+object LoggingImplicits {
+  implicit case object WithRequestId extends CanLog[RequestId] {
+    override def logMessage(originalMsg: String, a: RequestId): String =
+      s"[REQ: ${a.id}] $originalMsg"
+  }
+}
+
+object TestApp extends App {
+  val sample = new ScalaLoggingSample
+  sample.loggerV1.info("This is an info message")
+  sample.loggerV2.error("This is an error message")
+  sample.loggerV3.warn("This is a warning message")
+  sample.loggerV4.debug("This is a debug message")
+  sample.loggerV5.trace("This is a trace message")
+
+  sample.loggerV5.whenDebugEnabled {
+    println("This block is executed only if logger level is DEBUG")
+  }
+
+  def contextUsageMethod = {
+    import LoggingImplicits._
+    val ctxLogger = Logger.takingImplicit[RequestId]("ContextLogger")
+    implicit val reqId = RequestId("user-1234")
+    println()
+    println()
+    println()
+    val message = "This is a message with user request context"
+    ctxLogger.info(message)
+  }
+
+  contextUsageMethod
+
+  val country = "India"
+  val capital = "NewDelhi"
+  sample.loggerV5.info(s"$capital is the capital of $country")
+  val slf4jLogger = sample.loggerV5.underlying
+  slf4jLogger.info("{} is the capital of {}", capital, country)
+}
+
+class LazyLoggingSample extends LazyLogging {
+  logger.info("This is from lazy logging")
+}
+class StrictLoggingSample extends StrictLogging {
+  logger.info("This is from strict logging")
+}