Merge pull request #1525 from sgeorgakis/master

[SCALA-622] Logging in ZIO app

build.sbt

@@ -680,6 +680,13 @@ lazy val zio2 = (project in file("zio-2"))
     libraryDependencies += "dev.zio" %% "zio-json" % "0.7.3",
     libraryDependencies += "dev.zio" %% "zio-test" % zioVersion % Test,
     libraryDependencies += "dev.zio" %% "zio-test-sbt" % zioVersion % Test,
+    libraryDependencies += "dev.zio" %% "zio-logging" % "2.1.10",
+    libraryDependencies += "dev.zio" %% "zio-logging-slf4j2" % "2.1.10",
+    libraryDependencies += "ch.qos.logback" % "logback-classic" % "1.5.6",
+//    used in the article, but can't work with zio-logging-slf4j2 dependency
+//    libraryDependencies += "dev.zio" %% "zio-logging-slf4j2-bridge" % "2.1.10",
+    libraryDependencies += "dev.zio" %% "zio-metrics-connectors" % "2.1.0",
+    libraryDependencies += "dev.zio" %% "zio-metrics-connectors-prometheus" % "2.1.0",
     libraryDependencies ++= scalaTestDeps,
     testFrameworks += new TestFramework("zio.test.sbt.ZTestFramework")
   )

zio-2/src/main/resources/logback.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+        </encoder>
+    </appender>
+    <root level="info">
+        <appender-ref ref="STDOUT"/>
+    </root>
+</configuration>

zio-2/src/main/scala/com/baeldung/scala/zio/logging/BaeldungLogger.scala

@@ -0,0 +1,49 @@
+package com.baeldung.scala.zio.logging
+
+import zio.*
+import zio.logging.backend.SLF4J
+import zio.logging.{
+  LogColor,
+  LogFilter,
+  LogFormat,
+  LoggerNameExtractor,
+  console,
+  fileJson
+}
+import zio.logging.LogFormat.*
+
+import java.nio.file.Path
+import java.time.format.DateTimeFormatter
+
+object BaeldungLogger {
+
+  private val filter =
+    LogFilter.logLevelByName(
+      LogLevel.Trace,
+      ("com.baeldung.scala.zio.logging", LogLevel.Info)
+    )
+
+  private val logFormat: LogFormat = timestamp(
+    DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ssAZ")
+  ).highlight(_ => LogColor.BLUE)
+    |-| bracketStart |-| LogFormat.loggerName(
+      LoggerNameExtractor.trace
+    ) |-| text(":") |-| traceLine |-| bracketEnd |-|
+    fiberId |-| level.highlight |-| label("message", quoted(line)).highlight
+
+  val consoleLogger: ULayer[Unit] =
+    Runtime.removeDefaultLoggers >>> console(logFormat, filter)
+
+  val fileLogger: ULayer[Unit] = Runtime.removeDefaultLoggers >>> fileJson(
+    Path.of("baeldung-zio-logging.log"),
+    logFormat,
+    LogLevel.Debug
+  )
+
+  val slf4jLogger: ULayer[Unit] = Runtime.removeDefaultLoggers >>> SLF4J.slf4j
+
+//  val slf4jBridgeLogger: ULayer[Unit] = Runtime.removeDefaultLoggers >>> Slf4jBridge.initialize
+
+  val combinedLogger: ULayer[Unit] = consoleLogger ++ fileLogger
+
+}

zio-2/src/main/scala/com/baeldung/scala/zio/logging/BaeldungMetricsLogger.scala

@@ -0,0 +1,26 @@
+package com.baeldung.scala.zio.logging
+
+import zio.*
+import zio.logging.*
+import zio.metrics.connectors.MetricsConfig
+import zio.metrics.connectors.prometheus.{
+  PrometheusPublisher,
+  prometheusLayer,
+  publisherLayer
+}
+
+import java.io.IOException
+
+object BaeldungMetricsLogger {
+
+  private val prometheusConnector
+    : ZLayer[Unit, IOException, PrometheusPublisher] = (ZLayer.succeed(
+    MetricsConfig(10.millis)
+  ) ++ publisherLayer) >+> prometheusLayer
+  val metricsLogger: ZLayer[Unit, IOException, PrometheusPublisher] =
+    logMetrics ++ logMetricsWith(
+      "custom_log_counter",
+      "log_level"
+    ) ++ prometheusConnector
+
+}

zio-2/src/main/scala/com/baeldung/scala/zio/logging/BaeldungZIOLoggingApp.scala

@@ -0,0 +1,23 @@
+package com.baeldung.scala.zio.logging
+
+import zio.*
+import zio.metrics.connectors.prometheus.PrometheusPublisher
+
+object BaeldungZIOLoggingApp extends ZIOAppDefault {
+
+  val app: ZIO[PrometheusPublisher, Any, Unit] = for {
+    - <- ZIO.logTrace("This is a trace message")
+    _ <- ZIO.logDebug("This is a debug message")
+    _ <- ZIO.logInfo("This is an info message")
+    _ <- ZIO.logWarning("This is a warning message")
+    _ <- ZIO.logError("This is an error message")
+    _ <- ZIO.sleep(500.millis)
+    metricValues <- ZIO.serviceWithZIO[PrometheusPublisher](_.get)
+    _ <- Console.printLine(metricValues)
+  } yield ()
+
+  override def run: ZIO[ZIOAppArgs & Scope, Any, Any] =
+    app.provideLayer(
+      BaeldungLogger.slf4jLogger >>> BaeldungMetricsLogger.metricsLogger
+    )
+}

zio-2/src/test/scala/com/baeldung/scala/zio/logging/BaeldungZIOLoggingUnitTest.scala

@@ -0,0 +1,45 @@
+package com.baeldung.scala.zio.logging
+
+import zio.{Chunk, LogLevel, ZIO}
+import zio.test.Assertion.*
+import zio.test.*
+import zio.*
+
+object BaeldungZIOLoggingUnitTest extends ZIOSpecDefault {
+
+  override def spec: Spec[TestEnvironment, Any] =
+    suite("BaeldungZIOLoggingSpec")(
+      test("log trace level") {
+        for {
+          - <- ZIO.logTrace("This is a trace message")
+          _ <- ZIO.logDebug("This is a debug message")
+          _ <- ZIO.logInfo("This is an info message")
+          _ <- ZIO.logWarning("This is a warning message")
+          _ <- ZIO.logError("This is an error message")
+          loggerOutput <- ZTestLogger.logOutput
+        } yield assertTrue(loggerOutput.size == 5) &&
+          assert(loggerOutput.map(_.logLevel))(
+            equalTo(
+              Chunk(
+                LogLevel.Trace,
+                LogLevel.Debug,
+                LogLevel.Info,
+                LogLevel.Warning,
+                LogLevel.Error
+              )
+            )
+          ) &&
+          assert(loggerOutput.map(_.message()))(
+            equalTo(
+              Chunk(
+                "This is a trace message",
+                "This is a debug message",
+                "This is an info message",
+                "This is a warning message",
+                "This is an error message"
+              )
+            )
+          )
+      }
+    ).provideLayer(Runtime.removeDefaultLoggers >>> ZTestLogger.default)
+}