Add appendLoggerName aspect (#893)

core/jvm/src/test/scala/zio/logging/AppendLoggerNameSpec.scala

@@ -0,0 +1,19 @@
+package zio.logging
+
+import zio.ZIO
+import zio.logging.appendLoggerName
+import zio.test._
+
+object AppendLoggerNameSpec extends ZIOSpecDefault {
+
+  val spec: Spec[Environment, Any] = suite("AppendLoggerNameSpec")(
+    test("appendLoggerName") {
+      for {
+        name <- ZIO.logAnnotations.map(annotations => annotations.get(loggerNameAnnotationKey)) @@ appendLoggerName(
+                  "logging"
+                ) @@ appendLoggerName("zio")
+
+      } yield assertTrue(name == Some("zio.logging"))
+    }
+  )
+}

core/shared/src/main/scala/zio/logging/package.scala

@@ -54,6 +54,31 @@ package object logging extends LoggerLayers {
   def loggerName(value: String): ZIOAspect[Nothing, Any, Nothing, Any, Nothing, Any] =
     ZIOAspect.annotated(loggerNameAnnotationKey, value)
 
+  /**
+   * Logger name aspect, by this aspect is possible to set logger name (in general, logger name is extracted from [[Trace]])
+   *
+   * annotation key: [[zio.logging.loggerNameAnnotationKey]]
+   */
+  def loggerName(fn: Option[String] => String): ZIOAspect[Nothing, Any, Nothing, Any, Nothing, Any] =
+    new ZIOAspect[Nothing, Any, Nothing, Any, Nothing, Any] {
+      def apply[R, E, A](zio: ZIO[R, E, A])(implicit trace: Trace): ZIO[R, E, A] =
+        for {
+          annotations      <- ZIO.logAnnotations
+          currentLoggerName = annotations.get(loggerNameAnnotationKey)
+          newLoggerName     = fn(currentLoggerName)
+          a                <- ZIO.logAnnotate(loggerNameAnnotationKey, newLoggerName)(zio)
+        } yield a
+    }
+
+  /**
+   * Append logger name aspect, by which it is possible to append a logger name to the current logger name.
+   * The new name is appended using a dot (.) as the delimiter.
+   *
+   * annotation key: [[zio.logging.loggerNameAnnotationKey]]
+   */
+  def appendLoggerName(value: String): ZIOAspect[Nothing, Any, Nothing, Any, Nothing, Any] =
+    loggerName(currentLoggerName => currentLoggerName.fold(value)(currentLoggerName => s"$currentLoggerName.$value"))
+
   implicit final class LogAnnotationZIOSyntax[R, E, A](private val self: ZIO[R, E, A]) {
     def logAnnotate[V: Tag](key: LogAnnotation[V], value: V): ZIO[R, E, A] =
       self @@ key(value)