feat: Add subproject micrometer with generic PrefixMeterFilter (#219)

* feat: Add subproject micrometer with generic PrefixMeterFilter

feat: Add more configuration options to MicrometerStatsDModule

fix: prefix was not what it was meant to be

* fix: compilation issue

build.sbt

@@ -36,6 +36,7 @@ lazy val root = project
     jvm,
     jvmMicrometer,
     jvmPureConfig,
+    micrometer,
     micrometerJmx,
     micrometerJmxPureConfig,
     micrometerStatsD,
@@ -296,6 +297,17 @@ lazy val jvmPureConfig = project
     libraryDependencies += Dependencies.pureConfig
   )
 
+lazy val micrometer = project
+  .in(file("micrometer"))
+  .settings(BuildSettings.common)
+  .settings(
+    name := "sst-micrometer",
+    libraryDependencies ++= Seq(
+      Dependencies.micrometerCore,
+      Dependencies.jsr305 // required because of Scala compiler
+    )
+  )
+
 lazy val micrometerJmx = project
   .in(file("micrometer-jmx"))
   .settings(BuildSettings.common)
@@ -318,6 +330,7 @@ lazy val micrometerJmxPureConfig = project
 
 lazy val micrometerStatsD = project
   .in(file("micrometer-statsd"))
+  .dependsOn(micrometer)
   .settings(BuildSettings.common)
   .settings(
     name := "sst-micrometer-statsd",

micrometer-statsd/src/main/scala/com/avast/sst/micrometer/statsd/MicrometerStatsDConfig.scala

@@ -17,5 +17,6 @@ final case class MicrometerStatsDConfig(
     step: Duration = Duration(1, TimeUnit.MINUTES),
     publishUnchangedMeters: Boolean = true,
     buffered: Boolean = true,
-    prefix: String = "statsd"
+    prefix: String = "",
+    commonTags: Map[String, String] = Map.empty
 )

micrometer-statsd/src/main/scala/com/avast/sst/micrometer/statsd/MicrometerStatsDModule.scala

@@ -3,7 +3,9 @@ package com.avast.sst.micrometer.statsd
 import java.time.Duration
 
 import cats.effect.{Resource, Sync}
+import com.avast.sst.micrometer.PrefixMeterFilter
 import io.micrometer.core.instrument.Clock
+import io.micrometer.core.instrument.config.{MeterFilter, NamingConvention}
 import io.micrometer.core.instrument.util.HierarchicalNameMapper
 import io.micrometer.statsd.{StatsdConfig, StatsdFlavor, StatsdMeterRegistry, StatsdProtocol}
 
@@ -13,24 +15,40 @@ object MicrometerStatsDModule {
   def make[F[_]: Sync](
       config: MicrometerStatsDConfig,
       clock: Clock = Clock.SYSTEM,
-      nameMapper: HierarchicalNameMapper = HierarchicalNameMapper.DEFAULT
+      nameMapper: HierarchicalNameMapper = HierarchicalNameMapper.DEFAULT,
+      namingConvention: Option[NamingConvention] = None,
+      meterFilter: Option[MeterFilter] = None
   ): Resource[F, StatsdMeterRegistry] = {
     Resource
       .make {
         Sync[F].delay {
-          StatsdMeterRegistry
+          val registry = StatsdMeterRegistry
             .builder(new CustomStatsdConfig(config))
             .clock(clock)
             .nameMapper(nameMapper)
             .build
+
+          namingConvention.foreach(registry.config().namingConvention)
+
+          if (config.prefix.nonEmpty) {
+            registry.config().meterFilter(new PrefixMeterFilter(config.prefix))
+          }
+
+          meterFilter.foreach(registry.config().meterFilter)
+
+          val preprocessedTags = config.commonTags.foldRight(List.empty[String]) {
+            case (tag, acc) =>
+              tag._1 :: tag._2 :: acc
+          }
+          registry.config().commonTags(preprocessedTags: _*)
+
+          registry
         }
       }(registry => Sync[F].delay(registry.close()))
   }
 
   private class CustomStatsdConfig(c: MicrometerStatsDConfig) extends StatsdConfig {
 
-    override val prefix: String = c.prefix
-
     override val flavor: StatsdFlavor = c.flavor
 
     override val enabled: Boolean = c.enabled

micrometer/src/main/scala/com/avast/sst/micrometer/PrefixMeterFilter.scala

@@ -0,0 +1,10 @@
+package com.avast.sst.micrometer
+
+import io.micrometer.core.instrument.Meter
+import io.micrometer.core.instrument.config.MeterFilter
+
+class PrefixMeterFilter(prefix: String) extends MeterFilter {
+
+  override def map(id: Meter.Id): Meter.Id = id.withName(s"$prefix${id.getName}")
+
+}

micrometer/src/test/scala/com/avast/sst/micrometer/PrefixMeterFilterTest.scala

@@ -0,0 +1,16 @@
+package com.avast.sst.micrometer
+
+import io.micrometer.core.instrument.simple.SimpleMeterRegistry
+import org.scalatest.funsuite.AnyFunSuite
+
+class PrefixMeterFilterTest extends AnyFunSuite {
+
+  test("prefixing") {
+    val registry = new SimpleMeterRegistry
+    registry.config().meterFilter(new PrefixMeterFilter("this.is.prefix."))
+    val counter = registry.counter("test")
+
+    assert(counter.getId.getName === "this.is.prefix.test")
+  }
+
+}