Split project into modules (#39)

.github/workflows/ci.yml

@@ -94,11 +94,11 @@ jobs:
 
       - name: Make target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
-        run: mkdir -p target .js/target site/target core/.js/target core/.jvm/target .jvm/target .native/target java/.jvm/target testkit/jvm/target project/target
+        run: mkdir -p testkit/metrics/jvm/target java/metrics/target testkit/common/jvm/target target core/common/.jvm/target .js/target site/target core/metrics/.jvm/target core/all/.js/target java/all/target java/common/target core/metrics/.js/target core/all/.jvm/target .jvm/target .native/target core/common/.js/target testkit/all/jvm/target project/target
 
       - name: Compress target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
-        run: tar cf targets.tar target .js/target site/target core/.js/target core/.jvm/target .jvm/target .native/target java/.jvm/target testkit/jvm/target project/target
+        run: tar cf targets.tar testkit/metrics/jvm/target java/metrics/target testkit/common/jvm/target target core/common/.jvm/target .js/target site/target core/metrics/.jvm/target core/all/.js/target java/all/target java/common/target core/metrics/.js/target core/all/.jvm/target .jvm/target .native/target core/common/.js/target testkit/all/jvm/target project/target
 
       - name: Upload target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')

build.sbt

@@ -21,57 +21,127 @@ val Scala213 = "2.13.8"
 ThisBuild / crossScalaVersions := Seq(Scala213, "3.1.3")
 ThisBuild / scalaVersion := Scala213 // the default Scala
 
+val CatsVersion = "2.8.0"
+val CatsEffectVersion = "3.3.14"
+val MUnitVersion = "0.7.29"
+val MUnitCatsEffectVersion = "1.0.7"
+val OpenTelemetryVersion = "1.15.0"
+
+lazy val scalaReflectDependency = Def.settings(
+  libraryDependencies ++= {
+    if (tlIsScala3.value) Nil
+    else Seq("org.scala-lang" % "scala-reflect" % scalaVersion.value % Provided)
+  }
+)
+
 lazy val root = tlCrossRootProject
-  .aggregate(core, testkit, java)
+  .aggregate(
+    `core-common`,
+    `core-metrics`,
+    core,
+    `testkit-common`,
+    `testkit-metrics`,
+    testkit,
+    `java-common`,
+    `java-metrics`,
+    java
+  )
   .settings(name := "otel4s")
 
+lazy val `core-common` = crossProject(JVMPlatform, JSPlatform)
+  .crossType(CrossType.Pure)
+  .in(file("core/common"))
+  .settings(
+    name := "otel4s-core-common",
+    libraryDependencies ++= Seq(
+      "org.typelevel" %%% "cats-core" % CatsVersion,
+      "org.scalameta" %%% "munit" % MUnitVersion % Test
+    )
+  )
+
+lazy val `core-metrics` = crossProject(JVMPlatform, JSPlatform)
+  .crossType(CrossType.Pure)
+  .in(file("core/metrics"))
+  .dependsOn(`core-common`)
+  .settings(scalaReflectDependency)
+  .settings(
+    name := "otel4s-core-metrics",
+    libraryDependencies ++= Seq(
+      "org.typelevel" %%% "cats-effect-kernel" % CatsEffectVersion,
+      "org.scalameta" %%% "munit" % MUnitVersion % Test,
+      "org.typelevel" %%% "munit-cats-effect-3" % MUnitCatsEffectVersion % Test,
+      "org.typelevel" %%% "cats-effect-testkit" % CatsEffectVersion % Test
+    )
+  )
+
 lazy val core = crossProject(JVMPlatform, JSPlatform)
   .crossType(CrossType.Pure)
-  .in(file("core"))
+  .in(file("core/all"))
+  .dependsOn(`core-common`, `core-metrics`)
+  .settings(
+    name := "otel4s-core"
+  )
+
+lazy val `testkit-common` = crossProject(JVMPlatform)
+  .crossType(CrossType.Full)
+  .in(file("testkit/common"))
+  .dependsOn(`core-common`)
   .settings(
-    name := "otel4s-core",
+    name := "otel4s-testkit-common"
+  )
+
+lazy val `testkit-metrics` = crossProject(JVMPlatform)
+  .crossType(CrossType.Full)
+  .in(file("testkit/metrics"))
+  .dependsOn(`testkit-common`, `core-metrics`)
+  .settings(
+    name := "otel4s-testkit-metrics"
+  )
+  .jvmSettings(
     libraryDependencies ++= Seq(
-      "org.typelevel" %%% "cats-core" % "2.8.0",
-      "org.typelevel" %%% "cats-effect" % "3.3.14",
-      "org.scalameta" %%% "munit" % "0.7.29" % Test,
-      "org.typelevel" %%% "munit-cats-effect-3" % "1.0.7" % Test,
-      "org.typelevel" %%% "cats-effect-testkit" % "3.3.14" % Test
-    ),
-    libraryDependencies ++= {
-      if (tlIsScala3.value) Nil
-      else
-        Seq("org.scala-lang" % "scala-reflect" % scalaVersion.value % Provided)
-    }
+      "io.opentelemetry" % "opentelemetry-api" % OpenTelemetryVersion,
+      "io.opentelemetry" % "opentelemetry-sdk" % OpenTelemetryVersion,
+      "io.opentelemetry" % "opentelemetry-sdk-testing" % OpenTelemetryVersion
+    )
   )
 
 lazy val testkit = crossProject(JVMPlatform)
   .crossType(CrossType.Full)
-  .in(file("testkit"))
+  .in(file("testkit/all"))
+  .dependsOn(`testkit-common`, `testkit-metrics`)
   .settings(
     name := "otel4s-testkit"
   )
-  .jvmSettings(
+
+lazy val `java-common` = project
+  .in(file("java/common"))
+  .dependsOn(`core-common`.jvm, `testkit-common`.jvm)
+  .settings(
+    name := "otel4s-java-common",
     libraryDependencies ++= Seq(
-      "io.opentelemetry" % "opentelemetry-api" % "1.15.0",
-      "io.opentelemetry" % "opentelemetry-sdk" % "1.15.0",
-      "io.opentelemetry" % "opentelemetry-sdk-testing" % "1.15.0"
+      "io.opentelemetry" % "opentelemetry-api" % OpenTelemetryVersion
     )
   )
-  .dependsOn(core)
 
-lazy val java = crossProject(JVMPlatform)
-  .crossType(CrossType.Pure)
-  .in(file("java"))
+lazy val `java-metrics` = project
+  .in(file("java/metrics"))
+  .dependsOn(`java-common`, `core-metrics`.jvm, `testkit-metrics`.jvm)
   .settings(
-    name := "otel4s-java",
+    name := "otel4s-java-metrics",
     libraryDependencies ++= Seq(
-      "io.opentelemetry" % "opentelemetry-api" % "1.15.0",
-      "io.opentelemetry" % "opentelemetry-sdk" % "1.15.0" % Test,
-      "io.opentelemetry" % "opentelemetry-sdk-testing" % "1.15.0" % Test,
-      "org.scalameta" %% "munit" % "0.7.29" % Test,
-      "org.typelevel" %% "munit-cats-effect-3" % "1.0.7" % Test
+      "io.opentelemetry" % "opentelemetry-api" % OpenTelemetryVersion,
+      "io.opentelemetry" % "opentelemetry-sdk" % OpenTelemetryVersion % Test,
+      "io.opentelemetry" % "opentelemetry-sdk-testing" % OpenTelemetryVersion % Test,
+      "org.scalameta" %% "munit" % MUnitVersion % Test,
+      "org.typelevel" %% "munit-cats-effect-3" % MUnitCatsEffectVersion % Test
     )
   )
-  .dependsOn(core, testkit)
+
+lazy val java = project
+  .in(file("java/all"))
+  .dependsOn(core.jvm, `java-metrics`)
+  .settings(
+    name := "otel4s-java"
+  )
 
 lazy val docs = project.in(file("site")).enablePlugins(TypelevelSitePlugin)

core/src/main/scala/org/typelevel/otel4s/Otel4s.scala → core/all/src/main/scala/org/typelevel/otel4s/Otel4s.scala

@@ -20,7 +20,7 @@ import org.typelevel.otel4s.metrics.MeterProvider
 
 trait Otel4s[F[_]] {
 
-  /** A registry for creating named [[org.typelevel.otel4s.metrics.Meter]].
+  /** A registry for creating named meters.
     */
   def meterProvider: MeterProvider[F]
 }

core/common/src/main/scala/org/typelevel/otel4s/meta/InstrumentMeta.scala

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s.meta
+
+import cats.Applicative
+
+trait InstrumentMeta[F[_]] {
+
+  /** Indicates whether instrumentation is enabled or not.
+    */
+  def isEnabled: Boolean
+
+  /** A no-op effect.
+    */
+  def unit: F[Unit]
+
+}
+
+object InstrumentMeta {
+
+  def enabled[F[_]: Applicative]: InstrumentMeta[F] =
+    make(enabled = true)
+
+  def disabled[F[_]: Applicative]: InstrumentMeta[F] =
+    make(enabled = false)
+
+  private def make[F[_]: Applicative](enabled: Boolean): InstrumentMeta[F] =
+    new InstrumentMeta[F] {
+      val isEnabled: Boolean = enabled
+      val unit: F[Unit] = Applicative[F].unit
+    }
+
+}

core/src/main/scala/org/typelevel/otel4s/metrics/InstrumentBackend.scala → core/common/src/test/scala/org/typelevel/otel4s/meta/InstrumentMetaSuite.scala

@@ -14,11 +14,24 @@
  * limitations under the License.
  */
 
-package org.typelevel.otel4s.metrics
+package org.typelevel.otel4s.meta
+
+import munit.FunSuite
+
+class InstrumentMetaSuite extends FunSuite {
+
+  test("enabled") {
+    val disabled = InstrumentMeta.enabled[cats.Id]
+
+    assertEquals(disabled.unit, ())
+    assertEquals(disabled.isEnabled, true)
+  }
+
+  test("disabled") {
+    val disabled = InstrumentMeta.disabled[cats.Id]
+
+    assertEquals(disabled.unit, ())
+    assertEquals(disabled.isEnabled, false)
+  }
 
-/** A backend that implements instrument operations: add, record, etc.
-  */
-trait InstrumentBackend[F[_]] {
-  def isEnabled: Boolean
-  def unit: F[Unit]
 }

core/src/main/scala-2/org/typelevel/otel4s/metrics/CounterMacro.scala → core/metrics/src/main/scala-2/org/typelevel/otel4s/metrics/CounterMacro.scala

@@ -29,13 +29,40 @@ private[otel4s] trait CounterMacro[F[_], A] {
     *   the set of attributes to associate with the value
     */
   def add(value: A, attributes: Attribute[_]*): F[Unit] =
-    macro MetricsMacro.add[A]
+    macro CounterMacro.add[A]
 
   /** Increments a counter by one.
     *
     * @param attributes
     *   the set of attributes to associate with the value
     */
   def inc(attributes: Attribute[_]*): F[Unit] =
-    macro MetricsMacro.inc
+    macro CounterMacro.inc
+
+}
+
+object CounterMacro {
+  import scala.reflect.macros.blackbox
+
+  def add[A](c: blackbox.Context)(
+      value: c.Expr[A],
+      attributes: c.Expr[Attribute[_]]*
+  ): c.universe.Tree = {
+    import c.universe._
+    val backend = q"${c.prefix}.backend"
+    val meta = q"$backend.meta"
+
+    q"if ($meta.isEnabled) $backend.add($value, ..$attributes) else $meta.unit"
+  }
+
+  def inc(c: blackbox.Context)(
+      attributes: c.Expr[Attribute[_]]*
+  ): c.universe.Tree = {
+    import c.universe._
+    val backend = q"${c.prefix}.backend"
+    val meta = q"$backend.meta"
+
+    q"if ($meta.isEnabled) $backend.inc(..$attributes) else $meta.unit"
+  }
+
 }

core/src/main/scala-2/org/typelevel/otel4s/metrics/HistogramMacro.scala → core/metrics/src/main/scala-2/org/typelevel/otel4s/metrics/HistogramMacro.scala

@@ -17,7 +17,7 @@
 package org.typelevel.otel4s
 package metrics
 
-import cats.effect.Resource
+import cats.effect.kernel.Resource
 
 import scala.concurrent.duration.TimeUnit
 
@@ -33,7 +33,7 @@ private[otel4s] trait HistogramMacro[F[_], A] {
     *   the set of attributes to associate with the value
     */
   def record(value: A, attributes: Attribute[_]*): F[Unit] =
-    macro MetricsMacro.record[A]
+    macro HistogramMacro.record[A]
 
   /** Records duration of the given effect.
     *
@@ -58,6 +58,33 @@ private[otel4s] trait HistogramMacro[F[_], A] {
       timeUnit: TimeUnit,
       attributes: Attribute[_]*
   ): Resource[F, Unit] =
-    macro MetricsMacro.recordDuration
+    macro HistogramMacro.recordDuration
+
+}
+
+object HistogramMacro {
+  import scala.reflect.macros.blackbox
+
+  def record[A](c: blackbox.Context)(
+      value: c.Expr[A],
+      attributes: c.Expr[Attribute[_]]*
+  ): c.universe.Tree = {
+    import c.universe._
+    val backend = q"${c.prefix}.backend"
+    val meta = q"$backend.meta"
+
+    q"if ($meta.isEnabled) $backend.record($value, ..$attributes) else $meta.unit"
+  }
+
+  def recordDuration(c: blackbox.Context)(
+      timeUnit: c.Expr[TimeUnit],
+      attributes: c.Expr[Attribute[_]]*
+  ): c.universe.Tree = {
+    import c.universe._
+    val backend = q"${c.prefix}.backend"
+    val meta = q"$backend.meta"
+
+    q"if ($meta.isEnabled) $backend.recordDuration($timeUnit, ..$attributes) else $meta.resourceUnit"
+  }
 
 }