trace: add @span macro

.github/workflows/ci.yml

@@ -30,7 +30,7 @@ jobs:
         os: [ubuntu-latest]
         scala: [2.13, 3]
         java: [temurin@8]
-        project: [rootJVM]
+        project: [rootJS, rootJVM, rootNative]
     runs-on: ${{ matrix.os }}
     timeout-minutes: 60
     steps:
@@ -63,6 +63,14 @@ jobs:
         if: matrix.java == 'temurin@8' && matrix.os == 'ubuntu-latest'
         run: sbt 'project ${{ matrix.project }}' '++ ${{ matrix.scala }}' 'scalafixAll --check'
 
+      - name: scalaJSLink
+        if: matrix.project == 'rootJS'
+        run: sbt 'project ${{ matrix.project }}' '++ ${{ matrix.scala }}' Test/scalaJSLinkerResult
+
+      - name: nativeLink
+        if: matrix.project == 'rootNative'
+        run: sbt 'project ${{ matrix.project }}' '++ ${{ matrix.scala }}' Test/nativeLink
+
       - name: Test
         run: sbt 'project ${{ matrix.project }}' '++ ${{ matrix.scala }}' test
 
@@ -76,11 +84,11 @@ 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 modules/metrics/jvm/target project/target
+        run: mkdir -p modules/trace/.jvm/target modules/trace/.js/target modules/metrics/jvm/target modules/trace/.native/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 modules/metrics/jvm/target project/target
+        run: tar cf targets.tar modules/trace/.jvm/target modules/trace/.js/target modules/metrics/jvm/target modules/trace/.native/target project/target
 
       - name: Upload target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
@@ -117,6 +125,16 @@ jobs:
         if: matrix.java == 'temurin@8' && steps.setup-java-temurin-8.outputs.cache-hit == 'false'
         run: sbt +update
 
+      - name: Download target directories (2.13, rootJS)
+        uses: actions/download-artifact@v4
+        with:
+          name: target-${{ matrix.os }}-${{ matrix.java }}-2.13-rootJS
+
+      - name: Inflate target directories (2.13, rootJS)
+        run: |
+          tar xf targets.tar
+          rm targets.tar
+
       - name: Download target directories (2.13, rootJVM)
         uses: actions/download-artifact@v4
         with:
@@ -127,6 +145,26 @@ jobs:
           tar xf targets.tar
           rm targets.tar
 
+      - name: Download target directories (2.13, rootNative)
+        uses: actions/download-artifact@v4
+        with:
+          name: target-${{ matrix.os }}-${{ matrix.java }}-2.13-rootNative
+
+      - name: Inflate target directories (2.13, rootNative)
+        run: |
+          tar xf targets.tar
+          rm targets.tar
+
+      - name: Download target directories (3, rootJS)
+        uses: actions/download-artifact@v4
+        with:
+          name: target-${{ matrix.os }}-${{ matrix.java }}-3-rootJS
+
+      - name: Inflate target directories (3, rootJS)
+        run: |
+          tar xf targets.tar
+          rm targets.tar
+
       - name: Download target directories (3, rootJVM)
         uses: actions/download-artifact@v4
         with:
@@ -137,6 +175,16 @@ jobs:
           tar xf targets.tar
           rm targets.tar
 
+      - name: Download target directories (3, rootNative)
+        uses: actions/download-artifact@v4
+        with:
+          name: target-${{ matrix.os }}-${{ matrix.java }}-3-rootNative
+
+      - name: Inflate target directories (3, rootNative)
+        run: |
+          tar xf targets.tar
+          rm targets.tar
+
       - name: Import signing key
         if: env.PGP_SECRET != '' && env.PGP_PASSPHRASE == ''
         env:

README.md

@@ -12,7 +12,7 @@
 * Provide access to the unstable functionality without breaking the `otel4s`
 * Some features may be upstreamed to the `otel4s` eventually
 
-## Getting started
+## Metrics - getting started
 
 Add the `otel4s-experimental-metrics` dependency to the `build.sbt`:
 ```scala
@@ -42,5 +42,49 @@ object Main extends IOApp.Simple {
 
 The metrics can be visualized in Grafana using this [dashboard][grafana-ce-dashboard].
 
+## Trace - getting started
+
+Add the `otel4s-experimental-trace` dependency to the `build.sbt`:
+```scala
+libraryDependencies ++= Seq(
+  "org.typelevel" %% "otel4s-experimental-trace" % "<version>"
+)
+```
+
+### 1) `@span` annotation
+
+The body of a method annotated with `@span` will be wrapped into a span:
+```scala
+import org.typelevel.otel4s.experimental.{attribute, trace}
+
+@span
+def findUser(
+  @attribute userId: Long, 
+  @attribute("user.hash") hash: String
+): F[User] = ???
+
+// expands into
+
+def findUser(
+    userId: Long, 
+    hash: String
+): F[User] = 
+  Tracer[F].span(
+    "findUser", 
+    Attribute("userId", userId), Attribute("user.hash", hash)
+  ).surround(???)
+```
+
+The macro works with variables too:
+```scala
+@span("custom_name")
+val findUser: IO[User] = ???
+
+// expands into
+
+val findUser: IO[User] = 
+  Tracer[IO].span("custom_name").surround(???)
+```
+
 [otel4s]: https://github.com/typelevel/otel4s
 [grafana-ce-dashboard]: https://grafana.com/grafana/dashboards/21487-cats-effect-runtime-metrics/

build.sbt

@@ -29,7 +29,7 @@ ThisBuild / scalaVersion       := Versions.Scala213 // the default Scala
 
 lazy val root = tlCrossRootProject
   .settings(name := "otel4s-experimental")
-  .aggregate(metrics)
+  .aggregate(metrics, trace)
 
 lazy val metrics = crossProject(JVMPlatform)
   .crossType(CrossType.Full)
@@ -39,12 +39,26 @@ lazy val metrics = crossProject(JVMPlatform)
     name        := "otel4s-experimental-metrics",
     Test / fork := true,
     libraryDependencies ++= Seq(
-      "org.typelevel" %%% "otel4s-core-metrics"        % Versions.Otel4s,
       "org.typelevel" %%% "otel4s-core-metrics"        % Versions.Otel4s,
       "org.typelevel" %%% "otel4s-sdk-metrics-testkit" % Versions.Otel4s % Test
     )
   )
 
+lazy val trace = crossProject(JVMPlatform, JSPlatform, NativePlatform)
+  .crossType(CrossType.Pure)
+  .in(file("modules/trace"))
+  .settings(munitDependencies)
+  .settings(scalaReflectDependency)
+  .settings(
+    name := "otel4s-experimental-trace",
+    libraryDependencies ++= Seq(
+      "org.typelevel" %%% "otel4s-core-trace" % Versions.Otel4s
+    ),
+    scalacOptions ++= {
+      if (tlIsScala3.value) Nil else Seq("-Ymacro-annotations")
+    }
+  )
+
 lazy val scalaReflectDependency = Def.settings(
   libraryDependencies ++= {
     if (tlIsScala3.value) Nil