Add helper methods for manual spans in mutiny pipelines

docs/src/main/asciidoc/opentelemetry-tracing.adoc

@@ -526,6 +526,60 @@ public void tracedWork() {
 }
 ----
 
+=== Mutiny
+Methods returning reactive types can also be annotated with `@WithSpan` and `@AddingSpanAttributes` to create a new span or add attributes to the current span.
+
+If you need to create spans manually within a mutiny pipeline, use `wrapWithSpan` method from `io.quarkus.opentelemetry.runtime.tracing.mutiny.MutinyTracingHelper`.
+
+Example. Assuming you have the following pipeline:
+[source,java]
+----
+Uni<String> uni = Uni.createFrom().item("hello")
+        //start trace here
+        .onItem().transform(item -> item + " world")
+        .onItem().transform(item -> item + "!")
+        //end trace here
+        .subscribe().with(
+                item -> System.out.println("Received: " + item),
+                failure -> System.out.println("Failed with " + failure)
+        );
+----
+wrap it like this:
+[source,java]
+----
+import static io.quarkus.opentelemetry.runtime.tracing.mutiny.MutinyTracingHelper.wrapWithSpan;
+...
+@Inject
+Tracer tracer;
+...
+Context context = Context.current();
+Uni<String> uni = Uni.createFrom().item("hello")
+        .transformToUni(m -> wrapWithSpan(tracer, Optional.of(context), "my-span-name",
+                                Uni.createFrom().item(m)
+                                    .onItem().transform(item -> item + " world")
+                                    .onItem().transform(item -> item + "!")
+        ))
+        .subscribe().with(
+                item -> System.out.println("Received: " + item),
+                failure -> System.out.println("Failed with " + failure)
+        );
+
+----
+for multi-pipelines it works similarly:
+[source,java]
+----
+Multi.createFrom().items("Alice", "Bob", "Charlie")
+        .transformToMultiAndConcatenate(m -> TracingHelper.withTrace("my-span-name",
+                                Multi.createFrom().item(m)
+                                    .onItem().transform(name -> "Hello " + name)
+        ))
+        .subscribe().with(
+                item -> System.out.println("Received: " + item),
+                failure -> System.out.println("Failed with " + failure)
+        );
+----
+Instead of `transformToMultiAndConcatenate` you can use `transformToMultiAndMerge` if you don't care about the order of the items.
+
 === Quarkus Messaging - Kafka
 
 When using the Quarkus Messaging extension for Kafka,

extensions/opentelemetry/deployment/pom.xml

@@ -90,6 +90,11 @@
             <artifactId>vertx-web-client</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>io.smallrye.reactive</groupId>
+            <artifactId>smallrye-mutiny-vertx-junit5</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>io.quarkus</groupId>
             <artifactId>quarkus-reactive-routes-deployment</artifactId>

extensions/opentelemetry/deployment/src/test/java/io/quarkus/opentelemetry/deployment/traces/MutinyTracingHelperTest.java

@@ -0,0 +1,313 @@
+package io.quarkus.opentelemetry.deployment.traces;
+
+import static io.quarkus.opentelemetry.runtime.tracing.mutiny.MutinyTracingHelper.wrapWithSpan;
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Stream;
+
+import jakarta.inject.Inject;
+
+import org.jboss.shrinkwrap.api.ShrinkWrap;
+import org.jboss.shrinkwrap.api.asset.StringAsset;
+import org.jboss.shrinkwrap.api.spec.JavaArchive;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.extension.RegisterExtension;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import io.opentelemetry.api.trace.Span;
+import io.opentelemetry.api.trace.Tracer;
+import io.opentelemetry.context.Scope;
+import io.opentelemetry.sdk.trace.data.SpanData;
+import io.quarkus.opentelemetry.deployment.common.exporter.TestSpanExporter;
+import io.quarkus.opentelemetry.deployment.common.exporter.TestSpanExporterProvider;
+import io.quarkus.opentelemetry.runtime.QuarkusContextStorage;
+import io.quarkus.test.QuarkusUnitTest;
+import io.smallrye.common.vertx.VertxContext;
+import io.smallrye.mutiny.Multi;
+import io.smallrye.mutiny.Uni;
+import io.smallrye.mutiny.helpers.test.AssertSubscriber;
+import io.smallrye.mutiny.helpers.test.UniAssertSubscriber;
+import io.vertx.core.Context;
+import io.vertx.core.Vertx;
+
+class MutinyTracingHelperTest {
+
+    @RegisterExtension
+    static final QuarkusUnitTest TEST = new QuarkusUnitTest()
+            .setArchiveProducer(
+                    () -> ShrinkWrap.create(JavaArchive.class)
+                            .addClasses(TestSpanExporter.class, TestSpanExporterProvider.class)
+                            .addAsResource(new StringAsset(TestSpanExporterProvider.class.getCanonicalName()),
+                                    "META-INF/services/io.opentelemetry.sdk.autoconfigure.spi.traces.ConfigurableSpanExporterProvider"));
+
+    @Inject
+    private TestSpanExporter spanExporter;
+
+    @Inject
+    private Tracer tracer;
+
+    @Inject
+    private Vertx vertx;
+
+    @AfterEach
+    void tearDown() {
+        spanExporter.reset();
+    }
+
+    @ParameterizedTest(name = "{index}: Simple uni pipeline {1}")
+    @MethodSource("generateContextRunners")
+    void testSimpleUniPipeline(final String contextType, final String contextName) {
+
+        final UniAssertSubscriber<String> subscriber = Uni.createFrom()
+                .item("Hello")
+                .emitOn(r -> runOnContext(r, vertx, contextType))
+                .onItem()
+                .transformToUni(m -> wrapWithSpan(tracer, "testSpan",
+                        Uni.createFrom().item(m).onItem().transform(s -> {
+                            final Span span = tracer.spanBuilder("subspan").startSpan();
+                            try (final Scope scope = span.makeCurrent()) {
+                                return s + " world";
+                            } finally {
+                                span.end();
+                            }
+                        })))
+                .subscribe()
+                .withSubscriber(new UniAssertSubscriber<>());
+
+        subscriber.awaitItem().assertItem("Hello world");
+
+        //ensure there are two spans with subspan as child of testSpan
+        final List<SpanData> spans = spanExporter.getFinishedSpanItems(2);
+        assertThat(spans.stream().map(SpanData::getName)).containsExactlyInAnyOrder("testSpan", "subspan");
+        assertChildSpan(spans, "testSpan", "subspan");
+    }
+
+    @ParameterizedTest(name = "{index}: Explicit parent {1}")
+    @MethodSource("generateContextRunners")
+    void testSpanWithExplicitParent(final String contextType, final String contextName) {
+
+        final String parentSpanName = "parentSpan";
+        final String pipelineSpanName = "pipelineSpan";
+        final String subspanName = "subspan";
+
+        final Span parentSpan = tracer.spanBuilder(parentSpanName).startSpan();
+        final io.opentelemetry.context.Context parentContext = io.opentelemetry.context.Context.current().with(parentSpan);
+
+        final UniAssertSubscriber<String> subscriber = Uni.createFrom()
+                .item("Hello")
+                .emitOn(r -> runOnContext(r, vertx, contextType))
+                .onItem()
+                .transformToUni(m -> wrapWithSpan(tracer, Optional.of(parentContext),
+                        pipelineSpanName,
+                        Uni.createFrom().item(m).onItem().transform(s -> {
+                            final Span span = tracer.spanBuilder(subspanName).startSpan();
+                            try (final Scope scope = span.makeCurrent()) {
+                                return s + " world";
+                            } finally {
+                                span.end();
+                            }
+                        })))
+                .subscribe()
+                .withSubscriber(new UniAssertSubscriber<>());
+
+        subscriber.awaitItem().assertItem("Hello world");
+        parentSpan.end();
+
+        //ensure there are 3 spans with proper parent-child relationships
+        final List<SpanData> spans = spanExporter.getFinishedSpanItems(3);
+        assertThat(spans.stream().map(SpanData::getName)).containsExactlyInAnyOrder(parentSpanName, pipelineSpanName,
+                subspanName);
+        assertChildSpan(spans, parentSpanName, pipelineSpanName);
+        assertChildSpan(spans, pipelineSpanName, subspanName);
+    }
+
+    @ParameterizedTest(name = "{index}: Nested uni pipeline with implicit parent {1}")
+    @MethodSource("generateContextRunners")
+    void testNestedPipeline_implicitParent(final String contextType,
+            final String contextName) {
+
+        final String parentSpanName = "parentSpan";
+        final String childSpanName = "childSpan";
+
+        final UniAssertSubscriber<String> subscriber = Uni.createFrom()
+                .item("test")
+                .emitOn(r -> runOnContext(r, vertx, contextType))
+                .onItem()
+                .transformToUni(m -> wrapWithSpan(tracer, parentSpanName,
+                        Uni.createFrom().item(m)
+                                .onItem().transform(s -> s + " in outer span")
+                                .onItem().transformToUni(m1 -> wrapWithSpan(tracer, childSpanName,
+                                        Uni.createFrom().item(m1)
+                                                .onItem().transform(s -> "now in inner span")))
+
+                ))
+                .subscribe()
+                .withSubscriber(new UniAssertSubscriber<>());
+
+        subscriber.awaitItem();
+
+        //ensure there are 2 spans with doSomething and doSomethingAsync as children of testSpan
+        final List<SpanData> spans = spanExporter.getFinishedSpanItems(2);
+        assertThat(spans.stream().map(SpanData::getName)).containsExactlyInAnyOrder(parentSpanName, childSpanName);
+        assertChildSpan(spans, parentSpanName, childSpanName);
+    }
+
+    @ParameterizedTest(name = "{index}: Nested uni pipeline with explicit no parent {1}")
+    @MethodSource("generateContextRunners")
+    void testNestedPipeline_explicitNoParent(final String contextType, final String contextName) {
+
+        final String parentSpanName = "parentSpan";
+        final String childSpanName = "childSpan";
+
+        final UniAssertSubscriber<String> subscriber = Uni.createFrom()
+                .item("test")
+                .emitOn(r -> runOnContext(r, vertx, contextType))
+                .onItem()
+                .transformToUni(m -> wrapWithSpan(tracer, parentSpanName,
+                        Uni.createFrom().item(m)
+                                .onItem().transform(s -> s + " in outer span")
+                                .onItem().transformToUni(m1 -> wrapWithSpan(tracer, Optional.empty(), childSpanName,
+                                        Uni.createFrom().item(m1)
+                                                .onItem().transform(s -> "now in inner span")))
+
+                ))
+                .subscribe()
+                .withSubscriber(new UniAssertSubscriber<>());
+
+        subscriber.awaitItem();
+
+        //ensure there are 2 spans but without parent-child relationship
+        final List<SpanData> spans = spanExporter.getFinishedSpanItems(2);
+        assertThat(spans.stream().map(SpanData::getName)).containsExactlyInAnyOrder(parentSpanName, childSpanName);
+        assertThat(spans.stream()
+                .filter(span -> span.getName().equals(childSpanName))
+                .findAny()
+                .orElseThrow()
+                .getParentSpanId()).isEqualTo("0000000000000000");//signifies no parent
+    }
+
+    @ParameterizedTest(name = "{index}: Concatenating multi pipeline {1}")
+    @MethodSource("generateContextRunners")
+    void testSimpleMultiPipeline_Concatenate(final String contextType, final String contextName) {
+
+        final AssertSubscriber<String> subscriber = Multi.createFrom()
+                .items("test1", "test2", "test3")
+                .emitOn(r -> runOnContext(r, vertx, contextType))
+                .onItem()
+                .transformToUniAndConcatenate(m -> wrapWithSpan(tracer, Optional.empty(), "testSpan " + m,
+                        //the traced pipeline
+                        Uni.createFrom().item(m).onItem().transform(s -> {
+                            final Span span = tracer.spanBuilder("subspan " + s).startSpan();
+                            try (final Scope scope = span.makeCurrent()) {
+                                return s + " transformed";
+                            } finally {
+                                span.end();
+                            }
+                        })))
+                .subscribe()
+                .withSubscriber(AssertSubscriber.create(3));
+
+        subscriber.awaitCompletion().assertItems("test1 transformed", "test2 transformed", "test3 transformed");
+
+        //ensure there are six spans with three pairs of subspan as child of testSpan
+        final List<SpanData> spans = spanExporter.getFinishedSpanItems(6);
+        for (int i = 1; i <= 3; i++) {
+            final int currentI = i;
+            assertThat(spans.stream().anyMatch(span -> span.getName().equals("testSpan test" + currentI))).isTrue();
+            assertThat(spans.stream().anyMatch(span -> span.getName().equals("subspan test" + currentI))).isTrue();
+            assertChildSpan(spans, "testSpan test" + currentI, "subspan test" + currentI);
+        }
+    }
+
+    @ParameterizedTest(name = "{index}: Merging multi pipeline {1}")
+    @MethodSource("generateContextRunners")
+    void testSimpleMultiPipeline_Merge(final String contextType, final String contextName) {
+
+        final AssertSubscriber<String> subscriber = Multi.createFrom()
+                .items("test1", "test2", "test3")
+                .emitOn(r -> runOnContext(r, vertx, contextType))
+                .onItem()
+                .transformToUniAndMerge(m -> wrapWithSpan(tracer, Optional.empty(), "testSpan " + m,
+                        Uni.createFrom().item(m).onItem().transform(s -> {
+                            final Span span = tracer.spanBuilder("subspan " + s).startSpan();
+                            try (final Scope scope = span.makeCurrent()) {
+                                return s + " transformed";
+                            } finally {
+                                span.end();
+                            }
+                        })))
+                .subscribe()
+                .withSubscriber(AssertSubscriber.create(3));
+
+        subscriber.awaitCompletion();
+
+        //ensure there are six spans with three pairs of subspan as child of testSpan
+        final List<SpanData> spans = spanExporter.getFinishedSpanItems(6);
+        for (int i = 1; i <= 3; i++) {
+            final int currentI = i;
+            assertThat(spans.stream().anyMatch(span -> span.getName().equals("testSpan test" + currentI))).isTrue();
+            assertThat(spans.stream().anyMatch(span -> span.getName().equals("subspan test" + currentI))).isTrue();
+            assertChildSpan(spans, "testSpan test" + currentI, "subspan test" + currentI);
+        }
+    }
+
+    private static void assertChildSpan(final List<SpanData> spans, final String parentSpanName,
+            final String childSpanName1) {
+        assertThat(spans.stream()
+                .filter(span -> span.getName().equals(childSpanName1))
+                .findAny()
+                .orElseThrow()
+                .getParentSpanId()).isEqualTo(
+                        spans.stream().filter(span -> span.getName().equals(parentSpanName)).findAny().get().getSpanId());
+    }
+
+    private static Stream<Arguments> generateContextRunners() {
+        return Stream.of(
+                Arguments.of("WITHOUT_CONTEXT", "Without Context"),
+                Arguments.of("ROOT_CONTEXT", "On Root Context"),
+                Arguments.of("DUPLICATED_CONTEXT", "On Duplicated Context"));
+    }
+
+    private void runOnContext(final Runnable runnable, final Vertx vertx, final String contextType) {
+        switch (contextType) {
+            case "WITHOUT_CONTEXT":
+                runWithoutContext(runnable);
+                break;
+            case "ROOT_CONTEXT":
+                runOnRootContext(runnable, vertx);
+                break;
+            case "DUPLICATED_CONTEXT":
+                runOnDuplicatedContext(runnable, vertx);
+                break;
+            default:
+                throw new IllegalArgumentException("Unknown context type: " + contextType);
+        }
+    }
+
+    private static void runWithoutContext(final Runnable runnable) {
+        assertThat(QuarkusContextStorage.getVertxContext()).isNull();
+        runnable.run();
+    }
+
+    private static void runOnRootContext(final Runnable runnable, final Vertx vertx) {
+        final Context rootContext = VertxContext.getRootContext(vertx.getOrCreateContext());
+        assertThat(rootContext).isNotNull();
+        assertThat(VertxContext.isDuplicatedContext(rootContext)).isFalse();
+        assertThat(rootContext).isNotEqualTo(QuarkusContextStorage.getVertxContext());
+
+        rootContext.runOnContext(v -> runnable.run());
+    }
+
+    private static void runOnDuplicatedContext(final Runnable runnable, final Vertx vertx) {
+        final Context duplicatedContext = VertxContext.createNewDuplicatedContext(vertx.getOrCreateContext());
+        assertThat(duplicatedContext).isNotNull();
+        assertThat(VertxContext.isDuplicatedContext(duplicatedContext)).isTrue();
+
+        duplicatedContext.runOnContext(v -> runnable.run());
+    }
+
+}