[3.x] - Make Jaeger Tracer OpenTelemetry Agent aware. (#6537)

* Refactor Java Agent detector.

* Remove redundant AgentDetection class

* Detector aligned with 4.x. Package name in tests fixed.

* Utility class

* Formatting

* Formatting

* Formatting

* fix style

* fix style

tracing/jaeger/src/main/java/io/helidon/tracing/jaeger/JaegerTracerBuilder.java

@@ -169,6 +169,7 @@ public class JaegerTracerBuilder implements TracerBuilder<JaegerTracerBuilder> {
     private byte[] certificate;
     private byte[] trustedCertificates;
     private String path;
+    private Config config;
 
     /**
      * Default constructor, does not modify any state.
@@ -253,6 +254,7 @@ public JaegerTracerBuilder addTracerTag(String key, boolean value) {
 
     @Override
     public JaegerTracerBuilder config(Config config) {
+        this.config = config;
         config.get("enabled").asBoolean().ifPresent(this::enabled);
         config.get("service").asString().ifPresent(this::serviceName);
         config.get("protocol").asString().ifPresent(this::collectorProtocol);
@@ -419,6 +421,12 @@ public JaegerTracerBuilder addPropagation(PropagationFormat propagationFormat) {
     public Tracer build() {
         Tracer result;
 
+        if (HelidonOpenTelemetry.AgentDetector.isAgentPresent(config)) {
+            return HelidonOpenTelemetry.create(GlobalOpenTelemetry.get(),
+                                               GlobalOpenTelemetry.getTracer(this.serviceName),
+                                               tags);
+        }
+
         if (enabled) {
             if (serviceName == null) {
                 throw new IllegalArgumentException(
@@ -449,10 +457,10 @@ public Tracer build() {
             Resource serviceName = Resource.create(Attributes.of(ResourceAttributes.SERVICE_NAME, this.serviceName));
             OpenTelemetry ot = OpenTelemetrySdk.builder()
                     .setTracerProvider(SdkTracerProvider.builder()
-                                               .addSpanProcessor(SimpleSpanProcessor.create(exporter))
-                                               .setSampler(sampler)
-                                               .setResource(serviceName)
-                                               .build())
+                            .addSpanProcessor(SimpleSpanProcessor.create(exporter))
+                            .setSampler(sampler)
+                            .setResource(serviceName)
+                            .build())
                     .setPropagators(ContextPropagators.create(TextMapPropagator.composite(createPropagators())))
                     .build();
 

tracing/opentelemetry/pom.xml

@@ -58,5 +58,15 @@
             <artifactId>hamcrest-all</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>io.helidon.microprofile.tests</groupId>
+            <artifactId>helidon-microprofile-tests-junit5</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.helidon.microprofile.server</groupId>
+            <artifactId>helidon-microprofile-server</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 </project>

tracing/opentelemetry/src/main/java/io/helidon/tracing/opentelemetry/HelidonOpenTelemetry.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022 Oracle and/or its affiliates.
+ * Copyright (c) 2022, 2023 Oracle and/or its affiliates.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,6 +17,9 @@
 
 
 import java.util.Map;
+import java.util.Optional;
+
+import io.helidon.config.Config;
 
 import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.api.trace.Span;
@@ -26,6 +29,10 @@
  * Open Telemetry factory methods to create wrappers for Open Telemetry types.
  */
 public final class HelidonOpenTelemetry {
+
+    private static final System.Logger LOGGER = System.getLogger(HelidonOpenTelemetry.class.getName());
+    static final String OTEL_AGENT_PRESENT_PROPERTY = "otel.agent.present";
+    static final String IO_OPENTELEMETRY_JAVAAGENT = "io.opentelemetry.javaagent";
     private HelidonOpenTelemetry() {
     }
     /**
@@ -49,4 +56,55 @@ public static OpenTelemetryTracer create(OpenTelemetry telemetry, Tracer tracer,
     public static io.helidon.tracing.Span create(Span span) {
         return new OpenTelemetrySpan(span);
     }
+
+
+    /**
+     * Check if OpenTelemetry is present by indirect properties.
+     * This class does best explicit check if OTEL_AGENT_PRESENT_PROPERTY config property is set and uses its
+     * value to set the behaviour of OpenTelemetry producer.
+     *
+     * If the value is not explicitly set, the detector does best effort to estimate indirect means if the agent is present.
+     * This detector may stop working if OTEL changes the indirect indicators.
+     */
+    public static final class AgentDetector {
+
+        //Private constructor for a utility class.
+        private AgentDetector() {
+        }
+
+        /**
+         * Check if the OTEL Agent is present.
+         *
+         * @param config Configuration
+         * @return boolean
+         */
+        public static boolean isAgentPresent(Config config) {
+
+            //Explicitly check if agent property is set
+            if (config != null) {
+                Optional<Boolean> agentPresent = config.get(OTEL_AGENT_PRESENT_PROPERTY).asBoolean().asOptional();
+                if (agentPresent.isPresent()) {
+                    return agentPresent.get();
+                }
+            }
+
+            if (checkContext() || checkSystemProperties()) {
+                if (LOGGER.isLoggable(System.Logger.Level.INFO)) {
+                    LOGGER.log(System.Logger.Level.INFO, "OpenTelemetry Agent detected");
+                }
+                return true;
+            }
+            return false;
+        }
+
+        private static boolean checkSystemProperties() {
+            return System.getProperties().stringPropertyNames()
+                    .stream()
+                    .anyMatch(property -> property.contains(IO_OPENTELEMETRY_JAVAAGENT));
+        }
+
+        private static boolean checkContext() {
+            return io.opentelemetry.context.Context.current().getClass().getName().contains("agent");
+        }
+    }
 }

tracing/opentelemetry/src/test/java/io/helidon/tracing/opentelemetry/AgentDetectorTest.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2023 Oracle and/or its affiliates.
+ *
+ * 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 io.helidon.tracing.opentelemetry;
+
+import io.helidon.config.Config;
+import io.helidon.microprofile.server.ServerCdiExtension;
+import io.helidon.microprofile.tests.junit5.AddConfig;
+import io.helidon.microprofile.tests.junit5.AddExtension;
+import io.helidon.microprofile.tests.junit5.HelidonTest;
+import jakarta.enterprise.inject.spi.CDI;
+import org.junit.jupiter.api.Test;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.is;
+
+
+/**
+ * Check Agent Detector working correctly.
+ */
+@HelidonTest(resetPerTest = true)
+@AddExtension(ServerCdiExtension.class)
+class AgentDetectorTest {
+
+    @Test
+    @AddConfig(key = HelidonOpenTelemetry.OTEL_AGENT_PRESENT_PROPERTY, value = "true")
+    void shouldBeNoOpTelemetry() {
+        Config config = CDI.current().select(Config.class).get();
+        boolean present = HelidonOpenTelemetry.AgentDetector.isAgentPresent(config);
+        assertThat(present, is(true));
+    }
+
+    @Test
+    @AddConfig(key = HelidonOpenTelemetry.OTEL_AGENT_PRESENT_PROPERTY, value = "false")
+    void shouldNotBeNoOpTelemetry() {
+        Config config = CDI.current().select(Config.class).get();
+        boolean present = HelidonOpenTelemetry.AgentDetector.isAgentPresent(config);
+        assertThat(present, is(false));
+    }
+
+    @Test
+    void checkEnvVariable() {
+        System.setProperty(HelidonOpenTelemetry.IO_OPENTELEMETRY_JAVAAGENT, "true");
+        Config config = CDI.current().select(Config.class).get();
+        boolean present = HelidonOpenTelemetry.AgentDetector.isAgentPresent(config);
+        assertThat(present, is(true));
+    }
+}

tracing/opentelemetry/src/test/java/io/helidon/tracing/opentelemetery/BaggageTest.java → tracing/opentelemetry/src/test/java/io/helidon/tracing/opentelemetry/BaggageTest.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package io.helidon.tracing.opentelemetery;
+package io.helidon.tracing.opentelemetry;
 
 import java.util.Optional;
 
@@ -37,7 +37,7 @@ class BaggageTest {
     private final Tracer tracer = TracerBuilder.create("test-service").registerGlobal(false).build();
 
     @Test
-    void testBaggage(){
+    void testBaggage() {
         Span span = tracer.spanBuilder("test-span").start();
         Span spanWithBaggage = span.baggage("key", "value");
         Optional<String> result = spanWithBaggage.baggage("key");
@@ -47,7 +47,7 @@ void testBaggage(){
     }
 
     @Test
-    void testBadBaggage(){
+    void testBadBaggage() {
         Span span = tracer.spanBuilder("test-bad-span").start();
         assertThrows(NullPointerException.class, () -> span.baggage(null, "value"));
         assertThrows(NullPointerException.class, () -> span.baggage("key", null));