Use OTel AgentDetector instead of just system property - review comme…

…nts from earlier PR (helidon-io#8374)

* Review comments from earlier PR

* One more place to use the AgentDetector

* remove duplicate constant declarations

microprofile/telemetry/src/main/java/io/helidon/microprofile/telemetry/HelidonTelemetryContainerFilter.java

@@ -21,6 +21,8 @@
 import java.util.Objects;
 
 import io.helidon.common.context.Contexts;
+import io.helidon.config.mp.MpConfig;
+import io.helidon.tracing.providers.opentelemetry.HelidonOpenTelemetry;
 
 import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.api.baggage.Baggage;
@@ -93,7 +95,7 @@ public Iterable<String> keys(ContainerRequestContext containerRequestContext) {
     HelidonTelemetryContainerFilter(Tracer tracer, OpenTelemetry openTelemetry, org.eclipse.microprofile.config.Config mpConfig) {
         this.tracer = tracer;
         this.openTelemetry = openTelemetry;
-        isAgentPresent = Boolean.getBoolean(TelemetryCdiExtension.OTEL_AGENT_PRESENT);
+        isAgentPresent = HelidonOpenTelemetry.AgentDetector.isAgentPresent(MpConfig.toHelidonConfig(mpConfig));
 
         mpConfig.getOptionalValue(SPAN_NAME_FULL_URL, Boolean.class).ifPresent(e -> spanNameFullUrl = e);
     }

microprofile/telemetry/src/main/java/io/helidon/microprofile/telemetry/TelemetryCdiExtension.java

@@ -28,15 +28,8 @@
  */
 public class TelemetryCdiExtension implements Extension {
 
-    /**
-     * Property name indicating the presence of the OpenTelemetry Java agent.
-     */
-    static final String OTEL_AGENT_PRESENT = "otel.agent.present";
-
     private static final System.Logger LOGGER = System.getLogger(TelemetryCdiExtension.class.getName());
 
-    private boolean isAgentPresent;
-
     /**
      * Add {@code HelidonWithSpan} annotation with interceptor.
      *
@@ -45,8 +38,6 @@ public class TelemetryCdiExtension implements Extension {
     void before(@Observes BeforeBeanDiscovery discovery) {
         LOGGER.log(System.Logger.Level.TRACE, () -> "Before Telemetry bean discovery " + discovery);
 
-        isAgentPresent = Boolean.getBoolean(OTEL_AGENT_PRESENT);
-
         // Register annotations, interceptors and producers.
         discovery.addAnnotatedType(HelidonWithSpan.class, HelidonWithSpan.class.getName());
         discovery.addAnnotatedType(WithSpanInterceptor.class, WithSpanInterceptor.class.getName());

microprofile/telemetry/src/main/java/io/helidon/microprofile/telemetry/WithSpanInterceptor.java

@@ -18,6 +18,9 @@
 import java.lang.reflect.Method;
 import java.lang.reflect.Parameter;
 
+import io.helidon.config.Config;
+import io.helidon.tracing.providers.opentelemetry.HelidonOpenTelemetry;
+
 import io.opentelemetry.api.trace.Span;
 import io.opentelemetry.api.trace.SpanBuilder;
 import io.opentelemetry.api.trace.Tracer;
@@ -46,9 +49,9 @@ class WithSpanInterceptor {
     private final boolean isAgentPresent;
 
     @Inject
-    WithSpanInterceptor(Tracer tracer) {
+    WithSpanInterceptor(Tracer tracer, Config config) {
         this.tracer = tracer;
-        isAgentPresent = Boolean.getBoolean(TelemetryCdiExtension.OTEL_AGENT_PRESENT);
+        isAgentPresent = HelidonOpenTelemetry.AgentDetector.isAgentPresent(config);
     }
 
     /**

microprofile/telemetry/src/test/java/io/helidon/microprofile/telemetry/AgentDetectorTest.java

@@ -36,18 +36,16 @@
 @AddExtension(ServerCdiExtension.class)
 class AgentDetectorTest {
 
-    public static final String IO_OPENTELEMETRY_JAVAAGENT = "io.opentelemetry.javaagent";
-
     @Test
-    @AddConfig(key = TelemetryCdiExtension.OTEL_AGENT_PRESENT, value = "true")
+    @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 = TelemetryCdiExtension.OTEL_AGENT_PRESENT, value = "false")
+    @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);
@@ -56,7 +54,7 @@ void shouldNotBeNoOpTelemetry(){
 
     @Test
     void checkEnvVariable(){
-        System.setProperty(IO_OPENTELEMETRY_JAVAAGENT, "true");
+        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/providers/opentelemetry/src/main/java/io/helidon/tracing/providers/opentelemetry/HelidonOpenTelemetry.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, 2023 Oracle and/or its affiliates.
+ * Copyright (c) 2022, 2024 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.
@@ -32,9 +32,17 @@
  */
 public final class HelidonOpenTelemetry {
 
+    /**
+     * OpenTelemetry property for indicating if the Java agent is present.
+     */
+    public static final String OTEL_AGENT_PRESENT_PROPERTY = "otel.agent.present";
+
+    /**
+     * OpenTelemetry property for the Java agent.
+     */
+    public static final String IO_OPENTELEMETRY_JAVAAGENT = "io.opentelemetry.javaagent";
+
     private static final System.Logger LOGGER = System.getLogger(HelidonOpenTelemetry.class.getName());
-    private static final String OTEL_AGENT_PRESENT_PROPERTY = "otel.agent.present";
-    private static final String IO_OPENTELEMETRY_JAVAAGENT = "io.opentelemetry.javaagent";
     private HelidonOpenTelemetry() {
     }
     /**