[File based config] Appd agent version resource supported

custom/src/main/java/com/splunk/opentelemetry/AppDynamicsVersionResourceDetector.java

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+/*
+ * Copyright Splunk Inc.
+ *
+ * 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 com.splunk.opentelemetry;
+
+import static io.opentelemetry.api.common.AttributeKey.stringKey;
+
+import com.google.auto.service.AutoService;
+import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
+import io.opentelemetry.sdk.autoconfigure.spi.internal.ComponentProvider;
+import io.opentelemetry.sdk.resources.Resource;
+
+@AutoService(ComponentProvider.class)
+public class AppDynamicsVersionResourceDetector implements ComponentProvider {
+  static final AttributeKey<String> APPD_AGENT_VER_KEY = stringKey("appdynamics.agent.version");
+
+  @Override
+  public Class<Resource> getType() {
+    return Resource.class;
+  }
+
+  @Override
+  public String getName() {
+    return "appd_agent_version";
+  }
+
+  @Override
+  public Resource create(DeclarativeConfigProperties config) {
+    // When AppD Agent starts Splunk Agent then it passes its version to Splunk Agent as a system
+    // property
+    String version = System.getProperty(APPD_AGENT_VER_KEY.getKey());
+    if (version == null) {
+      return Resource.empty();
+    }
+
+    Attributes attributes = Attributes.of(APPD_AGENT_VER_KEY, version);
+    return Resource.create(attributes);
+  }
+}

custom/src/test/java/com/splunk/opentelemetry/AppDynamicsVersionResourceDetectorTest.java

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+/*
+ * Copyright Splunk Inc.
+ *
+ * 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 com.splunk.opentelemetry;
+
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+
+import io.opentelemetry.sdk.resources.Resource;
+import org.junit.jupiter.api.Test;
+
+class AppDynamicsVersionResourceDetectorTest {
+  @Test
+  void shouldDetectAppDynamicsVersion() {
+    try {
+      // given
+      String appDVersion = "version X";
+      System.setProperty(
+          AppDynamicsVersionResourceDetector.APPD_AGENT_VER_KEY.getKey(), appDVersion);
+      AppDynamicsVersionResourceDetector detector = new AppDynamicsVersionResourceDetector();
+
+      // when
+      Resource resource = detector.create(null);
+
+      // then
+      assertThat(
+              resource.getAttributes().get(AppDynamicsVersionResourceDetector.APPD_AGENT_VER_KEY))
+          .isEqualTo(appDVersion);
+    } finally {
+      System.clearProperty(AppDynamicsVersionResourceDetector.APPD_AGENT_VER_KEY.getKey());
+    }
+  }
+
+  @Test
+  void shouldHandleMissingAppDynamicsVersion() {
+    // given
+    AppDynamicsVersionResourceDetector detector = new AppDynamicsVersionResourceDetector();
+
+    // when
+    Resource resource = detector.create(null);
+
+    // then
+    assertThat(resource.getAttributes().isEmpty()).isTrue();
+  }
+}