Create 'otel.extension.library.version' attribute in all spans

otel-extensions/src/main/java/org/hypertrace/agent/otel/extensions/SpanUtils.java

@@ -0,0 +1,112 @@
+/*
+ * Copyright The Hypertrace Authors
+ *
+ * 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 org.hypertrace.agent.otel.extensions;
+
+import io.opentelemetry.api.trace.Span;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.function.Supplier;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public abstract class SpanUtils {
+
+  static final String AGENT_VERSION_ATTRIBUTE_KEY = "otel.extension.library.version";
+  private static final Logger logger = LoggerFactory.getLogger(SpanUtils.class.getName());
+
+  private static final ConcurrentMap<String, String> ATTRIBUTE_MAP = new ConcurrentHashMap<>();
+
+  private static Supplier<String> agentVersionSupplier = () -> getAgentVersion();
+
+  private static boolean errorObtainingAgentVersion;
+
+  /**
+   * Obtains the current version of the Hypertrace agent. This is used to populate the
+   * "otel.extension.library.version" that is added to the Span.
+   *
+   * @return
+   */
+  private static boolean setAgentVersion() {
+    String agentVersion = ATTRIBUTE_MAP.get(AGENT_VERSION_ATTRIBUTE_KEY);
+
+    if (agentVersion == null && !errorObtainingAgentVersion) {
+      agentVersion = agentVersionSupplier.get();
+
+      if (agentVersion != null) {
+        ATTRIBUTE_MAP.put(AGENT_VERSION_ATTRIBUTE_KEY, agentVersion);
+      } else {
+        errorObtainingAgentVersion = true;
+      }
+    }
+    return !errorObtainingAgentVersion;
+  }
+
+  /**
+   * Adds the hypertrace-specific attributes to the Span.
+   *
+   * @param span
+   */
+  public static void setSpanAttributes(Span span) {
+    if (span == null) {
+      return;
+    }
+
+    collect();
+
+    for (Map.Entry<String, String> nextAttribute : ATTRIBUTE_MAP.entrySet()) {
+      span.setAttribute(nextAttribute.getKey(), nextAttribute.getValue());
+    }
+  }
+
+  /**
+   * Collects the data that is used for the attribute values.
+   *
+   * @return
+   */
+  private static boolean collect() {
+    if (!setAgentVersion()) {
+      return false;
+    }
+
+    return true;
+  }
+
+  /**
+   * Obtain the agent version by obtaining the implementation version of the HypertraceAgent class.
+   *
+   * @return
+   */
+  static String getAgentVersion() {
+    try {
+      Class<?> clazz = Class.forName("org.hypertrace.agent.instrument.HypertraceAgent", true, null);
+      return clazz.getPackage().getImplementationVersion();
+    } catch (ClassNotFoundException e) {
+      logger.warn("Could not load HypertraceAgent class");
+      return null;
+    }
+  }
+
+  /**
+   * For unit tests, replace the default agentVersionSupplier.
+   *
+   * @param _agentVersionSupplier
+   */
+  static void setVersionSupplier(Supplier<String> _agentVersionSupplier) {
+    agentVersionSupplier = _agentVersionSupplier;
+  }
+}

otel-extensions/src/main/java/org/hypertrace/agent/otel/extensions/processor/AddTagsSpanProcessor.java

@@ -23,6 +23,7 @@
 import io.opentelemetry.sdk.trace.SpanProcessor;
 import io.opentelemetry.semconv.resource.attributes.ResourceAttributes;
 import org.hypertrace.agent.otel.extensions.CgroupsReader;
+import org.hypertrace.agent.otel.extensions.SpanUtils;
 
 public class AddTagsSpanProcessor implements SpanProcessor {
 
@@ -40,6 +41,8 @@ public void onStart(Context parentContext, ReadWriteSpan span) {
     if (containerId != null && !containerId.isEmpty()) {
       span.setAttribute(ResourceAttributes.CONTAINER_ID, containerId);
     }
+
+    SpanUtils.setSpanAttributes(span);
   }
 
   @Override

otel-extensions/src/test/java/org/hypertrace/agent/otel/extensions/SpanUtilsTest.java

@@ -0,0 +1,118 @@
+/*
+ * Copyright The Hypertrace Authors
+ *
+ * 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 org.hypertrace.agent.otel.extensions;
+
+import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.trace.Span;
+import io.opentelemetry.api.trace.SpanContext;
+import io.opentelemetry.api.trace.StatusCode;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+/** Unit tests for SpanUtils. */
+public class SpanUtilsTest {
+
+  /**
+   * We can't seem to create mocks using Mockito in this environment, so we create a concrete
+   * implementation of the Span interface, to serve as a mock.
+   */
+  private static class MockSpan implements Span {
+
+    private final Map<AttributeKey<String>, String> attributeMap = new HashMap<>();
+
+    @Override
+    public <T> Span setAttribute(AttributeKey<T> key, T value) {
+      this.attributeMap.put((AttributeKey<String>) key, (String) value);
+      return this;
+    }
+
+    @Override
+    public Span addEvent(String name, Attributes attributes) {
+      return null;
+    }
+
+    @Override
+    public Span addEvent(String name, Attributes attributes, long timestamp, TimeUnit unit) {
+      return null;
+    }
+
+    @Override
+    public Span setStatus(StatusCode statusCode, String description) {
+      return null;
+    }
+
+    @Override
+    public Span recordException(Throwable exception, Attributes additionalAttributes) {
+      return null;
+    }
+
+    @Override
+    public Span updateName(String name) {
+      return null;
+    }
+
+    @Override
+    public void end() {}
+
+    @Override
+    public void end(long timestamp, TimeUnit unit) {}
+
+    @Override
+    public SpanContext getSpanContext() {
+      return null;
+    }
+
+    @Override
+    public boolean isRecording() {
+      return false;
+    }
+
+    String getAttribute(String attributeKey) {
+      AttributeKey key = AttributeKey.stringKey(attributeKey);
+      return attributeMap.get(key);
+    }
+  }
+
+  private static final String AGENT_VERSION = "1.2.3";
+
+  private MockSpan mockSpan;
+
+  public SpanUtilsTest() {
+    super();
+  }
+
+  @BeforeEach
+  public void setup() {
+    mockSpan = new MockSpan();
+  }
+
+  @Test
+  public void testSetSpanAttributes() {
+    SpanUtils.setVersionSupplier(() -> AGENT_VERSION);
+
+    SpanUtils.setSpanAttributes(mockSpan);
+
+    String attrValue = mockSpan.getAttribute(SpanUtils.AGENT_VERSION_ATTRIBUTE_KEY);
+
+    Assertions.assertEquals(AGENT_VERSION, attrValue);
+  }
+}