Contribute OTLP UDP Exporter (#1035)

*Issue #, if available:*

*Description of changes:*
Contributing our OTLP UDP exporter.

Testing:
Published the package to MavenLocal and tried running the sample app
![Screenshot 2025-03-04 at 1 11
32 PM](https://github.com/user-attachments/assets/585950fd-49ec-4f97-8101-17e00c9a21ce)
Ran the unit tests as well
![Screenshot 2025-03-04 at 1 06
20 PM](https://github.com/user-attachments/assets/65ac480f-eec2-449e-a557-e953337e643f)


By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license.

---------

Co-authored-by: Jeel Mehta <[email protected]>

Author: Jeel-mehta

exporters/aws-opentelemetry-xray-lambda-exporter/build.gradle.kts

@@ -0,0 +1,101 @@
+/*
+ * Copyright Amazon.com, Inc. 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.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file 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.
+ */
+
+plugins {
+  id("java")
+  id("java-library")
+  id("maven-publish")
+}
+
+group = "software.amazon.distro.opentelemetry.exporter.xray.lambda"
+version = "0.1.0"
+
+dependencies {
+  implementation(platform("io.opentelemetry.instrumentation:opentelemetry-instrumentation-bom:2.10.0"))
+  compileOnly("io.opentelemetry:opentelemetry-api")
+  compileOnly("io.opentelemetry:opentelemetry-sdk")
+  compileOnly("io.opentelemetry:opentelemetry-exporter-otlp-common")
+  compileOnly("com.google.code.findbugs:jsr305:3.0.2")
+  testImplementation("io.opentelemetry:opentelemetry-api")
+  testImplementation("io.opentelemetry:opentelemetry-sdk")
+  testImplementation("io.opentelemetry:opentelemetry-exporter-otlp-common")
+  testImplementation(platform("org.junit:junit-bom:5.9.2"))
+  testImplementation("org.junit.jupiter:junit-jupiter-api")
+  testImplementation("org.junit.jupiter:junit-jupiter-engine")
+  testImplementation("org.mockito:mockito-core:5.3.1")
+  testImplementation("org.assertj:assertj-core:3.24.2")
+  testImplementation("org.mockito:mockito-junit-jupiter:5.3.1")
+}
+
+java {
+  withSourcesJar()
+  withJavadocJar()
+}
+
+tasks.javadoc {
+  options {
+    (this as CoreJavadocOptions).addStringOption("Xdoclint:none", "-quiet")
+  }
+  isFailOnError = false
+}
+
+sourceSets {
+  main {
+    java {
+      srcDirs("src/main/java")
+    }
+  }
+  test {
+    java {
+      srcDirs("src/test/java")
+    }
+  }
+}
+
+tasks.test {
+  useJUnitPlatform()
+  testLogging {
+    events("passed", "skipped", "failed")
+  }
+}
+
+tasks.jar {
+  manifest {
+    attributes(
+      "Implementation-Title" to project.name,
+      "Implementation-Version" to project.version,
+    )
+  }
+  duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+}
+
+tasks.named<Jar>("javadocJar") {
+  duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+}
+
+tasks.named<Jar>("sourcesJar") {
+  duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+}
+
+publishing {
+  publications {
+    create<MavenPublication>("mavenJava") {
+      from(components["java"])
+      groupId = project.group.toString()
+      artifactId = "aws-opentelemetry-xray-lambda-exporter"
+      version = project.version.toString()
+    }
+  }
+}

exporters/aws-opentelemetry-xray-lambda-exporter/settings.gradle.kts

@@ -0,0 +1,12 @@
+rootProject.name = "aws-opentelemetry-xray-lambda-exporter"
+
+dependencyResolutionManagement {
+  repositories {
+    mavenCentral()
+    mavenLocal()
+
+    maven {
+      setUrl("https://oss.sonatype.org/content/repositories/snapshots")
+    }
+  }
+}

exporters/aws-opentelemetry-xray-lambda-exporter/src/main/java/software/amazon/distro/opentelemetry/exporter/xray/lambda/AwsXrayLambdaExporter.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright Amazon.com, Inc. 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.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file 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 software.amazon.distro.opentelemetry.exporter.xray.lambda;
+
+import io.opentelemetry.exporter.internal.otlp.traces.TraceRequestMarshaler;
+import io.opentelemetry.sdk.common.CompletableResultCode;
+import io.opentelemetry.sdk.trace.data.SpanData;
+import io.opentelemetry.sdk.trace.export.SpanExporter;
+import java.io.ByteArrayOutputStream;
+import java.nio.charset.StandardCharsets;
+import java.util.Base64;
+import java.util.Collection;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * Exports spans via UDP, using OpenTelemetry's protobuf model. The protobuf modelled spans are
+ * Base64 encoded and prefixed with AWS X-Ray specific information before being sent over to {@link
+ * UdpSender}.
+ *
+ * <p>This exporter is NOT meant for generic use since the payload is prefixed with AWS X-Ray
+ * specific information.
+ */
+@Immutable
+public class AwsXrayLambdaExporter implements SpanExporter {
+
+  private static final Logger logger = Logger.getLogger(AwsXrayLambdaExporter.class.getName());
+
+  private final AtomicBoolean isShutdown = new AtomicBoolean();
+
+  private final UdpSender sender;
+  private final String payloadPrefix;
+
+  AwsXrayLambdaExporter(UdpSender sender, String payloadPrefix) {
+    this.sender = sender;
+    this.payloadPrefix = payloadPrefix;
+  }
+
+  @Override
+  public CompletableResultCode export(Collection<SpanData> spans) {
+    if (isShutdown.get()) {
+      return CompletableResultCode.ofFailure();
+    }
+
+    TraceRequestMarshaler exportRequest = TraceRequestMarshaler.create(spans);
+    ByteArrayOutputStream baos = new ByteArrayOutputStream();
+    try {
+      exportRequest.writeBinaryTo(baos);
+      String payload = payloadPrefix + Base64.getEncoder().encodeToString(baos.toByteArray());
+      sender.send(payload.getBytes(StandardCharsets.UTF_8));
+      return CompletableResultCode.ofSuccess();
+    } catch (Exception e) {
+      logger.log(Level.SEVERE, "Failed to export spans. Error: " + e.getMessage(), e);
+      return CompletableResultCode.ofFailure();
+    }
+  }
+
+  @Override
+  public CompletableResultCode flush() {
+    // TODO: implement
+    return CompletableResultCode.ofSuccess();
+  }
+
+  @Override
+  public CompletableResultCode shutdown() {
+    if (!isShutdown.compareAndSet(false, true)) {
+      logger.log(Level.INFO, "Calling shutdown() multiple times.");
+      return CompletableResultCode.ofSuccess();
+    }
+    return sender.shutdown();
+  }
+
+  // Visible for testing
+  UdpSender getSender() {
+    return sender;
+  }
+
+  // Visible for testing
+  String getPayloadPrefix() {
+    return payloadPrefix;
+  }
+}

exporters/aws-opentelemetry-xray-lambda-exporter/src/main/java/software/amazon/distro/opentelemetry/exporter/xray/lambda/AwsXrayLambdaExporterBuilder.java

@@ -0,0 +1,121 @@
+/*
+ * Copyright Amazon.com, Inc. 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.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file 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 software.amazon.distro.opentelemetry.exporter.xray.lambda;
+
+import static java.util.Objects.requireNonNull;
+
+import java.util.Map;
+
+public final class AwsXrayLambdaExporterBuilder {
+
+  private static final String DEFAULT_HOST = "127.0.0.1";
+  private static final int DEFAULT_PORT = 2000;
+
+  // The protocol header and delimiter is required for sending data to X-Ray Daemon or when running
+  // in Lambda.
+  // https://docs.aws.amazon.com/xray/latest/devguide/xray-api-sendingdata.html#xray-api-daemon
+  private static final String PROTOCOL_HEADER = "{\"format\": \"json\", \"version\": 1}";
+  private static final char PROTOCOL_DELIMITER = '\n';
+
+  // These prefixes help the backend identify if the spans payload is sampled or not.
+  private static final String FORMAT_OTEL_SAMPLED_TRACES_BINARY_PREFIX = "T1S";
+  private static final String FORMAT_OTEL_UNSAMPLED_TRACES_BINARY_PREFIX = "T1U";
+
+  private UdpSender sender;
+  private String tracePayloadPrefix = FORMAT_OTEL_SAMPLED_TRACES_BINARY_PREFIX;
+  private Map<String, String> environmentVariables = System.getenv();
+
+  private static final String AWS_LAMBDA_FUNCTION_NAME_CONFIG = "AWS_LAMBDA_FUNCTION_NAME";
+  private static final String AWS_XRAY_DAEMON_ADDRESS_CONFIG = "AWS_XRAY_DAEMON_ADDRESS";
+
+  public AwsXrayLambdaExporterBuilder setEndpoint(String endpoint) {
+    requireNonNull(endpoint, "endpoint must not be null");
+    try {
+      this.sender = createSenderFromEndpoint(endpoint);
+    } catch (Exception e) {
+      throw new IllegalArgumentException("Invalid endpoint, must be a valid URL: " + endpoint, e);
+    }
+    return this;
+  }
+
+  public AwsXrayLambdaExporterBuilder setPayloadSampleDecision(TracePayloadSampleDecision decision) {
+    this.tracePayloadPrefix =
+        decision == TracePayloadSampleDecision.SAMPLED
+            ? FORMAT_OTEL_SAMPLED_TRACES_BINARY_PREFIX
+            : FORMAT_OTEL_UNSAMPLED_TRACES_BINARY_PREFIX;
+    return this;
+  }
+
+  private UdpSender createSenderFromEndpoint(String endpoint) {
+        String[] parts = endpoint.split(":");
+        String host = parts[0];
+        int port = Integer.parseInt(parts[1]);
+        return new UdpSender(host, port);
+    }
+
+  // For testing purposes
+  AwsXrayLambdaExporterBuilder withEnvironmentVariables(Map<String, String> env) {
+    this.environmentVariables = env;
+    return this;
+  }
+
+  // NEW: Added getter for testing
+  Map<String, String> getEnvironmentVariables() {
+    return environmentVariables;
+  }
+
+  public AwsXrayLambdaExporter build() {
+    if (sender == null) {
+      String endpoint = null;
+
+      // If in Lambda environment, try to get X-Ray daemon address
+      if (isLambdaEnvironment()) {
+        endpoint = environmentVariables.get(AWS_XRAY_DAEMON_ADDRESS_CONFIG);
+        if (endpoint != null && !endpoint.isEmpty()) {
+          try {
+            this.sender = createSenderFromEndpoint(endpoint);
+            return new AwsXrayLambdaExporter(
+                this.sender, PROTOCOL_HEADER + PROTOCOL_DELIMITER + tracePayloadPrefix);
+          } catch (Exception e) {
+            // Fallback to defaults if parsing fails
+            this.sender = new UdpSender(DEFAULT_HOST, DEFAULT_PORT);
+          }
+        }
+      }
+
+      // Use defaults if not in Lambda or if daemon address is invalid/unavailable
+      this.sender = new UdpSender(DEFAULT_HOST, DEFAULT_PORT);
+    }
+    return new AwsXrayLambdaExporter(
+        this.sender, PROTOCOL_HEADER + PROTOCOL_DELIMITER + tracePayloadPrefix);
+  }
+
+  private boolean isLambdaEnvironment() {
+    String functionName = environmentVariables.get(AWS_LAMBDA_FUNCTION_NAME_CONFIG);
+    return functionName != null && !functionName.isEmpty();
+  }
+
+  // Only for testing
+  AwsXrayLambdaExporterBuilder setSender(UdpSender sender) {
+    this.sender = sender;
+    return this;
+  }
+}
+
+enum TracePayloadSampleDecision {
+  SAMPLED,
+  UNSAMPLED
+}