feat(spanner): Update OpenTelemetry OTLP trace sample to use Google C…

spanner/opentelemetry_traces/src/main/java/com/example/spanner/OpenTelemetryUsage.java

@@ -16,6 +16,7 @@
 
 package com.example.spanner;
 
+import com.google.auth.oauth2.GoogleCredentials;
 import com.google.cloud.opentelemetry.trace.TraceConfiguration;
 import com.google.cloud.opentelemetry.trace.TraceExporter;
 import com.google.cloud.spanner.DatabaseClient;
@@ -26,16 +27,20 @@
 import com.google.cloud.spanner.Statement;
 import io.opentelemetry.api.OpenTelemetry;
 import io.opentelemetry.exporter.otlp.trace.OtlpGrpcSpanExporter;
+import io.opentelemetry.exporter.otlp.trace.OtlpGrpcSpanExporterBuilder;
 import io.opentelemetry.sdk.OpenTelemetrySdk;
 import io.opentelemetry.sdk.resources.Resource;
 import io.opentelemetry.sdk.trace.SdkTracerProvider;
 import io.opentelemetry.sdk.trace.export.BatchSpanProcessor;
 import io.opentelemetry.sdk.trace.export.SpanExporter;
 import io.opentelemetry.sdk.trace.samplers.Sampler;
+import java.io.IOException;
+import java.net.URI;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
 
-/**
- * This sample demonstrates how to configure OpenTelemetry and inject via Spanner Options.
- */
+/** This sample demonstrates how to configure OpenTelemetry and inject via Spanner Options. */
 public class OpenTelemetryUsage {
 
   static SdkTracerProvider sdkTracerProvider;
@@ -46,20 +51,32 @@ public class OpenTelemetryUsage {
   static String instanceId = "my-instance";
   static String databaseId = "my-database";
 
-  // Replace these variables to use OTLP Exporter
-  static boolean useCloudTraceExporter = true; // Replace to false for OTLP
-  static String otlpEndpoint = "http://localhost:4317"; // Replace with your OTLP endpoint
+  // Use the OTLP exporter by default. Set to true to use the Cloud Trace exporter instead.
+  static boolean useCloudTraceExporter = false;
+
+  // The OTLP endpoint to send traces to.
+  // It is recommended to use environment variables (OTEL_EXPORTER_OTLP_ENDPOINT) for configuration.
+  static String otlpEndpoint = System.getenv("OTEL_EXPORTER_OTLP_TRACES_ENDPOINT");
+
+  static {
+    if (otlpEndpoint == null) {
+      otlpEndpoint = System.getenv("OTEL_EXPORTER_OTLP_ENDPOINT");
+    }
+    if (otlpEndpoint == null) {
+      otlpEndpoint = "https://telemetry.googleapis.com"; // Google OTLP gRPC endpoint
+    }
+  }
 
-  public static void main(String[] args) {
+  public static void main(String[] args) throws IOException {
 
     if (useCloudTraceExporter) {
       spanner = getSpannerWithCloudTraceExporter();
     } else {
       spanner = getSpannerWithOtlpExporter();
     }
 
-    DatabaseClient dbClient = spanner
-        .getDatabaseClient(DatabaseId.of(projectId, instanceId, databaseId));
+    DatabaseClient dbClient =
+        spanner.getDatabaseClient(DatabaseId.of(projectId, instanceId, databaseId));
 
     try (ResultSet resultSet =
         dbClient
@@ -74,84 +91,80 @@ public static void main(String[] args) {
     sdkTracerProvider.forceFlush();
   }
 
-  public static Spanner getSpannerWithOtlpExporter() {
+  public static Spanner getSpannerWithOtlpExporter() throws IOException {
     // [START spanner_opentelemetry_traces_otlp_usage]
-    Resource resource = Resource
-        .getDefault().merge(Resource.builder().put("service.name", "My App").build());
+    Resource resource =
+        Resource.getDefault().merge(Resource.builder().put("gcp.project_id", projectId).build());
+
+    OtlpGrpcSpanExporterBuilder exporterBuilder =
+        OtlpGrpcSpanExporter.builder().setEndpoint(otlpEndpoint);
+
+    // Add authentication only if the endpoint is the Google Cloud Telemetry API.
+    // The standard endpoint is telemetry.googleapis.com
+    if (otlpEndpoint.contains("telemetry.googleapis.com")) {
+      GoogleCredentials credentials =
+          GoogleCredentials.getApplicationDefault()
+              .createScoped(Collections.singleton("https://www.googleapis.com/auth/trace.append"));
+      credentials.refreshIfExpired();
+      Map<String, List<String>> metadata = credentials.getRequestMetadata(URI.create(otlpEndpoint));
+      if (metadata != null) {
+        metadata.forEach((key, values) -> exporterBuilder.addHeader(key, String.join(",", values)));
+      }
+    }
 
-    OtlpGrpcSpanExporter otlpGrpcSpanExporter =
-        OtlpGrpcSpanExporter
-            .builder()
-            .setEndpoint(otlpEndpoint) // Replace with your OTLP endpoint
+    sdkTracerProvider =
+        SdkTracerProvider.builder()
+            .addSpanProcessor(BatchSpanProcessor.builder(exporterBuilder.build()).build())
+            .setResource(resource)
+            .setSampler(Sampler.traceIdRatioBased(0.1))
             .build();
 
-    // Using a batch span processor
-    // You can use `.setScheduleDelay()`, `.setExporterTimeout()`,
-    // `.setMaxQueueSize`(), and `.setMaxExportBatchSize()` to further customize.
-    BatchSpanProcessor otlpGrpcSpanProcessor =
-        BatchSpanProcessor.builder(otlpGrpcSpanExporter).build();
-
-    // Create a new tracer provider
-    sdkTracerProvider = SdkTracerProvider.builder()
-        // Use Otlp exporter or any other exporter of your choice.
-        .addSpanProcessor(otlpGrpcSpanProcessor)
-        .setResource(resource)
-        .setSampler(Sampler.traceIdRatioBased(0.1))
-        .build();
-
-    // Export to a collector that is expecting OTLP using gRPC.
-    OpenTelemetry openTelemetry = OpenTelemetrySdk.builder()
-        .setTracerProvider(sdkTracerProvider).build();
+    OpenTelemetry openTelemetry =
+        OpenTelemetrySdk.builder().setTracerProvider(sdkTracerProvider).build();
 
     // Enable OpenTelemetry traces before Injecting OpenTelemetry
     SpannerOptions.enableOpenTelemetryTraces();
 
     // Inject OpenTelemetry object via Spanner options or register as GlobalOpenTelemetry.
-    SpannerOptions options = SpannerOptions.newBuilder()
-        .setOpenTelemetry(openTelemetry)
-        .build();
-    Spanner spanner = options.getService();
+    SpannerOptions options = SpannerOptions.newBuilder().setOpenTelemetry(openTelemetry).build();
+    return options.getService();
     // [END spanner_opentelemetry_traces_otlp_usage]
-
-    return spanner;
   }
 
   public static Spanner getSpannerWithCloudTraceExporter() {
     // [START spanner_opentelemetry_traces_cloudtrace_usage]
-    Resource resource = Resource
-        .getDefault().merge(Resource.builder().put("service.name", "My App").build());
+    Resource resource =
+        Resource.getDefault().merge(Resource.builder().put("service.name", "My App").build());
 
-    SpanExporter traceExporter = TraceExporter.createWithConfiguration(
-        TraceConfiguration.builder().setProjectId(projectId).build()
-    );
+    SpanExporter traceExporter =
+        TraceExporter.createWithConfiguration(
+            TraceConfiguration.builder().setProjectId(projectId).build());
 
     // Using a batch span processor
     // You can use `.setScheduleDelay()`, `.setExporterTimeout()`,
     // `.setMaxQueueSize`(), and `.setMaxExportBatchSize()` to further customize.
-    BatchSpanProcessor otlpGrpcSpanProcessor =
-        BatchSpanProcessor.builder(traceExporter).build();
+    BatchSpanProcessor otlpGrpcSpanProcessor = BatchSpanProcessor.builder(traceExporter).build();
 
     // Create a new tracer provider
-    sdkTracerProvider = SdkTracerProvider.builder()
-        // Use Otlp exporter or any other exporter of your choice.
-        .addSpanProcessor(otlpGrpcSpanProcessor)
-        .setResource(resource)
-        .setSampler(Sampler.traceIdRatioBased(0.1))
-        .build();
+    sdkTracerProvider =
+        SdkTracerProvider.builder()
+            // Use Otlp exporter or any other exporter of your choice.
+            .addSpanProcessor(otlpGrpcSpanProcessor)
+            .setResource(resource)
+            .setSampler(Sampler.traceIdRatioBased(0.1))
+            .build();
 
     // Export to a collector that is expecting OTLP using gRPC.
-    OpenTelemetry openTelemetry = OpenTelemetrySdk.builder()
-        .setTracerProvider(sdkTracerProvider).build();
+    OpenTelemetry openTelemetry =
+        OpenTelemetrySdk.builder().setTracerProvider(sdkTracerProvider).build();
 
     // Enable OpenTelemetry traces before Injecting OpenTelemetry
     SpannerOptions.enableOpenTelemetryTraces();
 
     // Inject OpenTelemetry object via Spanner options or register it as global object.
     // To register as the global OpenTelemetry object,
     // use "OpenTelemetrySdk.builder()....buildAndRegisterGlobal()".
-    SpannerOptions options = SpannerOptions.newBuilder()
-        .setOpenTelemetry(openTelemetry)
-        .build();
+    SpannerOptions options = SpannerOptions.newBuilder().setOpenTelemetry(openTelemetry).build();
     Spanner spanner = options.getService();
     // [END spanner_opentelemetry_traces_cloudtrace_usage]