Report OTLP export status in tracer startup log

dd-trace-core/src/main/java/datadog/trace/core/StatusLogger.java

@@ -158,6 +158,12 @@ public void toJson(JsonWriter writer, Config config) throws IOException {
     writer.value(config.isDataStreamsEnabled());
     writer.name("data_streams_transaction_extractors");
     writer.value(config.getDataStreamsTransactionExtractors());
+    writer.name("otlp_traces_export_enabled");
+    writer.value(config.isTraceOtlpExporterEnabled());
+    writer.name("otlp_metrics_export_enabled");
+    writer.value(config.isMetricsOtelEnabled() && config.isMetricsOtlpExporterEnabled());
+    writer.name("otlp_logs_export_enabled");
+    writer.value(config.isLogsOtelEnabled() && config.isLogsOtlpExporterEnabled());
 
     writer.name("app_logs_collection_enabled");
     writer.value(config.isAppLogsCollectionEnabled());

dd-trace-core/src/test/java/datadog/trace/core/StatusLoggerTest.java

@@ -0,0 +1,61 @@
+package datadog.trace.core;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import com.squareup.moshi.Moshi;
+import datadog.trace.api.Config;
+import datadog.trace.api.config.OtlpConfig;
+import datadog.trace.test.junit.utils.config.WithConfig;
+import java.io.IOException;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Timeout;
+
+@Timeout(value = 10, unit = TimeUnit.SECONDS)
+public class StatusLoggerTest extends DDCoreJavaSpecification {
+
+  @Test
+  void otlpExportDisabledByDefault() throws IOException {
+    Map<String, Object> startupLog = startupLog(Config.get());
+
+    assertEquals(false, startupLog.get("otlp_traces_export_enabled"));
+    assertEquals(false, startupLog.get("otlp_metrics_export_enabled"));
+    assertEquals(false, startupLog.get("otlp_logs_export_enabled"));
+  }
+
+  @Test
+  @WithConfig(key = OtlpConfig.TRACE_OTEL_EXPORTER, value = "otlp")
+  @WithConfig(key = OtlpConfig.METRICS_OTEL_ENABLED, value = "true")
+  @WithConfig(key = OtlpConfig.METRICS_OTEL_EXPORTER, value = "otlp")
+  @WithConfig(key = OtlpConfig.LOGS_OTEL_ENABLED, value = "true")
+  @WithConfig(key = OtlpConfig.LOGS_OTEL_EXPORTER, value = "otlp")
+  void otlpExportEnabledWhenConfigured() throws IOException {
+    Map<String, Object> startupLog = startupLog(Config.get());
+
+    assertEquals(true, startupLog.get("otlp_traces_export_enabled"));
+    assertEquals(true, startupLog.get("otlp_metrics_export_enabled"));
+    assertEquals(true, startupLog.get("otlp_logs_export_enabled"));
+  }
+
+  @Test
+  @WithConfig(key = OtlpConfig.TRACE_OTEL_EXPORTER, value = "otlp")
+  @WithConfig(key = OtlpConfig.METRICS_OTEL_EXPORTER, value = "otlp")
+  @WithConfig(key = OtlpConfig.LOGS_OTEL_EXPORTER, value = "otlp")
+  void metricsAndLogsRequireOtelSignalEnabled() throws IOException {
+    // The OTLP exporter is selected for every signal, but the metrics and logs OTel signals are
+    // left disabled, so only trace export should be reported as enabled.
+    Map<String, Object> startupLog = startupLog(Config.get());
+
+    assertEquals(true, startupLog.get("otlp_traces_export_enabled"));
+    assertEquals(false, startupLog.get("otlp_metrics_export_enabled"));
+    assertEquals(false, startupLog.get("otlp_logs_export_enabled"));
+  }
+
+  @SuppressWarnings("unchecked")
+  private static Map<String, Object> startupLog(Config config) throws IOException {
+    String json =
+        new Moshi.Builder().add(new StatusLogger()).build().adapter(Config.class).toJson(config);
+    return (Map<String, Object>) new Moshi.Builder().build().adapter(Object.class).fromJson(json);
+  }
+}