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.isOtlpTracesExportEnabled());
+    writer.name("otlp_metrics_export_enabled");
+    writer.value(config.isOtlpMetricsExportEnabled());
+    writer.name("otlp_logs_export_enabled");
+    writer.value(config.isOtlpLogsExportEnabled());
 
     writer.name("app_logs_collection_enabled");
     writer.value(config.isAppLogsCollectionEnabled());

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

@@ -0,0 +1,135 @@
+package datadog.trace.core;
+
+import static datadog.trace.api.config.OtlpConfig.LOGS_OTEL_ENABLED;
+import static datadog.trace.api.config.OtlpConfig.LOGS_OTEL_EXPORTER;
+import static datadog.trace.api.config.OtlpConfig.METRICS_OTEL_ENABLED;
+import static datadog.trace.api.config.OtlpConfig.METRICS_OTEL_EXPORTER;
+import static datadog.trace.api.config.OtlpConfig.OTEL_TRACES_SPAN_METRICS_ENABLED;
+import static datadog.trace.api.config.OtlpConfig.TRACE_OTEL_EXPORTER;
+import static datadog.trace.api.config.TracerConfig.WRITER_TYPE;
+import static datadog.trace.bootstrap.instrumentation.api.WriterConstants.DD_AGENT_WRITER_TYPE;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import com.squareup.moshi.Moshi;
+import datadog.json.JsonMapper;
+import datadog.trace.api.Config;
+import datadog.trace.test.junit.utils.config.WithConfig;
+import datadog.trace.test.util.DDJavaSpecification;
+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 DDJavaSpecification {
+
+  @Test
+  void otlpExportDisabledByDefault() throws IOException {
+    Map<String, Object> startupLog = startupLog();
+
+    assertFalse(flag(startupLog, "otlp_traces_export_enabled"));
+    assertFalse(flag(startupLog, "otlp_metrics_export_enabled"));
+    assertFalse(flag(startupLog, "otlp_logs_export_enabled"));
+  }
+
+  @Test
+  @WithConfig(key = TRACE_OTEL_EXPORTER, value = "otlp")
+  @WithConfig(key = METRICS_OTEL_ENABLED, value = "true")
+  @WithConfig(key = METRICS_OTEL_EXPORTER, value = "otlp")
+  @WithConfig(key = LOGS_OTEL_ENABLED, value = "true")
+  @WithConfig(key = LOGS_OTEL_EXPORTER, value = "otlp")
+  void otlpExportEnabledWhenConfigured() throws IOException {
+    Map<String, Object> startupLog = startupLog();
+
+    assertTrue(flag(startupLog, "otlp_traces_export_enabled"));
+    assertTrue(flag(startupLog, "otlp_metrics_export_enabled"));
+    assertTrue(flag(startupLog, "otlp_logs_export_enabled"));
+  }
+
+  @Test
+  @WithConfig(key = TRACE_OTEL_EXPORTER, value = "otlp")
+  @WithConfig(key = METRICS_OTEL_EXPORTER, value = "otlp")
+  @WithConfig(key = LOGS_OTEL_EXPORTER, value = "otlp")
+  void metricsAndLogsRequireOtelSignalEnabled() throws IOException {
+    Map<String, Object> startupLog = startupLog();
+
+    assertTrue(flag(startupLog, "otlp_traces_export_enabled"));
+    assertFalse(flag(startupLog, "otlp_metrics_export_enabled"));
+    assertFalse(flag(startupLog, "otlp_logs_export_enabled"));
+  }
+
+  @Test
+  @WithConfig(key = TRACE_OTEL_EXPORTER, value = "otlp")
+  @WithConfig(key = WRITER_TYPE, value = DD_AGENT_WRITER_TYPE)
+  void tracesNotExportedWhenWriterTypeOverridesOtlpExporter() throws IOException {
+    assertFalse(flag(startupLog(), "otlp_traces_export_enabled"));
+  }
+
+  @Test
+  @WithConfig(key = WRITER_TYPE, value = "MultiWriter:OtlpWriter,DDAgentWriter")
+  void tracesExportedWhenMultiWriterIncludesOtlpWriter() throws IOException {
+    assertTrue(flag(startupLog(), "otlp_traces_export_enabled"));
+  }
+
+  @Test
+  @WithConfig(key = WRITER_TYPE, value = "MultiWriter:LoggingWriter,DDAgentWriter")
+  void tracesNotExportedWhenMultiWriterExcludesOtlpWriter() throws IOException {
+    assertFalse(flag(startupLog(), "otlp_traces_export_enabled"));
+  }
+
+  @Test
+  @WithConfig(key = WRITER_TYPE, value = "MultiWriter: OtlpWriter")
+  void tracesNotExportedWhenMultiWriterSubTypeIsPadded() throws IOException {
+    assertFalse(flag(startupLog(), "otlp_traces_export_enabled"));
+  }
+
+  @Test
+  @WithConfig(key = WRITER_TYPE, value = "MultiWriter:OtlpWriterExtra")
+  void tracesNotExportedWhenMultiWriterSubTypeOnlyPrefixesOtlpWriter() throws IOException {
+    assertFalse(flag(startupLog(), "otlp_traces_export_enabled"));
+  }
+
+  @Test
+  @WithConfig(key = WRITER_TYPE, value = "DDAgentWriter,OtlpWriter")
+  void tracesNotExportedWhenCommaSeparatedWithoutMultiWriterPrefix() throws IOException {
+    assertFalse(flag(startupLog(), "otlp_traces_export_enabled"));
+  }
+
+  @Test
+  @WithConfig(key = WRITER_TYPE, value = "TraceStructureWriter:/tmp/out,OtlpWriter")
+  void tracesNotExportedWhenTraceStructureWriterTakesPrecedence() throws IOException {
+    assertFalse(flag(startupLog(), "otlp_traces_export_enabled"));
+  }
+
+  @Test
+  @WithConfig(key = OTEL_TRACES_SPAN_METRICS_ENABLED, value = "true")
+  void metricsExportedWhenSpanMetricsEnabled() throws IOException {
+    assertTrue(flag(startupLog(), "otlp_metrics_export_enabled"));
+  }
+
+  @Test
+  @WithConfig(key = METRICS_OTEL_ENABLED, value = "true")
+  @WithConfig(key = METRICS_OTEL_EXPORTER, value = "otlp")
+  @WithConfig(key = OTEL_TRACES_SPAN_METRICS_ENABLED, value = "false")
+  void metricsExportedWhenOtelMetricsSignalEnabledWithoutSpanMetrics() throws IOException {
+    assertTrue(flag(startupLog(), "otlp_metrics_export_enabled"));
+  }
+
+  private static Map<String, Object> startupLog() throws IOException {
+    String json =
+        new Moshi.Builder()
+            .add(new StatusLogger())
+            .build()
+            .adapter(Config.class)
+            .toJson(Config.get());
+    return JsonMapper.fromJsonToMap(json);
+  }
+
+  private static boolean flag(Map<String, Object> startupLog, String name) {
+    Object value = startupLog.get(name);
+    assertTrue(value instanceof Boolean, name + " should be a boolean, was " + value);
+    return (Boolean) value;
+  }
+}

internal-api/src/main/java/datadog/trace/api/Config.java

@@ -741,6 +741,7 @@
 import static datadog.trace.api.featureflag.config.FeatureFlaggingConfig.isSupportedConfigurationSource;
 import static datadog.trace.api.featureflag.config.FeatureFlaggingConfig.resolveConfiguration;
 import static datadog.trace.api.telemetry.LogCollector.SEND_TELEMETRY;
+import static datadog.trace.bootstrap.instrumentation.api.WriterConstants.MULTI_WRITER_TYPE;
 import static datadog.trace.bootstrap.instrumentation.api.WriterConstants.OTLP_WRITER_TYPE;
 import static datadog.trace.util.CollectionUtils.tryMakeImmutableList;
 import static datadog.trace.util.CollectionUtils.tryMakeImmutableSet;
@@ -5747,6 +5748,10 @@ public boolean isLogsOtlpExporterEnabled() {
     return "otlp".equalsIgnoreCase(logsOtelExporter);
   }
 
+  public boolean isOtlpLogsExportEnabled() {
+    return isLogsOtelEnabled() && isLogsOtlpExporterEnabled();
+  }
+
   public int getLogsOtelInterval() {
     return logsOtelInterval;
   }
@@ -5791,6 +5796,11 @@ public boolean isMetricsOtlpExporterEnabled() {
     return "otlp".equalsIgnoreCase(metricsOtelExporter);
   }
 
+  public boolean isOtlpMetricsExportEnabled() {
+    return (isMetricsOtelEnabled() && isMetricsOtlpExporterEnabled())
+        || isOtelTracesSpanMetricsEnabled();
+  }
+
   public boolean isMetricsOtelExperimentalEnabled() {
     return metricsOtelExperimentalEnabled;
   }
@@ -5847,6 +5857,19 @@ public boolean isTraceOtlpExporterEnabled() {
     return "otlp".equalsIgnoreCase(traceOtelExporter);
   }
 
+  public boolean isOtlpTracesExportEnabled() {
+    if (!writerType.startsWith(MULTI_WRITER_TYPE)) {
+      return OTLP_WRITER_TYPE.equals(writerType);
+    }
+    String multiWriterConfig = writerType.substring(MULTI_WRITER_TYPE.length() + 1);
+    for (CharSequence subWriterType : Strings.split(multiWriterConfig, ',')) {
+      if (OTLP_WRITER_TYPE.contentEquals(subWriterType)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   public String getOtlpTracesEndpoint() {
     return otlpTracesEndpoint;
   }