React native exporter (#381)

splunk-otel-android/src/main/java/com/splunk/rum/RumInitializer.java

@@ -342,6 +342,10 @@ SpanExporter buildFilteringExporter(ConnectionUtil connectionUtil) {
         SpanExporter filteredExporter = builder.decorateWithSpanFilter(exporter);
         initializationEvents.add(
                 new InitializationEvent("zipkin exporter initialized", timingClock.now()));
+
+        if (builder.reactNativeSupportEnabled) {
+            return builder.decorateWithReactNativeExporter(filteredExporter);
+        }
         return filteredExporter;
     }
 

splunk-otel-android/src/main/java/com/splunk/rum/SplunkRumBuilder.java

@@ -21,6 +21,7 @@
 import android.app.Application;
 import android.util.Log;
 import androidx.annotation.Nullable;
+import com.splunk.rum.reactnative.ReactNativeExporter;
 import io.opentelemetry.api.common.Attributes;
 import io.opentelemetry.sdk.trace.export.SpanExporter;
 import io.opentelemetry.semconv.resource.attributes.ResourceAttributes;
@@ -50,6 +51,7 @@ public final class SplunkRumBuilder {
     int maxUsageMegabytes = DEFAULT_MAX_STORAGE_USE_MB;
     boolean sessionBasedSamplerEnabled = false;
     double sessionBasedSamplerRatio = 1.0;
+    boolean reactNativeSupportEnabled = false;
 
     /**
      * Sets the application name that will be used to identify your application in the Splunk RUM
@@ -138,6 +140,11 @@ public SplunkRumBuilder enableDiskBuffering() {
         return this;
     }
 
+    public SplunkRumBuilder enableReactNativeSupport() {
+        this.reactNativeSupportEnabled = true;
+        return this;
+    }
+
     /**
      * Disables the crash reporting feature.
      *
@@ -310,6 +317,10 @@ SpanExporter decorateWithSpanFilter(SpanExporter exporter) {
         return spanFilterBuilder.build().apply(exporter);
     }
 
+    public SpanExporter decorateWithReactNativeExporter(SpanExporter exporter) {
+        return new ReactNativeExporter(exporter);
+    }
+
     Attributes buildInitialGlobalAttributes() {
         Attributes attrs = globalAttributes;
         if (deploymentEnvironment != null) {

splunk-otel-android/src/main/java/com/splunk/rum/reactnative/RNSpanData.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright Splunk Inc.
+ *
+ * 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 com.splunk.rum.reactnative;
+
+import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.internal.ImmutableSpanContext;
+import io.opentelemetry.api.trace.SpanContext;
+import io.opentelemetry.sdk.trace.data.DelegatingSpanData;
+import io.opentelemetry.sdk.trace.data.SpanData;
+
+public final class RNSpanData extends DelegatingSpanData {
+
+    private final SpanContext modifiedContext;
+    private final Attributes modifiedAttributes;
+
+    static SpanData create(SpanData original) {
+        SpanContext originalSpanContext = original.getSpanContext();
+        Attributes attributes = original.getAttributes();
+        AttributeKey<String> traceIdKey = AttributeKey.stringKey("_reactnative_traceId");
+        AttributeKey<String> spanIdKey = AttributeKey.stringKey("_reactnative_spanId");
+
+        String traceIdFromRN = attributes.get(traceIdKey);
+        String spanIdFromRN = attributes.get(spanIdKey);
+        if (traceIdFromRN == null || spanIdFromRN == null) {
+            return original;
+        }
+
+        Attributes attributesWithoutRNIds =
+                attributes.toBuilder().remove(traceIdKey).remove(spanIdKey).build();
+
+        SpanContext rnContext =
+                ImmutableSpanContext.create(
+                        traceIdFromRN,
+                        spanIdFromRN,
+                        originalSpanContext.getTraceFlags(),
+                        originalSpanContext.getTraceState(),
+                        originalSpanContext.isRemote(),
+                        false);
+        return new RNSpanData(original, rnContext, attributesWithoutRNIds);
+    }
+
+    private RNSpanData(
+            SpanData delegate, SpanContext modifiedContext, Attributes modifiedAttributes) {
+        super(delegate);
+        this.modifiedContext = modifiedContext;
+        this.modifiedAttributes = modifiedAttributes;
+    }
+
+    @Override
+    public SpanContext getSpanContext() {
+        return this.modifiedContext;
+    }
+
+    @Override
+    public Attributes getAttributes() {
+        return this.modifiedAttributes;
+    }
+}

splunk-otel-android/src/main/java/com/splunk/rum/reactnative/ReactNativeExporter.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright Splunk Inc.
+ *
+ * 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 com.splunk.rum.reactnative;
+
+import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.sdk.common.CompletableResultCode;
+import io.opentelemetry.sdk.trace.data.SpanData;
+import io.opentelemetry.sdk.trace.export.SpanExporter;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+public final class ReactNativeExporter implements SpanExporter {
+    private final SpanExporter delegate;
+
+    public ReactNativeExporter(SpanExporter delegate) {
+        this.delegate = delegate;
+    }
+
+    @Override
+    public CompletableResultCode export(Collection<SpanData> spans) {
+        List<SpanData> modified = new ArrayList<>();
+        for (SpanData span : spans) {
+            modified.add(modify(span));
+        }
+        return delegate.export(modified);
+    }
+
+    private SpanData modify(SpanData span) {
+        Attributes attributes = span.getAttributes();
+        if (attributes.get(AttributeKey.stringKey("_reactnative_traceId")) == null) {
+            return span;
+        }
+        return RNSpanData.create(span);
+    }
+
+    @Override
+    public CompletableResultCode flush() {
+        return delegate.flush();
+    }
+
+    @Override
+    public CompletableResultCode shutdown() {
+        return delegate.shutdown();
+    }
+}