Makes Export methods async

This commit recognises that the export and flush methods of span and trace exporters can be, and often are, implemented with long-lived operations over networks. We therefore see that these method return types are represented using Java's Future type to account for this common behaviour.

exporters/inmemory/src/main/java/io/opentelemetry/exporters/inmemory/InMemoryMetricExporter.java

@@ -16,6 +16,7 @@
 
 package io.opentelemetry.exporters.inmemory;
 
+import io.opentelemetry.sdk.common.export.CompletableResultCode;
 import io.opentelemetry.sdk.metrics.data.MetricData;
 import io.opentelemetry.sdk.metrics.export.MetricExporter;
 import java.util.ArrayList;
@@ -103,12 +104,12 @@ public void reset() {
    * <p>If this is called after {@code shutdown}, this will return {@code ResultCode.FAILURE}.
    */
   @Override
-  public ResultCode export(Collection<MetricData> metrics) {
+  public CompletableResultCode export(Collection<MetricData> metrics) {
     if (isStopped) {
-      return ResultCode.FAILURE;
+      return CompletableResultCode.ofFailure();
     }
     finishedMetricItems.addAll(metrics);
-    return ResultCode.SUCCESS;
+    return CompletableResultCode.ofSuccess();
   }
 
   /**
@@ -118,8 +119,8 @@ public ResultCode export(Collection<MetricData> metrics) {
    * @return always Success
    */
   @Override
-  public ResultCode flush() {
-    return ResultCode.SUCCESS;
+  public CompletableResultCode flush() {
+    return CompletableResultCode.ofSuccess();
   }
 
   /**

exporters/inmemory/src/main/java/io/opentelemetry/exporters/inmemory/InMemorySpanExporter.java

@@ -16,6 +16,7 @@
 
 package io.opentelemetry.exporters.inmemory;
 
+import io.opentelemetry.sdk.common.export.CompletableResultCode;
 import io.opentelemetry.sdk.trace.data.SpanData;
 import io.opentelemetry.sdk.trace.export.SpanExporter;
 import java.util.ArrayList;
@@ -85,14 +86,14 @@ public void reset() {
   }
 
   @Override
-  public ResultCode export(Collection<SpanData> spans) {
+  public CompletableResultCode export(Collection<SpanData> spans) {
     synchronized (this) {
       if (isStopped) {
-        return ResultCode.FAILURE;
+        return CompletableResultCode.ofFailure();
       }
       finishedSpanItems.addAll(spans);
     }
-    return ResultCode.SUCCESS;
+    return CompletableResultCode.ofSuccess();
   }
 
   /**
@@ -102,8 +103,8 @@ public ResultCode export(Collection<SpanData> spans) {
    * @return always Success
    */
   @Override
-  public ResultCode flush() {
-    return ResultCode.SUCCESS;
+  public CompletableResultCode flush() {
+    return CompletableResultCode.ofSuccess();
   }
 
   @Override

exporters/inmemory/src/test/java/io/opentelemetry/exporters/inmemory/InMemoryMetricExporterTest.java

@@ -23,7 +23,6 @@
 import io.opentelemetry.sdk.metrics.data.MetricData;
 import io.opentelemetry.sdk.metrics.data.MetricData.Descriptor;
 import io.opentelemetry.sdk.metrics.data.MetricData.LongPoint;
-import io.opentelemetry.sdk.metrics.export.MetricExporter.ResultCode;
 import io.opentelemetry.sdk.resources.Resource;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -54,7 +53,7 @@ void test_getFinishedMetricItems() {
     metrics.add(generateFakeMetric());
     metrics.add(generateFakeMetric());
 
-    assertThat(exporter.export(metrics)).isEqualTo(ResultCode.SUCCESS);
+    assertThat(exporter.export(metrics).isSuccess()).isTrue();
     List<MetricData> metricItems = exporter.getFinishedMetricItems();
     assertThat(metricItems).isNotNull();
     assertThat(metricItems.size()).isEqualTo(3);
@@ -67,7 +66,7 @@ void test_reset() {
     metrics.add(generateFakeMetric());
     metrics.add(generateFakeMetric());
 
-    assertThat(exporter.export(metrics)).isEqualTo(ResultCode.SUCCESS);
+    assertThat(exporter.export(metrics).isSuccess()).isTrue();
     List<MetricData> metricItems = exporter.getFinishedMetricItems();
     assertThat(metricItems).isNotNull();
     assertThat(metricItems.size()).isEqualTo(3);
@@ -84,7 +83,7 @@ void test_shutdown() {
     metrics.add(generateFakeMetric());
     metrics.add(generateFakeMetric());
 
-    assertThat(exporter.export(metrics)).isEqualTo(ResultCode.SUCCESS);
+    assertThat(exporter.export(metrics).isSuccess()).isTrue();
     exporter.shutdown();
     List<MetricData> metricItems = exporter.getFinishedMetricItems();
     assertThat(metricItems).isNotNull();
@@ -98,13 +97,13 @@ void testShutdown_export() {
     metrics.add(generateFakeMetric());
     metrics.add(generateFakeMetric());
 
-    assertThat(exporter.export(metrics)).isEqualTo(ResultCode.SUCCESS);
+    assertThat(exporter.export(metrics).isSuccess()).isTrue();
     exporter.shutdown();
-    assertThat(exporter.export(metrics)).isEqualTo(ResultCode.FAILURE);
+    assertThat(exporter.export(metrics).isSuccess()).isFalse();
   }
 
   @Test
   void test_flush() {
-    assertThat(exporter.flush()).isEqualTo(ResultCode.SUCCESS);
+    assertThat(exporter.flush().isSuccess()).isTrue();
   }
 }

exporters/inmemory/src/test/java/io/opentelemetry/exporters/inmemory/InMemorySpanExporterTest.java

@@ -22,7 +22,6 @@
 import io.opentelemetry.sdk.trace.TracerSdkProvider;
 import io.opentelemetry.sdk.trace.data.SpanData;
 import io.opentelemetry.sdk.trace.export.SimpleSpanProcessor;
-import io.opentelemetry.sdk.trace.export.SpanExporter.ResultCode;
 import io.opentelemetry.trace.Span.Kind;
 import io.opentelemetry.trace.SpanId;
 import io.opentelemetry.trace.Status;
@@ -89,16 +88,13 @@ void shutdown() {
 
   @Test
   void export_ReturnCode() {
-    assertThat(exporter.export(Collections.singletonList(makeBasicSpan())))
-        .isEqualTo(ResultCode.SUCCESS);
+    assertThat(exporter.export(Collections.singletonList(makeBasicSpan())).isSuccess()).isTrue();
     exporter.shutdown();
     // After shutdown no more export.
-    assertThat(exporter.export(Collections.singletonList(makeBasicSpan())))
-        .isEqualTo(ResultCode.FAILURE);
+    assertThat(exporter.export(Collections.singletonList(makeBasicSpan())).isSuccess()).isFalse();
     exporter.reset();
     // Reset does not do anything if already shutdown.
-    assertThat(exporter.export(Collections.singletonList(makeBasicSpan())))
-        .isEqualTo(ResultCode.FAILURE);
+    assertThat(exporter.export(Collections.singletonList(makeBasicSpan())).isSuccess()).isFalse();
   }
 
   static SpanData makeBasicSpan() {

exporters/jaeger/src/main/java/io/opentelemetry/exporters/jaeger/JaegerGrpcSpanExporter.java

@@ -21,6 +21,7 @@
 import io.opentelemetry.exporters.jaeger.proto.api_v2.Collector;
 import io.opentelemetry.exporters.jaeger.proto.api_v2.CollectorServiceGrpc;
 import io.opentelemetry.exporters.jaeger.proto.api_v2.Model;
+import io.opentelemetry.sdk.common.export.CompletableResultCode;
 import io.opentelemetry.sdk.common.export.ConfigBuilder;
 import io.opentelemetry.sdk.trace.data.SpanData;
 import io.opentelemetry.sdk.trace.export.SpanExporter;
@@ -107,7 +108,7 @@ private JaegerGrpcSpanExporter(String serviceName, ManagedChannel channel, long
    * @return the result of the operation
    */
   @Override
-  public ResultCode export(Collection<SpanData> spans) {
+  public CompletableResultCode export(Collection<SpanData> spans) {
     Collector.PostSpansRequest request =
         Collector.PostSpansRequest.newBuilder()
             .setBatch(
@@ -126,10 +127,10 @@ public ResultCode export(Collection<SpanData> spans) {
       // for now, there's nothing to check in the response object
       //noinspection ResultOfMethodCallIgnored
       stub.postSpans(request);
-      return ResultCode.SUCCESS;
+      return CompletableResultCode.ofSuccess();
     } catch (Throwable e) {
       logger.log(Level.WARNING, "Failed to export spans", e);
-      return ResultCode.FAILURE;
+      return CompletableResultCode.ofFailure();
     }
   }
 
@@ -139,8 +140,8 @@ public ResultCode export(Collection<SpanData> spans) {
    * @return always Success
    */
   @Override
-  public ResultCode flush() {
-    return ResultCode.SUCCESS;
+  public CompletableResultCode flush() {
+    return CompletableResultCode.ofSuccess();
   }
 
   /**

exporters/logging/src/main/java/io/opentelemetry/exporters/logging/LoggingMetricExporter.java

@@ -16,6 +16,7 @@
 
 package io.opentelemetry.exporters.logging;
 
+import io.opentelemetry.sdk.common.export.CompletableResultCode;
 import io.opentelemetry.sdk.metrics.data.MetricData;
 import io.opentelemetry.sdk.metrics.export.MetricExporter;
 import java.util.Collection;
@@ -27,12 +28,12 @@ public class LoggingMetricExporter implements MetricExporter {
   private static final Logger logger = Logger.getLogger(LoggingMetricExporter.class.getName());
 
   @Override
-  public ResultCode export(Collection<MetricData> metrics) {
+  public CompletableResultCode export(Collection<MetricData> metrics) {
     logger.info("Received a collection of " + metrics.size() + " metrics for export.");
     for (MetricData metricData : metrics) {
       logger.log(Level.INFO, "metric: {0}", metricData);
     }
-    return ResultCode.SUCCESS;
+    return CompletableResultCode.ofSuccess();
   }
 
   /**
@@ -41,16 +42,16 @@ public ResultCode export(Collection<MetricData> metrics) {
    * @return the result of the operation
    */
   @Override
-  public ResultCode flush() {
-    ResultCode resultCode = ResultCode.SUCCESS;
+  public CompletableResultCode flush() {
+    CompletableResultCode resultCode = new CompletableResultCode();
     for (Handler handler : logger.getHandlers()) {
       try {
         handler.flush();
       } catch (Throwable t) {
-        resultCode = ResultCode.FAILURE;
+        resultCode.fail();
       }
     }
-    return resultCode;
+    return resultCode.succeed();
   }
 
   @Override

exporters/logging/src/main/java/io/opentelemetry/exporters/logging/LoggingSpanExporter.java

@@ -16,6 +16,7 @@
 
 package io.opentelemetry.exporters.logging;
 
+import io.opentelemetry.sdk.common.export.CompletableResultCode;
 import io.opentelemetry.sdk.trace.data.SpanData;
 import io.opentelemetry.sdk.trace.export.SpanExporter;
 import java.util.Collection;
@@ -28,11 +29,11 @@ public class LoggingSpanExporter implements SpanExporter {
   private static final Logger logger = Logger.getLogger(LoggingSpanExporter.class.getName());
 
   @Override
-  public ResultCode export(Collection<SpanData> spans) {
+  public CompletableResultCode export(Collection<SpanData> spans) {
     for (SpanData span : spans) {
       logger.log(Level.INFO, "span: {0}", span);
     }
-    return ResultCode.SUCCESS;
+    return CompletableResultCode.ofSuccess();
   }
 
   /**
@@ -41,16 +42,16 @@ public ResultCode export(Collection<SpanData> spans) {
    * @return the result of the operation
    */
   @Override
-  public ResultCode flush() {
-    ResultCode resultCode = ResultCode.SUCCESS;
+  public CompletableResultCode flush() {
+    CompletableResultCode resultCode = new CompletableResultCode();
     for (Handler handler : logger.getHandlers()) {
       try {
         handler.flush();
       } catch (Throwable t) {
-        resultCode = ResultCode.FAILURE;
+        resultCode.fail();
       }
     }
-    return resultCode;
+    return resultCode.succeed();
   }
 
   @Override

exporters/logging/src/test/java/io/opentelemetry/exporters/logging/LoggingSpanExporterTest.java

@@ -18,14 +18,13 @@
 
 import static java.util.Collections.singletonList;
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import io.opentelemetry.common.AttributeValue;
 import io.opentelemetry.common.Attributes;
+import io.opentelemetry.sdk.common.export.CompletableResultCode;
 import io.opentelemetry.sdk.trace.TestSpanData;
 import io.opentelemetry.sdk.trace.data.EventImpl;
 import io.opentelemetry.sdk.trace.data.SpanData;
-import io.opentelemetry.sdk.trace.export.SpanExporter.ResultCode;
 import io.opentelemetry.trace.Span.Kind;
 import io.opentelemetry.trace.SpanId;
 import io.opentelemetry.trace.Status;
@@ -77,8 +76,8 @@ void returnCode() {
             .setTotalRecordedEvents(1)
             .setTotalRecordedLinks(0)
             .build();
-    ResultCode resultCode = exporter.export(singletonList(spanData));
-    assertEquals(ResultCode.SUCCESS, resultCode);
+    CompletableResultCode resultCode = exporter.export(singletonList(spanData));
+    assertThat(resultCode.isSuccess()).isTrue();
   }
 
   @Test