ConfigurationReader handles null values as empty

sdk-extensions/incubator/build.gradle.kts

@@ -55,7 +55,7 @@ dependencies {
 // ... proceed with normal sourcesJar, compileJava, etc
 
 // TODO(jack-berg): update ref to be released version when available
-val configurationRef = "0eb96de17c6533f668163873d95bd026bce1d8fb"
+val configurationRef = "0508846f82ed54b230fa638e1e7556c52efee25e"
 val configurationRepoZip = "https://github.com/open-telemetry/opentelemetry-configuration/archive/$configurationRef.zip"
 val buildDirectory = layout.buildDirectory.asFile.get()
 

sdk-extensions/incubator/src/main/java/io/opentelemetry/sdk/extension/incubator/fileconfig/ConfigurationReader.java

@@ -5,6 +5,8 @@
 
 package io.opentelemetry.sdk.extension.incubator.fileconfig;
 
+import com.fasterxml.jackson.annotation.JsonSetter;
+import com.fasterxml.jackson.annotation.Nulls;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.OpenTelemetryConfiguration;
 import java.io.InputStream;
@@ -13,7 +15,10 @@
 
 final class ConfigurationReader {
 
-  private static final ObjectMapper MAPPER = new ObjectMapper();
+  private static final ObjectMapper MAPPER =
+      new ObjectMapper()
+          // Create empty object instances for keys which are present but have null values
+          .setDefaultSetterInfo(JsonSetter.Value.forValueNulls(Nulls.AS_EMPTY));
 
   private ConfigurationReader() {}
 

sdk-extensions/incubator/src/test/java/io/opentelemetry/sdk/extension/incubator/fileconfig/AggregationFactoryTest.java

@@ -11,7 +11,10 @@
 import io.opentelemetry.sdk.autoconfigure.internal.SpiHelper;
 import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.Aggregation;
 import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.Base2ExponentialBucketHistogram;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.Drop;
 import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.ExplicitBucketHistogram;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.LastValue;
+import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.Sum;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -45,13 +48,12 @@ private static Stream<Arguments> createTestCases() {
         Arguments.of(
             new Aggregation(), io.opentelemetry.sdk.metrics.Aggregation.defaultAggregation()),
         Arguments.of(
-            new Aggregation().withDrop(new Object()),
+            new Aggregation().withDrop(new Drop()),
             io.opentelemetry.sdk.metrics.Aggregation.drop()),
         Arguments.of(
-            new Aggregation().withSum(new Object()),
-            io.opentelemetry.sdk.metrics.Aggregation.sum()),
+            new Aggregation().withSum(new Sum()), io.opentelemetry.sdk.metrics.Aggregation.sum()),
         Arguments.of(
-            new Aggregation().withLastValue(new Object()),
+            new Aggregation().withLastValue(new LastValue()),
             io.opentelemetry.sdk.metrics.Aggregation.lastValue()),
         Arguments.of(
             new Aggregation()

sdk-extensions/incubator/src/test/java/io/opentelemetry/sdk/extension/incubator/fileconfig/ConfigurationReaderTest.java

@@ -44,8 +44,10 @@
 import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.TracerProvider;
 import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.View;
 import io.opentelemetry.sdk.extension.incubator.fileconfig.internal.model.Zipkin;
+import java.io.ByteArrayInputStream;
 import java.io.FileInputStream;
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
@@ -276,4 +278,60 @@ void read_KitchenSinkExampleFile() throws IOException {
       assertThat(config).isEqualTo(expected);
     }
   }
+
+  @Test
+  void nullValuesParsedToEmptyObjects() {
+    String objectPlaceholderString =
+        "file_format: \"0.1\"\n"
+            + "tracer_provider:\n"
+            + "  processors:\n"
+            + "    - batch:\n"
+            + "        exporter:\n"
+            + "          console: {}\n"
+            + "meter_provider:\n"
+            + "  views:\n"
+            + "    - selector:\n"
+            + "        instrument_type: histogram\n"
+            + "      stream:\n"
+            + "        aggregation:\n"
+            + "          drop: {}\n";
+    OpenTelemetryConfiguration objectPlaceholderModel =
+        ConfigurationReader.parse(
+            new ByteArrayInputStream(objectPlaceholderString.getBytes(StandardCharsets.UTF_8)));
+
+    String noOjbectPlaceholderString =
+        "file_format: \"0.1\"\n"
+            + "tracer_provider:\n"
+            + "  processors:\n"
+            + "    - batch:\n"
+            + "        exporter:\n"
+            + "          console:\n"
+            + "meter_provider:\n"
+            + "  views:\n"
+            + "    - selector:\n"
+            + "        instrument_type: histogram\n"
+            + "      stream:\n"
+            + "        aggregation:\n"
+            + "          drop:\n";
+    OpenTelemetryConfiguration noObjectPlaceholderModel =
+        ConfigurationReader.parse(
+            new ByteArrayInputStream(noOjbectPlaceholderString.getBytes(StandardCharsets.UTF_8)));
+
+    SpanExporter exporter =
+        noObjectPlaceholderModel
+            .getTracerProvider()
+            .getProcessors()
+            .get(0)
+            .getBatch()
+            .getExporter();
+    assertThat(exporter.getConsole()).isNotNull();
+    assertThat(exporter.getOtlp()).isNull();
+
+    Aggregation aggregation =
+        noObjectPlaceholderModel.getMeterProvider().getViews().get(0).getStream().getAggregation();
+    assertThat(aggregation.getDrop()).isNotNull();
+    assertThat(aggregation.getSum()).isNull();
+
+    assertThat(objectPlaceholderModel).isEqualTo(noObjectPlaceholderModel);
+  }
 }