Allow configuring endpoint with environment variable. (#67)

aws-xray/src/main/java/io/opentelemetry/contrib/awsxray/AwsXrayRemoteSamplerProvider.java

@@ -9,13 +9,24 @@
 import io.opentelemetry.sdk.autoconfigure.OpenTelemetrySdkAutoConfiguration;
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigurableSamplerProvider;
 import io.opentelemetry.sdk.trace.samplers.Sampler;
+import java.util.Map;
 
 @AutoService(ConfigurableSamplerProvider.class)
 public class AwsXrayRemoteSamplerProvider implements ConfigurableSamplerProvider {
 
   @Override
   public Sampler createSampler(ConfigProperties config) {
-    return AwsXrayRemoteSampler.newBuilder(OpenTelemetrySdkAutoConfiguration.getResource()).build();
+    AwsXrayRemoteSamplerBuilder builder =
+        AwsXrayRemoteSampler.newBuilder(OpenTelemetrySdkAutoConfiguration.getResource());
+
+    Map<String, String> params = config.getCommaSeparatedMap("otel.traces.sampler.arg");
+
+    String endpoint = params.get("endpoint");
+    if (endpoint != null) {
+      builder.setEndpoint(endpoint);
+    }
+
+    return builder.build();
   }
 
   @Override

aws-xray/src/test/java/io/opentelemetry/contrib/awsxray/AwsXrayRemoteSamplerProviderTest.java

@@ -6,19 +6,59 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.InstanceOfAssertFactories.type;
+import static org.mockito.Mockito.when;
 
+import io.opentelemetry.sdk.autoconfigure.ConfigProperties;
 import io.opentelemetry.sdk.autoconfigure.spi.ConfigurableSamplerProvider;
+import java.util.Collections;
 import java.util.ServiceLoader;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
 
+@ExtendWith(MockitoExtension.class)
 class AwsXrayRemoteSamplerProviderTest {
 
+  @Mock private ConfigProperties config;
+
   @Test
   void serviceProvider() {
     ServiceLoader<ConfigurableSamplerProvider> samplerProviders =
         ServiceLoader.load(ConfigurableSamplerProvider.class);
     assertThat(samplerProviders)
         .singleElement(type(AwsXrayRemoteSamplerProvider.class))
-        .satisfies(provider -> assertThat(provider.getName()).isEqualTo("xray"));
+        .satisfies(
+            provider -> {
+              assertThat(provider.getName()).isEqualTo("xray");
+            });
+  }
+
+  @Test
+  void emptyConfig() {
+    try (AwsXrayRemoteSampler sampler =
+        (AwsXrayRemoteSampler) new AwsXrayRemoteSamplerProvider().createSampler(config)) {
+      // Inspect implementation details for simplicity, otherwise we'd probably need to make a
+      // test HTTP server that records requests.
+      assertThat(sampler)
+          .extracting("client")
+          .extracting("getSamplingRulesEndpoint", type(String.class))
+          .isEqualTo("http://localhost:2000/GetSamplingRules");
+    }
+  }
+
+  @Test
+  void setEndpoint() {
+    when(config.getCommaSeparatedMap("otel.traces.sampler.arg"))
+        .thenReturn(Collections.singletonMap("endpoint", "http://localhost:3000"));
+    try (AwsXrayRemoteSampler sampler =
+        (AwsXrayRemoteSampler) new AwsXrayRemoteSamplerProvider().createSampler(config)) {
+      // Inspect implementation details for simplicity, otherwise we'd probably need to make a
+      // test HTTP server that records requests.
+      assertThat(sampler)
+          .extracting("client")
+          .extracting("getSamplingRulesEndpoint", type(String.class))
+          .isEqualTo("http://localhost:3000/GetSamplingRules");
+    }
   }
 }

buildSrc/src/main/kotlin/otel.java-conventions.gradle.kts

@@ -85,6 +85,7 @@ dependencies {
     testImplementation("org.awaitility:awaitility")
     testImplementation("org.junit.jupiter:junit-jupiter-api")
     testImplementation("org.junit.jupiter:junit-jupiter-params")
+    testImplementation("org.mockito:mockito-junit-jupiter")
 
     testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine")
     testRuntimeOnly("org.junit.vintage:junit-vintage-engine")

dependencyManagement/build.gradle.kts

@@ -38,6 +38,11 @@ val DEPENDENCY_SETS = listOf(
         "0.11.0",
         listOf("simpleclient", "simpleclient_common", "simpleclient_httpserver")
     ),
+    DependencySet(
+        "org.mockito",
+        "3.10.0",
+        listOf("mockito-core", "mockito-junit-jupiter")
+    ),
     DependencySet(
         "org.slf4j",
         "1.7.30",