Fix NullPointerException when uri is null

instrumentation/reactor/reactor-netty/reactor-netty-1.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/reactornetty/v1_0/ReactorNettyHttpClientAttributesGetter.java

@@ -25,6 +25,12 @@ public String url(HttpClientConfig request) {
 
     // use the baseUrl if it was configured
     String baseUrl = request.baseUrl();
+
+    if (uri == null) {
+      // internally reactor netty appends "/" to the baseUrl
+      return baseUrl.endsWith("/") ? baseUrl : baseUrl + "/";
+    }
+
     if (baseUrl != null) {
       if (baseUrl.endsWith("/") && uri.startsWith("/")) {
         baseUrl = baseUrl.substring(0, baseUrl.length() - 1);
@@ -48,7 +54,7 @@ public String url(HttpClientConfig request) {
   }
 
   private static boolean isAbsolute(String uri) {
-    return uri.startsWith("http://") || uri.startsWith("https://");
+    return uri != null && !uri.isEmpty() && !uri.startsWith("/");
   }
 
   @Nullable

instrumentation/reactor/reactor-netty/reactor-netty-1.0/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/reactornetty/v1_0/ReactorNettyNetClientAttributesGetter.java

@@ -56,7 +56,7 @@ private static String getHost(HttpClientConfig request) {
     String baseUrl = request.baseUrl();
     String uri = request.uri();
 
-    if (baseUrl != null && uri.startsWith("/")) {
+    if (baseUrl != null && !isAbsolute(uri)) {
       return UrlParser.getHost(baseUrl);
     } else {
       return UrlParser.getHost(uri);
@@ -68,10 +68,14 @@ private static Integer getPort(HttpClientConfig request) {
     String baseUrl = request.baseUrl();
     String uri = request.uri();
 
-    if (baseUrl != null && uri.startsWith("/")) {
+    if (baseUrl != null && !isAbsolute(uri)) {
       return UrlParser.getPort(baseUrl);
     } else {
       return UrlParser.getPort(uri);
     }
   }
+
+  private static boolean isAbsolute(String uri) {
+    return uri != null && !uri.isEmpty() && !uri.startsWith("/");
+  }
 }

instrumentation/reactor/reactor-netty/reactor-netty-1.0/javaagent/src/test/java/io/opentelemetry/javaagent/instrumentation/reactornetty/v1_0/ReactorNettyBaseUrlOnlyTest.java

@@ -0,0 +1,123 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.javaagent.instrumentation.reactornetty.v1_0;
+
+import static io.opentelemetry.api.trace.SpanKind.CLIENT;
+import static io.opentelemetry.api.trace.SpanKind.INTERNAL;
+import static io.opentelemetry.api.trace.SpanKind.SERVER;
+import static io.opentelemetry.sdk.testing.assertj.OpenTelemetryAssertions.equalTo;
+import static io.opentelemetry.sdk.testing.assertj.OpenTelemetryAssertions.satisfies;
+import static io.opentelemetry.semconv.trace.attributes.SemanticAttributes.HttpFlavorValues.HTTP_1_1;
+import static org.assertj.core.api.Assertions.assertThat;
+
+import io.opentelemetry.api.GlobalOpenTelemetry;
+import io.opentelemetry.api.trace.SpanBuilder;
+import io.opentelemetry.context.Context;
+import io.opentelemetry.instrumentation.test.server.http.RequestContextGetter;
+import io.opentelemetry.instrumentation.testing.junit.AgentInstrumentationExtension;
+import io.opentelemetry.instrumentation.testing.junit.InstrumentationExtension;
+import io.opentelemetry.semconv.trace.attributes.SemanticAttributes;
+import io.opentelemetry.testing.internal.armeria.common.HttpData;
+import io.opentelemetry.testing.internal.armeria.common.HttpResponse;
+import io.opentelemetry.testing.internal.armeria.common.HttpStatus;
+import io.opentelemetry.testing.internal.armeria.common.ResponseHeaders;
+import io.opentelemetry.testing.internal.armeria.common.ResponseHeadersBuilder;
+import io.opentelemetry.testing.internal.armeria.server.ServerBuilder;
+import io.opentelemetry.testing.internal.armeria.testing.junit5.server.ServerExtension;
+import org.assertj.core.api.AbstractLongAssert;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+import reactor.netty.http.client.HttpClient;
+
+class ReactorNettyBaseUrlOnlyTest {
+
+  @RegisterExtension
+  static final InstrumentationExtension testing = AgentInstrumentationExtension.create();
+
+  static ServerExtension server;
+
+  @BeforeAll
+  static void setUp() {
+    server =
+        new ServerExtension() {
+          @Override
+          protected void configure(ServerBuilder sb) {
+            sb.service(
+                "/base/",
+                (ctx, req) -> {
+                  ResponseHeadersBuilder headers = ResponseHeaders.builder(HttpStatus.OK);
+
+                  SpanBuilder span =
+                      GlobalOpenTelemetry.getTracer("test")
+                          .spanBuilder("test-http-server")
+                          .setSpanKind(SERVER)
+                          .setParent(
+                              GlobalOpenTelemetry.getPropagators()
+                                  .getTextMapPropagator()
+                                  .extract(Context.current(), ctx, RequestContextGetter.INSTANCE));
+
+                  span.startSpan().end();
+
+                  return HttpResponse.of(headers.build(), HttpData.ofAscii("Hello."));
+                });
+          }
+        };
+    server.start();
+  }
+
+  @AfterAll
+  static void tearDown() {
+    server.stop();
+  }
+
+  @Test
+  void testSuccessfulRequest() {
+    HttpClient httpClient = HttpClient.create();
+    String uri = "http://localhost:" + server.httpPort() + "/base";
+
+    int responseCode =
+        testing.runWithSpan(
+            "parent",
+            () ->
+                httpClient
+                    .baseUrl(uri)
+                    .get()
+                    .responseSingle(
+                        (resp, content) -> {
+                          // Make sure to consume content since that's when we close the span.
+                          return content.map(unused -> resp);
+                        })
+                    .block()
+                    .status()
+                    .code());
+
+    assertThat(responseCode).isEqualTo(200);
+
+    testing.waitAndAssertTraces(
+        trace ->
+            trace.hasSpansSatisfyingExactlyInAnyOrder(
+                span -> span.hasName("parent").hasKind(INTERNAL).hasNoParent(),
+                span ->
+                    span.hasName("HTTP GET")
+                        .hasKind(CLIENT)
+                        .hasParent(trace.getSpan(0))
+                        .hasAttributesSatisfyingExactly(
+                            equalTo(SemanticAttributes.HTTP_METHOD, "GET"),
+                            equalTo(SemanticAttributes.HTTP_URL, uri + "/"),
+                            equalTo(SemanticAttributes.HTTP_FLAVOR, HTTP_1_1),
+                            equalTo(SemanticAttributes.HTTP_STATUS_CODE, 200),
+                            satisfies(
+                                SemanticAttributes.HTTP_RESPONSE_CONTENT_LENGTH,
+                                AbstractLongAssert::isNotNegative),
+                            equalTo(SemanticAttributes.NET_PEER_NAME, "localhost"),
+                            equalTo(SemanticAttributes.NET_PEER_PORT, server.httpPort()),
+                            equalTo(SemanticAttributes.NET_SOCK_PEER_ADDR, "127.0.0.1")),
+                span ->
+                    span.hasName("test-http-server").hasKind(SERVER).hasParent(trace.getSpan(1))));
+  }
+}