Improve configuration error handling of HttpAppender

log4j-core-test/src/test/java/org/apache/logging/log4j/core/appender/HttpAppenderBuilderTest.java

@@ -0,0 +1,130 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to you 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 org.apache.logging.log4j.core.appender;
+
+import static org.assertj.core.api.AssertionsForInterfaceTypes.assertThat;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.net.MalformedURLException;
+import java.net.URL;
+import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.core.Layout;
+import org.apache.logging.log4j.core.config.Configuration;
+import org.apache.logging.log4j.core.config.DefaultConfiguration;
+import org.apache.logging.log4j.core.config.Property;
+import org.apache.logging.log4j.core.layout.JsonLayout;
+import org.apache.logging.log4j.core.net.ssl.SslConfiguration;
+import org.apache.logging.log4j.test.ListStatusListener;
+import org.apache.logging.log4j.test.junit.UsingStatusListener;
+import org.junit.jupiter.api.Test;
+
+class HttpAppenderBuilderTest {
+
+    private HttpAppender.Builder<?> getBuilder() {
+        Configuration mockConfig = new DefaultConfiguration();
+        return HttpAppender.newBuilder().setConfiguration(mockConfig).setName("TestHttpAppender"); // Name is required
+    }
+
+    @Test
+    @UsingStatusListener
+    void testBuilderWithoutUrl(final ListStatusListener listener) throws Exception {
+        HttpAppender appender = HttpAppender.newBuilder()
+                .setConfiguration(new DefaultConfiguration())
+                .setName("TestAppender")
+                .setLayout(JsonLayout.createDefaultLayout()) // Providing a layout here
+                .build();
+
+        assertThat(listener.findStatusData(Level.ERROR))
+                .anyMatch(statusData ->
+                        statusData.getMessage().getFormattedMessage().contains("HttpAppender requires URL to be set."));
+    }
+
+    @Test
+    @UsingStatusListener
+    void testBuilderWithUrlAndWithoutLayout(final ListStatusListener listener) throws Exception {
+        HttpAppender appender = HttpAppender.newBuilder()
+                .setConfiguration(new DefaultConfiguration())
+                .setName("TestAppender")
+                .setUrl(new URL("http://localhost:8080/logs"))
+                .build();
+
+        assertThat(listener.findStatusData(Level.ERROR)).anyMatch(statusData -> statusData
+                .getMessage()
+                .getFormattedMessage()
+                .contains("HttpAppender requires a layout to be set."));
+    }
+
+    @Test
+    void testBuilderWithValidConfiguration() throws Exception {
+        URL url = new URL("http://example.com");
+        Layout<?> layout = JsonLayout.createDefaultLayout();
+
+        HttpAppender.Builder<?> builder = getBuilder().setUrl(url).setLayout(layout);
+
+        HttpAppender appender = builder.build();
+        assertNotNull(appender, "HttpAppender should be created with valid configuration.");
+    }
+
+    @Test
+    void testBuilderWithCustomMethod() throws Exception {
+        URL url = new URL("http://example.com");
+        Layout<?> layout = JsonLayout.createDefaultLayout();
+        String customMethod = "PUT";
+
+        HttpAppender.Builder<?> builder =
+                getBuilder().setUrl(url).setLayout(layout).setMethod(customMethod);
+
+        HttpAppender appender = builder.build();
+        assertNotNull(appender, "HttpAppender should be created with a custom HTTP method.");
+    }
+
+    @Test
+    void testBuilderWithHeaders() throws Exception {
+        URL url = new URL("http://example.com");
+        Layout<?> layout = JsonLayout.createDefaultLayout();
+        Property[] headers = new Property[] {
+            Property.createProperty("Header1", "Value1"), Property.createProperty("Header2", "Value2")
+        };
+
+        HttpAppender.Builder<?> builder =
+                getBuilder().setUrl(url).setLayout(layout).setHeaders(headers);
+
+        HttpAppender appender = builder.build();
+        assertNotNull(appender, "HttpAppender should be created with headers.");
+    }
+
+    @Test
+    void testBuilderWithSslConfiguration() throws Exception {
+        URL url = new URL("https://example.com");
+        Layout<?> layout = JsonLayout.createDefaultLayout();
+
+        // Use real SslConfiguration instead of Mockito mock
+        SslConfiguration sslConfig = SslConfiguration.createSSLConfiguration(null, null, null, false);
+
+        HttpAppender.Builder<?> builder =
+                getBuilder().setUrl(url).setLayout(layout).setSslConfiguration(sslConfig);
+
+        HttpAppender appender = builder.build();
+        assertNotNull(appender, "HttpAppender should be created with SSL configuration.");
+    }
+
+    @Test
+    void testBuilderWithInvalidUrl() {
+        assertThrows(MalformedURLException.class, () -> new URL("invalid-url"));
+    }
+}

log4j-core/src/main/java/org/apache/logging/log4j/core/appender/HttpAppender.java

@@ -32,16 +32,15 @@
 import org.apache.logging.log4j.core.config.plugins.PluginElement;
 import org.apache.logging.log4j.core.config.plugins.validation.constraints.Required;
 import org.apache.logging.log4j.core.net.ssl.SslConfiguration;
+import org.apache.logging.log4j.status.StatusLogger;
 
-/**
- * Sends log events over HTTP.
- */
 @Plugin(name = "Http", category = Node.CATEGORY, elementType = Appender.ELEMENT_TYPE, printObject = true)
 public final class HttpAppender extends AbstractAppender {
 
+    private static final StatusLogger LOGGER = StatusLogger.getLogger();
+
     /**
      * Builds HttpAppender instances.
-     * @param <B> The type to build
      */
     public static class Builder<B extends Builder<B>> extends AbstractAppender.Builder<B>
             implements org.apache.logging.log4j.core.util.Builder<HttpAppender> {
@@ -70,6 +69,18 @@ public static class Builder<B extends Builder<B>> extends AbstractAppender.Build
 
         @Override
         public HttpAppender build() {
+            // Validate URL presence
+            if (url == null) {
+                LOGGER.error("HttpAppender requires URL to be set.");
+                return null; // Return null if URL is missing
+            }
+
+            // Validate layout presence
+            if (getLayout() == null) {
+                LOGGER.error("HttpAppender requires a layout to be set.");
+                return null; // Return null if layout is missing
+            }
+
             final HttpManager httpManager = new HttpURLConnectionManager(
                     getConfiguration(),
                     getConfiguration().getLoggerContext(),
@@ -81,10 +92,12 @@ public HttpAppender build() {
                     headers,
                     sslConfiguration,
                     verifyHostname);
+
             return new HttpAppender(
                     getName(), getLayout(), getFilter(), isIgnoreExceptions(), httpManager, getPropertyArray());
         }
 
+        // Getter and Setter methods
         public URL getUrl() {
             return url;
         }
@@ -149,9 +162,6 @@ public B setVerifyHostname(final boolean verifyHostname) {
         }
     }
 
-    /**
-     * @return a builder for a HttpAppender.
-     */
     @PluginBuilderFactory
     public static <B extends Builder<B>> B newBuilder() {
         return new Builder<B>().asBuilder();

src/changelog/.2.x.x/3011_http_appender_validation.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<entry xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+       xmlns="https://logging.apache.org/xml/ns"
+       xsi:schemaLocation="https://logging.apache.org/xml/ns https://logging.apache.org/xml/ns/log4j-changelog-0.xsd"
+       type="fixed">
+  <issue id="3011" link="https://github.com/apache/logging-log4j2/issues/3011"/>
+  <description format="asciidoc">Improves validation of HTTP Appender.</description>
+</entry>