SAP CF Logging Async Servlet bug

DemoApplication.java

package com.example.demo;

import com.sap.hcp.cf.logging.servlet.filter.RequestLoggingFilter;
import org.apache.catalina.Context;
import org.apache.catalina.startup.Tomcat;
import org.apache.tomcat.util.descriptor.web.FilterDef;
import org.apache.tomcat.util.descriptor.web.FilterMap;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;


public class DemoApplication {
	private static final Logger LOG = LoggerFactory.getLogger(DemoApplication.class);

	public static void main(String[] args) {
		Tomcat tomcat = new Tomcat();
		tomcat.setPort(8080);

		File baseDir = new File("tomcat");
		tomcat.setBaseDir(baseDir.getAbsolutePath());

		File applicationDir = new File(baseDir + "/webapps", "/ROOT");
		if (!applicationDir.exists()) {
			applicationDir.mkdirs();
		}

		try {
			Context appContext = tomcat.addWebapp("/", "ROOT");

			Tomcat.addServlet(appContext, "demoServlet", new DemoServlet()).setAsyncSupported(true);
			appContext.addServletMapping("/*", "demoServlet");

			FilterDef filterDef = new FilterDef();
			filterDef.setAsyncSupported("true");
			filterDef.setFilterName("requestFilter");
			filterDef.setFilter(new RequestLoggingFilter());
			appContext.addFilterDef(filterDef);

			FilterMap filterMap = new FilterMap();
			filterMap.setDispatcher("ASYNC");
			filterMap.setDispatcher("REQUEST");
			filterMap.setFilterName("requestFilter");
			filterMap.addURLPattern("/*");
			appContext.addFilterMap(filterMap);

			tomcat.start();
			LOG.info("Tomcat server: http://localhost:8080/");
			tomcat.getServer().await();
		} catch (Exception e) {
			LOG.error("Unable to start tomcat.", e);
		}
	}
}

DemoServlet.java

package com.example.demo;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.AsyncContext;
import javax.servlet.DispatcherType;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;

public class DemoServlet extends HttpServlet {
	private static final Logger LOG = LoggerFactory.getLogger(DemoServlet.class);

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) {
		if (req.getDispatcherType() == DispatcherType.ASYNC) {
			return;
		}
		try {
			LOG.info("Inside sync method.");
			AsyncContext context = req.startAsync();
			context.start(() -> {
				try {
					LOG.info("Inside async method.");
					Thread.sleep(1000);
					HttpServletResponse response = (HttpServletResponse) context.getResponse();
					response.setStatus(201);
					try (PrintWriter writer = response.getWriter()) {
						writer.print("Something");
					}
					context.dispatch();
				} catch (Exception e) {
					LOG.error("Unable to process request.", e);
				}
			});
		} catch (Exception e) {
			LOG.error("Unable to service request.", e);
		}
	}
}

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.example</groupId>
	<artifactId>demo</artifactId>
	<version>0.0.1</version>
	<packaging>war</packaging>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
		<tomcat.version>8.5.2</tomcat.version>
		<cf-logging-version>2.1.4</cf-logging-version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.apache.tomcat.embed</groupId>
			<artifactId>tomcat-embed-core</artifactId>
			<version>${tomcat.version}</version>
		</dependency>
		<dependency>
			<groupId>org.apache.tomcat.embed</groupId>
			<artifactId>tomcat-embed-jasper</artifactId>
			<version>${tomcat.version}</version>
		</dependency>
		<dependency>
			<groupId>org.apache.tomcat</groupId>
			<artifactId>tomcat-jasper</artifactId>
			<version>${tomcat.version}</version>
		</dependency>
		<dependency>
			<groupId>org.apache.tomcat</groupId>
			<artifactId>tomcat-jasper-el</artifactId>
			<version>${tomcat.version}</version>
		</dependency>
		<dependency>
			<groupId>org.apache.tomcat</groupId>
			<artifactId>tomcat-jsp-api</artifactId>
			<version>${tomcat.version}</version>
		</dependency>
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>jstl</artifactId>
			<version>1.2</version>
		</dependency>
		<dependency>
			<groupId>org.apache.tomcat.embed</groupId>
			<artifactId>tomcat-embed-logging-log4j</artifactId>
			<version>${tomcat.version}</version>
		</dependency>

		<dependency>
			<groupId>com.sap.hcp.cf.logging</groupId>
			<artifactId>cf-java-logging-support-servlet</artifactId>
			<version>${cf-logging-version}</version>
		</dependency>
		<dependency>
			<groupId>com.sap.hcp.cf.logging</groupId>
			<artifactId>cf-java-logging-support-log4j2</artifactId>
			<version>${cf-logging-version}</version>
		</dependency>
		<dependency>
			<groupId>org.apache.logging.log4j</groupId>
			<artifactId>log4j-slf4j-impl</artifactId>
			<version>2.8.2</version>
		</dependency>
		<dependency>
			<groupId>org.apache.logging.log4j</groupId>
			<artifactId>log4j-core</artifactId>
			<version>2.8.2</version>
		</dependency>

	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-compiler-plugin</artifactId>
				<version>3.3</version>
				<configuration>
					<source>1.8</source>
					<target>1.8</target>
				</configuration>
			</plugin>

			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-jar-plugin</artifactId>
				<configuration>
					<archive>
						<manifest>
							<addClasspath>true</addClasspath>
							<classpathPrefix>lib/</classpathPrefix>
							<mainClass>org.junjun.util.spring.AppLauncher</mainClass>
						</manifest>
						<manifestEntries>
							<Class-Path>conf/</Class-Path>
						</manifestEntries>
					</archive>
					<includes>
						<include>**/*.class</include>
						<include>*.properties.not.configurable</include>
					</includes>
				</configuration>
			</plugin>
			<plugin>
				<artifactId>maven-assembly-plugin</artifactId>
				<executions>
					<execution>
						<id>build-distribution</id>
						<phase>verify</phase>
						<goals>
							<goal>attached</goal>
						</goals>
					</execution>
				</executions>
				<configuration>
					<descriptors>
						<descriptor>src/assembly/dist-build.xml</descriptor>
					</descriptors>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

sap-cf-logging-async-servlet.md

SAP CF Logging Async Servlet Bug

Small example which shows the async servlet logging missmatch.