How to enable embedded tomcat logging

Question

I m using embedded tomcat in my java application. below is my source code. however tomcat is not generating any log.

        embedded = new Embedded();
        embedded.setDebug(3);

        org.apache.catalina.logger.FileLogger embeddedFileLogger = new org.apache.catalina.logger.FileLogger();         
        embeddedFileLogger.setDirectory(tomcatHome+"/log");
        embeddedFileLogger.setPrefix("Embedded_log_");
        embeddedFileLogger.setSuffix(".txt");
        embeddedFileLogger.setTimestamp(true);
        embeddedFileLogger.setVerbosity(3);



        //embedded.setLogger(new SystemOutLogger());
        engine = embedded.createEngine();
        //engine.setLogger(embeddedFileLogger);
        embeddedFileLogger.setContainer(engine);
        engine.setDefaultHost("localhost");

        host = embedded.createHost("localhost", tomcatHome + "/webapps");
        //host.setLogger(embeddedFileLogger);
        engine.addChild(host);

        _context = embedded.createContext("", tomcatHome + "/webapps/ROOT");
        host.addChild(_context);

        embedded.addEngine(engine);

        CoyoteConnector connector = (CoyoteConnector)embedded.createConnector(InetAddress.getByName(ipAddress), port, false);               
                   embedded.addConnector(connector);
        embedded.setLogger(embeddedFileLogger);
        embedded.start();

Please let me know how can i enable embedded tomcat logging through code or tomcat configuration.

Answer 1

Here is what worked for me (Tomcat 9.0.38):

Add system property to point to my logging config:

-Djava.util.logging.config.file=/absolute/path/to/logging.properties

And the contents of logging.properties is:

java.util.logging.ConsoleHandler.level = FINE
java.util.logging.ConsoleHandler.formatter = org.apache.juli.OneLineFormatter
java.util.logging.ConsoleHandler.encoding = UTF-8
handlers = java.util.logging.ConsoleHandler
org.apache.coyote.http2.level = FINE

Answer 2

By default the embedded Tomcat uses the logging configuration provided by the JDK. If you haven't changed the configuration only a ConsoleHandler is configured. If you wanted to programmatically add a FileHandler you can add it to the root logger. Here's an example that writes to the file catalina.out by appending the messages on INFO level. This works for Tomcat 6.x and 7.x.

Logger logger = Logger.getLogger("");
Handler fileHandler = new FileHandler("catalina.out", true);
fileHandler.setFormatter(new SimpleFormatter());
fileHandler.setLevel(Level.INFO);
fileHandler.setEncoding("UTF-8");
logger.addHandler(fileHandler);