com.peterphi.std.guice.common.Log4JModule Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of stdlib-guice-common Show documentation
stdlib guice common
There is a newer version: 10.1.5
package com.peterphi.std.guice.common;

import com.codahale.metrics.MetricRegistry;
import com.codahale.metrics.log4j.InstrumentedAppender;
import com.google.inject.AbstractModule;
import com.peterphi.std.guice.apploader.GuiceProperties;
import com.peterphi.std.guice.common.serviceprops.composite.GuiceConfig;
import com.peterphi.std.io.PropertyFile;
import org.apache.commons.lang.StringUtils;
import org.apache.log4j.LogManager;
import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;

/**
 * Reads the log4j.properties value from the service config; if a value is supplied it searches the classpath for
 * this and loads it into log4j.

 * If the log4j.properties property is not specified then the default behaviour is observed (log4j configures itself
 * automatically)
 */
public class Log4JModule extends AbstractModule
{
	private static final Logger log = Logger.getLogger(Log4JModule.class);

	private static boolean allowAutoReconfigure = true;

	private GuiceConfig guiceConfig;
	private MetricRegistry registry;


	public Log4JModule(GuiceConfig configuration, MetricRegistry registry)
	{
		this.registry = registry;
		this.guiceConfig = configuration;
	}


	@Override
	protected void configure()
	{
		reconfigure(guiceConfig);

		// Register a custom appender for metrics gathering
		InstrumentedAppender log4jmetrics = new InstrumentedAppender(registry);
		log4jmetrics.activateOptions();
		LogManager.getRootLogger().addAppender(log4jmetrics);
	}


	public static void manualReconfigure(final GuiceConfig guice)
	{
		log.info("Manual reconfiguration of log4j.properties - disabling automatic reload!");
		allowAutoReconfigure = false;
		reconfigure(guice);
	}


	public static void autoReconfigure(final GuiceConfig guice)
	{
		if (allowAutoReconfigure)
			reconfigure(guice);
	}


	public static void setAllowAutoReconfigure(final boolean value)
	{
		allowAutoReconfigure = value;
	}


	public static boolean getAllowAutoReconfigure()
	{
		return allowAutoReconfigure;
	}


	private static void reconfigure(final GuiceConfig guice)
	{
		final PropertyFile config = getProperties(guice);

		if (config != null)
		{
			//reset any existing log config
			LogManager.resetConfiguration();

			//apply the specified properties
			PropertyConfigurator.configure(config.toProperties());
		}
		else
		{
			log.debug("Leaving logging subsystem to initialise itself");
		}
	}


	public static PropertyFile getProperties(final GuiceConfig guice)
	{
		final String log4jProperties = guice.get(GuiceProperties.LOG4J_PROPERTIES_FILE, null);

		if (log4jProperties == null)
			return null; // No log4j set up!

		if (StringUtils.contains(log4jProperties, '\n'))
		{
			log.debug("Assuming log4j.properties contains literal log4j.properties file, not a resource/file reference");
			return PropertyFile.fromString(log4jProperties, "log4j.inline");
		}
		else if (log4jProperties != null)
		{
			log.debug("Loading log4j configuration from " + log4jProperties);

			if (log4jProperties.equals("embedded"))
			{
				// Load the log4j config from the guice configuration
				return guice.toPropertyFile(key -> StringUtils.startsWithIgnoreCase(key, "log4j."));
			}
			else
			{
				// Load the log4j file directly
				PropertyFile props = PropertyFile.find(log4jProperties);

				// Now resolve any ${} properties within the log4j file against the guice config
				GuiceConfig temp = new GuiceConfig();
				temp.setAll(guice);
				temp.setAll(props);

				// Finally, extract the original property values with their values resolved
				return temp.toPropertyFile(key -> props.keySet().contains(key));
			}
		}
		else
		{
			// Won't actually happen but to guarantee there is a value for config later on
			throw new RuntimeException("log4j configuration is null!");
		}
	}
}