I have created the below basic program in JAVA to display the log message in console using log4j,
import org.apache.logging.log4j.*;
import org.apache.logging.*;
public class Test {
public final static Logger log=LogManager.getLogger(Test.class.getName());
public static void main(String[] args) {
log.log(Level.TRACE,"Testing");
if(log.isTraceEnabled())
System.out.println("Trace Enabled");
else
System.out.println("Trace not Enabled");
log.trace("Entering Log4j Example.");
log.info("Started");
log.fatal("Error occured");
log.error("Dkjdsfh");
log.debug("Debugging");
log.info("Success");
log.warn("Warning");
}
}
But, the above code displaying only ERROR/FATAL message, other log messages not displayed in console. Below is my log4j.xml configuration,
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
<!-- Define custom levels before using them for filtering below. -->
<CustomLevels>
<CustomLevel name="DIAG" intLevel="350" />
<CustomLevel name="NOTICE" intLevel="450" />
<CustomLevel name="VERBOSE" intLevel="550" />
</CustomLevels>
<Appenders>
<Console name="Console" target="SYSTEM_OUT">
<PatternLayout pattern="%d %-7level %logger{36} - %msg%n"/>
</Console>
<File name="MyFile" fileName="logs/app.log">
<PatternLayout pattern="%d %-7level %logger{36} - %msg%n"/>
</File>
</Appenders>
<Loggers>
<Root level="trace">
<!-- Only events at DIAG level or more specific are sent to the console. -->
<AppenderRef ref="Console" level="diag" />
<AppenderRef ref="MyFile" level="trace" />
</Root>
</Loggers>
</Configuration>
Also, I have the below jar files to the build path,
log4j-api-2.13.3.jar
log4j-core-2.13.3.
Output of my program:
Trace not Enabled
16:55:40.104 [main] FATAL Test - Error occured
16:55:40.107 [main] ERROR Test - Dkjdsfh
Can someone please help me where I am doing mistake?
Thanks in advance.
You set your custom "DIAG" level to 350. 350 is lower than INFO (400), so INFO, DEBUG and TRACE levels are not shown on the console.
If you check your file output, it should contain everything.
OFF 0
FATAL 100
ERROR 200
WARN 300
INFO 400
DEBUG 500
TRACE 600
Either change the intLevel or pass a different level to the appender.
See custom log levels
I am trying to set up log4j in a simple Java project. I keep getting the following message when running my project.
ERROR StatusLogger No log4j2 configuration file found. Using default configuration: logging only errors to the console.
However I have added log4j.xml to my classpath. For example am I doing this in my main method:
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import java.io.InputStream;
import java.io.StringWriter;
import java.net.URL;
import java.net.URLClassLoader;
public class main {
private static Logger logger = LogManager.getLogger("Test");
static String convertStreamToString(java.io.InputStream is) {
java.util.Scanner s = new java.util.Scanner(is).useDelimiter("\\A");
return s.hasNext() ? s.next() : "";
}
public static void main(String [] args) {
InputStream cl = ClassLoader.getSystemClassLoader().getResourceAsStream("log4j.xml");
System.out.println(convertStreamToString(cl));
}
}
When I execute this code I get the contents of my log4j.xml file, which would make it seem the the file is being loaded onto my class path properly?
Here is the content of my xml file:
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
<Appenders>
<Console name="Console" target="SYSTEM_OUT">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
</Console>
</Appenders>
<Loggers>
<Logger name="com.foo.Bar" level="trace">
<AppenderRef ref="Console"/>
</Logger>
<Root level="error">
<AppenderRef ref="Console"/>
</Root>
</Loggers>
</Configuration>
Any ideas on what I am doing wrong?
Change the file name of log4j.xml to log4j2.xml.
I hope it helps.
I'm trying to figure out how I can add an appender to a logger dependent on whether a java system property is given / set.
So let's say I have a basic configuration like this:
<Logger name="myLogger" level="info" additivity="false">
<AppenderRef ref="myAppender1" />
<AppenderRef ref="myAppender2" />
</Logger>
So now I'd like to figure out a way to conditionally only add the 2nd appender if I provide a parameter -PaddAppender2. Something like this:
<Logger name="myLogger" level="info" additivity="false">
<AppenderRef ref="myAppender1" />
<?if (${sys:enableAppender2:-false) == "true"}>
<AppenderRef ref="myAppender2" />
</?if>
</Logger>
How do I do that?
I know I can for example make the level dynamic on a given property ("logLevel") like that (where "info" is the default if the property is not given):
<Logger name="test" level="${sys:logLevel:-info}" additivity="false">
I looked at the documentation for filters, and I can't figure it out. That is of course if filters are even the right way to go here.
Solution without any scripting:
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="error" strict="true">
<Properties>
<Property name="appenderToUse">stdout_${sys:LOG4J_LAYOUT:-plain}</Property>
</Properties>
<Appenders>
<Appender type="Console" name="stdout_plain">
<Layout type="PatternLayout" pattern="%d [%t] %-5p %c - %m%n"/>
</Appender>
<Appender type="Console" name="stdout_json">
<Layout type="JSONLayout" compact="true" eventEol="true" stacktraceAsString="true" properties="true"/>
</Appender>
</Appenders>
<Loggers>
<Root level="info">
<AppenderRef ref="${appenderToUse}"/>
</Root>
</Loggers>
</Configuration>
The solution provided by Robert works, but it is not efficient as the script will be evaluated once per log record.
A more efficient solution that evaluates the script only once is to use ScriptAppenderSelector together with the NullAppender:
According to the docs:
ScriptAppenderSelector
When the configuration is built, the ScriptAppenderSelector appender calls a Script to compute an appender name. Log4j then creates one of the appender named listed under AppenderSet using the name of the ScriptAppenderSelector. After configuration, Log4j ignores the ScriptAppenderSelector.
NullAppender
An Appender that ignores log events. Use for compatibility with version 1.2 and handy for composing a ScriptAppenderSelector.
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="warn" name="ScriptAppenderSelectorExample">
<Appenders>
<ScriptAppenderSelector name="SelectConsole">
<Script language="groovy"><![CDATA[
if (System.getProperty("CONSOLE_APPENDER_ENABLED", 'true').equalsIgnoreCase('true')) {
return "Console"
} else {
return "Null"
}
]]></Script>
<AppenderSet>
<Console name="Console" target="SYSTEM_OUT">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
</Console>
<Null name="Null" />
</AppenderSet>
</ScriptAppenderSelector>
<ScriptAppenderSelector name="SelectFile">
<Script language="groovy"><![CDATA[
if (System.getProperty("FILE_APPENDER_ENABLED", 'true').equalsIgnoreCase('true')) {
return "File"
} else {
return "Null"
}
]]></Script>
<AppenderSet>
<File name="File" fileName="application.log">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n" />
</File>
<Null name="Null" />
</AppenderSet>
</ScriptAppenderSelector>
<ScriptAppenderSelector name="SelectSMTP">
<Script language="groovy"><![CDATA[
if (System.getProperty("SMTP_APPENDER_ENABLED", 'true').equalsIgnoreCase('true')) {
return "SMTP"
} else {
return "Null"
}
]]></Script>
<AppenderSet>
<SMTP name="SMTP"
subject="App: Error"
from="log4j#example.com"
to="support#example.com"
smtpHost="smtp.example.com"
smtpPort="25"
bufferSize="5">
</SMTP>
<Null name="Null" />
</AppenderSet>
</ScriptAppenderSelector>
</Appenders>
<Loggers>
<Root level="info">
<AppenderRef ref="SelectConsole"/>
<AppenderRef ref="SelectFile"/>
<AppenderRef ref="SelectSMTP"/>
</Root>
</Loggers>
</Configuration>
References
Is there a low overhead way to enable/disable a given appender based on the value of an environment variable or system property?
Similar to rgoers solution but using nashorn instead of groovy. This solution benefits from fact that Nashorn engine is part of
Java 8 so there is no additional dependencies needed.
<Scripts>
<Script name="isAppender2Enabled" language="nashorn"><![CDATA[
var System = Java.type('java.lang.System'),
Boolean = Java.type('java.lang.Boolean');
Boolean.parseBoolean(System.getProperty('enableAppender2', 'false'));
]]></Script>
</Scripts>
<Loggers>
<Logger name="myLogger" level="info" additivity="false">
<AppenderRef ref="myAppender1" />
<AppenderRef ref="myAppender2">
<ScriptFilter onMatch="ACCEPT" onMisMatch="DENY">
<ScriptRef ref="isAppender2Enabled" />
</ScriptFilter>
</AppenderRef>
</Logger>
</Loggers>
Note that ScriptFilter is evaluating the script every time when Log4j event occurs. Therefore it is possible to enable/disable the appender on the run time (by changing the value of the system property) with immediate effect. On the other hand, script evaluation can have negative impact on logging performance.
I wasn't able to figure out a solution via config file alone, but I found one that solves the problem programmatically.
Note that in our specific case, we always log to a "local log" ("splunk local"), but in given cases (controlled by the property), we also want to log the same information to another location (that is not relative) and is periodically read and forwarded to a splunk server ("splunk forwarder").
And that's why we can copy most of the properties from one logger to the other.
private static final Logger SPLUNK_LOG = getLogger();
private static Logger getLogger() {
if (!BooleanUtils.toBoolean(SystemUtils.getJavaPropertyValue(ENABLE_PROPERTY_NAME, "false"))) {
return LoggerFactory.getLogger(SPLUNK_LOG_NAME);
} else {
LOG.info("Dynamically adding splunk forwarder appender");
try {
final LoggerContext loggerContext = (LoggerContext) LogManager.getContext();
final Configuration configuration = loggerContext.getConfiguration();
// configure appender based on local splunk appender
final RollingFileAppender splunkLocal = (RollingFileAppender) configuration.getAppender(LOCAL_LOG_NAME);
final RollingFileAppender splunkForwarder = RollingFileAppender.createAppender(FORWARDER_FILE_NAME,
FORWARDER_FILE_PATTERN, FORWARDER_APPEND, FORWARDER_NAME, null, null, null,
splunkLocal.getManager().getTriggeringPolicy(), splunkLocal.getManager().getRolloverStrategy(),
splunkLocal.getLayout(), splunkLocal.getFilter(), null, FORWARDER_ADVERTISE, null, null);
splunkForwarder.start();
// add splunk forwarder appender to splunk logger
final LoggerConfig loggerConfig = configuration.getLoggerConfig(SPLUNK_LOG_NAME);
loggerConfig.addAppender(splunkForwarder, Level.INFO, null);
LOG.info("Successfully added splunk forwarder appender");
return loggerContext.getLogger(SPLUNK_LOG_NAME);
} catch (Exception ex) {
throw new IllegalStateException("Failed to dynamically add splunk forwarder appender", ex);
}
}
}
If anyone knows how to do this via config file alone, that would be great.
The way this is intended to be handled is by using a filter. In this case you can use a Script filter.
<Logger name="myLogger" level="info" additivity="false">
<AppenderRef ref="myAppender1" />
<AppenderRef ref="myAppender2">
<ScriptFilter onMatch="ACCEPT" onMisMatch="DENY">
<Script language="groovy"><![CDATA[
return System.getProperty("enableAppender2", "false").equalsIgnoreCase("true");
]]></Script>
</ScriptFilter>
</AppenderRef>
</Logger>
Building on some of the ideas in this thread, here's what I did to conditionally log to console.
Example use-case
Always log to a file appender.
Log to Console only in some environments.
Solution
For Console logging, set system property additional.log.appender=console
Or, disable Console logging by omitting this property.
In the Logger AppenderRef, use ${sys:additional.log.appender:-null}.
Sends logs to the console appender if the system property was set, or defaults to null appender if not set. (null appender ignores logs)
System Property
# set for console logging
additional.log.appender=console
log4j2.xml
<?xml version="1.0" encoding="UTF-8"?>
<Configuration>
<Appenders>
<RollingFile name="file"
fileName="my-file.log"
filePattern="my-file%i.log">
<PatternLayout pattern="%d %5p [%t] %c - %m%n" />
<Policies>
<SizeBasedTriggeringPolicy size="10 MB" />
</Policies>
<DefaultRolloverStrategy max="10" />
</RollingFile>
<Console name="console" target="SYSTEM_OUT">
<PatternLayout pattern="%d %5p [%t] %c - %m%n" />
</Console>
<Null name="null" />
</Appenders>
<Loggers>
<Logger name="com.acme" level="DEBUG">
</Logger>
<Root level="INFO">
<AppenderRef ref="file" />
<AppenderRef ref="${sys:additional.log.appender:-null}" />
</Root>
</Loggers>
</Configuration>
I cannot get Log4j 2 to log to the console. Nothing is showing up when running with gradle.
log4j2.xml in the projects root directory:
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="ALL">
<Appenders>
<Console name="Console" target="SYSTEM_OUT">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
</Console>
</Appenders>
<Loggers>
<Root level="all">
<AppenderRef ref="Console"/>
</Root>
</Loggers>
</Configuration>
Usage in my classes:
public class ABCHandler {
private final Logger logger = LogManager.getLogger();
public ABC(String serialPortName) {
logger.info("Opening serial port {}", serialPortName);
}
}
Loading your file and configurations on my machine works.
This was the class I used:
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
public class Test
{
private final Logger logger = LogManager.getLogger(Test.class);
public Test(String serialPortName) {
System.out.println(logger.isInfoEnabled());
logger.entry();
logger.info("info! {}", serialPortName);
logger.error("error! {}", serialPortName);
logger.debug("debug! {}", serialPortName);
}
public static void main(String args[])
{
Test h1 = new Test("1001");
}
}
This is the log4j2.xml:
<ThresholdFilter level="all"/>
<Appenders>
<Console name="STDOUT" target="SYSTEM_OUT">
<PatternLayout pattern="%d %-5p method: [%t] %C{2} (%F:%L) - %m%n"/>
</Console>
</Appenders>
<Loggers>
<Root level="all">
<AppenderRef ref="STDOUT"/>
</Root>
</Loggers>
and finally, this is the output:
true
2014-05-29 12:19:15,266 TRACE method: [main] Test (Test.java:10) - entry
2014-05-29 12:19:15,268 INFO method: [main] Test (Test.java:11) - info! 1001
2014-05-29 12:19:15,269 ERROR method: [main] Test (Test.java:12) - error! 1001
2014-05-29 12:19:15,269 DEBUG method: [main] Test (Test.java:13) - debug! 1001
One common error when using Log4j2 is placing the log4j2.xml in a file that is not in the classpath.
To diagnose if that is the problem, change the line
logger.info("Opening serial port {}", serialPortName);
to
logger.error("Opening serial port {}", serialPortName);
If you see any output it is because log4j can't load your file. This is because the default log level when the file is not found is ERROR, not DEBUG.
The location of the log4j2.xml on my project (Maven) is in src/main/resources, which I know it is in my classpath.
My problems were:
I was using a log4j.properties file. Once renamed to log4j2.properties the main and test classpaths picked it up
I had to add logging to standard output to build.gradle
test {
testLogging.showStandardStreams = true
}
note: when I added sourcesets according to here it still didn't find the log4j.properties file only renaming it worked!
I'm using log4j 2.0-beta9. I have a question about the SMTP appender. I need to configure the subject, from and to values from properties. I'm logging a MapMessage and my config is as below -
<?xml version="1.0" encoding="UTF-8"?>
<configuration status="DEBUG">
<appenders>
<Console name="Console" target="SYSTEM_OUT">
<PatternLayout pattern="%d [%t] %-5p %c - %m%n"/>
</Console>
<SMTP name="Mail" subject="Error Log for ${env:HOSTNAME}" to="${sys:mail.to}" from="${sys:mail.from}"
smtpHost="${sys:mail.host}" smtpPort="${sys:mail.port}" smtpDebug="true" bufferSize="1">
<PatternLayout>
<pattern>%d [%t] %-5p %c - %m%n</pattern>
</PatternLayout>
</SMTP>
<Async name="AsyncMail">
<appender-ref ref="Mail" />
</Async>
</appenders>
<loggers>
<root level="info">
<appender-ref ref="Console"/>
<appender-ref ref="AsyncMail">
<MapFilter onMatch="ACCEPT" onMismatch="DENY">
<KeyValuePair key="throwable.class" value="java.lang.RuntimeException" />
</MapFilter>
</appender-ref>
</root>
</loggers>
</configuration>
// Java Code to log the msg
Throwable throwable; // this is the exception that is thrown by the app.
MapMessage message = new MapMessage();
message.put("throwable.message", throwable.getMessage());
message.put("throwable.class", throwable.getClass().getName());
message.put("throwable.stacktrace", ExceptionUtils.getStackTrace(throwable)); // ExceptionUtils from apache-commons
LOGGER.error(message, throwable); // org.apache.logging.log4j.Logger
The problem is that none of these values are replaced dynamically. Is there any way to do this?
Thanks in advance.
You need to set the mail.to and mail.from System properties. The problem you're having might be that you're running in a Servlet 3.0 environment, in which case the Log4j2.xml file is being processed before your code that sets the properties is executed.
If that is the case, you can create a servlet container initializer that you configure in your web.xml file to load before Log4j2's servlet container initializer is loaded.