Axis log4j setup

As was described previously, Log4j will first attempt to configure itself from configuration files. A configuration equivalent to the default would look like:. Once the file above is placed into the classpath as log4j2. Changing the root level to trace will result in results similar to:.

Simply changing the log level would not accomplish the task. Instead, the solution is to add a new logger definition to the configuration:. With this configuration all log events from com. Bar will be recorded while only error events will be recorded from all other components. In the previous example all the events from com. Bar were still written to the Console. This is because the logger for com. Bar did not have any appenders configured while its parent did.

In fact, the following configuration. Notice that the trace messages from com. Bar appear twice. This is because the appender associated with logger com. Bar is first used, which writes the first instance to the Console. Next, the parent of com. Bar , which in this case is the root logger, is referenced. The event is then passed to its appender, which is also writes to the Console, resulting in the second instance. This is known as additivity. While additivity can be quite a convenient feature as in the first previous example where no appender reference needed to be configured , in many cases this behavior is considered undesirable and so it is possible to disable it by setting the additivity attribute on the logger to false:.

Once an event reaches a logger with its additivity set to false the event will not be passed to any of its parent loggers, regardless of their additivity setting. When configured from a File, Log4j has the ability to automatically detect changes to the configuration file and reconfigure itself.

The example below shows how to configure the attribute so that the configuration file will be checked for changes only after at least 30 seconds have elapsed. The minimum interval is 5 seconds. Log4j provides the ability to 'advertise' appender configuration details for all file-based appenders as well as socket-based appenders. For example, for file-based appenders, the file location and the pattern layout in the file are included in the advertisement.

Chainsaw and other external systems can discover these advertisements and use that information to intelligently process the log file. The mechanism by which an advertisement is exposed, as well as the advertisement format, is specific to each Advertiser implementation. An external system which would like to work with a specific Advertiser implementation must understand how to locate the advertised configuration as well as the format of the advertisement.

For example, a 'database' Advertiser may store configuration details in a database table. An external system can read that database table in order to discover the file location and the file format. Chainsaw automatically discovers log4j's multicastdns-generated advertisements and displays those discovered advertisements in Chainsaw's Zeroconf tab if the jmdns library is in Chainsaw's classpath.

To begin parsing and tailing a log file provided in an advertisement, just double-click the advertised entry in Chainsaw's Zeroconf tab. Currently, Chainsaw only supports FileAppender advertisements. FileAppender-based configurations require an additional 'advertiseURI' attribute to be specified on the appender.

The 'advertiseURI' attribute provides Chainsaw with information on how the file can be accessed. As of version 2. If you want to split the configuration in multiple files, use XInclude or Composite Configuration.

As the previous examples have shown as well as those to follow, Log4j allows you to easily redefine logging behavior without needing to modify your application. It is possible to disable logging for certain parts of the application, log only when specific criteria are met such as the action being performed for a specific user, route output to Flume or a log reporting system, etc.

Being able to do this requires understanding the syntax of the configuration files. The level of internal Log4j events that should be logged to the console. Valid values for this attribute are "trace", "debug", "info", "warn", "error" and "fatal". Log4j will log details about initialization, rollover and other internal actions to the status logger. Alternatively, setting system property log4j2. Log4j can be configured using two XML flavors; concise and strict. The concise format makes configuration very easy as the element names match the components they represent however it cannot be validated with an XML schema.

For example, the ConsoleAppender is configured by declaring an XML element named Console under its parent appenders element. However, element and attribute names are are not case sensitive.

In addition, attributes can either be specified as an XML attribute or as an XML element that has no attributes and has a text value. The file below represents the structure of an XML configuration, but note that the elements in italics below represent the concise element names that would appear in their place. See the many examples on this page for sample appender, filter and logger declarations. This is accomplished by replacing the friendly element names above with their object type as shown below.

For example, instead of the ConsoleAppender being configuerd using an element named Console it is instead configured as an appender element with a type attribute containing "Console". Where a key contains more than a simple value it itself will be a subordinate plugin. Note that in the RoutingAppender the Route element has been declared as an array. This is valid because each array element will be a Route component.

This won't work for elements such as appenders and filters, where each element has a different name in the concise format. Appenders and filters can be defined as array elements if each appender or filter declares an attribute named "type" that contains the type of the appender. The following example illustrates this as well as how to declare multiple loggers as an array.

Additional runtime dependencies are required for using JSON configuration files. Log4j also supports using YAML for configuration files.

For example:. Additional runtime dependencies are required for using YAML configuration files. An understanding of how loggers work in Log4j is critical before trying to configure them. Please reference the Log4j architecture if more information is required. Trying to configure Log4j without understanding those concepts will lead to frustration.

A LoggerConfig is configured using the logger element. The logger element must have a name attribute specified, will usually have a level attribute specified and may also have an additivity attribute specified. The additivity attribute may be assigned a value of true or false. If the attribute is omitted the default value of true will be used.

A LoggerConfig including the root LoggerConfig can be configured with properties that will be added to the properties copied from the ThreadContextMap. These properties can be referenced from Appenders, Filters, Layouts, etc just as if they were part of the ThreadContext Map. The properties can contain variables that will be resolved either when the configuration is parsed or dynamically when each event is logged.

See Property Substitution for more information on using variables. The LoggerConfig may also be configured with one or more AppenderRef elements. Each appender referenced will become associated with the specified LoggerConfig.

If multiple appenders are configured on the LoggerConfig each of them be called when processing logging events. Every configuration must have a root logger. The main differences between the root logger and other loggers are. An appender is configured either using the specific appender plugin's name or with an appender element and the type attibute containing the appender plugin's name.

In addition each appender must have a name attribute specified with a value that is unique within the set of appenders. The name will be used by loggers to reference the appender as described in the previous section. Most appenders also support a layout to be configured which again may be specified either using the specific Layout plugin's name as the element or with "layout" as the element name along with a type attribute that contains the layout plugin's name.

The various appenders will contain other attributes or elements that are required for them to function properly. Although only a single filter element can be configured, that element may be the filters element which represents the CompositeFilter.

The filters element allows any number of filter elements to be configured within it. The following example shows how multiple filters can be configured on the ConsoleAppender. Note that the property syntax is NOT the same as the syntax used in Log4j 1. Like the XML and JSON configurations, properties configurations define the configuration in terms of plugins and attributes to the plugins.

Prior to version 2. Each of those components will then be expected to be defined in sets of properties that begin with component. The identifier does not have to match the name of the component being defined but must uniquely identify all the attributes and subcomponents that are part of the component.

If the list of identifiers is not present the identier must not contain a '. Logging is invaluable when troubleshooting Java applications. In fact, logging is invaluable in troubleshooting in general, no matter if that is a Java application or a hardware switch or firewall. Both the software and hardware give us a look into how they are working in the form of parametrized logs enriched with contextual information. In this article, we introduced you to Log4j 2.

I hope this article gave you an idea on how to deal with Java application logs using Log4j 2. Try Sematext Logs to see how much easier things could be. Start Your Free Trial. LogManager; import org. A simple test — running the above code gives the following output: Log4j 2 Configuration Log4j 2 can be configured in one of the two ways: By using the configuration file. In this blog post, we will use this method. Programmatically by creating the ConfigurationFactory and Configuration implementations, or by using the exposed APIs in the Configuration interface or by calling internal Logger methods.

If we run the example code mentioned above with our new XML configuration the output will be as follows: Just as we expected we have both log messages present in the console.

To achieve similar results as we got with the XML based configuration we would use the following properties: appender. Log4j 2 Logger The Logger is the main entity that our application uses to create LogRecord, so basically to log what we want to output as the log message.

Log4j 2 Appenders Log4j 2 appender is responsible for delivering LogEvents to their destination. The not-so-full list of appenders in Log4j 2: ConsoleAppender — writes the data to System. After running the above code we will see the following output on the console: Syslog Appender One of the useful appenders is the SyslogAppender that enables sending the log events generated by our application to a Syslog compatible destination.

Custom Appenders If the appenders that come out of the box with Log4j 2 are not enough we can create our own implementations.

For example: package com. Appender; import org. Core; import org. Filter; import org. LogEvent; import org. AbstractAppender; import org.

Plugin; import org. PluginAttribute; import org. PluginElement; import org. Finally, we just need to configure Log4j to include our plugin. Log4j 2 Layouts Layout is used by the appender to format a LogEvent into a form that is defined.

By default, there are a few layouts available in Log4j 2 some of them require additional runtime dependencies : Pattern — uses a string pattern to format log events learn more about the Pattern layout CSV — the layout for writing data in the CSV format GELF — layout for writing events in the Graylog Extended Log Format 1.

Filters can be configured in one of the following locations: Directly in the Configuration for context — wide filters In the Logger for the logger specific filtering In the Appender for appender specific filtering In the Appender reference to determine if the log event should reach a given appender There are a few out-of-the-box filters and we can also develop our own filters.

Log4j 2 Asynchronous Logging The asynchronous logging is a new addition to Log4j 2. There are several benefits and drawbacks of using asynchronous logging. The benefits are: Higher peak throughput Lower logging response time latency There are also drawbacks: Complicated error handling Will not give a higher performance on machines with low CPU count If you log more than the appender can process, the speed of logging will be dedicated by the slowest appender because of the queue filling up If at this point you still think about turning on asynchronous logging you need to be aware that additional runtime dependencies are needed.

This could be done by using the Thread Context in the following way: package com. Logger; import org. The output of running the above code with the above configuration would be as follows: What Is a Marker Markers are named objects that are used to enrich the data. How to do that? Look at the following code example that uses filtering to achieve that: package com.

LoggerFactory; import org. Marker; import org. While the file that is created by the File appender will contain the following log message: Exactly what we wanted! Java Logging with Log Management Tools: How Sematext Logs Can Help Now that we know how to use and configure logging with Log4j 2 in our Java application you may be overwhelmed by how many logs your applications will produce.

Wrapping up Logging is invaluable when troubleshooting Java applications. Good luck! When a logger receives a log message, it passes it on or filters it based on its configured level. This table shows the relationship between logger configuration and log message level. Next, rerun the program. The application logs all of the messages that are debug level or higher. Log4j arranges loggers in a hierarchy. This makes specifying a different configuration for individual classes possible. After Main does its logging, it calls LoggerChild.

Loggers are named in the logger section. We set com. If set to true, both loggers will process the same message. Some systems want to add the same message to two different logs. We only saw the error message from Main but still saw the debug message from LoggerChild! Add a second file appender.

To do this, create a list with the original appender and the second one with a different name and file. Your Appenders section should look like this:.

Next, point the LoggerChild logger at the new appender. Your Loggers section will look like this. PatternLayout is an instance of a Log4j layout class. By specifying a pattern, we control the format of log messages when they are written by the appender.

There are many additional operators for PatternLayout. The interface maps closely to Log4J and LogKit. While semantics for these methods are ultimately defined by the implementation of the Log interface, it is expected that the severity of messages is ordered as shown in the above list.

These are typically used to guard code that only needs to execute in support of logging, and that introduces undesirable runtime overhead in the general case logging disabled. It is important to ensure that log message are appropriate in content and severity. The following guidelines are suggested:. Configuration of the behavior of the JCL ultimately depends upon the logging toolkit being used. Use this system property to specify the name of a Log4J configuration file. If not specified, the default configuration file is log4j.

A log4j. This properties file can sometimes be overridden by placing a file of the same name so as to appear before axis. However, the precise behaviour depends on the classloader that is in use at the time, so we don't recommend this technique. A safe way of overriding the properties file is to replace it in axis. However, this isn't very convenient, especially if you want to tweak the properties during a debug session to filter out unwanted log entries.

A more convenient alternative is to use an absolute file path to specify the properties file. This will even ignore web app's and their classloaders. So, for example on Linux, you could specify the system property:. A good way of telling where log4j is getting its configuration from is to set this system property and look at the messages on standard output. Set the priority for the named logger and all loggers hierarchically lower than, or below, the named logger.

Log4J understands hierarchical names, enabling control by package or high-level qualifiers: log4j. Likewise, setting log4j. A combination of settings will enable you to see the log events that you are interested in and omit the others. For example, the combination:. Log4J appenders correspond to different output devices: console, files, sockets, and others.

If appender's threshold is less than or equal to the message priority then the message is written by that appender. This allows different levels of detail to be appear at different log destinations. Any servlet that is derived from the org. AxisServlet class supports a number of standard query strings? Axis servlets are not limited to these three query strings and developers may create their own "plug-ins" by implementing the org.

QSHandler interface. There is one method in this interface that must be implemented, with the following signature:. MessageContext instance provides the developer with a number of useful objects such as the Axis engine instance, and HTTP servlet objects that are accessible by its getProperty method. The following constants can be used to retrieve various objects provided by the Axis servlet invoking the query string plug-in:.

A String containing the name of the query string plug-in. For instance, if the query string? A Boolean containing true if this version of Axis is considered to be in development mode, false otherwise. A Boolean containing true if listing of the Axis server configuration is allowed, false otherwise. The javax. HttpServletRequest object from the Axis servlet that invoked the query string plug-in. HttpServletResponse object from the Axis servlet that invoked the query string plug-in. The java.

PrintWriter object from the Axis servlet that invoked the query string plug-in. Log object from the Axis servlet that invoked the query string plug-in, which is used to log messages. Log object from the Axis servlet that invoked the query string plug-in, which is used to log exceptions.

Query string plug-in development is much like normal servlet development since the same basic information and methods of output are available to the developer. Below is an example query string plug-in which simply displays the value of the system clock import statements have been omitted for brevity :. Once a query string plug-in class has been created, the Axis server must be set up to recognize the query string which invokes it.

Axis is in the process of moving away from using system properties as the primary point of internal configuration. Avoid calling System. Using this central point of access will allow the global configuration system to be redesigned to better support multiple Axis engines in a single JVM.

Guidelines for Axis exception handling are based on best-practices for exception handling. While there are details specific to Axis in these guidelines, they apply in principle to any project; they are included here for two reasons. Second, because adherence to these guidelines is considered crucial to enterprise ready middleware. These guidelines are fundamentally independent of programming language. Finally, these are guidelines.

There will always be exceptions to these guidelines, in which case all that can be asked as per these guidelines is that they be logged in the form of comments in the code. If code catches an exception, it should know what to do with it at that point in the program.

Any exception to this rule must be documented with a GOOD reason. Code reviewers are invited to put on their vulture beaks and peck away Inner code is code deep within the program. Such code should catch specific exceptions, or categories of exceptions parents in exception hierarchies , if and only if the exception can be resolved and normal flow restored to the code. Note that behaviour of this sort may be significantly different between non-interactive code versus an interactive tool.

Ultimately, all exceptions must be dealt with at one level or another. For command-line tools, this means the main method or program. For a middleware component, this is the entry point s into the component. For Axis this is AxisServlet or equivalent. After catching specific exceptions which can be resolved internally, the outermost code must ensure that all internally generated exceptions are caught and handled.

While there is generally not much that can be done, at a minimum the code should log the exception. In addition to logging, the Axis Server wraps all such exceptions in AxisFaults and returns them to the client code.