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| <document> |
| |
| <properties> |
| <author email="nicko at apache dot org">Nicko Cadell</author> |
| <title>Apache log4net: Features</title> |
| </properties> |
| |
| <meta name="keywords" content="log4net features, log4net" /> |
| |
| <body> |
| <section id="main" name="Apache log4net™ Features"> |
| |
| <section id="overview" name="Overview"> |
| <p> |
| log4net is a tool to help the programmer output log statements to a |
| variety of output targets. In case of problems with an application, |
| it is helpful to enable logging so that the problem can be located. |
| With log4net it is possible to enable logging at runtime without |
| modifying the application binary. The log4net package is designed so |
| that log statements can remain in shipped code without incurring a |
| high performance cost. It follows that the speed of logging (or |
| rather not logging) is crucial. |
| </p> |
| <p> |
| At the same time, log output can be so voluminous that it quickly becomes |
| overwhelming. One of the distinctive features of log4net is the notion of |
| hierarchical loggers. Using these loggers it is possible to selectively |
| control which log statements are output at arbitrary granularity. |
| </p> |
| <p> |
| log4net is designed with two distinct goals in mind: speed and flexibility |
| </p> |
| </section> |
| |
| <section id="features" name="Features"> |
| <ul> |
| <li>Support for multiple frameworks</li> |
| <li>Output to multiple logging targets</li> |
| <li>Hierarchical logging architecture</li> |
| <li>XML Configuration</li> |
| <li>Dynamic Configuration</li> |
| <li>Logging Context</li> |
| <li>Proven architecture</li> |
| <li>Modular and extensible design</li> |
| <li>High performance with flexibility</li> |
| </ul> |
| </section> |
| |
| <section id="frameworks" name="Support for multiple frameworks"> |
| <p> |
| log4net runs on all ECMA CLI 1.0 compatible runtimes. |
| log4net has specific builds for the following frameworks: |
| </p> |
| <ul> |
| <li>.NET Core 1.0 - using netstandard-1.3</li> |
| <li>Microsoft® .NET Framework 1.0<sup><a href="#no-bin-support">*</a></sup></li> |
| <li>Microsoft .NET Framework 1.1<sup><a href="#no-bin-support">*</a></sup></li> |
| <li>Microsoft .NET Framework 2.0</li> |
| <li>Microsoft .NET Framework 3.5</li> |
| <li>Microsoft .NET Framework 4.0</li> |
| <li>Microsoft .NET Framework 4.5</li> |
| <li>Microsoft .NET Framework 3.5 Client Profile</li> |
| <li>Microsoft .NET Framework 4.0 Client Profile</li> |
| <li>Microsoft .NET Compact Framework 1.0<sup><a href="#no-bin-support">*</a></sup></li> |
| <li>Microsoft .NET Compact Framework 2.0<sup><a href="#no-bin-support">*</a></sup></li> |
| <li>Mono 1.0<sup><a href="#no-bin-support">*</a></sup></li> |
| <li>Mono 2.0</li> |
| <li>Mono 3.5</li> |
| <li>Mono 4.0</li> |
| <li>Microsoft Shared Source CLI 1.0<sup><a href="#no-bin-support">*</a></sup></li> |
| <li>CLI 1.0 Compatible<sup><a href="#no-bin-support">*</a></sup></li> |
| </ul> |
| <p>The "Client Profile" builds are stripped down |
| versions of the "normal" builds that don't contain any |
| ASP.NET releated code - which for example means the |
| <code>%aspnet-*</code> patterns and the |
| <code>AspNetTraceAppender</code> are not available.</p> |
| |
| <p style="font-size:smaller"> |
| <sup><a name="no-bin-support">*</a></sup>Not |
| supported by the binary release but can be built |
| from the source release. |
| </p> |
| </section> |
| |
| <section id="appenders" name="Output to multiple logging targets"> |
| <p> |
| log4net ships with the following appenders (not on all frameworks): |
| </p> |
| <div class="table"> |
| <table cellspacing="0"> |
| <tr> |
| <th> |
| Type</th> |
| <th> |
| Description</th> |
| </tr> |
| <tr> |
| <td>log4net.Appender.AdoNetAppender</td> |
| <td> |
| Writes logging events to a database using either prepared statements or stored |
| procedures. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.AnsiColorTerminalAppender</td> |
| <td> |
| Writes color highlighted logging events to a an ANSI terminal window. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.AspNetTraceAppender</td> |
| <td> |
| Writes logging events to the ASP trace context. These can then be rendered at |
| the end of the ASP page or on the ASP trace page. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.ColoredConsoleAppender</td> |
| <td> |
| Writes color highlighted logging events to the application's Windows Console. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.ConsoleAppender</td> |
| <td> |
| Writes logging events to the application's Console. The events may go to either |
| the standard our stream or the standard error stream. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.DebugAppender</td> |
| <td> |
| Writes logging events to the .NET system. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.EventLogAppender</td> |
| <td> |
| Writes logging events to the Windows Event Log. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.FileAppender</td> |
| <td> |
| Writes logging events to a file in the file system. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.LocalSyslogAppender</td> |
| <td> |
| Writes logging events to the local syslog service (UNIX only). |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.MemoryAppender</td> |
| <td> |
| Stores logging events in an in memory buffer. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.NetSendAppender</td> |
| <td> |
| Writes logging events to the Windows Messenger service. These messages are |
| displayed in a dialog on a users terminal. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.OutputDebugStringAppender</td> |
| <td> |
| Writes logging events to the debugger. If the application has no |
| debugger, the system debugger displays the string. If the application has no |
| debugger and the system debugger is not active, the message is ignored. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.RemoteSyslogAppender</td> |
| <td> |
| Writes logging events to a remote syslog service using UDP networking. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.RemotingAppender</td> |
| <td> |
| Writes logging events to a remoting sink using .NET remoting. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.RollingFileAppender</td> |
| <td> |
| Writes logging events to a file in the file system. The RollingFileAppender can |
| be configured to log to multiple files based upon date or file size |
| constraints. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.SmtpAppender</td> |
| <td> |
| Sends logging events to an email address. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.SmtpPickupDirAppender</td> |
| <td> |
| Sends logging events to an email |
| address but writes the emails to a |
| configurable directory rather than |
| sending them directly via SMTP. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.TelnetAppender</td> |
| <td> |
| Clients connect via Telnet to receive logging events. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.TraceAppender</td> |
| <td> |
| Writes logging events to the .NET trace system. |
| </td> |
| </tr> |
| <tr> |
| <td>log4net.Appender.UdpAppender</td> |
| <td> |
| Sends logging events as connectionless UDP datagrams to a remote host or a |
| multicast group using a UdpClient. |
| </td> |
| </tr> |
| </table> |
| </div> |
| <p>A special log4net.Appender.ForwardingAppender can |
| be used to wrap another appender, for example to |
| attach additional filters.</p> |
| </section> |
| |
| <section id="hierarchy" name="Hierarchical logging architecture"> |
| <p> |
| Hierarchical logging is an ideal fit with component based development. |
| Each component has its own of logger. When individually tested, the |
| properties of these loggers may be set as the developer requires. |
| When combined with other components, the loggers inherit the properties |
| determined by the integrator of the components. One can selectively elevate |
| logging priorities on one component without affecting the other components. |
| This is useful when you need a detailed trace from just a single component |
| without crowding the trace file with messages from other components. All |
| this can be done through configuration files; no code changes are required. |
| </p> |
| </section> |
| |
| <section id="xml-config" name="XML Configuration"> |
| <p> |
| log4net is configured using an XML configuration file. The configuration |
| information can be embedded within other XML configuration files |
| (such as the application's .config file) or in a separate file. The |
| configuration is easily readable and updateable while retaining the |
| flexibility to express all configurations. |
| </p> |
| <p> |
| Alternatively log4net can be configured programmatically. |
| </p> |
| </section> |
| |
| <section id="dynamic-config" name="Dynamic Configuration"> |
| <p> |
| log4net can monitor its configuration file for changes and dynamically |
| apply changes made by the configurator. The logging levels, appenders, |
| layouts, and just about everything else can be adjusted at runtime. |
| In many cases it is possible to diagnose application issues without |
| terminating the process in question. This can a very valuable tool in |
| investigating issues with deployed applications. |
| </p> |
| </section> |
| |
| <section id="context" name="Logging Context"> |
| <p> |
| log4net can be used to collect logging context data in a way that is transparent |
| to the developer at the point of logging. The GlobalContext and the |
| ThreadContext allow the application to store contextual data that is |
| attached to logging messages. For instance, in a web service, |
| once the caller is authenticated the username of the caller could be |
| stored in a ThreadContext property. This property would then be automatically |
| logged as part of each subsequent logging message made from the same thread. |
| </p> |
| </section> |
| |
| <section id="history" name="Proven architecture"> |
| <p> |
| log4net is based on the highly successful Apache log4j™ logging library, |
| in development since 1996. This popular and proven architecture has |
| so far been ported to 12 languages. |
| </p> |
| </section> |
| |
| </section> |
| </body> |
| </document> |
