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14.4 配置 ActiveMQ日志

14.4 Configuring ActiveMQ logging

14.4 配置ActiveMQ日志

So far we’ve seen how you can monitor ActiveMQ either programmatically or usingtools such as JConsole. But there’s one more way you can peek at the broker status,and that’s through its internal logging mechanism. When you experience problemswith the broker’s behavior, the first and most common place to begin looking for apotential cause of the problem is the data/activemq.log file. In this section you’lllearn how you can adjust the logging to suit your needs and how it can help you indetecting potential broker problems.

到目前为止,我们已经可以通过编程或者使用诸如JConsole之类的工具来监控ActiveMQ了.同样,还有另外一种方式来监控代理状态,即使用时代理的内部日志机制.当你遇到代理问题,排查问题原因的起点同时也是最常用到的文件就是data/activemq.log日志文件.本节中,你讲看到如何调整日志以便符合需求并且会看到如何借用日志来侦测潜在的代理问题.

In this section we’ll see how we can adapt ActiveMQ logging for brokers and clients.We’ll also introduce a logging interceptor that can be used to track messages betweenbrokers and clients. Let’s start with the broker-related logging discussion.

本节中,我们就爱那个看到如何调整ActiveMQ代理和客户端的日志.我们将介绍使用日志拦截器来追踪代理和客户端之间的消息.下面,我们从代理相关的日志开始讨论.

14.4.1 Broker logging

14..4.1 代理日志

ActiveMQ  uses  the  Apache Commons  Logging  API  (http://mng.bz/xdQM) for  itsinternal logging purposes.  So if you  embed ActiveMQ in  your Java application,it’ll fit whatever  logging mechanisms you  already use. The  standalone binarydistribution of ActiveMQ uses  Apache Log4J (http://mng.bz/940F) library  as itslogging  facility.  The  ActiveMQ  logging configuration  can  be  found  in theconf/log4j.properties file. By default, it  defines two log appenders: one  thatprints to  standard output,  and another  that prints  to the  data/activemq.logfile. The following listing shows the standard Log4J logger configuration.
Listing 14.12 Default logger configuration

ActiveMQ使用Apache Commons  Logging  API  (http://mng.bz/xdQM)作为其内部日志工具.因此,如果在你的Java程序中嵌入ActiveMQ,ActiveMQ可以适应你用到的任意日志机制.独立二进制格式分发的ActiveMQ使用Log4J(http://mng.bz/940F)库作为其日志工具.ActiveMQ的日志配置文件爱你是conf/log4j.properties.默认情况下,该配置文件中定义了两个日志appender:一个打印到标准输出,另一个打印到data/activemq.log文件爱你.下面的代码片段显示了标准的Log4J日志配置.
代码清单 14.12 默认的日志配置

As you can see in listing 14.12, by default ActiveMQ will only print messages with a loglevel of INFO or above, which should be enough for you to monitor its usual behavior.In case you detect a problem with your application and want to enable more detaileddebugging, you should change the level for the root logger to DEBUG. Just be awarethat the DEBUG logging level will output considerably more logging information, soyou’ll probably want to narrow debug messages to a particular Java package. To dothis, you should leave the root logger at the INFO level and add a line that enablesdebug logging for the desired class or package. For example, to enable trace-levellogging for the TCP transport, add the following configuration to the conf/log4j.properties file:

如代码清单14.12所示,默认时,ActiveMQ仅打印等级为INFO或者更高的日志,这在监控代理日常行为时足够用了.在排查应用程序问题而需要更多调试细节信息时,你应该修改root logger的等级为DEBUG.需要注意的是,DEBUG等级的日志将多打印出相关可观数量的信息,因此你可能需要设置特殊的Java包能打印DEBUG信息,以便精简调试信息.我i次,你应当配置root logger的日志等级为INFO,并添加一行配置以便为特殊的类或包启用DEBUG等级的日志.例如,

After making this change in the conf/log4j.properties file and restarting ActiveMQ,you’ll begin to see the following log output:

在conf/log4j.properties文件中做了上述修改之后,重启ActiveMQ,你将看到下面的日志输出:

In  addition   to  starting/stopping   ActiveMQ  after   changing  the   loggingconfiguration, one common question is how to change the logging configuration atruntime. This is a reasonable request,  since you may not want to  stop ActiveMQto change the logging configuration.  Luckily, you can use the  JMX capabilitiesin ActiveMQ along with JConsole to achieve this. Just make the necessary changesto the conf/log4j.properties file and  save them. Then open JConsole  and selectthe   Broker   MBean   as   shown   in   figure   14.15.   Locate   the   buttonreloadLog4jProperties on the  Broker MBean’s Operations  tab. Click the  buttonnamed reloadLog4jProperties and the conf/log4j.properties file will be  reloadedand your changes will be applied.  In addition to logging from the  broker side,logging is also available on the client side.

除了在修改日志配置文件后重启代理,一个厂家爱你的问题是如何在运行时修改日志配置文件.这是一个很合理的要求,因为你可能不打算在修改日志配置文件后重启ActiveMQ.幸运的是,你可以使用ActiveMQ的JMX功能通过JConsole来完成.conf/log4j.properties文件做了必要修改之后保存.然后打开JConsole然后选择如图14.15所示的代理的MBean,从操作节点找到reloadLog4jProperties按钮,点击该按钮后,conf/log4j.properties文件会被重新加载,该文件的修改即会生效.除了代理端可以记录日志之外,客户端也可以记日志.

14.4.2 Client logging

14.4.2 客户端日志

Logging  on  the broker  side  is definitely  necessary,  but how  do  you debugproblems on the client side in your Java applications? The ActiveMQ Java  clientAPIs use the same logging approach as the broker, so you can use the same  styleof Log4J configuration file in your client application as well. In this  sectionwe’ll show you a few tips on how you can customize client-side logging and  seemore   information  about   what’s  going   on  inside   the  client-to-brokercommunication.

代理端日志无疑是很有必要的,但是在客户端你自己的Java程序中如何调试问题呢?ActiveMQ的Java客户端API使用了和代理端一样的日志系统,因此你可以在客户端程序中使用相同风格的Log4J配置文件.本节中,我们将展示一些自定义客户端日志方面的技巧,以便了解更多客户端和代理通讯时的内部信息.

For starters, a Log4J configuration file must be made available to the client-side application. The following listing shows an example Log4J configurationfile that will be used in this section.
Listing 14.13 Client logging

首先,客户端程序必须要配置一个Log4J配置文件.下面代码清单是本节中使用的Log4J示例配置文件:
代码清单 14.13 客户端日志

As you can see, the standard INFO level is being used for the root logger. Additionalconfiguration has been added (marked in bold) to monitor the failover transport andTCP communication.

如你所示,root logger使用了标准的INFO等级.添加的额外的配置信息用于监控失效转移协议和TCP通信(粗体部分).

Now, let’s run our stock portfolio publisher example, but with some additionalproperties that will allow us to use logging settings previously defined.

下面,让我们运行stock portfolio publisher,运行时需要一些额外属性,以便可以使用前面定义的日志配置文件.

The log4j.configuration system property is used to specify the location of the Log4Jconfiguration file. Also note that the trace parameter has been set to true via thetransport connection URI. Along with setting the TransportLogger level to DEBUG, thiswill allow all the commands exchanged between the client and the broker to be easilyviewed.

log4j.configuration系统属性用于指定Log4J文件的位置.另外,需要注意的是,在传输连接器’的RUI中trace参数值被设置为true了.设置TransportLogger的等级为DEBUG,使得所有客户端和代理之间信息交互的命令都能很容易的查看到.

Let’s say an application is started while the broker is down. What will be seen in thelog output are messages like the following:

假设应用程序启动之后代理停止运行了,此时日志将会输入如下信息:

With debug level logging enabled, the failover transport provides a detailed logof its attempts to establish a connection with the broker. This can be extremelyhelpful in  situations where  you experience  connection problems  from a clientapplication.

启用了DEBUG级别的日志后,失效转移连接器提供了其尝试建立和代理之间连接的详细日志.这在客户端程序出现连接问题时相当有用.

Once a connection with the broker  is established, the TCP transport will  starttracing all commands exchanged  with the broker to  the log. An example  of suchtraces is shown next:

一旦建立和和代理之间的连接,TCP传输连接器会追踪所有与代理之间交互的命令.下面是这种追踪的示例:

For the purpose of readability, some details of specific commands have been leftout except for  one log message,  which is marked  bold. These traces  provide afull  peek  into  the  client-broker communication,  which  can  help  to narrowapplication connection problems further.

为了便于阅读,一些命令的细节信息省略了只留下了一个日志信息,如粗体字所示.这些追踪信息记录了客户端代理之间通信的详细细节,可以帮助定位排查应用程序和代理之间的连接问题.

This simple example shows that with a few minor configuration changes, many morelogging details can be viewed. But beyond standard Log4J-style logging, ActiveMQalso provides a special logger for internal broker events.

这个简单的例子表明,只要做一些微小的配置调整,即可记录更多细节日志.除了标准的Log4J风格的日志,ActiveMQ还提供了一种特殊的记录内部代理事件的日志机制.

14.4.3 Internal broker event logging

14.4.3 代理内部事件日志

The previous sections demonstrated how the  broker side and the client side  canbe monitored through the use of standard Log4J logging. Similar functionality isavailable on  the broker  side for  internal broker  operations using  a logginginterceptor (aka logging plug-in). ActiveMQ plug-ins were introduced in  chapter6 where you  saw how they  can be used  to authenticate client  applications andauthorize access to broker resources. The logging interceptor is a simple brokerplug-in that uses the broker’s internal event mechanism to log internal  brokerevents.  The  types  of  events  that  are  logged  can  be  controlled  via theconfiguration of the logging plug-in using the properties shown in table 14.2.

前面的章节中介绍了如何使用标准的Log4J日志机制监控代理端和客户端.同样,在代理段可以使用日志拦截器(aka logging plug-in)监控代理的内部操作.第6章中介绍过使用ActiveMQ的插件机制实现客户端认证以及对访问代理资源实现授权.日志拦截器是一中简单的代理插件运用代理内部事件机制记录代理内部事件.

The logging plug-in is useful for seeing more information about the broker’s internalevents. This can be useful for debugging purposes during development as well asfor informational purposes during production deployment. It provides more finitelogging for particular event types and allows you to see more information about whatthe broker’s doing.

使用日志插件有助于了解代理内部事件的更多信息.这在开发阶段有助于调试而在生产部署阶段有助于了解更多信息.日志插件能针对特定的事件类型提供更多日志信息,并运行你了解更多当前代理正在进行的操作的相关信息.

To install this plug-in, add the <loggingBrokerPlugin/> element to the list of yourplug-ins in the conf/activemq.xml configuration file. Here’s an example of this:

添加<loggingBrokerPlugin/>元素到conf/activemq.xml配置文件中的插件列表中即可安装这个日志插件.示例代码如下所示:

After restarting the broker, you’ll see output indicating that the logging plug-in hasbeen activated. After table 14.2 we see an example of such output during the brokerstartup.

重启代理之后,从输出中可以看到日志插件已经被激活了.表14.2之后是代理启动时的输出信息:

Table 14.2 Logging plug-in properties

Property name Default value Description
logAll  false Log all events
logMessageEvents false Log only events related to producing, consuming, and dispatching messages
logConnectionEvents true Log only events related to connections and sessions
logTransactionEvents false Log only events related to transaction handling
logConsumerEvents false Log only events related to message consumption
logProducerEvents false Log only events related to message production
logInternalEvents false Log only events related to internal broker operations such as failover, querying internal objects, and so on

 表14.2 日志插件属性

属性名称 默认值 描述
 logAll  false 为所有事件记录日志
logMessageEvents false 只为消息生产,消费和分发事件记录日志
logConnectionEvents true 只为连接和session相关的事件记录日志
logTransactionEvents false 只为事务处理相关事件记录日志
logConsumerEvents false 只为消息处理相关事件记录日志
logProducerEvents false 只为消息生产相关事件记录日志
logInternalEvents false 只为代理内部操作比如,失效转移,查询内部对象等事件记录日志

Note that the logging plug-in is using the default configuration. Send some messagesto the broker, and you’ll see the following output from the broker:

注意日志插件使用了默认的配置.发送一些消息给代理后,你将看到下面的来自代理的输出消息:

Note that the output indicates that  a connection and session were added  to thebroker (a connection and a session  were created), and a connection and  sessionwere removed from  the broker (a  connection and session  were destroyed). Theseare events that  are logged from  a producer connecting  to the broker,  sendingsome  messages, and  disconnecting from  the broker.  If you  want to  see moredetailed information, then you need to enable the appropriate logging propertiesas listed in table 14.2. Coupled with the other logging techniques, the  logginginterceptor can  help you  to gain  a much  better perspective  of the  internalbroker activities while building message-oriented systems.

注意,由输出信息可以看出一个连接和session被添加到了代理中(即创建了一个连接和session),同时一个连接和session被从代理中移除(即,销毁了一个连接和session).这些日志信息来自一个消息生产者连接代理发送了一些信息,然后断开和代理之间的连接.如果你想了解更多细节方面信息你需要启用表14.2中所示的适当的日志属性.在构建面向消息的系统时,使用消息插件再配合其他日志技术可以帮助你获取更好的代理内部的信息.

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该日志由 边城网事 于2014年01月10日发表在 ActiveMQ in Action 读书笔记 分类下, 你可以发表评论,并在保留原文地址及作者的情况下引用到你的网站或博客。
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