Tracer Example
来源：互联网 发布：阿里云 开发主机 编辑：程序博客网 时间：2024/06/06 01:55
http://camel.apache.org/tracer-example.html
http://camel.apache.org/tracer.html
Tracer Interceptor
Camel supports a tracer interceptor that is used for logging the route executions atINFO level.
The Tracer is an InterceptStrategy which can be applied to a DefaultCamelContext or SpringCamelContext to ensure that there is a TracerInterceptor created for every node in the DSL.
You can enable or disable the Tracer's logging dynamically, by calling the tracer'ssetEnabled method.
Options
Formatting
The tracer formats the execution of exchanges to log lines. They are logged at INFO level in the log category:org.apache.camel.processor.interceptor.TraceInterceptor.
The tracer uses by default the org.apache.camel.processor.interceptor.DefaultTraceFormatter to format the log line.
DefaultTraceFormatter has the following options:
Logging stream bodiesCamel Tracer will by defaultnot log stream or files bodies from Camel 2.8 onwards. You can force Camel to log those by setting the property on theCamelContext properties
camelContext.getProperties().put(Exchange.LOG_DEBUG_BODY_STREAMS, true);Example:
ID-claus-acer/4412-1222625653890/2-0 -> to(mock:a) , Pattern:InOnly , Headers:{to=James} , BodyType:String , Body:Hello LondonID-claus-acer/3690-1214458315718/2-0 is the breadcrumb with the unique correlation id.
node3 is the id of the node in the route path. Is always shown.
To[mock:a] is the destination node.
InOnly is the exchange pattern. Is always shown.
Then the rest is properties, headers and the body.
Showing from and to
The trace log will output both the from and to so you can see where the Exchange came from, such as:
>>> direct:start --> process(MyProcessor)>>> process(MyProcessor) --> to(mock:a)>>> to(mock:a) --> to(mock:b)
Enabling
To enable tracer from the main run
java org.apache.camel.spring.Main -t
or
java org.apache.camel.spring.Main -trace
and the tracer will be active.
Enabling from Java DSL
context.setTracing(true);You can configure tracing at a higher granularity as you can configure it on camel context and then override and set it per route as well. For instance you could just enable tracer for one particular route.
INFO TraceInterceptor - ID-davsclaus-local-54403-1246038742624-0-0 >>> from(direct:start) --> MyProcessor , Pattern:InOnly, Headers:{to=James}, BodyType:String, Body:Hello LondonINFO TraceInterceptor - ID-davsclaus-local-54403-1246038742624-0-0 >>> MyProcessor --> mock:a , Pattern:InOnly, Headers:{to=James}, BodyType:String, Body:Hello LondonINFO TraceInterceptor - ID-davsclaus-local-54403-1246038742624-0-0 >>> mock:a --> mock:b , Pattern:InOnly, Headers:{to=James}, BodyType:String, Body:Hello London...INFO TraceInterceptor - ID-davsclaus-local-54403-1246038742624-0-1 >>> from(direct:start) --> MyProcessor , Pattern:InOnly, Headers:{from=Claus}, BodyType:String, Body:This is Copenhagen callingINFO TraceInterceptor - ID-davsclaus-local-54403-1246038742624-0-1 >>> MyProcessor --> mock:a , Pattern:InOnly, Headers:{from=Claus}, BodyType:String, Body:This is Copenhagen callingINFO TraceInterceptor - ID-davsclaus-local-54403-1246038742624-0-1 >>> mock:a --> mock:b , Pattern:InOnly, Headers:{from=Claus}, BodyType:String, Body:This is Copenhagen callingConfiguring from Java DSL
The tracer options can be configured from the Java DSL like this:
public void configure() throws Exception { // add tracer as an interceptor so it will log the exchange executions at runtime // this can aid us to understand/see how the exchanges is routed etc. Tracer tracer = new Tracer(); formatter.getDefaultTraceFormatter().setShowBreadCrumb(false); formatter.getDefaultTraceFormatter().setShowNode(false); ... getContext().addInterceptStrategy(tracer);
Using predicates to filter exchanges
In the code below we want the tracer only to trace if the body contains the textLondon. As this is just an example can of course set any Predicate that matches your criteria:
Tracer tracer = new Tracer(); // set the level to FATAL so we can easily spot it tracer.setLogLevel(LoggingLevel.FATAL); // and only trace if the body contains London as text tracer.setTraceFilter(body().contains(constant("London")));
Enabling from Spring XML
There is now a trace attribute you can specify on the *<camelContext/> for example
<camelContext trace="true" xmlns="http://activemq.apache.org/camel/schema/spring"> ... </camelContext>
You can see this in action with the SpringTraceTest and its spring.xml file
Another option is to just include a spring XML which defines the Tracer bean such as theone that is automatically included if you run the Main with -t above.
Configuration from Spring
You can configure the tracer as a Spring bean. Just add a bean with the bean classorg.apache.camel.processor.interceptor.Tracer and Camel will use it as the Tracer.
<!-- we can configure the tracer by defining the tracer bean and set the properties as we like --><!-- the id name can be anything its the class that must be org.apache.camel.processor.interceptor.Tracer --><bean id="camelTracer" class="org.apache.camel.processor.interceptor.Tracer"> <property name="traceExceptions" value="false"/> <property name="traceInterceptors" value="true"/> <property name="logLevel" value="ERROR"/> <property name="logName" value="com.mycompany.messages"/></bean><camelContext trace="true" xmlns="http://camel.apache.org/schema/spring"> <route> <from uri="direct:start"/> <to uri="mock:result"/> </route></camelContext>
You can configure the formatting of tracer as a Spring bean. Just add a bean with the idtraceFormatter and Camel will lookup this id and use the formatter, as the example below illustrates:
<bean id="traceFormatter" class="org.apache.camel.processor.interceptor.DefaultTraceFormatter"> <property name="showBody" value="true"/> <property name="showBodyType" value="false"/> <property name="showBreadCrumb" value="false"/> <property name="maxChars" value="100"/></bean><camelContext trace="true" xmlns="http://camel.apache.org/schema/spring"> <route> <from uri="direct:start"/> <to uri="mock:result"/> </route></camelContext>
Enable tracing of out messages
You can trace messages coming out of processing steps. To enable this, configure the tracer as follows
Tracer tracer = new Tracer();tracer.setTraceOutExchanges(true);// we configure the default trace formatter where we can// specify which fields we want in the outputDefaultTraceFormatter formatter = new DefaultTraceFormatter();formatter.setShowOutBody(true);formatter.setShowOutBodyType(true);// set to use our formattertracer.setFormatter(formatter);getContext().addInterceptStrategy(tracer);
or
<bean id="camelTracer" class="org.apache.camel.processor.interceptor.Tracer"> <property name="traceOutExchanges" value="true" /></bean><bean id="traceFormatter" class="org.apache.camel.processor.interceptor.DefaultTraceFormatter"> <property name="showOutBody" value="true" /> <property name="showOutBodyType" value="true" /></bean>
Running with these options, you'll get output similar to:
INFO TraceInterceptor - ID-mojo/59899-1225474989226/2-0 -> transform(body) , Pattern:InOnly , Headers:{to=James} , BodyType:String , Body:Hello LondonINFO TraceInterceptor - transform(body) -> ID-mojo/59899-1225474989226/2-0 , Pattern:InOnly , Headers:{to=James} , BodyType:String , Body:Hello London , OutBodyType:String , OutBody:Hello LondonUsing Custom Formatter
You can now implement your own org.apache.camel.processor.interceptor.TraceFormatter to be used for logging trace messages to the log.
The sample below shows how to configure a Tracer from Java DSL using custom formatter:
// we create a tracer where we want to use our own formatter instead of the default oneTracer tracer = new Tracer();// use our own formatter instead of the default oneMyTraceFormatter formatter = new MyTraceFormatter();tracer.setFormatter(formatter);// and we must remeber to add the tracer to CamelgetContext().addInterceptStrategy(tracer);
And here we have our custom logger that implements the TraceFormatter interface where we can construct the log message how we like:
// here we have out own formatter where we can create the output we want for trace logs// as this is a test we just create a simple string with * around the bodyclass MyTraceFormatter implements TraceFormatter { public Object format(TraceInterceptor interceptor, ProcessorDefinition<?> node, Exchange exchange) { return "***" + exchange.getIn().getBody(String.class) + "***"; }}
Using Destination for custom processing and routing
Tracer supports custom processing of trace events. This can be used to route a trace event to aJPA endpoint for persistence in a database.
This works by Camel creates a new TraceEventExchange containing:
- snapshot of the original traced Exchange as a immutable TraceEventMessage containing String values of the fields, when the interception occurred. This ensures the fields contains the exact data at the given time of interception.
- the original Exchange can be accessed using getTracedExchange()
Beware to access the original Exchange to avoid causing any side effects or alter its state. Prefer to access the information fromTraceEventMessageCamel routes the TraceEventExchange synchronously from the point of interception. When its completed Camel will continue routing the original Exchange.
The sample below demonstrates this feature, where we route traced Exchanges to thedirect:traced route:
// we create a tracer where we want to send TraveEvents to an endpoint// "direct:traced" where we can do some custom processing such as storing// it in a file or a databaseTracer tracer = new Tracer();tracer.setDestinationUri("direct:traced");// we disable regular trace logging in the log file. You can omit this and// have both.tracer.setLogLevel(LoggingLevel.OFF);// and we must remember to add the tracer to CamelgetContext().addInterceptStrategy(tracer);
Then we can configure a route for the traced messages:
from("direct:traced").process(new MyTraceMessageProcessor()).to("file://myapp/logs/trace);
And our processor where we can process the TraceEventMessage. Here we want to create a CSV format of the trace event to be stored as a file. We do this by constructing the CSV String and the replace the IN body with our String instead of theTraceEventMessage.
class MyTraceMessageProcessor implements Processor { public void process(Exchange exchange) throws Exception { // here we can transform the message how we like want it TraceEventMessage msg = exchange.getIn().getBody(DefaultTraceEventMessage.class); // we want to store it as a CSV with from;to;exchangeId;body String s = msg.getFromEndpointUri() + ";" + msg.getToNode() + ";" + msg.getExchangeId() + ";" + msg.getBody(); // so we replace the IN body with our CSV string exchange.getIn().setBody(s); }}
Using JPA as datastore for trace messages
See Tracer Example for complete documentation and how to use this feature.
Traced route path during runtime
Tracer also traces the actual route path taken during runtime. Camel will store the route path taken on the UnitOfWork whenTracer is enabled.
The example below demonstrates how we can use that for error handling where we can determine at which node in the route graph the error triggered.
First we define our route:
protected RouteBuilder createRouteBuilder() throws Exception { return new RouteBuilder() { public void configure() throws Exception { errorHandler(deadLetterChannel("mock:error").redeliveryDelay(0).maximumRedeliveries(3)); // must enable tracer to trace the route path taken during runtime context.setTracing(true); // let our my error processor handle all exceptions onException(Exception.class).handled(true).process(new MyErrorProcessor()); // our route where an exception can be thrown from either foo or bar bean // so we have enable tracing so we can check it at runtime to get the actual // node path taken from("direct:start").to("bean:foo").to("bean:bar"); } };}
And then our custom error processor where we can handle the exception and figure out at which node the exception occurred.
private static class MyErrorProcessor implements Processor { public void process(Exchange exchange) throws Exception { TracedRouteNodes traced = exchange.getUnitOfWork().getTracedRouteNodes(); // get the list of intercepted nodes List<RouteNode> list = traced.getNodes(); // get the 3rd last as its the bean Processor last = list.get(list.size() - 3).getProcessor(); // wrapped by JMX if (last instanceof InstrumentationProcessor) { InstrumentationProcessor ip = (InstrumentationProcessor) last; last = ip.getProcessor(); } // set error message exchange.getOut().setFault(true); exchange.getOut().setBody("Failed at: " + last.toString()); } public String toString() { return "MyErrorProcessor"; }}
=============
Tracer Example
Introduction
This example demonstrates the Tracer. Tracer is a tracing feature build in camel core to log snapshots of Exchanges while they are routed. This allows you to see:
- how a given Exchange was routed
- a snapshot of the content of the Exchange at any given node it passed in the route
When used Camel will by default log the snapshot at INFO level. This example demonstrates how to persist trace snapshots usingJPA into a database. This allows you to store this information and query them from a SQL prompt, giving you full power to analyze the data.
Requirements
This requires Camel 2.0, the camel-jpa component and configuration of the target database.
Data Model
Camel uses the org.apache.camel.processor.interceptor.JpaTraceEventMessage JPA @Entity as data model.
This class has been enhanced with JPA annotations.
The class has the following properties in the JPA model:
The table name for persisting trace events is: CAMEL_MESSAGETRACED
Configuration of the database
The Tracer uses standard JPA configuration for setting the database. In the META-INF/persistence.xml file we setup the service unit and the database configuration as:
<persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="1.0"> <persistence-unit name="tracer" transaction-type="RESOURCE_LOCAL"> <class>org.apache.camel.processor.interceptor.jpa.JpaTraceEventMessage</class> <properties> <property name="hibernate.dialect" value="org.apache.camel.example.tracer.FixedDerbyDialect"/> <property name="hibernate.connection.driver_class" value="org.apache.derby.jdbc.EmbeddedDriver"/> <property name="hibernate.connection.url" value="jdbc:derby:target/derby;create=true"/> <property name="hibernate.hbm2ddl.auto" value="create"/> <!-- debugging flags --> <!-- <property name="hibernate.show_sql" value="true"/> <property name="hibernate.format_sql" value="true"/> --> </properties> </persistence-unit></persistence>
What is important is to add the JpaTraceEventMessage as a class in the persistence.xml file to register our data model:
<class>org.apache.camel.processor.interceptor.JpaTraceEventMessage</class>
In this example we use Hibernate JPA and a HSQLDB as database.
Running the example
The README.txt states how to run the example from either ANT or Maven.
Here we show running with Maven:
mvn camel:run
When the application starts it start:
- in the console
- a GUI for browsing the SQL database
Select the console where the application should prompt you to enter some words. Try entering:Camel
The application should respond with a text quote.
You can also enter multiple quotes separate with space, and the response should be the best quote based on the list of words given.
See the file src/main/resources/META-INF/spring/camel-context.xml to give you an idea how it works.
You can enter: Camel Beer and it should be smart enough to find a quote for the beer
Seeing the trace events
When the program was started a GUI application was started as well. Its a SQL prompt for the database. So try entering:
select * from camel_messagetraced
And it should return the list of trace events in the SQL.
We enter this sql: select id, shortExchangeId, previousNode, toNode, body from camel_messagetraced and get the output as the picture below:
Routing
The diagram below illustrates the route diagram generated using Visualisation.
We receive an Exchange from the in stream, then its split using the splitWords method. Then the quote method is invoked before its aggregated and finally sent to the stream out to be printed in the console.
Trace the routing
If we look at the 6 rows from the traced SQL (the first picture) and with the route diagram in mind we can get a better understand how theExchange was routed.
1. The Exchange does not have a previousNode so its the first step where its consumed from the input stream and that its going to the splitter.
2. The exchange id has changed and this is the output of the splitter as it creates a new Exchange. We can also see this one has one word in the body. ThisExchange is being routed to the quote bean next.
3. This is the 2nd output from the splitter containing the 2nd word. This Exchange is being routed to the quote bean next.
4. This is the Beer Exchange where we can see the output from the quote server and that its being routed to the aggregator.
5. This is the Camel Exchange where we can see the output from the quote server and that its being routed to the aggregator.
6. This is the result of the aggregator where the Exchange ending with id 0-2 "was the winner" and is being routed as the aggregated result to the stream out.
Configuration ofJPA tracing in Camel
In Camel you need to configure it to use JPA for tracing. We do this as by adding a tracer in theMETA-INF/camel-context.mxl file:
<!-- use camel jpa trace so we can see all the traced exchanges in a database --><bean id="camelTracer" class="org.apache.camel.processor.interceptor.Tracer"> <!-- turn on jpa tracing, otherwise the TraceEventMessage is a non JPA Entity class --> <property name="useJpa" value="true"/> <!-- the destination to send the traced messages --> <property name="destination" ref="traced"/> <!-- we turn ordinary trace logging off so we only see the traced messages in the database, but you can have both if you like --> <property name="logLevel" value="OFF"/></bean>
To properly configure JPA for tracing we must complete these two steps:
1. enable the JPA tracing by setting the property useJpa=true
2. set the destination or destinationUri to a JPA producer endpoint
In this example we set the desintation that refers to a endpoint we define in the camel context:
<endpoint id="traced" uri="jpa://org.apache.camel.processor.interceptor.JpaTraceEventMessage?persistenceUnit=tracer"/>Here its important that the endpoint is configure with the {org.apache.camel.processor.interceptor.JpaTraceEventMessage}} as entity name and the persistenceUnit as an option. In out example we use tracer.
Then the following is standard Spring JPA configuration:
<!-- this is ordinary JPA spring configuration --><bean id="transactionTemplate" class="org.springframework.transaction.support.TransactionTemplate"> <property name="transactionManager"> <bean class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="entityManagerFactory"/> </bean> </property></bean><!-- this is ordinary JPA spring configuration --><bean id="jpaTemplate" class="org.springframework.orm.jpa.JpaTemplate"> <property name="entityManagerFactory" ref="entityManagerFactory"/></bean><!-- this is ordinary JPA spring configuration --><bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean"> <!-- we have named our presistence unit tracer in the META-INF/persistence.xml file --> <property name="persistenceUnitName" value="tracer"/></bean>
However we must set the persistenceUnitName to the same unit name we defined inpersistence.xml, such astracer as we are using in this example.
And if you are wondering how the Camel route is defined then its here:
<route> <!-- in stream to allow you to enter some text in the console --> <from uri="stream:in?initialPromptDelay=4000&promptDelay=2000&promptMessage=Enter some words:"/> <!-- split the text using parallel execution --> <split parallelProcessing="true"> <!-- use methodCall expression to split the words, using a java bean to do it --> <method bean="quoteService" method="splitWords"/> <!-- for each split message invoke the quote server to get a quote of the word --> <to uri="bean:quoteService?method=quote"/> <!-- now we need to find the best quote, so we aggregate all the splitted words we use our own strategy how to aggregate --> <aggregate strategyRef="myAggregateStrategy"> <!-- correlate everything using constant true, as they are all from the same source --> <correlationExpression> <constant>true</constant> </correlationExpression> <!-- complete after 1 sec on inactivity --> <completionTimeout> <constant>1000</constant> </completionTimeout> <!-- send the result to stream out so we can see the response in the console --> <to uri="stream:out"/> </aggregate> </split></route>
- Tracer Example
- Tracer Example
- Example 1 : A Single Sample Ray Tracer
- Tracer Interceptor
- Tracer Interceptor
- Packet Tracer
- example
- example
- Example
- example
- Example
- Example
- Example
- Example
- example
- Example
- Example
- Advanced Registry Tracer
- 构建高性能ASP.NET站点 网站优化需要考虑的方面二
- 面向对象的三个基本特征
- 中国移动如何用Java做开发
- oracle的oci和thin区别
- UTF8编码字符串转换成Unicode编码字符串算法
- Tracer Example
- 开始在CSDN扎根，以后和大牛们为伍
- CDC、CClientDC、CPaintDC、CWindowDC区别及相关操作
- SQLServer 日期格式（转）
- HTTP协议中的KeepAlive属性
- 新式转型操作符
- <每日一句英语>2012-11-5
- regedit修改mac地址
- asp.net点击按钮下载图片而不是打开图片
