Log

How can I log the processing of a Message?

Camel provides many ways to log the fact that you are processing a message. Here are just a few examples:

• You can use the Log component which logs the Message content.
• You can use the Tracer which trace logs message flow.
• You can also use a Processor or Bean and log from Java code.
• You can use the log DSL.

Using log DSL

In Camel 2.2 you can use the log DSL which allows you to use Simple language to construct a dynamic message which gets logged.
For example you can do

from("direct:start").log("Processing ${id}").to("bean:foo");

Which will construct a String message at runtime using the Simple language. The log message will by logged at INFO level using the route id as the log name. By default a route is named route-1, route-2 etc. But you can use the routeId("myCoolRoute") to set a route name of choice.

The log DSL have overloaded methods to set the logging level and/or name as well.

from("direct:start").log(LoggingLevel.DEBUG, "Processing ${id}").to("bean:foo");

and to set a logger name

from("direct:start").log(LoggingLevel.DEBUG, "com.mycompany.MyCoolRoute", "Processing ${id}").to("bean:foo");

Since Camel 2.12.4/2.13.1 the logger instance may be used as well:

from("direct:start").log(LoggingLeven.DEBUG, org.slf4j.LoggerFactory.getLogger("com.mycompany.mylogger"), "Processing ${id}").to("bean:foo");

For example you can use this to log the file name being processed if you consume files.

from("file://target/files").log(LoggingLevel.DEBUG, "Processing file ${file:name}").to("bean:foo");

Using log DSL from Spring

In Spring DSL it is also easy to use log DSL as shown below:

        <route id="foo">
            <from uri="direct:foo"/>
            <log message="Got ${body}"/>
            <to uri="mock:foo"/>
        </route>

The log tag has attributes to set the message, loggingLevel and logName. For example:

        <route id="baz">
            <from uri="direct:baz"/>
            <log message="Me Got ${body}" loggingLevel="FATAL" logName="com.mycompany.MyCoolRoute"/>
            <to uri="mock:baz"/>
        </route>

Since Camel 2.12.4/2.13.1 it is possible to reference logger instance. For example:

        <bean id="myLogger" class="org.slf4j.LoggerFactory" factory-method="getLogger" xmlns="http://www.springframework.org/schema/beans">
            <constructor-arg value="com.mycompany.mylogger" />
        </bean>

        <route id="moo" xmlns="http://camel.apache.org/schema/spring">
            <from uri="direct:moo"/>
            <log message="Me Got ${body}" loggingLevel="INFO" loggerRef="myLogger"/>
            <to uri="mock:baz"/>
        </route>

Configuring log name globally

Available as of Camel 2.17

By default the log name is the route id. If you want to use a different log name, you would need to configure the logName option. However if you have many logs and you want all of them to use the same log name, then you would need to set that logName option on all of them.

With Camel 2.17 onwards you can configure a global log name that is used instead of the route id, eg

CamelContext context = ...
context.getProperties().put(Exchange.LOG_EIP_NAME, "com.foo.myapp");

And in XML

<camelContext ...>
  <properties>
    <property key="CamelLogEipName" value="com.foo.myapp"/>
  </properties>

Using slf4j Marker

Available as of Camel 2.9

You can specify a marker name in the DSL

        <route id="baz">
            <from uri="direct:baz"/>
            <log message="Me Got ${body}" loggingLevel="FATAL" logName="com.mycompany.MyCoolRoute" marker="myMarker"/>
            <to uri="mock:baz"/>
        </route>

Using log DSL in OSGi

Improvement as of Camel 2.12.4/2.13.1

When using log DSL inside OSGi (e.g., in Karaf), the underlying logging mechanisms are provided by PAX logging. It searches for a bundle which invokes org.slf4j.LoggerFactory.getLogger() method and associates the bundle with the logger instance. Passing only logger name to log DSL results in associating camel-core bundle with the logger instance created.

In some scenarios it is required that the bundle associated with logger should be the bundle which contains route definition. This is possible using provided logger instance both for Java DSL and Spring DSL (see the examples above).