Log Component

Table of Contents

URI format
Options
Regular logger sample
Regular logger with formatter sample
Throughput logger with groupSize sample
Throughput logger with groupInterval sample
Full customization of the logging output
See Also

The log: component logs message exchanges to the underlying logging mechanism.

Camel uses sfl4j which allows you to configure logging via, among others:

URI format

log:loggingCategory[?options]

Where loggingCategory is the name of the logging category to use. You can append query options to the URI in the following format, ?option=value&option=value&…​

INFO:*Using Logger instance from the the Registry* As of Camel 2.12.4/2.13.1, if there’s single instance of org.slf4j.Logger found in the Registry, the loggingCategory is no longer used to create logger instance. The registered instance is used instead. Also it is possible to reference particular Logger instance using ?logger=#myLogger URI parameter. Eventually, if there’s no registered and URI logger parameter, the logger instance is created using loggingCategory.

For example, a log endpoint typically specifies the logging level using the level option, as follows:

log:org.apache.camel.example?level=DEBUG

The default logger logs every exchange (regular logging). But Camel also ships with the Throughput logger, which is used whenever the groupSize option is specified.

TIP:*Also a log in the DSL* There is also a log directly in the DSL, but it has a different purpose. Its meant for lightweight and human logs. See more details at LogEIP.

Options

The Log component supports 1 options which are listed below.

{% raw %}

NameJava TypeDescription

exchangeFormatter

ExchangeFormatter

Sets a custom ExchangeFormatter to convert the Exchange to a String suitable for logging. If not specified we default to DefaultExchangeFormatter.

{% endraw %}

The Log component supports 26 endpoint options which are listed below:

{% raw %}

NameGroupDefaultJava TypeDescription

loggerName

producer

 

String

Required The logger name to use

groupActiveOnly

producer

true

Boolean

If true will hide stats when no new messages have been received for a time interval if false show stats regardless of message traffic.

groupDelay

producer

 

Long

Set the initial delay for stats (in millis)

groupInterval

producer

 

Long

If specified will group message stats by this time interval (in millis)

groupSize

producer

 

Integer

An integer that specifies a group size for throughput logging.

level

producer

INFO

String

Logging level to use. The default value is INFO.

marker

producer

 

String

An optional Marker name to use.

synchronous

advanced

false

boolean

Sets whether synchronous processing should be strictly used or Camel is allowed to use asynchronous processing (if supported).

maxChars

formatting

10000

int

Limits the number of characters logged per line.

multiline

formatting

false

boolean

If enabled then each information is outputted on a newline.

showAll

formatting

false

boolean

Quick option for turning all options on. (multiline maxChars has to be manually set if to be used)

showBody

formatting

true

boolean

Show the message body.

showBodyType

formatting

true

boolean

Show the body Java type.

showCaughtException

formatting

false

boolean

f the exchange has a caught exception show the exception message (no stack trace). A caught exception is stored as a property on the exchange (using the key link org.apache.camel.ExchangeEXCEPTION_CAUGHT and for instance a doCatch can catch exceptions.

showException

formatting

false

boolean

If the exchange has an exception show the exception message (no stacktrace)

showExchangeId

formatting

false

boolean

Show the unique exchange ID.

showExchangePattern

formatting

true

boolean

Shows the Message Exchange Pattern (or MEP for short).

showFiles

formatting

false

boolean

If enabled Camel will output files

showFuture

formatting

false

boolean

If enabled Camel will on Future objects wait for it to complete to obtain the payload to be logged.

showHeaders

formatting

false

boolean

Show the message headers.

showOut

formatting

false

boolean

If the exchange has an out message show the out message.

showProperties

formatting

false

boolean

Show the exchange properties.

showStackTrace

formatting

false

boolean

Show the stack trace if an exchange has an exception. Only effective if one of showAll showException or showCaughtException are enabled.

showStreams

formatting

false

boolean

Whether Camel should show stream bodies or not (eg such as java.io.InputStream). Beware if you enable this option then you may not be able later to access the message body as the stream have already been read by this logger. To remedy this you will have to use Stream Caching.

skipBodyLineSeparator

formatting

true

boolean

Whether to skip line separators when logging the message body. This allows to log the message body in one line setting this option to false will preserve any line separators from the body which then will log the body as is.

style

formatting

Default

OutputStyle

Sets the outputs style to use.

{% endraw %}

Regular logger sample

In the route below we log the incoming orders at DEBUG level before the order is processed:

from("activemq:orders").to("log:com.mycompany.order?level=DEBUG").to("bean:processOrder");

Or using Spring XML to define the route:

  <route>
    <from uri="activemq:orders"/>
    <to uri="log:com.mycompany.order?level=DEBUG"/>
    <to uri="bean:processOrder"/>
  </route>

Regular logger with formatter sample

In the route below we log the incoming orders at INFO level before the order is processed.

from("activemq:orders").
    to("log:com.mycompany.order?showAll=true&multiline=true").to("bean:processOrder");

Throughput logger with groupSize sample

In the route below we log the throughput of the incoming orders at DEBUG level grouped by 10 messages.

from("activemq:orders").
    to("log:com.mycompany.order?level=DEBUG&groupSize=10").to("bean:processOrder");

Throughput logger with groupInterval sample

This route will result in message stats logged every 10s, with an initial 60s delay and stats should be displayed even if there isn’t any message traffic.

from("activemq:orders").
to("log:com.mycompany.order?level=DEBUG&groupInterval=10000&groupDelay=60000&groupActiveOnly=false").to("bean:processOrder");

The following will be logged:

"Received: 1000 new messages, with total 2000 so far. Last group took: 10000 millis which is: 100 messages per second. average: 100"

Full customization of the logging output

Available as of Camel 2.11

With the options outlined in the #Formatting section, you can control much of the output of the logger. However, log lines will always follow this structure:

Exchange[Id:ID-machine-local-50656-1234567901234-1-2, ExchangePattern:InOut,
Properties:{CamelToEndpoint=log://org.apache.camel.component.log.TEST?showAll=true,
CamelCreatedTimestamp=Thu Mar 28 00:00:00 WET 2013},
Headers:{breadcrumbId=ID-machine-local-50656-1234567901234-1-1}, BodyType:String, Body:Hello World, Out: null]

This format is unsuitable in some cases, perhaps because you need to…​

  • …​ filter the headers and properties that are printed, to strike a balance between insight and verbosity.
  • …​ adjust the log message to whatever you deem most readable.
  • …​ tailor log messages for digestion by log mining systems, e.g. Splunk.
  • …​ print specific body types differently.
  • …​ etc.

Whenever you require absolute customization, you can create a class that implements the ExchangeFormatter interface. Within the format(Exchange) method you have access to the full Exchange, so you can select and extract the precise information you need, format it in a custom manner and return it. The return value will become the final log message.

You can have the Log component pick up your custom ExchangeFormatter in either of two ways:

Explicitly instantiating the LogComponent in your Registry:

<bean name="log" class="org.apache.camel.component.log.LogComponent">
   <property name="exchangeFormatter" ref="myCustomFormatter" />
</bean>

Convention over configuration:

Simply by registering a bean with the name logFormatter; the Log Component is intelligent enough to pick it up automatically.

<bean name="logFormatter" class="com.xyz.MyCustomExchangeFormatter" />
[Note]Note

the ExchangeFormatter gets applied to all Log endpoints within that Camel Context. If you need different ExchangeFormatters for different endpoints, just instantiate the LogComponent as many times as needed, and use the relevant bean name as the endpoint prefix.

From Camel 2.11.2/2.12 onwards when using a custom log formatter, you can specify parameters in the log uri, which gets configured on the custom log formatter. Though when you do that you should define the "logFormatter" as prototype scoped so its not shared if you have different parameters, eg:

<bean name="logFormatter" class="com.xyz.MyCustomExchangeFormatter" scope="prototype"/>

And then we can have Camel routes using the log uri with different options:

<to uri="log:foo?param1=foo&amp;param2=100"/>
...
<to uri="log:bar?param1=bar&amp;param2=200"/>

Using Log component in OSGi

Improvement as of Camel 2.12.4/2.13.1

When using Log component 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. Without specifying custom org.sfl4j.Logger instance, the logger created by Log component is associated with camel-core bundle.

In some scenarios it is required that the bundle associated with logger should be the bundle which contains route definition. To do this, either register single instance of org.slf4j.Logger in the Registry or reference it using logger URI parameter.

See Also