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h2. Log Component

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

{include:Uses Commons Logging}

h3. URI format

{code}
log:loggingCategory[?options]
{code}

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&...}}

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

{code}
log:org.apache.camel.example?level=DEBUG
{code}

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:title=Also a log in the DSL}
In *Camel 2.2* onwards there is a {{log}} directly in the DSL, but it has a different purpose. Its meant for lightweight and human logs. See more details at [LogEIP].
{tip}

h3. Options
|| Option || Default || Type || Description ||
| {{level}} | {{INFO}} | {{String}} | Logging level to use. Possible values: {{FATAL}}, {{ERROR}}, {{WARN}}, {{INFO}}, {{DEBUG}}, {{TRACE}}, {{OFF}} |
| {{groupSize}} | {{null}} | {{Integer}} | An integer that specifies a group size for throughput logging. By default, regular logging is used. |

h3. Formatting
The log formats the execution of exchanges to log lines. 
By default, the log uses {{LogFormatter}} to format the log output, where {{LogFormatter}} has the following options:
{div:class=confluenceTableSmall}
|| Option || Default || Description ||
| {{showAll}} | {{false}} | Quick option for turning all options on. (multiline, maxChars has to be manually set if to be used) |
| {{showExchangeId}} | {{false}} | Show the unique exchange ID. |
| {{showExchangePattern}} | {{true}} | *Camel 2.3:* Shows the Message Exchange Pattern (or MEP for short). |
| {{showProperties}} | {{false}} | Show the exchange properties. |
| {{showHeaders}} | {{false}} | Show the In message headers. |
| {{showBodyType}} | {{true}} | Show the In body Java type. |
| {{showBody}} | {{true}} | Show the In body. |
| {{showOut}} | {{false}} | If the exchange has an Out message, show the Out message. |
| {{showException}} | {{false}} | *Camel 2.0:* If the exchange has an exception, show the exception message (no stack trace). |
| {{showCaughtException}} | {{false}} | *Camel 2.0:* If the exchange has a caught exception, show the exception message (no stack trace). A caught exception is stored as a property on the exchange and for instance a {{doCatch}} can catch exceptions. See [Try Catch Finally]. |
| {{showStackTrace}} | {{false}} | *Camel 2.0:* Show the stack trace, if an exchange has an exception. Only effective if one of {{showAll}}, {{showException}} or {{showCaughtException}} are enabled. | 
| {{showFuture}} | {{false}} | *Camel 2.1:* Whether Camel should show {{java.util.concurrent.Future}} bodies or not. If enabled Camel could potentially wait until the {{Future}} task is done. Will by default not wait. |
| {{multiline}} | {{false}} | If {{true}}, each piece of information is logged on a new line. |
| {{maxChars}} | | *Camel 2.0:* Limits the number of characters logged per line. |
{div}

h3. Regular logger sample
In the route below we log the incoming orders at {{DEBUG}} level before the order is processed:
{code:java}
from("activemq:orders").to("log:com.mycompany.order?level=DEBUG").to("bean:processOrder");
{code}

Or using Spring XML to define the route:
{code:xml}
  <route>
    <from uri="activemq:orders"/>
    <to uri="log:com.mycompany.order?level=DEBUG"/>
    <to uri="bean:processOrder"/>
  </route> 
{code}

h3. Regular logger with formatter sample
In the route below we log the incoming orders at {{INFO}} level before the order is processed.
{code:java}
from("activemq:orders").
    to("log:com.mycompany.order?showAll=true&multiline=true").to("bean:processOrder");
{code}

h3. Throughput logger sample
In the route below we log the throughput of the incoming orders at {{DEBUG}} level grouped by 10 messages.
{code:java}
from("activemq:orders").
    to("log:com.mycompany.order?level=DEBUG?groupSize=10").to("bean:processOrder");
{code}

{include:Endpoint See Also}
* [Tracer]
* [How do I use log4j]
* [How do I use Java 1.4 logging]
* [LogEIP] for using {{log}} directly in the DSL for human logs.